Using the Roman Numeral Converter
Enter either an integer or a Roman numeral in the same field. Roman input is normalized to uppercase and checked against the canonical representation, so an unusual or nonstandard sequence is rejected rather than assigned an ambiguous value.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Integer or Roman numeral
- 2026
Example result
- Roman numeral
- MMXXVI
Method and assumptions
Uses standard subtractive notation: IV, IX, XL, XC, CD and CM.
Distinguish notation from value
A number can be written in more than one system without changing its value. Conversion changes the representation, while arithmetic changes the number itself. This tool uses one documented notation convention and a limited range. A historical inscription or decorative variant may require interpretation beyond that convention.
Common question
Why is IIII rejected when it appears on some clocks?
Some clocks use IIII as a design convention, but this converter enforces the standard subtractive form IV. Its validation is based on one consistent notation rather than every historical or decorative variant.
Guide updated .