Roman Numerals Converter

Convert numbers to Roman numerals and back. Direction is auto-detected, range 1–3999.

Result
MMXXIV

The Roman numeral converter works in both directions. Enter an Arabic number (1–3999) and get its Roman numeral form (for example, 2024 → MMXXIV), or enter Roman numerals and get the ordinary number back. The direction is detected automatically based on what you type.

This comes up more often than you'd expect: centuries and millennia in history (the 21st century, written XXI), numbering chapters, volumes, acts and clauses, clock faces, dates on monuments, and movie credits. Converting "MCMLXXXIV" in your head isn't easy, but the tool does it instantly.

The maximum is 3999 (MMMCMXCIX): the classical notation doesn't use symbols larger than M, so bigger numbers would require a bar drawn over the digits, which isn't part of standard notation. The tool validates the notation (invalid combinations like IIII or VV are rejected), and case doesn't matter. Everything is computed right in your browser.

Frequently asked questions

Classical Roman notation uses symbols up to M (1000); 3999 (MMMCMXCIX) is the largest number expressible without a bar over the digits, which denotes multiplication by 1000.
Yes. Invalid combinations (such as IIII or VV) are rejected — only the canonical form is accepted.
No, you can type in either lowercase or uppercase letters.

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