13 in Roman numerals at a glance
- Roman numeral
- XIII
- Lowercase
- xiii
- Letters
- 4
- Parts
- X · I · I · I
- Subtractive pairs
- None
- In words
- thirteen
- Latin name
- tredecim
How XIII is built
Roman numerals are written one decimal place at a time, from the largest place to the smallest. Converting each digit of 13 separately and joining the pieces gives XIII:
| Place | Digit | Value | Numeral |
|---|---|---|---|
| Tens | 1 | 10 | X |
| Ones | 3 | 3 | III |
Reading it back, left to right:
- X = 10 → running total 10
- I = 1 → running total 11
- I = 1 → running total 12
- I = 1 → running total 13
The rules XIII follows
- Largest to smallest. XIII uses the symbols X and I (4 characters in all), and the values never increase from left to right except inside a subtractive pair.
- No subtraction needed. None of the digits of 13 is a 4 or a 9, so XIII is purely additive: just add the symbol values.
- Repetition. III repeats I three times. I, X, C and M may repeat up to three times in a row; V, L and D never repeat.
Where you will see XIII
- The U.S. Constitution. Amendments are often cited in Roman numerals: Amendment XIII abolished slavery (ratified in 1865).
- Monarchs and popes. Regnal numbers use Roman numerals, as in Pope Leo XIII, pope from 1878 to 1903.
- The modern Summer Games. They are officially numbered by Olympiad; the Games of the XIII Olympiad belong to 1944: London (cancelled because of World War II).
- Championship games. Pro football numbers its championship game with Roman numerals, starting from game I in January 1967. Game XIII was played in early 1979.
- Lists and outlines. Book chapters, acts of a play, outline headings and the preface pages of many books (in lowercase: xiii) are numbered this way.
Numbers near 13 in Roman numerals
Frequently asked questions
How do you write 13 in Roman numerals?
13 is written XIII. Break it into X (10), I (1), I (1), I (1) and add the parts: 10 + 1 + 1 + 1 = 13.
What is 13 in Latin?
The Latin cardinal number 13 is “tredecim.” The Romans wrote it as XIII.
What is XIII plus one?
XIII + I = XIV (14). Adding one can change the whole ending of a numeral, which is why it helps to convert to digits, add, and convert back.