Roman Numeral Converter
Convert between Arabic numbers and Roman numerals.
Type in either box — the other updates automatically.
Frequently asked questions
What range of numbers can I convert to Roman numerals?
This converter handles the numbers 1 through 3999, which is the standard range representable with the classic Roman symbols. Zero and negative numbers have no Roman numeral form.
Can it convert Roman numerals back to normal numbers?
Yes. It works both ways, so you can turn an Arabic number into a Roman numeral or decode a Roman numeral back into a regular number.
Why is there no Roman numeral for zero?
The Roman system had no symbol for zero because it was built for counting quantities rather than representing an empty value. That is why conversion starts at 1.
How are numbers like 4 and 9 written?
Roman numerals use subtractive notation, so 4 is written as IV and 9 as IX, placing a smaller symbol before a larger one to mean subtract. This avoids repeating a symbol four times.
What do the Roman letters stand for?
I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1000. Numbers are built by combining these symbols.
Does the tool need an internet connection?
No. The conversion runs entirely in your browser with no server involved, so it works offline once the page is loaded and sends nothing anywhere.
What happens if I enter an invalid Roman numeral?
If the input does not follow valid Roman numeral rules, the tool cannot decode it to a number and will flag it rather than guess. Correct the sequence and it will convert.