Roman Numeral Converter
Type a whole number from 1 to 3999 or a Roman numeral and the tool converts it the moment you stop typing. It detects the direction for you, so there is nothing to switch.
How to convert Roman numerals
- Type a number (like 2024) or a Roman numeral (like MMXXIV) into the box.
- The tool detects the direction and shows the converted value instantly.
- Copy the result with one click.
Examples
Number to Roman numerals
2024
MMXXIV
Roman numerals to a number
XLIX
49
Frequently asked questions
How do Roman numerals work?
Roman numerals use seven letters: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1000. Letters are added together from largest to smallest, so XVII is 10 plus 5 plus 1 plus 1, which equals 17.
What numbers can I convert?
Whole numbers from 1 to 3999. Classic Roman numerals have no symbol for zero and no standard single-character symbol above 1000, so 3999 (MMMCMXCIX) is the usual upper limit.
What is subtractive notation, like IV and IX?
When a smaller letter sits before a larger one it is subtracted instead of added. So IV is 5 minus 1 (4) and IX is 10 minus 1 (9). The same rule gives XL for 40, XC for 90, CD for 400 and CM for 900.
Why does IIII show an error?
Standard Roman numerals never repeat a letter four times in a row, so 4 is written IV, not IIII. The converter validates the input and flags forms like IIII or VV that are not valid numerals.
Where are Roman numerals still used?
Common places include copyright years and movie credits, Super Bowl numbers, book chapters and outlines, clock and watch faces, and the names of monarchs and popes such as Henry VIII.
Is my input private?
Yes. The conversion runs entirely in your browser and nothing is uploaded.
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