Roman Numeral Converter
Enter a number to see it as a Roman numeral, or enter a Roman numeral to see it as a number.
MMXXVI
2026
Your files are processed locally in your browser. They are not uploaded to our servers.
How to use
- Enter a whole number from 1 to 3999 to see its Roman numeral.
- Or enter a Roman numeral to see its numeric value.
- Both fields update live and independently.
What is this tool?
Roman Numeral Converter translates between standard Arabic numbers and Roman numerals using the classic subtractive notation (like IV for 4 and IX for 9). It works in both directions at once, live as you type, and validates that a Roman numeral entry is correctly formed.
Common uses
- Looking up the Roman numeral for a year, chapter or edition number
- Decoding a Roman numeral seen on a clock, monument or book
- Checking a Roman numeral is correctly formatted
- Formatting a movie sequel, book volume or event number the classic way
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FAQ
What's the valid range for numbers?
Standard Roman numerals support whole numbers from 1 to 3999.
Why does my Roman numeral show as invalid?
Roman numerals must follow strict formation rules — the tool checks that your input, when converted, produces exactly that numeral back.
Are lowercase Roman numerals accepted?
Yes, lowercase input is automatically converted to uppercase before validation.