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Home › Roman Numeral Converter

Roman Numeral Converter

Convert numbers to Roman numerals or Roman numerals to numbers — supports 1 to 3,999.

Number → Roman Numeral

Roman Numeral → Number

Roman Numeral Reference

Symbol Value Example
I1III = 3
V5IV = 4
X10XL = 40
L50LX = 60
C100CD = 400
D500DC = 600
M1,000MM = 2,000
Also try: Number to Words · Number Base Converter
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Quick Answer

Type a number (1–3,999) in the top box to get its Roman numeral, or type a Roman numeral in the bottom box to get the number. Both converters update as you type.

How Roman numerals work

Roman numerals use seven letters: I, V, X, L, C, D, and M. Numbers are formed by combining these letters — generally largest to smallest from left to right, adding their values. When a smaller numeral appears before a larger one, it's subtracted (the subtractive principle).

The subtractive principle

Six subtractive combinations are valid: IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900). Only I, X, and C can be used subtractively. This rule prevents awkward repetitions like IIII for 4 or VIIII for 9.

Where Roman numerals are used today

Roman numerals appear on clock faces, movie copyright dates, chapter and section numbers in books, Super Bowl numbering, Olympic Games, royal monarchs (Elizabeth II, Henry VIII), and architectural cornerstones. The year 2024 in Roman numerals is MMXXIV.

Frequently asked questions

What are Roman numerals?

Roman numerals are a numeral system originating in ancient Rome using letters from the Latin alphabet: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). They are still used today for clock faces, chapter numbers, movie sequels, and formal documents.

What is the largest Roman numeral?

In standard notation, the largest Roman numeral is MMMCMXCIX (3,999). Numbers above 3,999 traditionally required a vinculum (bar over the letter) to multiply by 1,000. This converter supports 1 to 3,999.

Why don't Roman numerals have a zero?

The concept of zero as a number didn't exist in ancient Rome. Roman numerals were used for counting and recording quantities, where zero (nothing) was not needed. The numeral system was designed around additive and subtractive combinations of fixed values.

How do you write 4 in Roman numerals?

4 is written as IV in Roman numerals. This uses the subtractive principle: I (1) placed before V (5) means 5 minus 1 = 4. Similarly, 9 is IX, 40 is XL, 90 is XC, 400 is CD, and 900 is CM.