Roman numerals converter
Roman numerals still appear on clock faces, book chapters, movie sequels, events like the Olympics, and in school syllabuses. This Roman numerals converter works both ways: type a number to get its Roman numeral, or type a Roman numeral to get the number. It checks that numerals follow the standard rules and explains how each part adds up.
How to use it
- Type a number from 1 to 3,999, or a Roman numeral such as MCMXCIV.
- The conversion and its breakdown appear instantly.
Example
2026 is MMXXVI: MM (2000) + XX (20) + VI (6). MCMXCIV is 1994: M (1000) + CM (900) + XC (90) + IV (4). A clock usually shows 4 as “IIII” for visual balance — a traditional exception. Converting between binary, hex and decimal instead? Use thenumber base converter.
Frequently asked questions
How do Roman numerals work?
Seven letters stand for values: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Letters are added from largest to smallest (VIII = 8), but a smaller letter before a larger one is subtracted (IV = 4, IX = 9, XC = 90, CM = 900).
What is the largest Roman numeral?
With standard letters, 3,999 (MMMCMXCIX). Larger numbers were written with a bar over a letter to multiply it by 1,000, which isn’t used in everyday writing.
Is there a Roman numeral for zero?
No. The Roman system had no zero; it was introduced to Europe later through Indian and Arabic mathematics.
Why was my numeral rejected?
The converter only accepts standard forms. “IIII” should be IV, and “IC” (99) should be XCIX, because only I, X and C can be subtracted, and only from the next two larger letters.