How do Roman numerals work?

Roman numerals use letters: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, and M is 1000. Letters are added together, but a smaller letter before a larger one is subtracted, so IV is 4 and IX is 9.

What is the largest Roman numeral?

Using the standard letters, the largest commonly written value is 3,999, or MMMCMXCIX. Beyond that, bars over letters were used to multiply by a thousand. This converter handles 1 to 3,999.

Is there a zero in Roman numerals?

No. The Roman system has no symbol for zero, which is one reason it is awkward for arithmetic. It starts at one, written I.

Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals back to numbers. Enter a number from 1 to 3,999, or type a Roman numeral, and the converter shows the other instantly. Handy for dates, clock faces, chapter numbers, and movie credits.

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Number to Roman numeral

Number (1 to 3999)

MMXXVI

Roman numeral

Roman numeral to number

Roman numeral

number

The rules

The letters are I, V, X, L, C, D, and M for 1, 5, 10, 50, 100, 500, and 1000. You add them up from largest to smallest, but when a smaller letter sits before a larger one it is subtracted, which is how IV is 4 and XC is 90.

Worked example

2026 is MMXXVI: two thousands (MM), two tens (XX), a five (V), and a one (I). The year 14 is XIV: ten (X) plus four (IV).

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Standard Calculator: everyday arithmetic.

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