Convert numbers to Roman numerals and Roman numerals back to numbers, from 1 to 3999.
What this calculator does
This converter turns ordinary numbers into Roman numerals and decodes Roman numerals back into numbers. Switch mode and type your value.
It’s handy for dates, clock faces, book chapters and movie sequels.
Getting your answer
- Choose the direction of conversion.
- Type the number or the Roman numeral.
- Read the converted result.
The formula
Standard symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000
subtractive pairs like IV=4 and IX=9
Try it with these numbers
As an example, with a number of 2,026, the calculator returns a result of MMXXVI. Alongside it, Input comes out at 2026. Change any field and every figure updates as you type.
Common questions
How do Roman numerals work?
Letters add up left to right, except when a smaller value sits before a larger one (like IV = 4 or IX = 9), where it subtracts.
Why only up to 3999?
Standard Roman numerals top out at MMMCMXCIX (3999); larger numbers need bars over letters that aren’t part of the basic system.
Is there a zero?
No — Roman numerals have no symbol for zero; the concept came later from other numbering systems.