Roman Numeral Converter
Convert numbers to Roman numerals, validate Roman input, and copy results for outlines, names, clocks, chapters, and documents.
A Roman numeral converter maps decimal numbers to symbols such as I, V, X, L, C, D, and M.
It also validates standard Roman numeral input and converts it back to decimal.
Use 1 to 3999
This covers the common standard range without overline notation.
Use standard notation
Values such as IV and IX are valid, while IIII is rejected.
Try a common Roman numeral
Valid range.
Roman numeral
MMXXVI
Valid standard Roman numeral.
Decimal number
2026
Suggested workflow
Number conversion workflow
Convert standard numbers, switch bases, and use random numbers for examples or tests.
Related tools
Related number tools
What range is supported?
The converter supports standard Roman numerals from 1 to 3999.
Does it validate Roman numerals?
Yes. It checks standard subtractive notation such as IV, IX, XL, XC, CD, and CM.
Does this require a backend?
No. Conversion runs locally in the browser.
Why is 4999 not supported?
This tool focuses on the common standard range without overline notation for larger values.