Convert between decimal numbers and Roman numerals. Supports values from 1 to 3999.
Frequently Asked Questions
Roman numerals are a numeral system originating in ancient Rome that uses combinations of letters from the Latin alphabet — I, V, X, L, C, D, and M — to represent values. They are still used today in clock faces, book chapters, movie sequels, and formal outlines.
Standard Roman numerals represent numbers from 1 to 3999. The upper limit exists because there is no single-letter symbol for 5000 in the basic system. Numbers outside this range require extended notation such as vinculum (overline) bars.
Subtractive notation places a smaller-value symbol before a larger one to indicate subtraction. For example, IV means 5 − 1 = 4, and IX means 10 − 1 = 9. This avoids repeating a symbol four times (IIII) and keeps numerals compact.