Roman Numeral Converter
This tool converts numbers into Roman numerals and Roman numerals back into ordinary numbers, so you never have to work out the rules by hand. Roman numerals still turn up on clock faces, in film and television credits, on building cornerstones, in book chapter and volume numbers, and for naming monarchs and popes. In the first field, enter any whole number from 1 to 3,999 and the converter instantly shows the matching Roman numeral, built from the seven letters I, V, X, L, C, D and M, standing for 1, 5, 10, 50, 100, 500 and 1,000. In the second field, type or paste a Roman numeral and it converts straight back into an ordinary number. The converter applies the two rules that govern the system: letters are normally added together from largest to smallest, but when a smaller letter sits immediately before a larger one, its value is subtracted instead, which is why IV reads as 4 rather than 6 and XC reads as 90 rather than 110. Because the classic Roman system has no symbol for zero and becomes unwieldy above 3,999, results outside that range are not shown, so check your number falls within it. Use it to check a date before it goes on an invitation, confirm a chapter numbering scheme, or simply satisfy your curiosity about how a particular year is written in Roman numerals.
The rules
The letters are I, V, X, L, C, D, and M for 1, 5, 10, 50, 100, 500, and 1000. You add them up from largest to smallest, but when a smaller letter sits before a larger one it is subtracted, which is how IV is 4 and XC is 90.
Worked example
2026 is MMXXVI: two thousands (MM), two tens (XX), a five (V), and a one (I). The year 14 is XIV: ten (X) plus four (IV).
Related calculators
- Binary Converter: binary, decimal, and hex.
- Superscript Generator: superscript text.
- Unit Converter: many units at once.
- Standard Calculator: everyday arithmetic.