A Roman numeral converter instantly converts between Roman numerals (XIV) and Arabic numbers (14) in both directions. Whether you are reading a historical document, deciphering clock faces, or working on a design project with Roman numerals, this free online converter gives you instant, accurate results. No signup required.
Try the Free Online Roman Numeral Converter
How It Works
Step 1: Choose conversion direction
Select whether you are converting from Roman numerals to Arabic numbers or vice versa.
Step 2: Enter your value
Type or paste your Roman numeral (e.g., MCMXCIV) or Arabic number (e.g., 1994) into the input field.
Step 3: Convert and copy
Click the Convert button to see the result. The output is ready to copy and use anywhere.
Real-World Examples
History Research: A document mentions the year MCMXLV. Convert to Arabic numbers to quickly see it means 1945.
Design Projects: You are creating a logo with the Roman numeral for 2024 (MMXXIV). Enter 2024 in Arabic mode to get the correct numeral.
Movie Credits: The copyright notice shows MMXXIII. Convert to Arabic to see it means 2023.
Roman Numeral Reference
Here are the seven Roman numeral symbols and their values:
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1000
Subtractive notation is used: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.
Features
- Bidirectional conversion: Roman → Arabic or Arabic → Roman
- Supports values from 1 to 3999 (MMMCMXCIX)
- Handles standard modern Roman numeral notation
- 100% private — all processing happens in your browser
- Instant results with no buttons to press
- Free forever with accurate conversion
Use Cases
Students & Educators
Learn and verify Roman numeral conversions for history, math, and classical studies coursework.
Designers & Creatives
Generate correct Roman numerals for logos, wedding invitations, book chapters, and artistic projects.
Researchers & Writers
Quickly convert Roman numerals in historical documents, legal texts, and academic papers.
Tips & Best Practices
- Learn the subtractive notation rules first: Roman numerals follow two simple rules that cover almost every number. Additive notation means you add symbol values together, as in VI (5 + 1 = 6). Subtractive notation means a smaller symbol placed before a larger one is subtracted, as in IV (5 - 1 = 4), IX (10 - 1 = 9), and CM (1000 - 100 = 900). Mastering these six subtractive pairs — IV, IX, XL, XC, CD, CM — lets you convert any number confidently without memorizing long tables.
- Never repeat a symbol more than three times: In standard modern notation you never write more than three identical symbols in a row. Instead of IIII for 4 you write IV, and instead of XXXX for 40 you write XL. If you ever see four repeated symbols, the numeral is non-standard. This convention is also why the largest number you can write in ordinary Roman numerals is 3999 (MMMCMXCIX), since 4000 would require four M symbols.
- Verify conversions with the reference list: When you are unsure whether a numeral was written correctly, mentally rebuild it from the largest symbol down. The Roman Numeral Reference on this page lists all seven symbols and their subtractive pairs. Converting a numeral like MCMXCIV becomes manageable when you break it into M (1000) + CM (900) + XC (90) + IV (4) = 1994, working from the largest place value to the smallest.
- Use the converter for error-prone editing tasks: Roman numerals are easy to transpose by hand, especially in long documents. Before you publish a thesis chapter, a movie credit, a clock face design, or a wedding invitation that uses numerals like MMXXIV, paste your value through the tool to confirm it is correct. A single misplaced letter such as writing MCMMIV instead of MCMXCIV silently changes the year entirely.
- Pair with the Number Base Converter: If your work also involves binary, octal, or hexadecimal, combine this tool with the Number Base Converter. Together they cover every common numeric representation you are likely to encounter in history research, design, and computer science, so you can keep all conversions in one convenient place.
Frequently Asked Questions
Q: What are Roman numerals?
A: Roman numerals are a numeric system from ancient Rome using letters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. They are still used in clock faces, movie credits, and chapter numbering.
Q: How do I convert Roman numerals to Arabic numbers?
A: Enter the Roman numeral (e.g., XIV) and select Roman to Arabic. The tool instantly shows the Arabic equivalent (14). You can also type a number and select Arabic to Roman.
Q: What is the range of valid Roman numerals?
A: The tool handles values from 1 to 3999 (MMMCMXCIX), the standard modern Roman numeral range. Values beyond 3999 require non-standard notations.
Q: Is my data kept private?
A: Yes. All conversion happens locally in your browser. No data is sent to any server.
Q: Where are Roman numerals still used?
A: Roman numerals appear on clock faces, in movie release years, book chapters, Super Bowl numbering, monarch names (Henry VIII), and musical movements.