Free tools. Real answers. Instantly.

CAGR Calculator

Calculate the Compound Annual Growth Rate of any investment, from starting value, endi...

Sharpe Ratio Calculator

Risk-adjusted return for any portfolio.

IRR Calculator

Calculate the Internal Rate of Return of a series of cash flows.

NPV Calculator

Calculate the Net Present Value of any investment or project.

Max Drawdown Calculator

Peak-to-trough decline of a portfolio.

Portfolio Volatility Calculator

Calculate the expected volatility (standard deviation) of a multi-asset portfolio, acco...

Dividend Yield Calculator

Dividend yield, yield on cost, and payout ratio.

401(k) Calculator

Estimate how much your 401(k) will be worth at retirement.

P/E Ratio Calculator

Price-to-earnings ratio and PEG ratio.

Annualised Return Calculator

Convert a total investment return into an annual figure.

Dollar-Cost Averaging Calculator

Calculate how dollar-cost averaging grows your investment over time.

Total Return Calculator

Calculate the total return on any investment including capital gains and dividends rein...

SIP Calculator

Calculate the returns on a Systematic Investment Plan (SIP).

Bond YTM Calculator

Calculate the yield to maturity (YTM) of a bond.

Lump Sum vs SIP Calculator

Compare lump sum investing against a Systematic Investment Plan (SIP/DCA).

Expense Ratio Calculator

Calculate the long-term cost of a fund's expense ratio and compare how different fees a...

Portfolio Rebalancing Calculator

Calculate the trades needed to rebalance your investment portfolio to your target alloc...

Future Value Calculator

Calculate what a sum of money will be worth at a future date.

Present Value Calculator

Calculate the present value of a future sum or series of cash flows.

Investment Growth Calculator

Model how your portfolio grows over time.

Calculate HHI market concentration from percentage or decimal market shares.

Exchange Rate Calculator

Convert between currencies using a user-supplied exchange rate. Supports direct rates and cross rates via a common anchor (USD, EUR, etc.).

Simple Interest Calculator

Compute simple interest I = P × r × t, total A = P + I, and a side-by-side compound-interest comparison for any principal, rate, and term.

Leverage Calculator

Compute Debt-to-Equity, Debt Ratio, Equity Multiplier, operating gearing (DOL), financial gearing (DFL) and Combined gearing (DCL).

Markup Calculator

Turn unit cost into a selling price using markup % (added to cost) or margin % (share of price), with profit per unit, markup↔margin conversion and a break-even table.

Currency Inflation Adjuster

Convert any US dollar amount between two years using the official BLS CPI-U (All Urban Consumers, NSA, 1982-84=100) annual averages. Includes a pre-1913 MeasuringWorth reconstruction, real vs nominal read-outs, cumulative inflation, and an annualised rate.

Mortgage Calculator

Monthly repayment, total interest, and overpayment savings.

Loan Calculator

Monthly payments and total interest on any loan.

Auto Loan Calculator

Work out your car finance payments.

Interest Calculator

Simple and compound interest on any amount.

Compound Interest Calculator

See how compound interest grows your money over time.

Investment Calculator

Project the future value of any investment.

Retirement Calculator

Find out if you're on track for retirement.

Savings Calculator

See how your savings grow with regular deposits.

Amortisation Calculator

Full payment schedule for any loan.

Payment Calculator

Monthly payment for any loan amount and rate.

Mortgage Affordability Calculator

Find out how much you can borrow based on your income, deposit, outgoings, and the lend...

Inflation Calculator

What is your money worth in today's prices?

Mortgage Comparison Calculator

Compare two mortgage products side by side, different rates, fees, terms, and deal types.

Salary Calculator

Convert salary between hourly, monthly, and annual.

Roof Pitch Calculator

Convert between roof pitch (rise:12 run), angle in degrees, and percent slope. Compute rafter length and roof surface area from pitch and run.

Oven Temperature Converter

Convert oven temperatures between Celsius, Fahrenheit, Gas Mark and descriptive terms with a fan-oven rule of thumb.

Readability Score Calculator

Score any English text with the six classic readability indices, Flesch, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and ARI, plus full word, sentence, and syllable statistics.

Paint Area Calculator

Work out how many litres (or gallons) of paint you need from wall dimensions, doors, windows, coats, coverage, and waste.

