Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals to numbers, from 1 to 3999. Shows how each numeral is built.
Roman Numeral Converter
How Roman Numerals Work
Roman numerals build a number out of seven letters - I, V, X, L, C, D, M - worth 1, 5, 10, 50, 100, 500, and 1000. You read them left to right and add the values up, working from the biggest piece to the smallest. So MMXXIV is 1000 + 1000 + 10 + 10 + 4.
The one twist is subtraction: when a smaller letter sits before a larger one, you subtract it. That is why 4 is IV (one before five) instead of IIII, and 9 is IX. This keeps numerals short and is the rule the tool uses in both directions.
How to Use It
- Choose the direction: number to Roman, or Roman to number.
- Type the number (1 to 3999) or the Roman numeral.
- Read the conversion and how it breaks down.
The Building Blocks
| Numeral | Value | Numeral | Value | |
|---|---|---|---|---|
| I | 1 | C | 100 | |
| V | 5 | D | 500 | |
| X | 10 | M | 1000 | |
| L | 50 |
The subtractive pairs are IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900).
Examples
| Number | Roman numeral |
|---|---|
| 4 | IV |
| 14 | XIV |
| 49 | XLIX |
| 2024 | MMXXIV |
| 3999 | MMMCMXCIX |
Why It Stops at 3999
Standard Roman numerals only go up to 3999 (MMMCMXCIX). Larger values needed a bar over a letter to mean “times 1000,” which is hard to type and rarely used, so this converter keeps to the everyday range.