Roman and Arabic numerals: How we calculate
How we calculate
We use subtractive pairs IV, IX, XL, XC, CD and CM and accept only input matching the chosen notation. Supported range is 1–5999; above 3999 we use an extension with repeated M. Other notations exist for larger Roman numerals.
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Worked example
2026 = 2,000 + 20 + 6 = MMXXVI. IV means 4; IIII is not canonical in this calculator’s chosen notation and is rejected. Repeated M for larger numbers is a separately supported extension.