9 in Roman numerals at a glance
- Roman numeral
- IX
- Lowercase
- ix
- Letters
- 2
- Parts
- IX
- Subtractive pairs
- IX
- In words
- nine
- Latin name
- novem
How IX is built
Roman numerals are written one decimal place at a time, from the largest place to the smallest. Converting each digit of 9 separately and joining the pieces gives IX:
| Place | Digit | Value | Numeral |
|---|---|---|---|
| Ones | 9 | 9 | IX |
Reading it back, left to right:
- IX = 9 (X minus I) → running total 9
The rules IX follows
- Largest to smallest. IX uses the symbols I and X (2 characters in all), and the values never increase from left to right except inside a subtractive pair.
- Subtraction. IX (9) is a subtractive pair: a smaller symbol in front of a larger one is taken away from it. Only six pairs are allowed — IV, IX, XL, XC, CD and CM — and IX uses one of them.
- No repeats. Every symbol in IX appears once in a row, which is why the numeral stays short.
Common mistakes when writing 9
- VIIII — wrong because standard numerals never repeat a symbol four times; 9 is written IX.
Where you will see IX
- Clock and watch faces. IX marks the 9 o’clock position.
- The U.S. Constitution. Amendments are often cited in Roman numerals: Amendment IX says rights not listed in the Constitution are still kept by the people (part of the Bill of Rights, ratified in 1791).
- Monarchs and popes. Regnal numbers use Roman numerals, as in Louis IX of France, the saint after whom St. Louis, Missouri, is named.
- The modern Summer Games. They are officially numbered by Olympiad; the Games of the IX Olympiad belong to 1928: Amsterdam.
- Championship games. Pro football numbers its championship game with Roman numerals, starting from game I in January 1967. Game IX was played in early 1975.
- A single character. Unicode has a dedicated symbol for IX: Ⅸ (U+2168), mainly so East Asian text can set the numeral in one character cell. For ordinary writing, use the plain letters.
- Lists and outlines. Book chapters, acts of a play, outline headings and the preface pages of many books (in lowercase: ix) are numbered this way.
Numbers near 9 in Roman numerals
Frequently asked questions
How do you write 9 in Roman numerals?
9 is written IX. It is a single symbol worth 9.
Is VIIII a correct way to write 9?
No. VIIII is wrong because standard numerals never repeat a symbol four times; 9 is written IX.
What is 9 in Latin?
The Latin cardinal number 9 is “novem.” The Romans wrote it as IX.
What is IX plus one?
IX + I = X (10). Adding one can change the whole ending of a numeral, which is why it helps to convert to digits, add, and convert back.