Roman Numeral Converter

How do Roman numerals work?

Seven letters build every Roman numeral: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. You add them from left to right, so XVI reads 10 + 5 + 1 = 16. When a smaller letter sits before a larger one, you subtract it instead, which gives the six pairs IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900), the only subtractions the classic system allows.

Take MMXXIV as a worked example. The two M count for 2,000, the two X add 20 and IV brings the final 4, so the whole numeral reads 2024. The converter shows this breakdown under the result, which makes it easy to check a date carved on a monument or shown at the end of a film's credits.

How do you convert Roman numerals back to numbers?

The field takes both directions and reads what you typed. Enter 2024 and the tool answers MMXXIV. Enter MMXXIV, or even mmxxiv in lowercase, and it answers 2024. It only accepts the strict classic form, so a malformed numeral such as IIII or VX returns an error rather than a guess. That strictness matters when the value ends up in a legal document or an engraving, where a silent misreading costs more than a visible error.

Why does the converter stop at 3,999?

Standard notation never repeats a letter more than three times, and M is the largest symbol available. Three M give 3,000, so MMMCMXCIX, or 3,999, is the highest value the classic system can write. The Romans handled larger numbers with a bar called a vinculum, drawn above a letter to multiply it by 1,000. Sources disagree on how to draw that bar and most fonts render it badly, so this converter stays inside the range every textbook agrees on.

How do you write years in Roman numerals?

Most lookups are about years, usually from film credits or a date engraved on a building. A few frequent ones:

Clock faces are the classic exception worth knowing. Many dials write 4 as IIII instead of IV, a habit watchmakers kept for the visual balance of the dial. The converter follows the standard rule and always returns IV.