What range is supported?

Classic Roman numerals from 1 through 3,999 (standard for clocks, outlines, and chapter numbers).

Why is IIII rejected for 4?

We follow the usual subtractive notation: IV = 4, IX = 9, etc., which is standard in modern use.

This tool uses the common 1–3999 range only; overline multiplication is not included.

Yes for input; output is typically uppercase Roman letters.

Useful for typography, trivia, puzzles, and checking homework or design copy.

No. Conversion runs in your browser.

Convert both ways (1–3999) with format validation.

Integer (1–3999)Roman numerals

Rules: I, V, X, L, C, D, M. I before V/X; X before L/C; C before D/M.

Standard form up to 3,999 is supported.

Informational only; verify critical results independently.

Type an Arabic integer from 1 to 3999, or type a Roman numeral using I, V, X, L, C, D, M.
The tool converts in the other direction automatically based on what you entered.
If input is invalid, fix subtractive pairs (e.g. IV for 4, IX for 9) instead of repeated letters.
Use uppercase or lowercase letters; output follows common uppercase convention.
Copy the result for outlines, copyright years, or game chapter numbers.
For learning, compare your manual conversion with the tool’s output.

What range is supported?: Classic Roman numerals from 1 through 3,999 (standard for clocks, outlines, and chapter numbers).
Why is IIII rejected for 4?: We follow the usual subtractive notation: IV = 4, IX = 9, etc., which is standard in modern use.
Did Romans use a bar for thousands?: This tool uses the common 1–3999 range only; overline multiplication is not included.
Are lowercase letters OK?: Yes for input; output is typically uppercase Roman letters.
Why convert at all?: Useful for typography, trivia, puzzles, and checking homework or design copy.
Is data sent to a server?: No. Conversion runs in your browser.

Last updated: 2025-09-05