Subnet Calculator

Calculate number of hosts, host address range, subnet ID, broadcast IP address etc



IP Subnet calculator uses IP address & subnet mask or /CIDR notation to calculate no. of hosts, IP address range, Network & Broadcast IP address, and Start & End of an IP Range in a network.


What is an IP Subnet?

An IP subnet or just a subnetwork is a logical subdivision of an IP network. The practice of dividing a network using subnet mask into two or more smaller networks is called subnetting

On a network, a computer is identified by its IP address. The IP address of a computer is logically divided into two fields, a network (The network to which the computer belongs) and the host field (an identifier for the computer as a host on that network).

If a network is large, we divide that network into smaller networks for better management using a subnet mask. A Subnet mask is a 32-bit number that masks an IP address, and divides the IP address into network address and host address.


How Subnetting is done?

Subnetting is done by performing a bitwise AND operation on the IP address of the host and the subnet mask.

Subnet Mask is made by setting network bits to all "1"s and setting host bits to all "0"s. Within a given network, two host addresses are reserved for special purpose, and cannot be assigned to hosts. The "0" address is assigned a network address and "255" is assigned to a broadcast address, and they cannot be assigned to hosts.

Here is an Example of Subnetting of Class C IP address:

IP Address 1100 0000 . 1010 1000 . 0000 1010 . 0000 0000 (192.168.10.0)
Subnet Mask 1111 1111 . 1111 1111 . 1111 1111 . 1010 1000 (255.255.255.168)
After AND operation 1100 0000 . 1010 1000 . 0000 1010 . 0000 0000 (192.168.10.0)

So total number of hosts in a network = 32
And total number of Subnetworks = = 8
That means each of these 8 subnetworks will have 32 hosts within them.

Here is the range of IP Address from the above example:
First IP address of the range (Or the Network address) Last IP address of the range (or the Broadcast Address) Number of Hosts
192.198.10.0 192.198.10.31 32
192.198.10.32 192.198.10.63 32
192.198.10.64 192.198.10.95 32
192.198.10.96 192.198.10.127 32
192.198.10.128 192.198.10.159 32
192.198.10.160 192.198.10.191 32
192.198.10.192 192.198.10.223 32
192.198.10.224 192.198.10.255 32

These all complex calculations can easily be calculated using the IP subnet Calculator or also called as the Subnet mask calculator.
IP subnet Calculator / Subnet mask calculator comes very handy if you are a network administrator and you have to create a subnet out of a large network.

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