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Investment
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8 toolscat.generator
12 tools๐ Investment
401(k) Calculator
Estimate how much your 401(k) will be worth at retirement.
Accrued Interest Calculator
Calculate the interest that has built up on a bond between coupon payment dates.
Annualised Return Calculator
Convert a total investment return into an annual figure.
Annuity Calculator
Calculate either the lump sum needed to fund an annuity or the regular income an annuit...
Beta Calculator
Calculate the beta of a stock or portfolio.
Black-Scholes Options Calculator
Price European call and put options using the Black-Scholes model.
Bond Equivalent Yield Calculator
Convert the yield of a bond or money market instrument to an annualised bond equivalent...
Bond Price Calculator
Calculate the fair price of a bond.
Book Value Per Share Calculator
Calculate the book value per share of a company.
Calmar Ratio Calculator
Calculate the Calmar ratio of an investment portfolio or fund.
Cash-Secured Put Calculator
Calculate the return on a cash-secured put strategy.
Convexity Calculator
Calculate the convexity of a bond.
Correlation Calculator
Calculate the Pearson correlation coefficient between two data series.
Covered Call Calculator
Calculate the return on a covered call strategy.
Credit Spread Calculator
Calculate the credit spread of a bond, the additional yield it offers above a risk-fre...
CVaR Calculator
Calculate the Conditional Value at Risk (CVaR) of a portfolio or investment.
Discounted Cash Flow (DCF) Calculator
Calculate the intrinsic value of a business or investment by discounting projected futu...
Dividend Discount Model (DDM)
dividend discount model (ddm).
DRIP Calculator
Calculate how your investment grows when dividends are automatically reinvested.
Duration Calculator
Calculate the Macaulay duration of a bond.
๐ฐ Financial
Herfindahl-Hirschman Index Calculator
Calculate HHI market concentration from percentage or decimal market shares.
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.
Inflation Calculator
What is your money worth in today's prices?
Salary Calculator
Convert salary between hourly, monthly, and annual.
Income Tax Calculator
Estimate your income tax liability.
Sales Tax Calculator
Add or remove sales tax from any price.
VAT Calculator
Add or remove VAT from any price.
Credit Card Calculator
See how long to pay off your credit card.
Debt Payoff Calculator
Plan your path to debt freedom.
Student Loan Calculator
Monthly payments and payoff timeline for student loans.
ROI Calculator
Return on investment as a percentage.
๐ Everyday
Password Generator
Generate a strong, secure password.
QR Code Generator
Create a QR code for any URL or text.
GPA Calculator
Calculate your GPA from any set of grades.
Grade Calculator
Overall grade from weighted assignments.
Concrete Calculator
How much concrete do you need?
Square Footage Calculator
Area of any room or space in square feet or metres.
BTU Calculator
Air conditioning BTU for any room size.
Electricity Cost Calculator
Cost to run any appliance.
IP Subnet Calculator
Subnet mask, network address, and host range.
IP Address Checker
See your public IP address, location, ISP, and timezone.
Coin Flip
Flip a virtual coin to get heads or tails.
Morse Code Translator
Translate text to Morse code and back. Play audio.
Mulch Calculator
Calculate cubic yards or meters of mulch needed for any garden bed or area.
NATO Phonetic Alphabet
Convert text to NATO phonetic alphabet (Alpha, Bravo, Charlie...).
Ohm's Law Calculator
Voltage, current, resistance, and power from Ohm's Law.
Wind Chill Calculator
Feels-like temperature from wind and air temperature.
Heat Index Calculator
Feels-like temperature from heat and humidity.
Periodic Table Lookup
Search elements by name, symbol, or atomic number.
Cooking Time Calculator
Meat roasting times, pasta, and egg cooking guides.
Sunrise & Sunset Calculator
Sunrise, sunset, and day length for any location and date.
โค๏ธ Health & Fitness
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.
Ovulation Calculator
Fertile window and ovulation date.
Sleep Calculator
Best times to wake up or go to sleep.
Protein Calculator
Daily protein target for your weight and goals.
Protein Intake Calculator
Daily protein target in grams from body weight, activity, and goal, with adjustable g/kg, per-meal split, and per-kg-LBM figure.
BAC Calculator
Estimated blood alcohol content.
Blood Pressure Calculator
Classify systolic/diastolic against AHA 2017 and compute MAP, pulse pressure, and 7-day averages.
Caffeine Calculator
Track caffeine intake and see active levels over time.
Nutrition Label Generator
Create an FDA-style nutrition label for any food.
Normal Vital Signs Reference
Blood pressure, heart rate, temperature, and SpO2 ranges by age.
Heart Rate Zone Calculator
Calculate your training heart rate zones from your age or measured maximum heart rate.
