Convert Roman numerals to numbers and numbers to Roman numerals.
Loading tool
About Roman Numeral Converter
Convert whole numbers from 1 to 3999 into Roman numerals and decode Roman numerals back into numbers. Each conversion shows a symbol-by-symbol breakdown. Input numerals are validated against canonical subtractive form, so a non-standard spelling like IIII is flagged along with its correct form.
Common uses
- Write a year such as 2026 as MMXXVI
- Read the Roman numeral year in film credits or on a building
- Check whether a Roman numeral is written correctly
- Number outline sections, chapters or clock faces
FAQ
- How do Roman numerals work?
- The symbols are I=1, V=5, X=10, L=50, C=100, D=500 and M=1000. Values are added from left to right, except when a smaller symbol comes before a larger one, in which case it is subtracted, as in IV=4 and XC=90.
- Why is the maximum 3999?
- Standard Roman numerals have no symbol above M (1000) and a symbol is not repeated more than three times, so MMMCMXCIX (3999) is the largest value. Larger numbers historically used extra notation such as an overline, which is not part of the standard form.
- Is there a Roman numeral for zero?
- No. The Roman numeral system has no symbol for zero, so the smallest value is I (1).