Roman numerals build numbers from seven letters — I, V, X, L, C, D, M — written largest to smallest and added together, with six subtractive pairs (IV, IX, XL, XC, CD, CM) handling the 4s and 9s. So 2024 is MMXXIV and 1994 is MCMXCIV. There's no zero and no negatives; standard numerals run 1–3999. This converter goes both ways and shows the symbol-by-symbol breakdown.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: standard (modern) Roman numeral rules, recomputed in code.
The rules
Read left to right: each symbol normally adds to the total, but a smaller symbol immediately before a larger one is subtracted. Only six subtractive pairs are allowed, which is why 4 is IV and 90 is XC. To build a numeral from a number, you greedily take the largest symbol or pair that fits and repeat. The repetition cap (three of any of I, X, C, M; never V, L, D) guarantees a single standard spelling.
Worked example — 2024 and 1994
Scenario: build two years.
2024 = MMXXIV: two thousands, two tens, and the subtractive four. 1994 = MCMXCIV stacks three subtractive pairs (CM, XC, IV) and is a classic "tricky" numeral. Reading backward, the converter walks the letters and applies the subtraction rule, so MMXXIV returns 2024 and XLIX returns 49. Input is case-insensitive, so "mmxxiv" works too.
Frequently Asked Questions
I 1, V 5, X 10, L 50, C 100, D 500, M 1000. Combined largest-to-smallest they add: MXV = 1015.
A smaller symbol before a larger one subtracts. Six pairs: IV 4, IX 9, XL 40, XC 90, CD 400, CM 900. 49 = XLIX.
MMXXIV: 2000 = MM, 20 = XX, 4 = IV. Take the largest symbol/pair that fits, repeat.
No — no zero, no negatives. Standard numerals run 1–3999, so this tool accepts that range.
No — I, X, C, M repeat at most three times (4 = IV, not IIII); V, L, D never repeat. The tool gives the standard form.