How to use the Roman numerals chart
- Scroll down the chart, or type a number (14), a numeral (XL) or a year into the filter box. Any number from 1 to 3999, or any valid numeral, is converted above the chart even if it isn't listed.
- Below 100 come the hundreds, the thousands and a set of years people often look up, ending at 3999.
- Click a numeral to copy it.
The seven symbols and the subtractive rule
| I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|
| 1 | 5 | 10 | 50 | 100 | 500 | 1000 |
Symbols are normally written from largest to smallest and added up, so LXVI is 50 + 10 + 5 + 1 = 66. To avoid writing four of the same symbol in a row, a smaller symbol placed before a larger one is subtracted:
| Pair | Value | Instead of |
|---|---|---|
| IV | 4 | IIII |
| IX | 9 | VIIII |
| XL | 40 | XXXX |
| XC | 90 | LXXXX |
| CD | 400 | CCCC |
| CM | 900 | DCCCC |
These six are the only pairs allowed. V, L and D are never subtracted.
Why the chart stops at 3999
3999 is MMMCMXCIX. Writing 4000 would need four Ms in a row, which breaks the rule that no symbol repeats more than three times. Larger numbers were written with a bar over a numeral to multiply it by 1000, but there is no standard way to type that bar, so most charts and converters stop at 3999. For any number up to there that isn’t listed, use the Roman numeral converter.
IIII on clock faces
Look at a clock with Roman numerals and you will often see 4 written as IIII rather than IV. It’s a long-standing tradition among clockmakers. People have offered several reasons, such as making the 4 balance the heavy VIII on the other side of the dial, but there’s no single agreed answer. Either way, it’s a convention of clock design and not a mistake.