Basic Roman numeral symbols
| Numeral | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Conversion rules
When the same symbol repeats, you add the values (e.g. III = 3). When a smaller value comes before a larger one, you subtract it (e.g. IV = 5 − 1 = 4, IX = 10 − 1 = 9). This subtractive notation is used for 4 (IV), 9 (IX), 40 (XL), 90 (XC), 400 (CD), and 900 (CM).
Why does this only support 1–3999?
M (1000) is the largest single Roman numeral symbol, and traditional notation can't represent numbers beyond 3999 (MMMCMXCIX). Larger numbers use a special notation with a bar drawn over a symbol to multiply it by 1000, but that's hard to represent in plain text, so this converter doesn't support it.
Frequently Asked Questions
Why is there no zero in Roman numerals?
Ancient Rome, when this numeral system was developed, didn't yet widely use the concept of zero in its number system. The concept of zero was later developed in India and spread worldwide through the Arabic numeral system.
Why are Roman numerals used in movies and books?
They're still used today to give a traditional, elegant feel — for example, a film's production year (MMXXIV = 2024), chapter numbers in books, or clock faces.