Convert whole numbers from 1 to 3,999 to standard Roman numerals and back.
Calculations happen locally. We do not send your values to our server.
The number 2026 converts to MMXXVI. In the opposite direction, MCMXCIX converts to 1999.
Numbers are composed greedily using the standard symbols I, V, X, L, C, D, and M, including subtractive pairs IV, IX, XL, XC, CD, and CM. Reverse conversion is accepted only if converting the result back produces the same canonical numeral.
This tool supports the commonly used standard range from 1 to 3,999. Zero, negative numbers, overline notation, non-standard repetitions, and values above 3,999 are not supported.
The symbols I, V, X, L, C, D and M represent 1, 5, 10, 50, 100, 500 and 1000. Standard subtractive pairs are IV, IX, XL, XC, CD and CM. For 944, combine 900 + 40 + 4 as CM + XL + IV, giving CMXLIV. Subtraction is limited to these pairs rather than any smaller symbol placed before a larger one.
For a year such as 2026, split it into 2000 + 20 + 6 and combine MM + XX + VI. Use the reverse direction to read a numeral from a title page or a chapter heading. Lowercase letters are accepted, but spaces inside a numeral, punctuation and other letters are not. The examples can be read in either direction.
This converter uses canonical subtractive notation from 1 to 3999. A clock face may use IIII for 4, but this tool expects IV and rejects IIII. That rejection does not mean every historical or decorative use of IIII is wrong; it means the input is outside this converter’s convention. Overlines, zero, fractions and numbers above 3999 require another notation and are not supported.
| Example | Result |
|---|---|
4 | IV |
9 | IX |
49 | XLIX |
944 | CMXLIV |
1999 | MCMXCIX |
2026 | MMXXVI |
3999 | MMMCMXCIX |
Yes. Letter case is ignored, and the converted Roman result is displayed in uppercase.
The canonical representation of 4 is IV. Non-standard forms are rejected to avoid presenting ambiguous or historically inconsistent notation as standard.
Not in the standard system used here. This converter accepts whole numbers from 1 through 3,999 and their canonical Roman numeral forms.
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