Octal to Decimal
Type a octal number below to get the decimal value — other bases are shown too. The manual method is explained further down.
Try it
Custom base
Two’s complement
How to convert by hand
Multiply each digit by 8 raised to its position, counting from 0 on the right:
755 = 7×8^2 + 5×8^1 + 5×8^0
= 7×64 + 5×8 + 5×1
= 493
Reference table
Octal → Decimal
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
10 8
11 9
12 10
13 11
14 12
15 13
16 14
17 15
20 16
40 32
100 64
144 100
177 127
200 128
377 255
400 256
1750 1000
2000 1024
10000 4096
177777 65535
In code
JavaScript
parseInt('755', 8) // 493Python
int('755', 8) # 493