Roman Numeral Converter

Roman numerals still turn up everywhere: on clock faces, book chapters, film copyright dates, Super Bowls, monarchs’ names and tattoos. Fileopia’s converter works in both directions, checks that a numeral follows the standard rules, and explains how the value is built, so you can trust the result before you engrave, print or ink it. It runs entirely in your browser – type and read, nothing to install.

Common uses

• Turn a birth year, wedding date or anniversary into numerals for a tattoo, ring or invitation.
• Number book chapters, appendices or preface pages (i, ii, iii…).
• Decode the copyright year at the end of a film or TV credits.
• Write outline or legal section numbers (Article IV, Section XII).
• Check your child’s maths homework on Roman numerals.

Tips for best results

• Lower case is traditional for front-matter page numbers – tick “Show lower case”.
• For dates, convert day, month and year separately: 14 July 2026 → XIV · VII · MMXXVI.
• The tool rejects non-standard forms such as IIII or VX, so a wrong numeral is caught before it is printed.
• Double-check anything permanent (a tattoo!) by converting the numeral back to a number.
• Spaces are ignored, so you can paste numerals copied from a document.

How Roman numerals work

Seven letters carry the values I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. Letters are normally written from largest to smallest and added up: MDCLXVI = 1,666. To avoid four identical letters in a row, a smaller letter placed before a larger one is subtracted. Only six such pairs are standard: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). That is why 1994 is MCMXCIV – M + CM + XC + IV – rather than MDCCCCLXXXXIIII.

Standard and non-standard forms

You will sometimes see IIII on clock faces or XIIX on old documents. Historically the Romans were flexible, but modern usage follows the strict subtractive rules above, and that is what exams, publishers and style guides expect. When you enter a numeral, the converter checks it against those rules; if it is not standard it tells you why instead of guessing a value. A numeral that converts back to the same number is guaranteed to be in canonical form.

Numbers above 3,999

Because no letter is repeated more than three times, plain numerals stop at 3,999. For bigger values a horizontal bar over a numeral multiplies it by one thousand, so V̅ is 5,000 and M̅ is a million. The converter writes these with a combining overline character, which displays correctly in most modern fonts. For everyday use – years, chapters, events – you will rarely need them, but they are handy for puzzles and history lessons.