🏛️ Roman Numeral Converter

What This Tool Does

This tool converts between regular numbers and Roman numerals, in both directions. Enter a number and it gives you the Roman numeral; enter a Roman numeral and it gives you the number. It handles the rules of Roman numeral notation automatically, so you get the correct result without having to remember how the system works — useful for dates, names, outlines, and anywhere Roman numerals appear.

Roman numerals are still all around us — on clocks, in book chapters, in movie credits, on monuments, and in the names of monarchs and events — but few people can read or write them fluently. This converter bridges that gap, translating instantly in either direction so you never have to puzzle over what MCMXCIV means or how to write a number in Roman form.

How Roman Numerals Work

Roman numerals use seven letters, each with a value: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, and M is 1,000. Numbers are built by combining these, generally from largest to smallest, adding the values together — so XV is 15 (10 + 5) and CCC is 300. The system has no zero and no place value in the way our decimal system does; it is purely additive, with one important twist.

That twist is subtractive notation, which keeps numerals from getting too long. When a smaller value sits before a larger one, it is subtracted rather than added: IV is 4 (5 − 1) rather than IIII, IX is 9, XL is 40, and CM is 900. This is why a year like 1994 becomes MCMXCIV — M (1000), CM (900), XC (90), IV (4). The rules about which subtractions are allowed are specific, and getting them right by hand is fiddly, which is exactly what makes an automatic converter handy.

Quick Tips

• The seven letters are I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000).
• A smaller numeral before a larger one is subtracted — IV is 4, IX is 9, CM is 900.
• Roman numerals have no zero and are built largest to smallest, with subtraction as the exception.
• For dates in film credits, converting is the quick way to decode the copyright year.

Frequently Asked Questions

How do Roman numerals work?

Seven letters carry values — I, V, X, L, C, D, M — and are combined, generally largest to smallest, adding up. The exception is subtractive notation, where a smaller numeral before a larger one is subtracted, as in IV for 4.

What is subtractive notation?

It is the rule that a smaller value placed before a larger one is subtracted, keeping numerals shorter. IV is 4 (not IIII), IX is 9, XL is 40, and CM is 900. The converter applies these rules automatically.

What is MCMXCIV?

It is 1994: M (1000) + CM (900) + XC (90) + IV (4). Reading it requires applying the subtractive rules, which is exactly the kind of thing this converter does instantly.

Do Roman numerals have a zero?

No. The Roman system has no symbol for zero and no place value like our decimal system. It is an additive system with subtractive exceptions, which is part of why large numbers can look complex.