Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers, from 1 to 3999.
How it works
M = 1000, D = 500, C = 100, L = 50, X = 10, V = 5, I = 1; a smaller symbol before a larger one is subtracted
Roman numerals build numbers by adding symbol values from largest to smallest: M is 1,000, D is 500, C is 100, L is 50, X is 10, V is 5 and I is 1. When a smaller symbol sits before a larger one it is subtracted instead, which is how IV means 4 and XC means 90. The system runs from 1 to 3,999 and has no symbol for zero.
Worked example
The year 2024 becomes MMXXIV: two Ms for 2,000, two Xs for 20, and IV for 4. Reading back, MM (2,000) + XX (20) + IV (4) returns 2,024.
Frequently asked questions
Why do Roman numerals stop at 3,999?
The largest common symbol is M (1,000), and standard notation never repeats a symbol more than three times, so MMMCMXCIX (3,999) is the ceiling. Larger values historically used a bar over a numeral to multiply it by 1,000, which this converter doesn’t use.
What is subtractive notation?
Placing a smaller symbol before a larger one subtracts it: IV is 5 − 1 = 4 and IX is 10 − 1 = 9. Only I, X and C are used this way, and only directly before the next one or two larger symbols.
Is there a Roman numeral for zero?
No — the system has no symbol for zero at all. The idea of zero as a placeholder reached Europe later through Arabic numerals, one reason those replaced Roman numerals for arithmetic.
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This calculator is for educational purposes. Double-check important results before acting on them.