Roman Numeral Converter
Convert between Roman numerals and decimal numbers. Roman numerals use I, V, X, L, C, D, M. Supports values 1 to 3999. Free online Roman numeral converter.
Roman numeral converter
Result
What is this?
Roman numerals use letters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Numbers are formed by combining symbols. Subtractive notation: IV=4, IX=9 (place smaller before larger to subtract). Used in outlines, clocks, and copyright years. The system has no zero and no place value like our decimal system. Standard form uses specific rules for which combinations are valid. The calculator supports values 1 to 3999, which covers most common uses. Larger numbers would require a vinculum (overline) notation.
When to use
Use for outlines (I, II, III), chapter numbers, copyright years (MMXXIV), clock faces, or education. Example: 2024 = MMXXIV; 49 = XLIX. Writers format outlines and book chapters. Filmmakers display copyright years. Clock makers use Roman numerals. Students learn ancient number systems. Monuments and buildings often use Roman numerals. Anyone encountering Roman numerals in documents or design needs to convert them.
How to use
Select conversion direction: Decimal to Roman or Roman to Decimal. Enter a value and get the instant conversion. Roman numerals: I=1, V=5, X=10, L=50, C=100, D=500, M=1000.
Frequently asked questions
- Roman numerals use letters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Numbers are formed by combining these symbols.
- 4 is written as IV (5 minus 1). The subtractive notation is used for 4, 9, 40, 90, etc.