IPv4 Subnet Calculator
Calculate network, broadcast, host range and mask for any IPv4 subnet, and split it.
Network details
Binary
Continue your work
- IPv6 Subnet Calculator — Calculate IPv6 prefixes and subnets.
- Number Base Converter — Convert between binary and decimal.
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How to use the IPv4 Subnet Calculator
The IPv4 subnet calculator does the binary math of subnetting for you. Enter an IP address with a prefix like /24 or pick a subnet mask, and it shows the network and broadcast addresses, the first and last usable hosts, the number of hosts, the subnet and wildcard masks, the address class and type, and the address in binary. It can also split the network into smaller subnets.
- 1 Enter an IP address, optionally with a CIDR prefix like 10.0.0.5/20.
- 2 Choose the subnet mask if you did not type a prefix.
- 3 Read the network details and pick a size to divide the network into subnets.
Example and practical tips
For 192.168.1.10/24, the network is 192.168.1.0, the broadcast is 192.168.1.255 and the usable hosts run from .1 to .254, giving 254 hosts. Splitting it into /26 networks gives four subnets of 62 hosts each.
Frequently asked questions
What does /24 mean?
It is CIDR notation for how many bits belong to the network. /24 means the first 24 bits (the mask 255.255.255.0) identify the network, leaving 8 bits, or 256 addresses, for hosts.
Why are two addresses not usable?
In most subnets the first address identifies the network and the last is the broadcast address. /31 and /32 networks are special cases where every address is usable.
What is a wildcard mask?
It is the inverse of the subnet mask, used in router access lists and OSPF. For /24 it is 0.0.0.255.