Roman Numeral Converter
Number to Roman numeral and back, 1 to 3 999 999 with the vinculum (overline) for thousands, the place-value breakdown, strict or lenient reading of IIII forms.
The numeral in standard form with its overline display, the number, a breakdown of every symbol group with its value, and whether a numeral you typed is in standard form.
Example: 1994 → MCMXCIV (M + CM + XC + IV); 4 226 → I̅V̅CCXXVI, or (IV)CCXXVI in plain text; MCMXCIV reads as 1994; IIII is accepted leniently as 4 and flagged as non-standard.
Subtractive form,
overlines for thousands.
How the numeral is written, how a typed numeral is read, and what strict and lenient mean.
Writing
The number is broken into place values from the largest down — M 1 000, CM 900, D 500, CD 400, C 100, XC 90, L 50, XL 40, X 10, IX 9, V 5, IV 4, I 1 — which produces the standard subtractive form (1994 → M CM XC IV) with at most three of a symbol in a row. Above 3 999 the thousands are written with a vinculum, an overline that multiplies by 1 000: 4 226 is I̅V̅CCXXVI, shown with combining overlines and, in plain text, as (IV)CCXXVI. The limit is 3 999 999.
Reading
The numeral is read left to right; a symbol smaller than the one after it is subtracted (IV = 4), otherwise added. Overlined letters or a group in parentheses are read first and multiplied by 1 000. Each group is listed with its value so the sum can be followed. Case and spaces are ignored.
Strict and lenient
Strict reading accepts only the standard form and refuses IIII, VIIII or IC. Lenient reading (the default) accepts any string of the seven letters, computes its value by the same rule and reports the standard spelling — useful for clock faces (IIII) and inscriptions. Roman numerals have no zero, no negative numbers and no fractions here. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- Standard subtractive notation I V X L C D M with IV IX XL XC CD CM and at most three repeats; vinculum (overline, U+0305) multiplies by 1 000, written in parentheses in plain text
Last reviewed 22 September 2026. How results are checked: How we verify.