Roman numerals write numbers with letters. I means 1, V means 5, and X means 10. Roman Numerals changes ordinary numbers into these letters and back.
Try a number both ways
Leave Direction on Number → Roman and type 14 in Number or Roman numeral. Result should show XIV: X is ten and IV is four. The I goes before V to mean one less than five.
Now switch Direction to Roman → number and replace the input with XIV. The result should be 14. It updates as you type; Copy takes the result if you need it elsewhere.
If the tool says the input is invalid
In number mode, enter a whole number from 1 through 3999. Zero and negative values have no output here. In Roman mode, use the standard order of letters. For example, IIII is rejected; write IV for four. This converter reads the text you entered, not the age of a document or a date shown in a picture.
Where your input goes
Processing runs in your browser. The tool does not upload your input to ilham.dev.
Related guide
For more background, read Calculators and Unit Conversion.
Questions you might have
- Why does it stop at 3999?
- Standard Roman notation has no zero and no way to write larger numbers without an overline or a different convention. 3999 is MMMCMXCIX, the largest value the plain form expresses.