21 in Roman Numerals
The number 21 is written XXI in Roman numerals. Reading left to right and adding the values gives 10 + 10 + 1 = 21. Roman numerals use seven letters: I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). A smaller letter before a larger one means subtraction (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900).
XXI in names
Popes, monarchs, films and Super Bowls whose name carries XXI. Source: Wikidata, retrieved 11 October 2026.
Nearby & popular values
Frequently asked
What is 21 in Roman numerals?
21 in Roman numerals is XXI.
How is 21 written in Roman numerals?
21 is written XXI, which breaks down as 10 + 10 + 1 = 21.
Is there a Roman numeral for zero?
No. The Roman system has no symbol for zero, which is one reason it was eventually replaced for calculation.