Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
How it works
Type any number from 1 to 3,999 to instantly convert it to Roman numerals, or enter a Roman numeral string to convert it back to a decimal number. Validates the input and handles edge cases correctly.
Why use this tool?
Used for chapter numbering, clock faces, copyright years, outlines, and formal documents. Also widely used by students for history, math, and classical literature assignments.
Frequently Asked Questions
What is the highest number in Roman numerals?
The standard Roman numeral system goes up to 3,999 (MMMCMXCIX). Numbers above 3,999 require a vinculum (overline) notation, which is rarely used.
How do I read Roman numerals?
Add symbols from left to right. When a smaller symbol appears before a larger one, subtract it instead. E.g. IV = 5 − 1 = 4, IX = 10 − 1 = 9, XL = 50 − 10 = 40.
Where are Roman numerals used today?
Clock faces, movie sequels (Rocky IV), book chapters, Super Bowl numbers, copyright years (MMXXV = 2025), building inscriptions, and formal outlines.
Is this free?
Yes, completely free with instant bidirectional conversion.
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