How to convert Roman numerals
- To get a Roman numeral, type the regular number in the first field.
- To get a number, type the Roman numeral in the second field.
- The other field fills in by itself and you see the result below.
- Use the reference chart to check the most common values.
How Roman numerals work
Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. Letters are added from largest to smallest (XVI = 10 + 5 + 1 = 16). When a smaller letter comes before a larger one, it is subtracted: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400 and CM = 900.
No letter is repeated more than three times in a row: 4 is IV, not IIII, and 40 is XL. With these rules the largest number you can write is 3999 (MMMCMXCIX). For example, 1994 is MCMXCIV: 1000 + (1000 − 100) + (100 − 10) + (5 − 1).
They show up on clocks, book chapters, centuries, the names of kings and popes, and Super Bowl editions. The tool rejects incorrectly written Roman numerals such as IIII or VX.
Good to know
- Only whole numbers from 1 to 3999 are converted: classical Roman numerals had no zero or fractions.
- Old clocks sometimes write IIII for 4; this tool uses the standard form IV.
- You can type Roman numerals in uppercase or lowercase.
Frequently asked questions
How do you write 2026 in Roman numerals?
MMXXVI: MM (2000) + XX (20) + VI (6). Type 2026 in the number field to check it.
How do you write 4 and 9?
4 is IV (5 − 1) and 9 is IX (10 − 1).
Is there a Roman numeral for zero?
No. The Roman system had no zero, which is why the tool starts at 1.
What's the largest number you can write?
Up to 3999 with the standard letters. Beyond that, bars over the letters were used, which aren't included.
Is what I type saved?
No. Everything is converted in your browser.