Roman Numeral Converter
Numbers to numerals and numerals to numbers, either way round.
Roman Numeral Converter
| Symbol | Value | Count | Subtotal |
|---|
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| Symbol | Value |
|---|---|
| C | 100 |
| D | 500 |
| M | 1000 |
| IV | 4 |
The Seven Letters
I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1000. Every Roman numeral is built from those seven and nothing else, which is why the system struggles past a few thousand.
The Subtraction Rule
A smaller letter before a larger one is subtracted rather than added, which is why IV is 4 and IX is 9. Only six pairs are permitted: IV, IX, XL, XC, CD and CM. Anything else, such as IL for 49, is not valid, however sensible it looks. 49 is XLIX.
The rule exists to stop four identical letters in a row, so IIII gives way to IV.
What the System Cannot Do
There is no zero, no way to write a negative, and no fraction. The largest value writable with the standard seven letters is 3999, or MMMCMXCIX. Above that, historical texts used a bar over a letter to multiply it by a thousand, a convention this converter does not use because it renders inconsistently.
Where You Still Meet Them
Clock faces, book chapters, film copyright lines, monarch and pope names, and the Super Bowl. Reading them is a more useful skill than writing them, which is why the reverse direction on this page gets more use than the forward one.