Tile Calculator

Estimate tiles and boxes needed for one or more rooms with a TCNA-recommended waste allowance (default 10%), area-per-box or tiles-per-box packaging input, and optional per-box cost.

Tile Area Calculator

Work out how many tiles and boxes you need to tile a floor or wall, with cutting waste and pattern multipliers.

Acres to Hectares Converter

Convert between acres and hectares, with square metres shown alongside. Exact factors (1 ac = 0.40468564224 ha).

Stones to Kilograms Converter

Convert stones (st) to kilograms (kg) and back, with the residual pounds (lb) shown alongside the UK / Ireland way.

Watts to BTU Per Hour Converter

Convert watts to BTU per hour and BTU/h to watts instantly. Shows kW and tons of refrigeration too.

Password Generator

Generate a strong, secure password.

IP Address Checker

See your public IP address, location, ISP, and timezone.

QR Code Generator

Create a QR code for any URL or text.

Coin Flip

Flip a virtual coin to get heads or tails.

GPA Calculator

Calculate your GPA from any set of grades.

Morse Code Translator

Translate text to Morse code and back. Play audio.

KPH to MPH Converter

Convert kilometres per hour to miles per hour (and back) with exact factors.

Grade Calculator

Overall grade from weighted assignments.

NATO Phonetic Alphabet

Convert text to NATO phonetic alphabet (Alpha, Bravo, Charlie...).

Gravel Calculator

How much gravel do you need for a driveway, path, or drain?

Concrete Calculator

How much concrete do you need?

Blood Pressure Calculator

Classify systolic/diastolic against AHA 2017 and compute MAP, pulse pressure, and 7-day averages.

BMI Calculator

BMI, category, and healthy weight range for your height.

Calorie Calculator

Daily calorie needs based on your goals.

Body Fat Calculator

Estimate your body fat percentage.

BMR Calculator

Basal metabolic rate, calories burned at rest.

Ideal Weight Calculator

Healthy weight range for your height.

Pregnancy Calculator

Due date and pregnancy week from last period.

Due Date Calculator

When is your baby due?

Pace Calculator

Running pace, speed, and finish time.

Calories Burned Calculator

Calories burned for 100+ activities.

Macro Calculator

Daily protein, carb, and fat targets.

Heart Rate Zone Calculator

Calculate your training heart rate zones from your age or measured maximum heart rate.

Ovulation Calculator

Fertile window and ovulation date.

VO2 Max Calculator

Estimate your VO2 max from common field tests (Cooper test, 1.5-mile run, or resting he...

Sleep Calculator

Best times to wake up or go to sleep.

One Rep Max (1RM) Calculator

Calculate your estimated one-repetition maximum for any exercise.

Protein Calculator

Daily protein target for your weight and goals.

Running Pace Calculator

Convert between pace, speed, and finish time for any distance.

BAC Calculator

Estimated blood alcohol content.

Life Expectancy Calculator

Estimate your life expectancy based on your age, sex, country, and lifestyle factors.

Knots to MPH Converter

Convert knots, miles per hour, kilometres per hour, metres per second, and feet per second, nautical, road, and aviation speeds.

Hex to RGB Converter

Convert hex colour codes to RGB, HSL, CMYK, and a live preview swatch.

ASCII to Hex Converter

Convert ASCII text to hexadecimal bytes and back, bidirectional encoder/decoder.

ASCII to Text Converter

Decode a stream of ASCII codes (decimal, hex, octal, or binary) back into readable text with separator and prefix options.

Gauge to mm Converter

Convert AWG wire gauge and sheet-metal gauge to millimetres and inches. Material-specific sheet tables (steel, aluminium), AWG reverse lookup, mm² area.

RGB to Hex Converter

Convert RGB colour values (0 to 255 per channel) to a hex code and back, with a live preview swatch.

Pint to Litre Converter

Convert pints to litres (and litres to pints) for both UK imperial and US liquid pints. Live cross-update with fl oz and mL read-outs.

Miles to Yards Converter

Convert between miles and yards with full precision. 1 mile = 1 760 yards exactly.

Yards ⇄ Feet Converter

Convert yards to feet and feet to yards instantly. 1 yard = 3 feet exactly (NIST SP 811). Includes metres, centimetres, millimetres, kilometres, inches, and miles bonus read-outs with a results table.

