UniGeniusNetwork+

Network+

Subnet calculator

Type any IPv4 address with a prefix or a mask. Everything updates as you type.

For example 10.20.30.40/22 or 10.20.30.40 255.255.252.0

The smallest prefix that holds them

Usable hosts

62

192.168.10.64/26

Network
192.168.10.64
Broadcast
192.168.10.127
Host range
192.168.10.65 to 192.168.10.126
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63
Addresses in block
64
Class
C
Type
Private (RFC 1918)
Prefix for 50 hosts
/26

Subnetting drill

One question at a time on a fresh network. Work it out by hand, then check.

Work it out by hand, then check.

Try the free subnetting lab

Prefixes, masks and host counts

PrefixMaskAddressesUsable hosts
/18255.255.192.016,38416,382
/19255.255.224.08,1928,190
/20255.255.240.04,0964,094
/21255.255.248.02,0482,046
/22255.255.252.01,0241,022
/23255.255.254.0512510
/24255.255.255.0256254
/25255.255.255.128128126
/26255.255.255.1926462
/27255.255.255.2243230
/28255.255.255.2401614
/29255.255.255.24886
/30255.255.255.25242

Then the whole exam

The free diagnostic has 15 questions across all five domains and takes 15 minutes. No account. You get your score in each domain and a short lesson on the one to fix first.

Take the free diagnosticTry the free subnetting lab

Questions people ask

How do you work out the number of usable hosts?

Take the host bits, 32 minus the prefix. 2 to that power is the number of addresses; subtract 2 for the network and broadcast addresses. A /26 has 6 host bits: 64 addresses, 62 usable.

What is the broadcast address of a subnet?

The last address in the block. Find the block size from the prefix, find the block the address sits in, and take its last address. 192.168.10.77/26 sits in .64 to .127, so the broadcast is 192.168.10.127.

What are the private IPv4 ranges?

10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (RFC 1918). 169.254.0.0/16 is link-local, which Windows calls APIPA, and 127.0.0.0/8 is loopback.