13 = XIII
13 in Roman numerals is XIII.
Thirteen written with the letters X I I I.
13 in words: Thirteen
Thirteen in Roman numerals is XIII. You build it as X (10) + III (3), writing the larger part first and reading left to right.
Everything in XIII is additive here, so you simply add each letter's value together. Numbers like this are a good place to get comfortable before tackling the subtractive forms such as IV and IX.
How 13 breaks down
Reading XIII from left to right, each group is added together to reach 13:
| Group | Value | Place |
|---|---|---|
| X | 10 | tens |
| III | 3 | ones |
| XIII | 13 | total |
Frequently asked questions
What is 13 in Roman numerals?
13 in Roman numerals is XIII.
How do you write 13 in words?
13 is written "Thirteen" in English.
What number comes before XIII?
The number before XIII is 12, written XII in Roman numerals.
What number comes after XIII?
The number after XIII is 14, written XIV in Roman numerals.
Related numbers
Last updated July 22, 2026. Reviewed for accuracy against the standard rules for Roman numerals.