ASCII 9
ASCII 9 is Horizontal Tab — the control character HT.
Every representation
| Character | HT (not printable) |
| Name | Horizontal Tab |
| Decimal | 9 |
| Hexadecimal | 0x09 |
| Octal | 0011 |
| Binary | 00001001 |
| HTML entity | 	 |
| Escape sequence | \\t |
| Unicode | U+0009 |
| Keyboard | Ctrl+I |
| Group | Control character |
What it is for
Advances to the next tab stop. The width of a tab is a display convention rather than a property of the character, which is the entire reason tabs-versus-spaces is an argument.
Where the number comes from
Codes 0 to 31 were reserved for control: instructions to a teleprinter rather than characters to print. Code 9 is Ctrl+I because the Ctrl key was originally wired to clear the top two bits of whatever you typed, mapping the letter I at 73 down to 9.
Frequently asked questions
What is ASCII 9?
Horizontal Tab (HT), a control character. In hexadecimal it is 0x09, in octal 0011, and in binary 00001001.
How do I type ASCII 9?
Press Ctrl+I in a terminal. In a string literal you can write it as \\t or \\x09 in most languages.
Is ASCII 9 printable?
No. Codes 0 to 31 and 127 are control characters — they were instructions to a teleprinter rather than marks on paper, and most terminals show nothing for them.
Nearby codes
- ASCII 2 — STX
- ASCII 3 — ETX
- ASCII 4 — EOT
- ASCII 5 — ENQ
- ASCII 6 — ACK
- ASCII 7 — BEL
- ASCII 8 — BS
- ASCII 10 — LF
- ASCII 11 — VT
- ASCII 12 — FF
- ASCII 13 — CR
- ASCII 14 — SO
- ASCII 15 — SI
- ASCII 16 — DLE
Full ASCII table · Text to binary converter · Number base converter