Hex to Decimal Converter

Convert hexadecimal numbers (0x...) to decimal, binary, and octal instantly with strict input validation.

Decimal to Hex Converter

Convert decimal (base-10) integers to hexadecimal, binary, and octal instantly with strict input validation.

Octal to Decimal Converter

Convert octal numbers (0o...) to decimal, binary, and hex instantly with strict input validation, perfect for Unix file permissions.

Milligrams to Grams Converter

Convert milligrams (mg) to grams (g) and back, with quick presets for medicine doses, kitchen measures, and chemistry lab quantities.

Days to Hours Converter

Convert days (d) to hours (h) and back, with quick presets for shifts, weeks, months, and years.

Watts to Kilowatts Converter

Convert watts (W) to kilowatts (kW) and back, with quick presets for appliances, lighting, heaters, and small industrial loads.

Liters to Gallons Converter

Bidirectional litre ↔ US/UK gallon converter with strict NIST factors and cross-displayed millilitres.

Pounds to Stones Converter

Convert pounds to stones and stones + pounds to kilograms using the exact UK definition (1 st = 14 lb, 1 lb = 0.45359237 kg by the 1959 international yard-and-pound agreement). Shows kg, g, oz, US short tons alongside.

HEX to HSL Color Converter

Convert a 6-digit or 3-digit hex colour to HSL (Hue, Saturation, Lightness) using the W3C CSS Color Module Level 4 algorithm, with live swatch, WCAG contrast, and palette generation.

Text to ASCII Converter

Convert any text to its ASCII code points in decimal, hex, or binary, and decode a numeric code stream back into text. Includes a per-character breakdown.

Hex to Binary Converter

Convert hexadecimal to binary using the exact 4-bit grouping shortcut, with octal and decimal shown alongside. Shows the padded nibble groups step by step, validates every digit, and uses BigInt so long hex strings stay exact.

Golden Ratio Calculator

Compute phi, segment lengths, total, and a live golden rectangle with nested squares and a spiral.

Cone Volume Calculator

Compute the volume V = (1/3)·π·r²·h, slant height l = √(r² + h²), base area π·r², lateral area π·r·l, and total surface area π·r² + π·r·l of a right circular cone from any positive radius and height, or solve the inverse to recover the radius from a known volume and height, or the height from a known volume and radius.

Sphere Volume Calculator

Compute sphere volume V = (4/3)·π·r³ and surface area A = 4·π·r² from any positive radius, or solve the inverse problem to recover the radius from a known volume or surface area.

Matrix Multiplication Calculator

Multiply any two matrices A (m×n) and B (n×p) and see the row × column dot-product for every cell of C = A × B.

Prime Number Checker

Check if a number is prime, sieve a range, find the next prime, or factor any integer into primes.

Prime Factor Calculator

Compute the prime factorization of any positive integer (up to 10²⁵ with BigInt). Shows the canonical form, divisor count τ(n), sum of divisors σ(n), and Euler totient φ(n), with a full trial-division step trace.

Degrees to Radians Converter

Convert degrees to radians and radians to degrees instantly. Bidirectional sync with quick-preset reference points.

Calculator

Basic and scientific calculations.

Percentage Calculator

Work out any percentage instantly.

Fraction Calculator

Add, subtract, multiply, and divide fractions.

Standard Deviation Calculator

Mean, variance, and standard deviation for any data set.

Average Calculator

Mean, median, and mode for any list of numbers.

Quadratic Formula Calculator

Solve any quadratic equation step by step.

Probability Calculator

Calculate probability for any event.

Scientific Calculator

Trig, logarithms, powers, and more.

Random Number Generator

Generate random numbers in any range.

Ratio Calculator

Simplify ratios and solve proportions.

Mean / Median / Mode Calculator

Calculate the mean, median, mode, range, variance, and standard deviation of any data set.

Permutation & Combination Calculator

Compute P(n,r) and C(n,r) for any non-negative integers n and r. BigInt precision up to 10,000!.

Exponent Calculator

Any base raised to any power.

Dew Point Calculator

Compute dew point, frost point note (below 0 °C), and absolute humidity from air temperature and relative humidity. Celsius / Fahrenheit toggle.

Centripetal Force Calculator

Calculate centripetal force, acceleration, velocity, or radius for circular motion.

