Roman Numeral Converter Online Free

How to convert Roman numerals

Type an ordinary number to get its Roman form, or a Roman numeral to get the value back. Conversion runs both ways as you type.

How the system works

Seven letters carry all the values: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1,000. Symbols are written from largest to smallest and added together, so MMXXVI is 1,000 + 1,000 + 10 + 10 + 5 + 1, which is the year 2026.

Subtractive notation is the exception that trips people up. When a smaller symbol precedes a larger one, it is subtracted: IV is 4, IX is 9, XL is 40, XC is 90, CD is 400, CM is 900. Only those six combinations are valid, which is why 1999 is MCMXCIX and never IMM. Each part of the number is expressed separately.

Where you still meet them

• Film and television copyright dates in closing credits, a convention that has outlived its original purpose of making a production's age less obvious.
• Monarchs and popes, such as Elizabeth II and Louis XIV.
• Book front matter, where prefaces are numbered separately in lowercase roman.
• Clock faces, watch bezels and building cornerstones.
• Super Bowl numbering, and legal documents with numbered clauses.

Frequently asked questions

Is there a zero?

No. The system has no symbol for zero and no way to write negative numbers or fractions of a unit, one of the reasons it was displaced for arithmetic.

What is the largest number I can write?

Standard notation runs to 3,999 (MMMCMXCIX). Beyond that, historical systems used bars over letters to multiply by a thousand, a convention this tool does not use.

Why is 4 sometimes written IIII on clocks?

Tradition and visual balance. Clock faces frequently use IIII opposite VIII, and it is considered correct in that context.

Is anything uploaded?

No. Conversion happens in your browser.