Roman Numeral Converter
Convert between Roman numerals and Arabic numbers instantly. Supports numbers from 1 to 3,999 with step-by-step breakdown.
Roman Numeral Reference
How Roman Numerals Work
Roman numerals use seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
Additive principle: Symbols placed left to right from largest to smallest are added together. Example: VIII = 5 + 3 = 8.
Subtractive principle: A smaller symbol placed before a larger one is subtracted. Example: IV = 5 − 1 = 4, XC = 100 − 10 = 90.
Valid subtractive pairs: IV (4), IX (9), XL (40), XC (90), CD (400), CM (900).
The maximum value representable with standard Roman numerals is 3,999 (MMMCMXCIX).
Frequently Asked Questions
Using standard notation, the largest number is 3,999, written as MMMCMXCIX. Numbers 4,000 and above require a vinculum (overline) notation which is not standard.
IV uses the subtractive principle — I (1) before V (5) means 5−1=4. This makes numerals shorter and clearer. Similarly IX=9, XL=40, XC=90, CD=400, CM=900.
Enter the year in the number input above and get the Roman numeral instantly. For example, 2024 = MMXXIV.
Yes! Roman numerals are used in clock faces, movie sequels, Super Bowl editions, book chapters, monarchs (King Charles III), and official documents.