Work-Energy Theorem Calculator

Solve for work, force, displacement, angle, or ΔKE using W = F·d·cos θ = ΔKE.

Angular Momentum Calculator

Solve L = I·ω (rigid body) or L = m·v·r·sin θ (point mass / orbital). Includes shape presets and verified astrophysical examples.

Decibel (dB) Calculator

Convert power and amplitude ratios to decibels (10·log₁₀ and 20·log₁₀), add sound levels logarithmically, subtract background noise, and convert dBm, dBW and watts.

Acoustic Impedance Calculator

Solve z = ρ·c, Z = ρ·c/A, or the reflection/transmission coefficients R and T at a normal-incidence boundary. Includes a verified material library (air, water, steel, bone, muscle, blood, etc.).

Capillary Action Calculator

Solve Jurin's law h = (2γ·cos θ) / (ρ·g·r) for the capillary rise (or depression) of a liquid in a tube.

Wave Frequency Calculator

Solve the wave equation v = f × λ for frequency, wavelength, or wave speed.

Stefan-Boltzmann Calculator

Solve P = εσAT⁴ for the thermal radiation emitted by a surface, or back-solve for temperature given power.

Projectile Motion Calculator

Solve time of flight, max height, and horizontal range for a projectile launched at speed v₀ and angle θ, from any initial height h₀. Includes trajectory samples and gravity presets.

Gravitational Potential Energy Calculator

Solve PE = mgh near a planetary surface or U = -GMm/r in space; for any variable.

Momentum Calculator

Solve linear momentum p = m × v for momentum, mass, or velocity.

Coulomb's Law Calculator

Calculate electrostatic force between two charges using F = k·q₁q₂/r².

Projectile Motion Calculator

Calculate height, flight time, range, trajectory, required velocity or angle, and target-height crossings.

Work-Energy Theorem Calculator

Calculate work, force, displacement, angle, or kinetic energy using W = F·d·cos θ = ΔKE.

Power Calculator

Solve power, work, time, force, velocity, voltage, current, or power factor across mechanical and electrical modes.

Ohm's Law Calculator (V, I, R, P)

Solve Ohm’s law V = IR and power P = VI for any variable.

Centripetal Force Calculator

Solve centripetal force, mass, velocity, or radius for uniform circular motion.

Work Calculator

Calculate mechanical work: constant force W = F·d·cos θ, variable force W = ∫F(x) dx, and spring W = ½k(x₁² − x₀²).

Free Fall Calculator

Solve free-fall time, final velocity, or fall distance under constant gravity.

Fourier Transform Calculator

Compute the discrete Fourier transform (DFT) of a finite input sequence, magnitude and phase for each frequency bin, with an inverse-DFT round-trip check.

Derivative Calculator

Enter a function to find its first and second derivative.

Indefinite Integral Calculator

Find the antiderivative of a function.

Definite Integral Calculator

Enter a function and upper and lower bounds to compute the definite integral ∫ₐᵇ f(x) dx.

Limit Calculator

Enter a function and the point x approaches to evaluate the limit.

Quadratic Equation Solver

Solve ax²+bx+c=0 with roots, discriminant, and vertex.

Average Rate of Change Calculator

Enter a function and two x-values to find the average rate of change (AROC), the slope...

Instantaneous Rate of Change Calculator

Enter a function and an x-value to find the instantaneous rate of change at that point.

Slope of Tangent Line Calculator

Enter a function and a point x = a to find the slope of the tangent line at that point ...

Linear Approximation Calculator

Enter a function, a base point a, and an x-value near a to get the linearisation L(x) a...

Riemann Sum Calculator

Approximate integrals using left, right, or midpoint sums.

Taylor Series Calculator

Expand a function as a Taylor series around any point.

Maclaurin Series Calculator

A Maclaurin series is a Taylor series centred at a = 0.

Chain Rule Calculator

Enter an outer function g and an inner function u(x) to compute d/dx[g(u(x))] = g'(u(x)...

Product Rule Calculator

Enter two functions f(x) and g(x) to compute d/dx[f(x)·g(x)] = f'(x)g(x) + f(x)g'(x).

Quotient Rule Calculator

Enter numerator f(x) and denominator g(x) to differentiate f(x)/g(x).

Implicit Differentiation Calculator

Find dy/dx for implicitly defined curves.

