Turn a number into a Roman numeral, or read a Roman numeral back as a number. Both directions update as you type.
What the Roman numeral converter does
Type a number from 1 to 3999 to see its Roman form, or type a Roman numeral to read it back as a number. Both directions update as you type.
Frequently asked questions
Why stop at 3999?
Roman numerals have no standard symbol for values of 4000 and above, so the classical system tops out there.
Are subtractive forms handled?
Yes. IV, IX, XL, XC, CD and CM are all recognised in both directions.
Is anything uploaded?
No. The conversion runs in the page.
How to use it
- Type a whole number between 1 and 3999 into the Number field.
- The Roman numeral appears immediately in the Roman numeral field.
- Clear the Number field and type a Roman numeral instead, such as MCMLXXXIV.
- The corresponding Arabic number appears in the Number from Roman field.
Where it comes in handy
When reading a book that uses Roman numerals for chapter numbers, such as Chapter XLII, you can paste or type the numeral to confirm it is chapter 42 without counting on your fingers.
If a product lists 247 features and you need to label a section in a presentation using Roman form, enter 247 to get CCXLVII and copy it directly into your slides.
Clock faces sometimes show XII instead of 12. Entering XII returns 12, which helps verify that the time displayed is noon or midnight rather than a different hour.
Worth knowing
- The converter stops at 3999 because classical Roman numerals lack a standard symbol for 4000 and above.
- Both subtractive combinations like IV and additive sequences like IIII are accepted as input, but the output always uses the subtractive form.
- The tool ignores lowercase letters and extra spaces in the Roman input, but it does not accept invalid letter combinations such as VX or IL.