13 in Roman numerals
XIII
The number 13 is written XIII in Roman numerals.
How XIII breaks down
| Symbols | Value |
|---|---|
X | 10 |
III | 3 × 1 = 3 |
XIII | 13 |
Every symbol here is written in descending order and simply added together — no subtractive pairs are involved.
Nearby numbers
| Number | Roman numeral |
|---|---|
| 8 | VIII |
| 9 | IX |
| 10 | X |
| 11 | XI |
| 12 | XII |
| 13 | XIII |
| 14 | XIV |
| 15 | XV |
| 16 | XVI |
| 17 | XVII |
| 18 | XVIII |
The seven symbols
I | 1 | C | 100 |
V | 5 | D | 500 |
X | 10 | M | 1,000 |
L | 50 |
13 in other notations
| Roman | XIII |
| Binary | 1101 |
| Hexadecimal | D |
| Octal | 15 |
| Written out | thirteen |
Writing it by hand
Work down through the symbol values, taking as many of each as will fit before moving to the next. For 13:
X = 10 remaining: 3
3 × I = 3 remaining: 0The result reads XIII — 4 characters, against 2 digits in Arabic numerals.
Frequently asked questions
What is 13 in Roman numerals?
XIII
How do you read XIII?
Work left to right, adding each symbol — except where a smaller symbol precedes a larger one, in which case it is subtracted. X is 10, III is 3, giving 13 in total.
How do you write 13 in words?
thirteen.
Why is there no zero?
Roman numerals have no symbol for zero. The concept reached Europe only with Hindu-Arabic numerals, centuries after the system was in use — which is a large part of why it was eventually replaced for arithmetic.