Convert Numbers to Roman Numerals, and Back
Type a number or Roman numerals: the direction is detected automatically and the conversion appears instantly, with the calculation broken down and the correct form if the numeral isn't written the standard way.
- From 1 to 3,999
- Direction detected automatically
- Step-by-step breakdown
- Mistakes flagged
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How to convert Roman numerals?
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Type a number or letters
Enter a number between 1 and 3,999, like “2026”, or Roman numerals, like “MCMXC”: the tool works out the direction of the conversion by itself.
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Read the breakdown
The result appears with the calculation broken down: MCMXC = M + CM + XC = 1000 + 900 + 90, which is 1990.
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Check the spelling
If the numeral isn't standard, like “IIII” or “VX”, the tool flags it and gives you the correct form to use.
Everything to read and write Roman numerals
Both directions
One field for both conversions: type digits to get the Roman numeral, or Roman letters to get the number.
Calculation explained
Every result is broken down symbol by symbol, so you can understand the conversion or check your homework.
Mistakes spotted
“IIII” or “VX” are flagged as non-standard, with the correct form: “IIII”, for example, is written IV.
Chart and examples
The chart of the seven symbols, I, V, X, L, C, D and M, stays in view, and examples of years can be tried in one click.
The rules of Roman numerals
Roman numerals use seven symbols: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. They're written from largest to smallest and added up: VIII = 5 + 1 + 1 + 1 = 8, MDCC = 1,700. A symbol placed before a larger one is subtracted, but only in six cases: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). Only I, X and C can be subtracted, and only from the next two larger symbols: 99 is XCIX, not IC. Finally, the same symbol is never repeated more than three times in a row (40 is XL, not XXXX), and V, L and D are never repeated.
Writing a year or a date in Roman numerals
To convert a number, split it into thousands, hundreds, tens and ones, then convert each part. 1990 = 1,000 + 900 + 90, so M + CM + XC = MCMXC. 2026 = 2,000 + 20 + 6, so MMXXVI. 1776 gives MDCCLXXVI and 1066 gives MLXVI. In English, Roman numerals are used for monarchs and popes (Elizabeth II, Charles III), world wars (World War II), sequels and events (Super Bowl LX was played in 2026), copyright years at the end of films and TV shows, book chapters and prefaces, outlines, clock faces and, more and more, tattoos of a meaningful date. For a date tattoo, convert the day, month and year separately: July 4, 1776 becomes VII.IV.MDCCLXXVI.
Why no zero and no numbers above 3,999?
The Romans had no symbol for zero: their system was used to record quantities, and there's no Roman numeral for 0, or for negative or decimal numbers. The largest number you can write with the standard rules is 3,999, or MMMCMXCIX, since M can't be repeated more than three times. For very large numbers, a bar was once placed over a symbol to multiply it by 1,000, a notation that's now rare. Another curiosity: many clocks show IIII instead of IV for 4. That's a clockmaking tradition, not the standard form, and the tool will point it out. To write a number out in words, use “Number to Words”.
Frequently Asked Questions
How do you write 2026 in Roman numerals?
MMXXVI: MM for 2,000, XX for 20 and VI for 6. Likewise, 2025 is MMXXV and 2000 is simply MM.
4 in Roman numerals: IV or IIII?
The standard form is IV (5 − 1). IIII appears on many clock faces by tradition, but it isn't the correct form; likewise, 9 is IX, not VIIII.
How do you write 1999 in Roman numerals?
MCMXCIX: M (1,000) + CM (900) + XC (90) + IX (9). The shortcut MIM is wrong, because I can only be subtracted from V and X.
What century are we in, in Roman numerals?
The 21st century, written XXI: X + X + I = 21. It began on January 1, 2001 and will end on December 31, 2100.
Why is there no zero in Roman numerals?
The Roman system has no symbol for zero: it was used to record quantities, and zero only reached Europe much later, with Arabic numerals. So only whole numbers from 1 upward can be written in Roman numerals.