Octal is a base8
numbering system that uses eight digits, from 0 to 7. Hexadecimal is a base16
numbering system that uses sixteen digits, from 0 to 9 and A to F. In order to convert an octal number to hexadecimal number, you need to first convert the octal number to binary number, and then convert the binary number to hexadecimal number.
Conversion
Here are the steps to convert an octal number to hexadecimal number:
 Identify the octal number you want to convert.
 Convert the octal number to binary number. You can use the steps outlined in our previous article on how to convert octal number to binary number to convert the octal number to binary number.
 Convert the binary number to hexadecimal number. You can use the table below.
Example
Here’s an example to illustrate the conversion process:
Let’s say we have the octal number 345. To convert this octal number to hexadecimal number, we need to first convert the octal number to binary number, and then convert the binary number to hexadecimal number:

Convert the octal number to binary number:
3 > 011 4 > 100 5 > 101
Combining these binary representations, we get the binary number
011100101
. 
Convert the binary number to hexadecimal number:
0111 > 7 0010 > 2 0101 > 5
Combining these hexadecimal digits, we get the hexadecimal number E5.
Therefore, the octal number 345
corresponds to the hexadecimal number E5
.
OctalBinary Table
Octal  Binary 

0  000 
1  001 
2  010 
3  011 
4  100 
5  101 
6  110 
7  111 
BinaryHexadecimal Table
Binary  Hexadecimal 

0000  0 
0001  1 
0010  2 
0011  3 
0100  4 
0101  5 
0110  6 
0111  7 
1000  8 
1001  9 
1010  A 
1011  B 
1100  C 
1101  D 
1110  E 
1111  F 