Arc Length Calculator

Enter a function and integration bounds to compute the arc length of the curve y = f(x)...

Area Between Two Curves Calculator

Enter two functions f(x) and g(x) and integration bounds to compute the area between th...

Volume of Revolution Calculator

Rotate y = f(x) about the x-axis or y-axis between x = a and x = b.

ISO 8601 Date Converter

Parse and reformat ISO 8601 / RFC 3339 timestamps into ISO, RFC 3339, RFC 2822, Unix epoch, and local time. Supports week dates and ordinal dates.

Unix Timestamp Converter

Convert Unix epoch (seconds or milliseconds) to human-readable dates and back, with live clock, ISO 8601, RFC 2822, and presets.

Age Calculator

Your exact age in years, months, and days.

Date Calculator

Days between dates, add or subtract days.

Time Zone Converter

Convert times between any two time zones.

Timer & Stopwatch

Countdown timer and stopwatch in one.

Hours Calculator

Time between two times in hours and minutes.

Hours Between Dates

Calculate total hours and minutes between any two dates and times.

Time Calculator

Add and subtract hours, minutes, and seconds.

Workday Calculator

Count working days between dates or add business days.

Day Counter

How many days until or since a date.

Moon Phase Calculator

Current moon phase, illumination, and upcoming phases.

Wedding Anniversary Calculator

Anniversary gift themes and milestones for any couple.

Leap Year Checker

Is any year a leap year?

Days Until Calculator

Count down the days until any future date.

Day of the Week Calculator

What day of the week was any date?

Business Days Calculator

Calculate the number of working days between two dates, or find a future date a set num...

World Clock

See the current time in any city worldwide.

Meeting Time Zone Planner

meeting time zone planner.

Flight Time Calculator

Estimate flight duration from distance and speed, with local arrival time across time zones.

Stopwatch & Split Calculator

Lap timer with split times, pace stats, pace chart, and CSV export. Free.

Word Game

Guess the 5-letter word in 6 tries.

Random Picker

Pick a random winner from any list.

Dice Roller

Roll any number and type of dice.

2048

Slide tiles and combine numbers to reach 2048.

Snake Game

Classic snake game, eat, grow, don't crash.

Minesweeper

Classic Minesweeper, clear the board without hitting a mine.

Hangman

Guess the word before the hangman is complete.

Memory Game

Flip cards and find all matching pairs.

Typing Speed Test

Test your typing speed in words per minute.

Sudoku

Classic 9×9 Sudoku puzzle.

Trivia Quiz

Test your knowledge across science, history, geography, and more.

Roulette Probability Calculator

Odds, house edge, and expected loss for every roulette bet.

Poker Hand Calculator

Identify and rank any 5-card poker hand.

Lottery Number Generator

Generate random lottery numbers from any pool (1..49, 1..70, etc.) with optional bonus ball.

Capacitor Code Calculator

Decode and encode ceramic capacitor markings. 3-digit body code (104, 223, 471), tolerance letter (K, M, J…), n-notation (4n7), and R-notation (4R7). Shows pF, nF and µF.

HTML Entity Encoder & Decoder

Encode and decode HTML entities live. Named (& < ©), decimal (©), and hex (©) with full Unicode and emoji support.

SQL Formatter

Format and beautify SQL with dialect-aware keyword highlighting.

URL Encoder / Decoder

Percent-encode and decode URLs and query parameters using encodeURIComponent, encodeURI, and their decoders. Includes a query-string parser.

ISBN Validator

Check ISBN-10 and ISBN-13 (Bookland / EAN-13) check digits and convert between formats, fully client-side.

.htaccess Generator

Generate Apache .htaccess rules with toggles for HTTPS, WWW, redirects, caching, compression, hotlink protection, and error pages.

Username Generator

Generate unique, memorable usernames with 4 patterns: word+digits, dice-style phrase, fantasy, and tech-handle.

IPv4 Subnet Calculator

CIDR subnet calculator, network, broadcast, host range, mask and wildcard.

Random Password Generator

Generate cryptographically secure random passwords with adjustable length, character classes, and ambiguous-character exclusion.

Pixels to REM Converter

Convert CSS px to rem and back with a configurable root font size. Live px ⇄ rem, separate em panel, pt and %, common-px reference table, and root-font presets (16, 10, 14, 18, 20).

