Roman Numeral Converter
Numbers to Roman numerals and back, with each letter's value shown.
How Roman numerals work
Seven letters carry values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Letters add from largest to smallest, except six subtractive pairs where a smaller letter before a larger one subtracts: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900. So 1994 is M CM XC IV: 1000+900+90+4.
The standard-form rules
A letter repeats at most three times (III yes, IIII no), V, L and D never repeat, and only the six pairs above subtract. That makes every number from 1 to 3999 have exactly one standard spelling. Clock faces famously break the rule with IIII for 4, a tradition older than the standardization.
Common years
1990 = MCMXC. 1994 = MCMXCIV. 2000 = MM. 2020 = MMXX. 2024 = MMXXIV. 2025 = MMXXV. 2026 = MMXXVI. Film credits and Super Bowls keep the system alive: Super Bowl LX is number 60.