๐ Converters
Area Converter
Convert square measurements between metric, imperial, acres, and hectares.
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 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.
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.
Unit Converter
Length, weight, volume, temperature, and more.
Temperature Converter
Celsius, Fahrenheit, and Kelvin.
Length Converter
Convert between km, miles, feet, inches, and more.
Weight Converter
Convert between kg, lbs, stone, and more.
Speed Converter
Convert between mph, km/h, m/s, and knots.
Roman Numeral Converter
Convert between Roman numerals and numbers.
Shoe Size Converter
Convert shoe sizes between US, UK, and EU.
Color Converter
Convert any color between HEX, RGB, HSL, and HSV/HSB. Live swatch, per-format validation, and quick presets for common web colors.
Centimetre โ Millimetre โ Inch Converter
Bidirectional cm โ mm โ inches with metres and feet read-outs.
Tyre Size Calculator
Tyre diameter, circumference, and speedometer error from size codes.
Clothing Size Converter
International clothing and shoe sizes across US, UK, EU, JP, and AU.
Ring Size Converter
Convert ring sizes between US, UK, EU systems with diameter chart.
Data Storage Converter
Convert between digital storage units instantly.
Energy Converter
Convert between energy units, joules, kilojoules, kilowatt-hours, BTUs, calories, kilo...
๐คฏ Interesting Facts
๐ข Math
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.
Exponent Calculator
Any base raised to any power.
Area Calculator
Area of any 2D shape.
Volume Calculator
Volume of any 3D shape.
Slope Calculator
Slope, angle, and equation of a line.
Log Calculator
Logarithm in any base.
Triangle Calculator
Sides, angles, and area of any triangle.
Pythagorean Theorem Calculator
Find the missing side of a right triangle.
Binary Calculator
Add, subtract, multiply binary numbers. Convert to decimal.
Statistics Calculator
Full descriptive statistics for any data set.
Golden Ratio Calculator
Compute phi, segment lengths, total, and a live golden rectangle with nested squares and a spiral.
โ๏ธ Physics
Work-Energy Theorem Calculator
Solve for work, force, displacement, angle, or ฮKE using W = Fยทdยทcos ฮธ = ฮKE.
Wave Frequency Calculator
Solve the wave equation v = f ร ฮป for frequency, wavelength, or wave speed.
Angular Momentum Calculator
Solve L = Iยทฯ (rigid body) or L = mยทvยทrยทsin ฮธ (point mass / orbital). Includes shape presets and verified astrophysical examples.
Projectile Motion Calculator
Solve time of flight, max height, and horizontal range for a projectile launched at speed vโ and angle ฮธ, from any initial height hโ. Includes trajectory samples and gravity presets.
Capillary Action Calculator
Solve Jurin's law h = (2ฮณยทcos ฮธ) / (ฯยทgยทr) for the capillary rise (or depression) of a liquid in a tube.
Stefan-Boltzmann Calculator
Solve P = ฮตฯATโด for the thermal radiation emitted by a surface, or back-solve for temperature given power.
Acoustic Impedance Calculator
Solve z = ฯยทc, Z = ฯยทc/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.).
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 ร v for momentum, mass, or velocity.
Power Calculator
Solve power, work, time, force, velocity, voltage, current, or power factor across mechanical and electrical modes.
Centripetal Force Calculator
Solve centripetal force, mass, velocity, or radius for uniform circular motion.
Free Fall Calculator
Solve free-fall time, final velocity, or fall distance under constant gravity.
Gravitational Force Calculator
Solve Newtonโs law of universal gravitation for force, mass, or distance.
Impulse Calculator
Solve impulse, average force, or time interval from the impulse-momentum theorem.
Potential Energy Calculator
Solve gravitational potential energy, mass, height, or gravity from PE = mgh.
Work Done Calculator
Solve work, force, displacement, or angle from W = Fยทdยทcosฮธ.
Coulomb's Law Calculator
Calculate electrostatic force between two charges using F = kยทqโqโ/rยฒ.
Work Calculator
Calculate mechanical work: constant force W = Fยทdยทcos ฮธ, variable force W = โซF(x) dx, and spring W = ยฝk(xโยฒ โ xโยฒ).
Wavelength & Frequency Calculator
Convert between wavelength, frequency, and photon energy using c = ฮปยทf and E = hยทf.
Dew Point Calculator
Compute dew point, frost point note (below 0 ยฐC), and absolute humidity from air temperature and relative humidity. Celsius / Fahrenheit toggle.
Decibel (dB) Calculator
Convert power and amplitude ratios to decibels (10ยทlogโโ and 20ยทlogโโ), add sound levels logarithmically, subtract background noise, and convert dBm, dBW and watts.
โซ Calculus
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 โซโแต f(x) dx.
Limit Calculator
Enter a function and the point x approaches to evaluate the limit.
