What are Roman numerals?

Roman numerals are a numeral system that uses letters from the Latin alphabet: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). They were the standard number system in ancient Rome and medieval Europe.

How do Roman numerals work?

Numbers are formed by combining the 7 basic numerals. When a smaller numeral appears before a larger one, it's subtracted: IV = 4 (5−1), IX = 9 (10−1), XL = 40 (50−10). Otherwise numerals are added: VIII = 8 (5+1+1+1), XII = 12 (10+1+1).

What is the range of numbers the converter supports?

The converter handles numbers from 1 to 3,999. Beyond 3,999, traditional Roman numerals require additional symbols (a bar over a numeral multiplies it by 1,000) which aren't covered by the standard 7-symbol system.

Where are Roman numerals used today?

Roman numerals appear in: movie copyright years (MMXXIV = 2024), Super Bowl numbering, book prefaces, chapter numbers, clock faces, monarchs and popes (King Charles III, Pope Francis), and formal legal and academic contexts.

What does MMXXVI mean?

MM = 2000, XX = 20, VI = 6. So MMXXVI = 2026.

Is my input stored anywhere?

No. All conversion happens in your browser. Your input never reaches any server.

Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals to numbers online. Free Roman numeral converter - instant results.

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Number (1–3999)

How to Use

Three steps to get started

Choose direction

Convert a number to Roman numerals, or parse Roman numerals to a number.

Enter your value

Type a number (1–3999) or a Roman numeral string like XLII or MMXXVI.

See the result

The converted value appears instantly. Click Copy to use it anywhere.

About This Tool

Convert numbers to Roman numerals instantly

Roman numerals are an additive-subtractive numeral system that originated in ancient Rome around 500 BCE, representing values with seven letters borrowed from the Latin alphabet rather than positional digits. Unlike the Hindu-Arabic system we use today, Roman numerals have no symbol for zero and no concept of place value - XI and IX use the same two letters but mean 11 and 9 because of order, not position.

The seven symbols and their values:

I = 1
V = 5
X = 10
L = 50
C = 100 (from centum)
D = 500
M = 1000 (from mille)

The governing rule is subtractive notation: when a smaller symbol precedes a larger one, subtract it. Only six subtractive pairs are valid in standard form -IV (4), IX (9), XL (40), XC (90),CD (400), and CM (900). Everything else is additive and written largest to smallest, so 1994 is MCMXCIV: M (1000) + CM (900) + XC (90) + IV (4).

Common mistakes when writing Roman numerals

The most frequent error is inventing subtractive pairs that standard form does not allow. IL for 49 looks logical but is invalid - the correct form isXLIX (XL + IX). Likewise 99 is XCIX, not IC. A second rule: I, X, C, and M may repeat up to three times consecutively, but V, L, and D never repeat, because VV would simply be X. That is why 4 isIV and not IIII in strict notation - though clock faces famously break this rule and print IIII at the four o'clock position for visual balance against the VIII opposite it.

The system tops out at 3,999 (MMMCMXCIX) because M cannot repeat a fourth time. Larger values historically required the vinculum, a bar drawn over a numeral to multiply it by 1,000, so V̄ meant 5,000. This converter covers the standard 1–3,999 range in both directions: type a number to get its numeral, or paste a numeral like MMXXVI to read it back as 2026.

Everything is computed locally in JavaScript on the page you are reading - no request is made to any server, so the numbers you convert stay on your machine.

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