Regex Tester

Test regular expressions with live match highlighting.

Cron Expression Builder

Build and decode cron expressions with next-run times.

Cron Expression Generator & Explainer

Parse any cron expression (5-field POSIX or 6-field Quartz) and see the next 10 to 20 fire times in your IANA timezone plus a plain-English description like "Runs at 09:30 on Monday".

JSON Formatter

Format, validate, and minify JSON instantly.

Text Diff Tool

Compare two texts and highlight the differences.

JWT Decoder

Decode and inspect JSON Web Tokens instantly.

JWT Secret Generator

Generate cryptographically secure HMAC secrets for signing JWTs (HS256/HS384/HS512).

Unix Timestamp Converter

Convert Unix timestamps to human dates and back.

UUID Generator

Generate random UUID v4 identifiers instantly.

CSV to JSON Converter

Convert RFC 4180 comma-separated text into a JSON array of objects. Header row, numeric autodetect, pretty, copy, download.

Aspect Ratio Converter

Convert between W:H notation, decimal ratio, and pixel dimensions. Includes fit-in-frame helper with centre offset.

Image Compressor

Reduce image file sizes without visible quality loss.

Image Resizer

Resize JPG, PNG, or WebP images to any dimensions.

Image Converter

Convert images between JPG, PNG, and WebP formats.

DPI / PPI Calculator

Compute screen pixel density (PPI), print size from pixels and DPI, and required pixels for a target print size.

Image Cropper

Click and drag to select any crop area on your image.

Favicon Generator

Upload any image and generate favicon files at 16×16, 32×32, and 48×48 pixels.

Image to PDF

Convert one or more images into a single PDF.

Colour Picker

Pick a colour and get its HEX, RGB, and HSL values.

SVG to PNG Converter

Convert SVG files to PNG at any resolution.

Image to Text (OCR)

Upload an image or take a photo and extract the text instantly using Tesseract.js, a br...

Background Remover

Remove backgrounds from photos and images using the @imgly/background-removal library.

Travel Customs

Local customs travellers get wrong, top 20 destinations.

Etiquette Rules

The most important etiquette rule in each of the world's top 20 countries.

Tipping Guide

Tipping norms for the world's top 30 destinations.

Essential Travel Phrases

Essential phrases in 25 languages, greetings, thanks, please and goodbye.

Titration Calculator

Solve acid-base titration for unknown concentration, volume, or moles. Includes strong/strong, weak/strong, polyprotic, indicator recommendation, and pH at equivalence.

Molarity Calculator

Calculate solution concentration from solute amount and volume.

Celsius to Kelvin Converter

Convert Celsius to Kelvin and Kelvin to Celsius instantly. Shows Fahrenheit as a bonus read-out.

Osmotic Pressure Calculator

Solve osmotic pressure, molar concentration, or temperature using the van’t Hoff equation π = iMRT.

pH Calculator

Solve pH, pOH, [H⁺], [OH⁻] from any input. Includes acid dilution series and temperature-corrected Kw.

Buffer Calculator

Prepare acid-base buffers from pKa, target pH, volume and concentration using Henderson-Hasselbalch. Includes buffer capacity β and a one-shot recipe.

pH Calculator

Calculate pH, pOH, hydrogen-ion concentration, and hydroxide concentration with temperature-corrected water constants.

Henderson-Hasselbalch Calculator

Solve buffer pH from pKa and the conjugate base/acid ratio. Includes Van Slyke buffer capacity.

Beer-Lambert Law Calculator

Solve for absorbance, molar absorptivity, concentration, or path length using A = ε × c × l.

Half-Life Calculator

Solve for half-life, elapsed time, or remaining amount using A(t) = A₀ × (½)^(t / t½).

Ideal Gas Law Calculator (PV = nRT)

Solve the ideal gas law PV = nRT for pressure, volume, moles, or temperature.

Dilution Calculator

Solve dilution problems with C₁V₁ = C₂V₂ for concentration or volume.

Ideal Gas Law Calculator

Solve PV = nRT for pressure, volume, moles, or temperature.

Molar Mass Calculator

Compute molar mass and percent composition from any chemical formula.

Molarity Calculator

Solve molarity, moles, or volume from M = n/V with mass-to-moles conversion.