Quadratic Equation Solver
Solve axยฒ+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)ยทg(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.
Critical Points Calculator
Enter a function to find all critical points (where f'(x) = 0 or f'(x) is undefined) an...
๐ Date & Time
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.
Time Calculator
Add and subtract hours, minutes, and seconds.
Day Counter
How many days until or since a date.
Hours Between Dates
Calculate total hours and minutes between any two dates and times.
Workday Calculator
Count working days between dates or add business days.
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?
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...
Days Until Calculator
Count down the days until any future date.
Meeting Time Zone Planner
meeting time zone planner.
World Clock
See the current time in any city worldwide.
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.
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.
Unix Timestamp Converter
Convert Unix epoch (seconds or milliseconds) to human-readable dates and back, with live clock, ISO 8601, RFC 2822, and presets.
Leap Year Calculator
Test any year for leap-year status under the Gregorian rule, list the next 10, and count leap years in any range.
๐ฎ Games
Word Unscrambler
Find all words from your letters.
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 9ร9 Sudoku puzzle.
Trivia Quiz
Test your knowledge across science, history, geography, and more.
Palindrome Checker
Check if a word or phrase is a palindrome.
Roulette Probability Calculator
Odds, house edge, and expected loss for every roulette bet.
Poker Hand Calculator
Identify and rank any 5-card poker hand.
Anagram Generator
Find all anagrams or scramble a word.
Crossword Helper
Find words matching a letter pattern for crossword puzzles.
Lottery Number Generator
Generate random lottery numbers from any pool (1..49, 1..70, etc.) with optional bonus ball.
Anagram Checker
Check whether two words or phrases are anagrams, with live histograms, sorting trace, and famous examples.
๐ป Developer Tools
AI Text Summariser
Summarise any text in seconds with AI.
AI Grammar Checker
Fix grammar, spelling, and style errors instantly.
AI Paraphraser
Rewrite text in a different tone or style.
AI Translator
Translate text into 30+ languages instantly.
Word Counter
Count words, characters, sentences, and paragraphs.
Character Counter
Count characters with and without spaces.
Text Case Converter
Convert text to UPPER, lower, Title, or camelCase.
IPv4 Subnet Calculator
CIDR subnet calculator, network, broadcast, host range, mask and wildcard.
Regex Tester
Test regular expressions with live match highlighting.
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".
Cron Expression Builder
Build and decode cron expressions with next-run times.
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).
UUID Generator
Generate random UUID v4 identifiers instantly.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes.
Text to Binary Converter
Convert text to binary, hex, or decimal and back.
URL Slug Generator
Convert any text into a clean URL-friendly slug.
Reading Time Estimator
How long to read any text at your pace.
๐ผ๏ธ Image Tools
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 16ร16, 32ร32, and 48ร48 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.
Aspect Ratio Converter
Convert between W:H notation, decimal ratio, and pixel dimensions. Includes fit-in-frame helper with centre offset.
๐ Travel & Culture
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.
๐งช Chemistry
Molarity Calculator
Calculate solution concentration from solute amount and volume.
Half-Life Calculator
Solve for half-life, elapsed time, or remaining amount using A(t) = Aโ ร (ยฝ)^(t / tยฝ).
Beer-Lambert Law Calculator
Solve for absorbance, molar absorptivity, concentration, or path length using A = ฮต ร c ร l.
Dilution Calculator
Solve dilution problems with CโVโ = CโVโ for concentration or volume.
Ideal Gas Law Calculator
Solve PV = nRT for pressure, volume, moles, or temperature.
Titration Calculator
Solve acid-base titration for unknown concentration, volume, or moles. Includes strong/strong, weak/strong, polyprotic, indicator recommendation, and pH at equivalence.
pH Calculator
Solve pH, pOH, [Hโบ], [OHโป] from any input. Includes acid dilution series and temperature-corrected Kw.
Henderson-Hasselbalch Calculator
Solve buffer pH from pKa and the conjugate base/acid ratio. Includes Van Slyke buffer capacity.
Buffer Calculator
Prepare acid-base buffers from pKa, target pH, volume and concentration using Henderson-Hasselbalch. Includes buffer capacity ฮฒ and a one-shot recipe.
Osmotic Pressure Calculator
Solve osmotic pressure, molar concentration, or temperature using the vanโt Hoff equation ฯ = iMRT.
Celsius to Kelvin Converter
Convert Celsius to Kelvin and Kelvin to Celsius instantly. Shows Fahrenheit as a bonus read-out.
๐ Conversion
Fahrenheit to Celsius Converter
Convert Fahrenheit to Celsius and Celsius to Fahrenheit instantly using the exact 9/5 and 32 definitions. Includes Kelvin bonus read-out.
