What is 11111111 binary in octal?

11111111 in binary (base 2) equals 377 in octal (base 8), which is 255 in decimal.

How do I convert binary to octal by hand?

Convert binary to decimal first (11111111 = 255), then convert that decimal value to octal (255 = 377). The tool above does both steps for you.

Is this exact for very large numbers?

Yes. The converter uses big-integer (BigInt) arithmetic in your browser, so even very long binary values convert to octal with no rounding or precision loss.

Which characters are valid in binary?

Base-2 binary uses the digits 0 and 1. Spaces, underscores and an optional 0x/0b/0o prefix are ignored; any other character is flagged as invalid.

Binary to Octal Converter

Convert a binary (base 2) number to octal (base 8) instantly. As an example, 11111111 = 377. It runs entirely in your browser.

Binary value

Octal result

Base	This number
Binary (base 2)	`—`
Octal (base 8)	`—`
Decimal (base 10)	`—`
Hexadecimal (base 16)	`—`

How to convert binary to octal

The simplest route from binary to octal goes through decimal: convert the binary value to decimal, then convert that to octal.

11111111 (binary) = 255 (decimal) = 377 (octal)

Worked example: 11111111 in octal

Reading 11111111 as base 2: 1 × 2⁷ (= 128) + 1 × 2⁶ (= 64) + 1 × 2⁵ (= 32) + 1 × 2⁴ (= 16) + 1 × 2³ (= 8) + 1 × 2² (= 4) + 1 × 2¹ (= 2) + 1 × 2⁰ (= 1) = 255 in decimal, which is 377 in octal.

More binary-to-octal examples: 1010 = 12, 10000 = 20, 1000000 = 100.

Binary, octal, decimal & hexadecimal reference table

Decimal	Binary	Octal	Hex
1	`1`	`1`	`1`
2	`10`	`2`	`2`
4	`100`	`4`	`4`
8	`1000`	`10`	`8`
10	`1010`	`12`	`A`
15	`1111`	`17`	`F`
16	`10000`	`20`	`10`
32	`100000`	`40`	`20`
64	`1000000`	`100`	`40`
100	`1100100`	`144`	`64`
128	`10000000`	`200`	`80`
255	`11111111`	`377`	`FF`
256	`100000000`	`400`	`100`
1024	`10000000000`	`2000`	`400`

About binary and octal

Binary: Binary is base-2: every digit (bit) is 0 or 1. It is how computers store and process all data at the hardware level.

Octal: Octal is base-8, using digits 0–7. Each octal digit maps to exactly three bits, which is why it appears in Unix file-permission modes such as 755.

Frequently asked questions

What is 11111111 binary in octal?: 11111111 in binary (base 2) equals 377 in octal (base 8), which is 255 in decimal.
How do I convert binary to octal by hand?: Convert binary to decimal first (11111111 = 255), then convert that decimal value to octal (255 = 377). The tool above does both steps for you.
Is this exact for very large numbers?: Yes. The converter uses big-integer (BigInt) arithmetic in your browser, so even very long binary values convert to octal with no rounding or precision loss.
Which characters are valid in binary?: Base-2 binary uses the digits 0 and 1. Spaces, underscores and an optional 0x/0b/0o prefix are ignored; any other character is flagged as invalid.

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