Roman Numeral Converter
Go both ways between everyday numbers and Roman numerals, from I all the way up to MMMCMXCIX.
How it works
Roman numerals stack seven letters — I, V, X, L, C, D, and M — for 1, 5, 10, 50, 100, 500, and 1000. You add them left to right, so XVI is 10 + 5 + 1, which is 16.
When a smaller letter sits before a larger one, you subtract it. That's why 4 is IV and 9 is IX rather than IIII or VIIII. The converter uses this standard subtractive form both directions.
There's no zero and no symbol above M in the classic system, so 3999 (MMMCMXCIX) is the ceiling here. Anything below 1 or above that returns a dash instead of a made-up numeral.
Frequently asked questions
What is 2026 in Roman numerals?
2026 is MMXXVI — that's MM for 2000, XX for 20, and VI for 6. Type it into the number field and the converter spells it out the same way.
Why can't I go past 3999?
The standard letters stop at M for 1000, and stacking four of them (MMMM) breaks the usual rule of no more than three in a row. Larger numbers need a bar-over notation that isn't part of everyday use.
How does subtractive notation work?
A smaller value in front of a larger one gets subtracted, so IV is 4 and XC is 90. It keeps numerals short and is why you won't see IIII on a properly written clock face — except, oddly, some clocks.
Will it catch a bad numeral?
Typing something like IIII or VX returns a dash, since those aren't valid. The converter checks that your input matches the one correct spelling before it hands back a number.