A Roman numeral converter converts between standard numbers and Roman numerals (I, V, X, L, C, D, M).
Convert numbers to Roman numerals and back instantly. Supports 1–3,999 with a detailed breakdown.
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |
| Pair | Value | Meaning |
|---|---|---|
| IV | 4 | 5 − 1 |
| IX | 9 | 10 − 1 |
| XL | 40 | 50 − 10 |
| XC | 90 | 100 − 10 |
| CD | 400 | 500 − 100 |
| CM | 900 | 1000 − 100 |
Rule 1 — Additive: When a smaller or equal value follows a larger one, add them. VI = 5+1 = 6. XV = 10+5 = 15. LXII = 50+10+1+1 = 62.
Rule 2 — Subtractive: When a smaller value precedes a larger one, subtract it. IV = 5−1 = 4. IX = 10−1 = 9. XL = 50−10 = 40. CM = 1000−100 = 900.
Rule 3 — No Four in a Row: The same symbol never repeats more than 3 times consecutively. Instead of IIII, use IV. Instead of XXXX, use XL.
Rule 4 — Read Left to Right: Start from the leftmost (largest) symbol and work right. If the next symbol is smaller, add it. If larger, subtract it.
Example: MCMXCIV = M(1000) + CM(900) + XC(90) + IV(4) = 1994
Roman numerals are a numeral system originating in ancient Rome, using combinations of letters from the Latin alphabet: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). They are still used today in clock faces, book chapters, movie sequels, and royal names.
Roman numerals are read by adding values from left to right, except when a smaller value precedes a larger one, in which case you subtract. For example: VI = 5+1 = 6, but IV = 5−1 = 4. The subtractive pairs are IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900).
The standard Roman numeral system represents numbers from 1 to 3,999. The largest standard Roman numeral is MMMCMXCIX (3,999). For larger numbers, an overline is sometimes used to indicate multiplication by 1,000, but this is not part of the standard system.
Roman numerals use subtractive notation to avoid four consecutive identical characters. Instead of IIII (4), the smaller value I is placed before V to indicate subtraction: IV = 5−1 = 4. Similarly, IX = 9 (10−1), XL = 40 (50−10), and so on.
2024 is converted by breaking it into place values: 2000 = MM, 20 = XX, 4 = IV. Combined: MMXXIV. The breakdown is 1000+1000+10+10+(5−1) = 2024.