Roman numeral rules and examples
Standard Roman numerals use seven symbols: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, and M = 1,000. Most values are built by adding symbols from larger to smaller values, for example VIII = 8 and LX = 60.
Subtraction notation
A smaller symbol immediately before a larger one can indicate subtraction in certain standard pairs: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, and CM = 900. Thus 1,944 is written MCMXLIV (1,000 + 900 + 40 + 4). The converter checks standard spelling rather than accepting every string that can be made from the letters I, V, X, L, C, D, and M.
Range supported by this converter
This tool handles whole numbers from 1 through 3,999. Classical modern Roman-numeral notation does not have one universally used everyday form for representing every larger number, so values outside the converter's range are rejected. Roman numerals also do not use a standard symbol for zero. Use the numeric form for arithmetic, then convert the result if a Roman numeral representation is needed.
Tips for accurate results
Roman numerals use I, V, X, L, C, D, and M for 1, 5, 10, 50, 100, 500, and 1,000. A smaller symbol before a larger one is subtracted, as in IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900). So 1994 is MCMXCIV.
Common mistakes and limits
Standard notation rarely repeats a symbol more than three times in a row and has no zero or negative numbers. The conventional range is 1 to 3,999. Older inscriptions sometimes used variants such as IIII for 4, so a clock face may not match the modern rule.