Octal

Numeral systems, bits and Gray code

hex	dec	oct	3	2	1	0	step
0hex	00dec	00oct	0	0	0	0	g0
1hex	01dec	01oct	0	0	0	1	h1
2hex	02dec	02oct	0	0	1	0	j3
3hex	03dec	03oct	0	0	1	1	i2
4hex	04dec	04oct	0	1	0	0	n7
5hex	05dec	05oct	0	1	0	1	m6
6hex	06dec	06oct	0	1	1	0	k4
7hex	07dec	07oct	0	1	1	1	l5
8hex	08dec	10oct	1	0	0	0	vF
9hex	09dec	11oct	1	0	0	1	uE
Ahex	10dec	12oct	1	0	1	0	sC
Bhex	11dec	13oct	1	0	1	1	tD
Chex	12dec	14oct	1	1	0	0	o8
Dhex	13dec	15oct	1	1	0	1	p9
Ehex	14dec	16oct	1	1	1	0	rB
Fhex	15dec	17oct	1	1	1	1	qA

Octal is a numeral system for representing a numeric value as base 8. Generally, an octal digit is represented as "0" to "7" with the same value as for decimal but with each place a power of 8. For example:

$\mathbf {112} _{8}=\mathbf {1} \times 8^{2}+\mathbf {1} \times 8^{1}+\mathbf {2} \times 8^{0}$

In decimal, each place is a power of ten. For example:

$\mathbf {74} _{10}=\mathbf {7} \times 10^{1}+\mathbf {4} \times 10^{0}$

An octal digit can represent the value of a 3-digit binary number (starting from the right). For example, the binary representation for decimal 74 is 1001010. Two zeroes can be added at the left: (00)1 001 010, corresponding to the octal digits 1 1 2, yielding the octal representation 112.