Fahrenheit โ Kelvin + Celsius Converter
Convert Fahrenheit to Kelvin (and Kelvin to Fahrenheit) instantly. Shows Celsius as a bonus and Rankine. 0 K = โ459.67 ยฐF = โ273.15 ยฐC exactly.
Ounces to Grams Converter
Convert avoirdupois ounces (oz) to grams (g) and back, also kilograms, milligrams, pounds, and troy ounces.
Mass/Weight Converter
Convert between metric and imperial mass units: kilograms, grams, pounds, ounces, stones and tonnes.
Volume Converter
Convert between volume units: litres, millilitres, cubic metres, US/UK gallons and cubic feet.
Kilograms to Pounds Converter
Convert kilograms to pounds (and pounds to kilograms) using the exact international avoirdupois factor. Free online kg โ lb calculator.
Watts to Horsepower Converter
Convert watts to mechanical and metric horsepower (and back).
cm to Inches Converter
Convert centimetres to inches and inches to centimetres instantly using the exact 2.54 cm/in factor.
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.
Meters to Feet Converter
Convert metres to feet and feet to metres instantly using the exact 0.3048 m/ft factor. Shows inches and centimetres too.
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 โ 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 โ 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.
Kelvin โ Fahrenheit + Celsius Converter
Convert Kelvin to Fahrenheit and Fahrenheit to Kelvin instantly. Shows Celsius and Rankine bonus. 0 K = โ459.67 ยฐF = โ273.15 ยฐC exactly.
๐ Ecology
Soil Texture Calculator
Classify soil from its sand, silt, and clay percentages.
Population Growth Calculator
Model exponential or logistic population growth and solve for population, time, or growth rate.
Logistic Growth Calculator
Calculate population with carrying capacity using the logistic equation N(t) = K / (1 + ((KโNโ)/Nโ)ยทe^(โrt)).
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.
Simpson Diversity Index Calculator
Compute Simpson's Index (D), Simpson's Diversity (1โD), reciprocal (1/D), Shannon-Wiener (Hโฒ), Pielou evenness (J), and Berger-Parker dominance (d) from species counts in any sample.
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.
Shannon Diversity Index Calculator
Calculate Shannon diversity Hโฒ, Pielou evenness Jโฒ, species richness, total abundance, and Simpson diversity (1 โ D) from comma-separated species counts.
๐ฆฌ Biology
Hardy-Weinberg Equilibrium Calculator
Solve pยฒ + 2pq + qยฒ = 1 for any of p, q, pยฒ, 2pq, or qยฒ. Includes carrier-frequency and population-genetics examples.
Protein Molecular Weight Calculator
Calculate molecular weight from an amino acid sequence using average residue masses.
DNA Codon Calculator
Translate a DNA or mRNA sequence into its amino acid chain using the standard genetic code.
DNA Calculator
Five molecular-biology tools in one: molecular weight (ssDNA / dsDNA), melting temperature (Wallace & nearest-neighbour), GC %, reverse complement, and translation.
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.
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.
๐ Statistics
Percentile Calculator
Percentile rank and inverse percentile with six interpolation methods.
One-Way ANOVA Calculator
Test whether 2-10 group means differ significantly using one-way ANOVA.
Hypothesis Test Calculator
One-proportion z-test and one-sample t-test (or z-test with known ฯ) for means, test statistic, p-value, critical value, and confidence interval.
Correlation Coefficient Calculator
Pearson r, Spearman ฯ, and Kendall ฯ for paired data.
Chi-Square Test Calculator
Chi-square test for independence or goodness of fit with observed vs expected frequencies.
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 = ฮฑ + ฮฒยทx to paired X and Y data with slope, intercept, Rยฒ, r, t, p-value, CI, prediction interval, residuals and scatter plot.
Poisson Distribution Calculator
Compute Poisson PMF, CDF, mean, variance, and quantile for a rate ฮป.
๐ฒ cat.generator
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 Date Generator
Generate random dates within any range, with weekend, weekday, and date exclusions.
Lorem Ipsum Generator
Generate placeholder text for any layout.
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.
Glitch Text Generator
Turn any text into Zalgo glitch text using combining Unicode marks. Pick an intensity from mild to total chaos.
Invisible Character Generator
Generate and copy invisible Unicode characters (zero-width space, joiner, soft hyphen) for testing, design, and watermarking.
Leetspeak Translator
Convert text to leetspeak (1337) with Classic, Mild, and Heavy intensity levels for gamer tags, bios, and aesthetic captions.
Mocking SpongeBob Text Generator
Convert any text into the alternating-case mocking SpongeBob meme style with adjustable intensity and a re-roll button.
Upside Down Text Flipper
Flip any text upside down using Unicode characters (uสopวpแดsdn style). Free online text flipper with copy button. No signup.
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.
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