Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers. Free online converter.
Frequently asked questions
- What is the largest number I can convert?
- Standard Roman numerals without overlines go up to 3999, so the number field accepts 1 to 3999 and rejects anything outside that range.
- How does subtractive notation work?
- A smaller value placed before a larger one is subtracted, which is why 4 is IV, 9 is IX, 40 is XL and 900 is CM. The converter handles this automatically in both directions.
- Can I convert Roman numerals back to numbers?
- Yes. Type a numeral such as MMXXVI into the Roman field and the number field updates; the two fields stay in sync in either direction.
- Why are zero and negative numbers not allowed?
- The Roman system has no symbol for zero and no concept of negative numbers, so only positive values can be represented.
This tool runs entirely in your browser. No data is uploaded anywhere.