Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers. Supports values from 1 to 3999 (I to MMMCMXCIX).
Roman numerals are a numeral system originating in ancient Rome that remained the standard way of writing numbers throughout Europe well into the Late Middle Ages. They use combinations of letters from the Latin alphabet — I, V, X, L, C, D, and M — to represent values. Today you still encounter them regularly: in clock faces, book chapter numbering, film and TV copyright dates, monarchs and popes (King Charles III, Pope John Paul II), and the names of major events like the Super Bowl or the Olympic Games. This tool converts between standard Arabic integers (1–3999) and their Roman numeral equivalents in both directions.
How Roman Numerals Work
Roman numerals are written from largest to smallest, left to right. When a smaller value appears before a larger one, it is subtracted rather than added. This is called subtractive notation and is used for six specific cases: IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900). All other combinations are simply additive — MMXXVI is M+M+X+X+V+I = 2026.
Common Use Cases
- Copyright dates: Films and TV programmes traditionally show the year of production as a Roman numeral in the credits — for example, MMXXVI for 2026.
- Book and document formatting: Preface and introductory pages in books are often numbered with lowercase Roman numerals (i, ii, iii) before the main Arabic numbering begins.
- Outlines and lists: Formal outlines, legal documents, and academic papers use Roman numerals for top-level headings (I, II, III).
- Named events and sequels: Checking the correct Roman numeral for a numbered edition, sequel title, or sporting event.
- Clocks and watches: Many analogue watch faces use Roman numerals, occasionally using IIII instead of IV for aesthetic balance.