Roman Numeral Converter
Convert between Roman numerals and decimal numbers. Supports values from 1 to 3,999.
Enter a number (1 to 3999) to convert it to Roman numerals, or paste a Roman numeral to see its decimal value. Supports the standard subtractive notation (IV, IX, XL, XC, CD, CM).
How Roman Numerals Work
Roman numerals use seven letters to represent numbers: I, V, X, L, C, D, and M. Unlike our decimal system where position determines value (the 3 in 300 means "three hundreds"), Roman numerals are additive, you combine symbols and add their values together. XVI is 10 + 5 + 1 = 16.
The clever part is the subtractive rule. When a smaller numeral appears before a larger one, you subtract instead of add. IV isn't 1 + 5 = 6, it's 5 − 1 = 4. This rule only applies to specific pairs: I before V or X, X before L or C, and C before D or M.
Standard Roman numerals max out at 3,999 (MMMCMXCIX). There's no symbol for zero, and numbers beyond 3,999 historically used an overline notation (a bar above a numeral multiplied its value by 1,000). This tool covers the standard range of 1 to 3,999.
Roman Numeral Reference Table
| Symbol | Value | Example | Combined Value |
|---|---|---|---|
| I | 1 | III | 3 |
| V | 5 | IV | 4 (5−1) |
| X | 10 | IX | 9 (10−1) |
| L | 50 | XL | 40 (50−10) |
| C | 100 | XC | 90 (100−10) |
| D | 500 | CD | 400 (500−100) |
| M | 1,000 | CM | 900 (1000−100) |
What this means for you: Memorise the six subtractive pairs (IV, IX, XL, XC, CD, CM) and you can read any Roman numeral. Everything else is just addition.
Common Roman Numerals You'll See
| Decimal | Roman | Where You'll See It |
|---|---|---|
| 4 | IV | Clock faces, chapter numbers |
| 9 | IX | Movie sequels, list numbering |
| 14 | XIV | Louis XIV, historical references |
| 50 | L | Super Bowl L, anniversaries |
| 100 | C | Centenary celebrations |
| 500 | D | Historical dates, monuments |
| 2024 | MMXXIV | Copyright notices, film credits |
| 2026 | MMXXVI | Current year |
Where Roman Numerals Still Appear
Film & Television
Movie copyright dates (© MMXXVI), sequel numbering (Rocky IV), and production credits still use Roman numerals as a tradition of formality.
Architecture & Monuments
Building cornerstones, memorial plaques, and clock faces use Roman numerals. Many clock faces famously use IIII instead of IV.
Academic & Legal
Book chapters, outline numbering (I, II, III), legal document sections, and academic paper divisions all use Roman numerals for hierarchical structure.
Events & Sports
The Super Bowl (LIX = 59), Olympic Games numbering, and royal succession (Elizabeth II, Charles III) all rely on Roman numerals.
Quick Year Conversions
Handy for copyright notices, film credits, and wedding invitations. The pattern is simple: MM = 2000, then add the last two digits in Roman numerals.
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How to use this tool
Enter a decimal number (1 to 3,999) or a Roman numeral
The conversion happens instantly in the other field
Copy the result for use in documents, designs, or projects
Common uses
- Converting years to Roman numerals for copyright notices
- Decoding Roman numerals on clocks, buildings, and monuments
- Numbering chapters, sections, and outlines in academic writing
- Converting Super Bowl and event numbers
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Frequently Asked Questions
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Are lowercase Roman numerals valid?
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Results are for general informational purposes only and should be checked before use. They are not professional advice. See our Disclaimer and Terms of Service.