Roman Numeral Converter

100% free · Runs 100% in your browser · No signup needed

Number → Roman Roman → Number

Enter a number (1 - 3999)

Roman numerals go up to 3999 (MMMCMXCIX).

Please enter a whole number between 1 and 3999.

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Enter a Roman numeral

Valid characters: I V X L C D M

Invalid Roman numeral - use only the letters I, V, X, L, C, D, M in a valid combination.

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Sobre Roman Numeral Converter

What is the Roman Numeral Converter?

The Roman Numeral Converter is a free online tool that translates between ordinary numbers and Roman numerals, the ancient numbering system of I, V, X, L, C, D and M. Roman numerals still appear everywhere: clock faces, book chapters, movie sequels, Super Bowl titles, monarch names like Elizabeth II, and formal outlines. Converting by hand is slow and error-prone, especially with subtractive pairs like IV for 4 and CM for 900.

This tool converts in both directions instantly. Enter 2026 to get MMXXVI, or paste MMXXIV to get 2024 back. It validates your input, explains invalid combinations, and handles the full standard range from 1 to 3999, all free in your browser with no signup.

How to Use the Roman Numeral Converter

Enter a number: Type any whole number from 1 to 3999.
Click Convert: The Roman numeral appears instantly with proper subtractive notation.
Go in reverse: Switch modes, paste a numeral like XIV, and get 14 back.
Copy the result: Use the copy button for documents, tattoos designs or titles.
Learn the rules: Read the built-in guide to understand how the symbols combine.

Key Benefits

Two-way translation: Numbers to numerals and numerals back to numbers.
Correct subtractive pairs: Proper IV, IX, XL, XC, CD and CM handling.
Input validation: Invalid numerals like IIII are flagged with explanations.
Instant results: No waiting, conversion happens as you type.
Free with no signup: Unlimited conversions for school, work or fun.

Pro Tips

Remember the values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000 covers everything.
Smaller before larger means subtract: IV is 4 because I before V subtracts 1 from 5.
Double-check tattoos: Roman numeral tattoos are popular and permanent, so verify with the tool twice.
Great for outlines: Use numerals for top-level headings in formal documents and reports.

Frequently Asked Questions

What is the largest number I can convert?

The standard system tops out at 3999 (MMMCMXCIX). Larger values need overline notation, which is not part of the classic system.

Why is 4 written as IV and not IIII?

Subtractive notation keeps numerals compact: placing a smaller value before a larger one subtracts it. Clock faces sometimes use IIII for symmetry, but IV is the standard form.

Are Roman numerals still used today?

Yes, in clocks, book chapters, movie titles, sporting events, monarch numbering and formal outlines.

Can I convert decimals or zero?

No. The Roman system has no zero and no fractions, so the tool accepts whole numbers from 1 to 3999.

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