Type a number between 1 and 3999 to get the Roman numeral, along with the value of each part that makes it up.
In Roman numerals
Built from
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Seven letters carry all the values: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1000. Writing a number means taking the largest value that fits, writing its letter, subtracting it, and repeating until nothing is left. For 2026 that gives M, another M, then X, X, V and I: MMXXVI. Letters run from the largest on the left to the smallest on the right, which is why the order is never a matter of taste.
The exception is subtraction, and there are exactly six cases: CM is 900, CD is 400, XC is 90, XL is 40, IX is 9 and IV is 4. A smaller letter placed before a larger one is taken away from it rather than added. Only I, X and C are ever subtracted, and only from the two values directly above them, which is why the list stops at six. It also means 49 is XLIX and never IL, however tempting the shorter form looks.
That rule is what keeps four of the same letter from appearing in a row. Four is IV rather than IIII, nine is IX rather than VIIII, and forty is XL rather than XXXX. V, L and D never repeat at all, because two of any of them would simply be the next letter up: VV would be X, and no one writes it.
You will still see IIII on clock faces, and that is not a mistake in the clock. Watchmakers settled on it long before the notation was standardised, and it survives for a visual reason: IIII at four balances VIII at eight across the dial, so the numerals look evenly weighted. It is a convention of the trade, not of the number system, and the two have simply lived side by side for centuries.
The standard system stops at 3999, which is MMMCMXCIX. Anything larger would need a fourth M, and four repeats are not standard notation. The Romans handled bigger numbers with a vinculum, a bar over a letter that multiplies it by a thousand, so V with a bar is 5000. That is a different system, it renders badly in most fonts, and it rarely survives a copy and paste, so this converter stops where the standard one does.
3999, written MMMCMXCIX. The next number up would need four M in a row, and four repeats are not standard notation. Larger values used a vinculum, a bar over a letter multiplying it by a thousand, but that is a separate system and is not covered here.
Because a smaller letter before a larger one is subtracted from it, so IV is 5 minus 1. The rule exists to avoid four identical letters in a row. Clock faces are the famous exception: watchmakers use IIII for balance with the VIII opposite, a convention from the trade rather than from the numeral system.
MMXXVI. Two thousand is MM, twenty is XX, five is V and one is I, and the letters go in descending order of value.
Only I, X and C are ever subtracted, and only from the two values immediately above them. I can come before V and X, so IV and IX exist, but IL is not a legal form. 49 is built as 40 plus 9, which is XL followed by IX.
No. The system counts things and has no symbol for nothing, so it starts at I. Roman writers who needed the idea used the word nulla instead of a numeral.
No. The conversion runs in your browser in a few lines of JavaScript. There is no server to send it to: this site is static files.
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