Roman Numeral Converter
Convert any number to Roman numerals — or any Roman numeral back to a number — in an instant.
What is it?
Roman numerals are a numeral system that originated in ancient Rome and used combinations of letters from the Latin alphabet to represent numbers. The seven core symbols are I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). By combining these symbols using additive and subtractive notation — for example, IV for 4 and IX for 9 — any integer from 1 to 3999 can be expressed. Our free Roman numeral converter lets you translate in both directions: enter an ordinary (Arabic) number and get the Roman numeral equivalent, or type a Roman numeral and get its numeric value. The converter validates your input in real time, highlights any errors, and explains why a number might fall outside the supported range. It supports the full standard range of 1 to 3999, which covers everyday uses like clock faces, movie release years, book chapters, Super Bowl numbers and historical dates.
How to use it
- Select the direction: "Number → Roman" or "Roman → Number" using the toggle.
- For number-to-Roman: type any integer between 1 and 3999. The Roman numeral appears instantly below.
- For Roman-to-number: type a valid Roman numeral string (e.g. MMXXVI). The decimal value appears instantly.
- If your input is invalid, a clear error message explains what went wrong.
- Click "Copy" to copy the result to your clipboard.
Why use this tool
Roman numerals might seem old-fashioned, but they appear constantly in everyday contexts: clock and watch faces, the credits and copyright years of films and TV shows, Super Bowl numbering, book preface page numbers, chapter headings in formal documents, the names of monarchs (King Charles III, Pope Francis I), and sporting event editions. Understanding and converting them accurately saves time and avoids mistakes. Students encounter Roman numerals in history, Latin and mathematics classes. Writers and editors need them for properly formatted front-matter page numbering or structured outlines. Tattoo artists and clients often translate years or personal dates into Roman numerals for body art. Game designers and puzzle creators use them for atmospheric effect. Our converter handles all of these use cases instantly, with no installation, no account and full privacy since the calculation happens entirely in your browser.
Frequently asked questions
Why do Roman numerals only go up to 3999?
The standard rules of Roman numeral notation max out at 3999 (MMMCMXCIX). Numbers above this traditionally required special notation (a vinculum/overline to multiply by 1000) that is not standardised in digital use.
Is the year 2024 in Roman numerals MMXXIV?
Yes. MM = 2000, XX = 20, IV = 4, so MMXXIV = 2024. Type 2024 in the converter to confirm.
What does the subtractive principle mean?
When a smaller value symbol appears before a larger one, you subtract it. IV = 5 − 1 = 4. IX = 10 − 1 = 9. XC = 100 − 10 = 90. This rule applies only to specific pairs and prevents more than three identical symbols in a row.
Can the tool handle lowercase roman numerals?
Yes. Input like "mmxxiv" or "xiv" is automatically converted to uppercase before processing, so you do not need to worry about case.
Are there other common uses of Roman numerals today?
Very much so: Super Bowl editions (Super Bowl LVIII), film sequels (Rocky IV), chapter numbers in the Bible, volumes of academic journals, and generation suffixes in electronics (iPhone XIV) all use Roman numerals.