Atmospheres to Pascals Converter

Convert between atmospheres (atm) and pascals (Pa). 1 atm = 101 325 Pa exactly.

Bar to PSI Converter

Convert between bar and pounds per square inch (psi). 1 bar = 14.5037738 psi exactly.

Millimeters to Feet Converter

Convert between millimetres (mm) and feet (ft) with full precision. 1 ft = 0.3048 m exactly.

Torr to Pascals Converter

Convert between torr/mmHg and pascals (Pa). Vacuum science, chemistry, medicine.

Decimal to Binary Converter

Convert decimal integers and fractions to binary, octal, and hexadecimal. Bidirectional dec ⇄ bin with bonus oct and hex read-outs.

Gallons to Liters Converter

Convert between US gallons, UK (imperial) gallons, and liters. 1 US gal = 3.785411784 L exactly; 1 UK gal = 4.54609 L exactly.

Cups to Milliliters Converter

Convert cups to milliliters (US legal, US customary, metric). 1 US legal cup = 240 mL exactly. 1 metric cup = 250 mL exactly.

Centimeters ⇄ Feet + Inches Converter

Convert centimeters to feet and inches (and back). 1 inch = 2.54 cm exactly; 1 foot = 30.48 cm exactly. Includes m, mm, yd, decimal ft/in.

Horsepower to Kilowatt Converter

Convert horsepower (mechanical hp(I), metric PS/CV, boiler hp(S), electrical hp(E)) to kilowatts. 1 hp(I) = 0.7456998715822702 kW exactly.

Joule to Calorie Converter

Convert joules to calories (thermochemical), kilocalories, and kilowatt-hours. 1 cal = 4.184 J exactly.

Inches ⇄ Feet Converter

Convert inches to feet and feet to inches instantly. 1 foot = 12 inches exactly (US customary, NIST SP 811). Includes yards, cm, m, mm read-outs and a combined feet+inches form.

Pressure Converter

Convert between pascals, bar, atmospheres, psi, torr, mmHg, inHg and more with live results.

Angle Converter

Convert angles between degrees, radians, gradians, turns, arcminutes, arcseconds, milliradians and NATO mils, with DMS notation and live results.

Illuminance Converter

Convert illuminance between lux, foot-candles, phot, nox, lumen/m² and lumen/ft², with reference lighting levels and a live results table.

Density Converter

Convert density between kg/m³, g/cm³, lb/ft³, lb/gal, slug/ft³, tonne/m³ and more. Live results table, material presets, specific-gravity readout.

Paper Size Converter

Reference and converter for ISO A/B/C and North American paper sizes, mm, cm, inches, points, and pixels at 72/150/300/600 DPI.

Fuel Economy Converter

Convert fuel economy between MPG (US/UK), km/L, L/100km, L/10km, L/km, miles/L, and km per US/UK gallon, with a cost-per-distance helper.

Wire Gauge Converter

Convert wire gauge between AWG, SWG, BWG, mm² cross-sectional area, mm and inch diameter. Includes copper resistance per km at 20 °C (IEC 60228) and an ampacity reference panel (NEC NFPA 70 Chapter 9 Table 8 family).

Knots to Kilometers per Hour Converter

Convert knots to kilometres per hour and back using the exact 1.852 factor. Includes bonus m/s and mph read-outs.

Kilograms to Pounds Converter

Convert kilograms to pounds and pounds to kilograms instantly. Live cross-update with exact 1959-pound factor plus grams and ounces display.

Population Growth Calculator

Calculate exponential population growth N = N₀·e^(rt) and solve for any variable.

Shannon Diversity Index Calculator

Calculate Shannon diversity H′, Pielou evenness J′, species richness, total abundance, and Simpson diversity (1 − D) from comma-separated species counts.

Water Footprint Calculator

Estimate your daily and annual water footprint in litres and cubic metres, plus the virtual water embedded in everyday products like beef, cotton and coffee.

Logistic Growth Calculator

Calculate population with carrying capacity using the logistic equation N(t) = K / (1 + ((K−N₀)/N₀)·e^(−rt)).

Carbon Footprint Calculator

Estimate annual household CO2e in tonnes from car km, flights, electricity, gas, diet and consumption using DEFRA 2024 and EPA 2024 factors.

