Roman Numerals Converter
Convert numbers to and from Roman numerals instantly. Learn the Roman numeral system with our free converter tool.
Read and write standard Roman numerals for whole numbers from 1 to 3999.
Only integers 1–3999 are supported. Zero, fractions, negatives, overbars and alternative historical spellings are rejected. No rounding is applied.
Reference Table
History
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Method and limits
Conversion uses M, CM, D, CD, C, XC, L, XL, X, IX, V, IV and I in descending order. Reverse conversion must reproduce the same canonical spelling.
Only integers 1–3999 are supported. Zero, fractions, negatives, overbars and alternative historical spellings are rejected. No rounding is applied.
These conversions run in this page. Roman history exists only until the page is closed or reloaded; no calculator storage is used.
About Roman Numerals Converter
Read and write standard Roman numerals for whole numbers from 1 to 3999.
1994 → MCMXCIV → 1994. Check a date written on a building or in a book.
3999 → MMMCMXCIX. Use the reference table to see the largest supported form.
Only integers 1–3999 are supported. Zero, fractions, negatives, overbars and alternative historical spellings are rejected. No rounding is applied.
Use Cases
How to use
Choose number-to-Roman or Roman-to-number and enter a value. Swap uses a valid result as the next input; an invalid draft is kept for correction.
Use the reference buttons to explore symbols. Valid conversions enter a 15-item session history after an 800 ms pause; Clear history also cancels a pending entry.
Pro Tips
- Only integers 1–3999 are supported. Zero, fractions, negatives, overbars and alternative historical spellings are rejected. No rounding is applied.
Frequently Asked Questions
The canonical subtractive forms are IV and IX, not IIV. Reverse conversion checks the entire spelling; 1994 is MCMXCIV.
This tool supports ordinary Roman notation from 1 to 3999 only. Extended notation and fractional numbers are outside its model.