Roman numeral calculator
Enter two Roman numerals and pick an operation to see the answer at once. Useful for practice and homework checks.
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How to use it
- Enter first numeral, operation and second numeral.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Each numeral is converted to a number, the operation is applied (+, −, ×, or whole-number division with remainder), and the result is converted back to Roman if it is between 1 and 3999.
Example
Inputs: First numeral = C, Operation = Divide (÷), Second numeral = VII. Result: Result in Roman numerals: XIV; Result in digits: 14; First numeral: 100.
C
XIV
Limits and caveats
- Division is whole-number only; any fraction shows as a remainder because standard Roman numerals have no fractions.
- The result must be between 1 and 3999.
Questions about this tool
How did Romans do arithmetic?
Mostly on a counting board or abacus, then wrote the result in numerals, because calculating directly with the symbols is awkward.
What is XIV + IX?
It is XXIII, that is 14 + 9 = 23.
Why do I get an error subtracting a numeral from itself?
The result is zero, and standard Roman numerals have no symbol for zero.