MATH TOOL
Roman Numeral Converter
Convert between Roman numerals and regular numbers.
Roman numeral
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About this tool
Convert whole numbers to Roman numerals, or Roman numerals back to regular numbers. Roman numerals are supported for values from 1 to 3999 — the traditional system doesn't have standard symbols beyond that range.
Frequently asked questions
- Why is there a maximum of 3999?
- Standard Roman numerals use combinations of I, V, X, L, C, D, and M, with no single symbol for numbers of 5,000 or more — so 3999 (MMMCMXCIX) is the largest value the traditional system represents cleanly.
- Is there a Roman numeral for zero?
- No — the Roman numeral system has no symbol for zero, so it can only represent whole numbers from 1 upward.
- What if I type an invalid Roman numeral?
- A hint explains the input isn't a valid Roman numeral sequence, instead of guessing at a number.