13 in Roman numerals is XIII, built from X + III (X = 10, III = 3), which add up to 13.
How 13 is written in Roman numerals
The number 13 is written XIII in Roman numerals. Roman numerals use seven letters — I (1), V (5), X (10), L (50), C (100), D (500) and M (1000) — combined from largest to smallest, with subtractive pairs such as IV (4) and IX (9). Need another number? Use the Roman numeral converter or see the 1–100 chart.
Building XIII step by step — take the largest value that fits, write its symbol, subtract, repeat.
| Write | Value | Remaining before | Remaining after |
|---|
| X | 10 | 13 | 3 |
| I | 1 | 3 | 2 |
| I | 1 | 2 | 1 |
| I | 1 | 1 | 0 |
Where you see XIII
Regnal and papal names use it the same way — a 13th ruler of a name is styled XIII, as in Louis XIII or Pope John XIII. The 13th Super Bowl was Super Bowl XIII; the NFL has used Roman numerals for every edition except Super Bowl 50.
Nearby numbers
Popular numbers in Roman numerals
Frequently Asked Questions
What is 13 in Roman numerals?
13 in Roman numerals is XIII. Reading it left to right gives X (10) + I (1) + I (1) + I (1) = 13. The number below it, 12, is written XII, and the number above it, 14, is written XIV.
How do you write 13 in Roman numerals?
Write 13 as XIII, combining X (10) + I (1) + I (1) + I (1). Roman numerals are built by taking the largest value that still fits, writing its symbol and subtracting it, which reduces 13 in 4 steps: X leaves 3, I leaves 2, I leaves 1, I leaves 0. Every symbol keeps the same value wherever it stands, so the order is fixed and XIII is the only standard spelling of 13.
Which letters make up XIII?
XIII is made up of X once and I three times. X is worth 10 and I is worth 1. Added together those values come to 13, because Roman numerals are read by summing the symbols from left to right.
How is XIII read out loud?
XIII is read as the number it stands for, thirteen, and never letter by letter. Roman numerals are a way of writing values rather than a separate set of names, so the spoken form is the same whether the page shows 13 or XIII. A chapter or volume numbered XIII, for instance, is simply chapter thirteen.