# Free Class A Subnetting tutorial, IP Address Subnetting, how to subnet Class A network

This lesson is only a part of a series of IPv4 subnetting lessons. All the basic concepts about subnetting are explained in Class C Subnetting Tutorial - Part 1 lesson. You must visit Class C Subnetting Tutorial - Part 1 lesson to understand the basic concepts of subnetting. Please visit below links in order to learn IPv4 subnetting completely.

### Class A 4-bit subnetting tutorial

If we include four bits to the network part from the host part in the second octet, the default subnet mask of a Class A network 255.0.0.0 is changed to 255.240.0.0. The four bits added to the network part from the host part, in the second octet, can have sixteen possible values. Those sixteen possible values are 0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 1010, 1011, 1100, 1101, 1110 and 1111.

That means, we get sixteen subnets if we do a 4-bit subnetting for a Class A network.

SN No Description Binaries Decimal

Class A IPv4 Subnetting can be summerized as below.

0 255.0.0.0 /8 1 16777214
1 255.128.0.0 /9 2 8388606
2 255.192.0.0 /10 4 4194302
3 255.224.0.0 /11 8 2097150
4 255.240.0.0 /12 16 1048574
5 255.248.0.0 /13 32 524286
6 255.252.0.0 /14 64 262142
7 255.254.0.0 /15 128 131070
8 255.255.0.0 /16 256 65534
9 255.255.128.0 /17 512 32766
10 255.255.192.0 /18 1024 16382
11 255.255.224.0 /19 2048 8190
12 255.255.240.0 /20 4096 4094
13 255.255.248.0 /21 8192 2046
14 255.255.252.0 /22 16384 1022
15 255.255.254.0 /23 32768 510
16 255.255.255.0 /24 65536 254
17 255.255.255.128 /25 131072 126
18 255.255.255.192 /26 262144 62
19 255.255.255.224 /27 524288 30
20 255.255.255.240 /28 1048576 14
21 255.255.255.248 /29 2097152 6
22 255.255.255.252 /30 4194304 2

If you practice previous lesson examples and the above example in this lesson, you can clearly understand how to subnet a Class A network. Try to practice and find yourself the network address, usable IPv4 address range and the directed broadcast address of remaining 5-bit and 6-bit, 7-bit, 8-bit, 9-bit, 10-bit, 11-bit, 12-bit, 13-bit, 14-bit, 15-bit, 17-bit, 18-bit, 19-bit, 20-bit, 21-bit and 22-bit Class A subnets.

In this Class A Subnetting Tutorial - Part 2, You have learned how to perform a Class A 4 bit subnetting. Click "Next" to continue.