Converters
Roman Numeral Converter
Convert Arabic numbers (1, 5, 10) to Roman Numerals (I, V, X) and vice versa instantly. Supports standard notation up to 3,999.
Use Roman Numeral Converter to get instant results without uploads or sign-ups. Everything runs securely in your browser for fast, reliable output.
Your results will appear here.
About this tool
Roman numerals originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. They are based on seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).
Today, they are used in names of monarchs and popes, Super Bowls, movie release years, and on clock faces. This tool helps you decipher them instantly.
Usage examples
Year Conversion
2024
2024 → MMXXIV
Complex Number
3999
3999 → MMMCMXCIX
How to use
- Enter a standard number (e.g. 2024) to see it in Roman Numerals.
- Enter a Roman Numeral (e.g. MMXXIV) to see it as a number.
- The tool automatically detects the input type.
- Works for years, dates, and super bowl numbers.
Benefits
- Bi-directional conversion
- Checks for invalid Roman Numeral syntax
- Supports up to 3,999 (Standard limit)
- Instant feedback
FAQs
Why only up to 3,999?
Standard Roman numerals only go up to 3,999 (MMMCMXCIX) because larger numbers required a "vinculum" (a line over the letter) to multiply by 1,000, which is not standard in ASCII. Extended Roman numeral systems exist for larger numbers but aren't universally recognized.
How do Roman numerals work?
Roman numerals use letters to represent values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. When a smaller value comes before a larger one, you subtract (IV=4, IX=9). Otherwise, you add (VI=6, XI=11). This subtractive notation only applies to specific pairs: IV, IX, XL, XC, CD, CM.
What does MCMXCIV mean?
MCMXCIV = 1994. Breaking it down: M=1000, CM=900 (1000-100), XC=90 (100-10), IV=4 (5-1). Total: 1000+900+90+4=1994. This demonstrates both additive (M+CM+XC+IV) and subtractive (CM, XC, IV) principles of Roman numerals.
Can I convert decimal numbers to Roman numerals?
Yes, enter any number from 1 to 3,999 and the tool will automatically convert it to Roman numerals. It also validates and converts Roman numerals back to numbers. The tool detects input type automatically, so just enter your value.
Where are Roman numerals still used today?
Roman numerals appear in: Super Bowl names (Super Bowl LVIII), copyright years in movies and TV, book chapter numbers, clock faces, monarchs and popes (Queen Elizabeth II, Pope Francis), building cornerstones, outlines (I, II, III, A, B, C), and formal documents. They add elegance and tradition to modern contexts.
Are there rules for writing Roman numerals?
Yes: never repeat a symbol more than 3 times consecutively (IIII is wrong, use IV). Only I, X, C, and M can repeat. Subtractive notation only applies to specific pairs. Never subtract more than one letter at a time. For example, 8 is VIII (not IIX), and 49 is XLIX (not IL). Our tool follows all standard rules automatically.
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