Simpson Diversity Index Calculator

Compute Simpson's Index (D), Simpson's Diversity (1−D), reciprocal (1/D), Shannon-Wiener (H′), Pielou evenness (J), and Berger-Parker dominance (d) from species counts in any sample.

Shannon Diversity Index Calculator

Calculate Shannon diversity, Pielou evenness, richness, and Simpson diversity from species counts.

Soil Texture Calculator

Classify soil from its sand, silt, and clay percentages.

Shannon Diversity Index Calculator

Calculate Shannon-Wiener H, Pielou evenness, species richness, and Simpson diversity from species counts with a row-by-row breakdown.

Population Growth Calculator

Model exponential or logistic population growth and solve for population, time, or growth rate.

DNA Codon Calculator

Translate a DNA or mRNA sequence into its amino acid chain using the standard genetic code.

DNA Molecular Weight Calculator

Calculate ssDNA and dsDNA molecular weight from a sequence. Includes GC content, length, Wallace / Marmur Tm, and 260 nm absorbance conversion.

DNA Calculator

Five molecular-biology tools in one: molecular weight (ssDNA / dsDNA), melting temperature (Wallace & nearest-neighbour), GC %, reverse complement, and translation.

Allele Frequency Calculator

Compute allele frequencies (p, q), Hardy-Weinberg expected genotype counts, chi-square goodness-of-fit, heterozygosity, inbreeding coefficient F, and PIC from observed AA, Aa, aa counts.

DNA Molecular Weight Calculator

Compute molecular weight, GC content, melting temperature and OD260 mass for ssDNA, dsDNA and RNA.

Hardy-Weinberg Equilibrium Calculator

Solve p² + 2pq + q² = 1 for any of p, q, p², 2pq, or q². Includes carrier-frequency and population-genetics examples.

Protein Molecular Weight Calculator

Calculate molecular weight from an amino acid sequence using average residue masses.

Percentile Calculator

Percentile rank and inverse percentile with six interpolation methods.

Poisson Distribution Calculator

Compute Poisson PMF, CDF, mean, variance, and quantile for a rate λ.

One-Way ANOVA Calculator

Test whether 2-10 group means differ significantly using one-way ANOVA.

Linear Regression Calculator

Fit a least-squares line y = α + β·x to paired X and Y data: slope, intercept, R², p-value, CI, scatter plot.

Margin of Error Calculator

Compute the margin of error, confidence interval, and required sample size for proportions or means (Cochran 1977).

Linear Regression Calculator

Fit an OLS line y = α + β·x to paired X and Y data with slope, intercept, R², r, t, p-value, CI, prediction interval, residuals and scatter plot.

Z-Score Calculator

Calculate a z-score from a value, mean, and standard deviation: z = (x − μ) / σ.

Standard Deviation Calculator

Calculate sample or population standard deviation, variance, and mean.

Linear Regression Calculator

Calculate the regression line y = mx + b with slope, intercept and R².

Correlation Coefficient Calculator

Pearson r, Spearman ρ, and Kendall τ for paired data.

Confidence Interval Calculator

Calculate a confidence interval for a mean: CI = x̄ ± z(σ/√n).

Hypothesis Test Calculator

One-proportion z-test and one-sample t-test (or z-test with known σ) for means, test statistic, p-value, critical value, and confidence interval.

Chi-Square Test Calculator

Chi-square test for independence or goodness of fit with observed vs expected frequencies.

ROT13 Cipher Encoder/Decoder

Encode and decode text with ROT13, the classic Caesar shift-13 substitution cipher.

Caesar Cipher Decoder & Encoder

Encode and decode text with the general Caesar shift cipher, pick any shift from 1 to 25 (ROT13, Caesar's shift-3, or any other).

Random Coin Flip Generator

Flip 1 to 100 coins at once using the Web Crypto API (cryptographically unbiased). Shows heads/tails counts and percentages, with optional fixed seed for reproducible flips.

Random Team Generator

Split a list of player names into 2 to 16 random teams using cryptographically unbiased shuffling. Free-text player input, even/nearest distribution modes, fixed seed for reproducible results, and round-robin pairings.

Random Date Generator

Generate random dates within any range, with weekend, weekday, and date exclusions.

Morse Code Encoder/Decoder

Convert text to Morse code (dots and dashes) and decode Morse back to text, with audio playback at ITU-standard timing.