Roman Numeral Converter
Convert integers to Roman numerals and Roman numerals back to integers. Supports 1 to 3999. Bidirectional, instant, free — no signup required.
What is Roman Numeral Converter?
Roman numerals are a numeral system that originated in ancient Rome. They use combinations of seven Latin letters to represent values: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are formed by combining these symbols and adding or subtracting their values. The subtractive notation — placing a smaller value before a larger one — is used for 4 (IV), 9 (IX), 40 (XL), 90 (XC), 400 (CD), and 900 (CM).
Roman numerals are still used today for clock faces, chapter numbers in books, movie sequel numbering, Olympic Games years, Super Bowl numbering, monarchy names (King Charles III), and some formal document outlines. Understanding them is useful for reading historical texts, legal documents, and recognising date notation in some contexts.
This tool converts in both directions: enter a number to get the Roman numeral, or enter a Roman numeral to get the decimal equivalent. The range is 1 to 3999 — standard Roman numerals don't have a conventional representation for zero or numbers above 3999.
How to use
Frequently asked questions
Standard Roman numerals go up to 3999 (MMMCMXCIX). Numbers 4000 and above would require the vinculum (overline) notation, which is not in common use.
IV uses subtractive notation: placing I before V means subtract 1 from 5. Both IV and IIII appear historically, but IV is the modern standard.
Yes. All conversions run locally in your browser. Nothing is sent to any server.
MMXXVI = 2000 + 20 + 6 = 2026. M=1000, MM=2000, XX=20, VI=6.