Free Online Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
Standard Roman numerals use values from 1 to 3,999.
Uppercase or lowercase letters are accepted. Subtractive pairs such as IV and IX are supported.
Roman numerals read left to right. A smaller value before a larger one is subtracted, as in IV (4) and CM (900).
Common Roman numerals
About the Roman Numeral Converter
Roman numerals use seven letters: I, V, X, L, C, D, and M. They were the standard number system across the Roman Empire and remain in use for clock faces, book chapters, film sequels, monarch names, and event numbering such as the Super Bowl.
Roman numeral values
- I = 1, V = 5, X = 10, L = 50
- C = 100, D = 500, M = 1,000
Subtractive notation
Instead of repeating a smaller symbol four times, Roman numerals place it before the larger value. For example 4 is IV, 9 is IX, 40 is XL, and 900 is CM. Standard conversion here supports values from 1 to 3,999.
Frequently asked questions
Why is there no zero in Roman numerals?
The classical system had no symbol for zero. Values were counted with positive symbols only, so zero has no standard Roman numeral form.
What is the largest number this tool converts?
3,999, written as MMMCMXCIX. Larger values traditionally use overbars or different notation that common keyboards cannot represent.
Why does IIII appear on some clocks instead of IV?
Clockmakers historically used IIII for visual symmetry with VIII on the opposite side. Both forms appear, but IV is the standard subtractive notation.