Can I convert zero or negatives?

Classical Roman numerals have no zero or negative representation, so those values are not supported.

What about numbers over 3999?

Standard notation stops at 3999. Some systems use overlines for larger values—add custom logic if you need that.

Why is my Roman input invalid?

Ensure you follow subtractive rules (e.g., IV for 4, not IIII) and avoid characters outside I, V, X, L, C, D, M.

ADVERT

🏛️ Roman Numeral Converter

Convert numbers to Roman numerals and back instantly. Great for history, education, or formatting. No sign-up required. Keeps your data private on-device.

Roman Numeral Converter

Convert numbers into Roman numerals and back again. Supports values from 1 to 3999.

Number → Roman

MCMXCIX

Roman → Number

1999

How to use this tool

Enter a number between 1 and 3999 to get its Roman numeral equivalent.
Paste a Roman numeral to convert it back to an integer and verify correctness.
Copy or download both conversions for documentation or educational materials.

Where it helps

Create classic numbering for outlines, clocks, or product SKUs.
Check student homework by quickly validating Roman numeral answers.
Design invitations or certificates with historically styled numerals.

Usage tips

The converter enforces traditional Roman numerals—no modern extensions beyond 3999.
Inputs are normalized to uppercase automatically for easier comparison.
Invalid sequences return 'Invalid' so you can correct typos instantly.

FAQ

Can I convert zero or negatives?: Classical Roman numerals have no zero or negative representation, so those values are not supported.
What about numbers over 3999?: Standard notation stops at 3999. Some systems use overlines for larger values—add custom logic if you need that.
Why is my Roman input invalid?: Ensure you follow subtractive rules (e.g., IV for 4, not IIII) and avoid characters outside I, V, X, L, C, D, M.