How Roman Numerals Work
Roman numerals use seven letters โ I, V, X, L, C, D, M โ for 1, 5, 10, 50, 100, 500, and 1000. Values are normally added left to right, but a smaller value before a larger one means subtraction: IV is 4, IX is 9, XL is 40, CM is 900.
The Subtractive Rule
- Only I, X, and C can be used subtractively (IV, IX, XL, XC, CD, CM).
- V, L, D are never subtracted.
- No symbol repeats more than three times in a row (so 4 is IV, not IIII).
Converting Step by Step
To convert 2026: take the largest symbol that fits โ M (1000) twice leaves 26; then X (10) twice leaves 6; then V (5) leaves 1; then I. Result: MMXXVI. The converter above shows this greedy breakdown for every number, and reverses the process just as easily.
Where You Still See Them
Clock faces, book chapters, movie sequels, monarch names (Elizabeth II), and sporting events (Super Bowl LX) all use Roman numerals. For other bases, try our binary/hex converter or spell numbers out with the number to words converter.