Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
About this tool
Convert whole numbers to Roman numerals, or Roman numerals back to numbers — detected automatically from what you type.
Key Features
- Works in both directions automatically
- Standard subtractive notation (IV, IX, XL…)
- Validates Roman numeral input
- Covers the standard range 1–3999
How to Use
- Type a number (like 1994) or a Roman numeral (like MCMXCIV).
- Click Convert.
- See the result in the other format.
Benefits
- Read dates on buildings, clocks, and film credits
- Check homework or crossword answers
- Understand movie sequel/edition numbering
Frequently Asked Questions
Roman numerals use "subtractive notation" for four specific cases: a smaller numeral placed before a larger one is subtracted rather than added. IV (5−1=4), IX (10−1=9), XL (50−10=40), XC (100−10=90), CD (500−100=400), and CM (1000−100=900) are the only subtractive pairs in standard use.
Using the standard symbols (I, V, X, L, C, D, M) without extensions, 3999 (MMMCMXCIX) is the largest representable number, since there is no standard single symbol for 5000 or higher without adding a line above a numeral (vinculum) to multiply it by 1000.
No — the Romans had no numeral for zero. The concept of zero as a number came later, primarily developed in Indian mathematics before spreading to the Arab world and eventually Europe, replacing Roman numerals for most everyday arithmetic.