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Convert between decimal numbers and Roman numerals (I, V, X, L, C, D, M).
Roman numerals are a numeral system from ancient Rome using seven letters (I, V, X, L, C, D, M) to represent numbers. They use additive and subtractive notation, supporting values from 1 (I) to 3,999 (MMMCMXCIX).
Enter a value in either field to convert. Valid Roman numerals: I, V, X, L, C, D, M
| Decimal | Roman | Note |
|---|---|---|
| 2024 | MMXXIV | Current year |
| 1999 | MCMXCIX | Complex example |
| 3999 | MMMCMXCIX | Maximum value |
| 49 | XLIX | Subtractive notation |
| 444 | CDXLIV | Multiple subtractions |
| Value | Symbol | Value | Symbol |
|---|---|---|---|
| 1 | I | 90 | XC |
| 4 | IV | 100 | C |
| 5 | V | 400 | CD |
| 9 | IX | 500 | D |
| 10 | X | 900 | CM |
| 40 | XL | 1000 | M |
| 50 | L |
Roman numerals combine seven basic symbols to represent numbers. Symbols are generally written from largest to smallest, left to right.
Basic Rules:
Subtractive pairs: Only I before V/X, X before L/C, and C before D/M are valid subtractive combinations.
Formula
I=1, V=5, X=10, L=50, C=100, D=500, M=1000, read left to right and added, except for the six subtractive pairsAdditive = a smaller or equal numeral after a larger one is added, so VI is 6
Subtractive = a smaller numeral before a larger one is subtracted, and only IV, IX, XL, XC, CD and CM are valid
Repetition = I, X, C and M may repeat up to three times; V, L and D never repeat
Worked Example
Writing 1994
Did you know? Standard Roman numerals stop at 3,999. There is no symbol above M, so larger numbers used a vinculum, a bar drawn over a numeral to multiply it by 1,000, which makes V with an overbar 5,000.
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