Roman Numeral Converter
Convert roman numerals
Convert roman numerals Runs locally in your browser
Enter a number to convert to Roman numerals, or Roman numerals to convert back.
About the
The Roman Numeral Converter converts in both directions between ordinary numbers and Roman numerals, detecting which way you mean from what you type. It covers 1 to 3999, which is the range the classical system can express without extra notation, and it handles subtractive pairs such as IV and CM correctly in both directions. Use it for dates in film credits, chapter numbering, clock faces, outlines and anywhere else the old form is still expected.
Where people use the
- Writing a release year in Roman numerals for a film or TV credit.
- Numbering front matter or appendix pages in a document.
- Checking a Roman numeral you have been given rather than parsing it by eye.
- Designing a clock face or a monument inscription.
How to use the
- 1
Type a value
Enter a number to convert to Roman numerals, or Roman numerals to convert back to a number.
- 2
Run it
Input made only of the letters M, D, C, L, X, V and I is treated as a numeral and converted to a number. Anything numeric is converted to numerals.
- 3
Check the range
Values must be between 1 and 3999. Outside that range the classical system has no standard form.
- 4
Copy the result
The result is plain text, ready to paste into a document or a design.
Tips and best practices
- Use the standard subtractive forms; IIII and VIIII are readable but non-standard.
- Stay within 1 to 3999; anything larger needs extended notation.
- Lowercase input works, so you do not need to shift-case before pasting.
Frequently asked questions
Why does it stop at 3999?
Because the standard system has no symbol for five thousand. Larger values were written with an overline or other extended notation, which is not universally agreed on, so the tool stays within the classical range.
Is the input case sensitive?
No. Lowercase letters are accepted and treated the same as uppercase.
Does it accept non-standard forms like IIII?
It will convert the value, since the letters are summed or subtracted pairwise, but IIII is not the standard form of 4. IV is.
Why is there no Roman numeral for zero?
The system has no symbol for zero. It was developed for counting and recording, not for arithmetic with a zero place value.
How are subtractive pairs handled?
A smaller symbol before a larger one is subtracted, so IV is 4 and CM is 900. The conversion applies that rule in both directions.