ASCII 127 — the DEL character

Not a visible character

DEL is control code 127, hex 7F. You type it as ^?, and it draws nothing on screen.

Characters that draw nothing and instead tell the device to do something.

What this control code did

Delete

Others · Deleting, cancelling, and ESC — the key that opens a second meaning.

Seven bits

ASCII is seven bits wide, which is why there are 128 of them. The eighth bit was long left for parity.

1111111

One bit — the sixth, worth 32 — separates the cases. Off gives a capital, on gives a lowercase letter.

Kind: Control
Decimal: 127
Hexadecimal: 0x7F
Octal: 177
Binary: 1111111
HTML entity
URL encoding: %7F
CSS escape: \7F
Ctrl key: ^?

The chart

Eight columns for the top three bits, sixteen rows for the bottom four. The capitals column sits right beside the lowercase one — that is the shape of the table.

Codes either side

124 · |125 · }126 · ~

How to read this

Add 32 to a capital and you get the lowercase letter — one bit flips.
Digits start at 48, so subtracting 48 from the code gives the number.
Holding Ctrl clears the top three bits — that is why Ctrl+I is a tab.
Everything under 32, plus 127, draws nothing. Those show their abbreviation instead.

Frequently asked questions

Q. What is the ASCII code for DEL?

Decimal 127, hex 7F, octal 177, binary 1111111.

Q. How do I write DEL in HTML?

As .

Q. How does it go in a URL?

It is encoded as %7F.

Q. How do I type DEL?

^?.