Convert numbers to Roman numerals and back — just type either one.
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How do you convert numbers to Roman numerals?
Roman numerals use I=1, V=5, X=10, L=50, C=100, D=500 and M=1000, with subtractive pairs such as IV=4, IX=9, XL=40 and CM=900. Standard numerals run from 1 to 3999. For example, 2026 becomes MMXXVI, and MCMLXXXIV converts back to 1984. Malformed numerals like IIII or VX are rejected.
Understanding your result
Standard Roman numerals run from 1 to 3999. The converter validates input so malformed numerals like “IIII” or “VX” are rejected.
Formula and method
Roman numerals use I=1, V=5, X=10, L=50, C=100, D=500 and M=1000, with subtractive pairs such as IV=4, IX=9, XL=40 and CM=900.
Worked example
2026 becomes MMXXVI; MCMLXXXIV becomes 1984.
How to use this tool
- Type a number between 1 and 3999, or a Roman numeral.
- Press Convert to see the result instantly.
About the Roman Numeral Converter
The Roman Numeral Converter turns ordinary numbers into Roman numerals and decodes Roman numerals back into numbers, automatically detecting which direction you need.
Frequently asked questions
Why is the maximum 3999?
Standard Roman numerals only go up to 3999 (MMMCMXCIX); larger numbers need a bar notation that isn’t part of the everyday system.