Roman Numeral Converter
Roman numerals are an ancient numeral system that originated in Rome and remain in use today for formal, stylistic, and traditional purposes. The system uses seven base symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Unlike the modern Arabic numeral system (0-9), which is positional and uses a zero, Roman numerals are additive and subtractive, with specific rules governing their arrangement. Numbers are generally written from largest to smallest value moving left to right, but subtractive notation is used in certain cases: I before V or X, X before L or C, and C before D or M. This allows for efficient representation of numbers while avoiding repetition of symbols. Roman numerals are commonly seen in book chapters, movie release years, clock faces, and formal documents. The standard Roman numeral system handles numbers from 1 to 3999. This calculator converts freely between Arabic numerals and Roman numerals in both directions. Enter an Arabic number (1-3999) or a valid Roman numeral, and the converter instantly shows the equivalent in the other system.
Roman numeral symbols and values
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |
Common Roman numerals
| Arabic | Roman | Arabic | Roman |
|---|---|---|---|
| 1 | I | 10 | X |
| 2 | II | 20 | XX |
| 3 | III | 30 | XXX |
| 4 | IV | 40 | XL |
| 5 | V | 50 | L |
| 6 | VI | 60 | LX |
| 7 | VII | 70 | LXX |
| 8 | VIII | 80 | LXXX |
| 9 | IX | 90 | XC |
| 100 | C | 500 | D |
| 1,000 | M | 2,000 | MM |
Roman numeral converter: frequently asked questions
What are Roman numerals?
Roman numerals are a numeral system used in ancient Rome, using letters I, V, X, L, C, D, and M to represent values. I=1, V=5, X=10, L=50, C=100, D=500, M=1000. They were used for everyday counting and record-keeping in ancient Rome and are still used today for formal numbering, like book chapters or film release dates.
What is the range of Roman numerals?
This converter handles Roman numerals from 1 to 3999. The standard Roman numeral system does not have a conventional way to represent numbers above 3999 (which would be MMMM). For larger numbers, the vinculum (overline) or other notations are used, but this converter stays within the traditional range.
What are the main rules for Roman numerals?
Each symbol represents a value: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Generally, symbols are arranged from largest to smallest (left to right). Subtractive notation is used for certain combinations: I before V or X, X before L or C, and C before D or M. For example, 4 is IV (5-1), not IIII.
Why are Roman numerals still used?
Roman numerals are used today for stylistic and formal purposes: numbering book chapters, clock faces, movie release years, legal documents, and monumental inscriptions. They add a sense of formality or tradition. They are not used for mathematical calculations because they are less efficient than Arabic numerals (0-9).
How do I convert a large number to Roman numerals?
Break the number into thousands, hundreds, tens, and ones. Convert each group separately, then concatenate. For example, 3749 is 3000 (MMM) + 700 (DCC) + 40 (XL) + 9 (IX) = MMMDCCXLIX.
Official sources
- Wikipedia: Roman numerals.
- Britannica: Roman numeral.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.