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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network18.192.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
18.192.0.0
Broadcast address
18.255.255.255
First usable
18.192.0.1
Last usable
18.255.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 12C00000 · Integer 314572800 to 318767103
Reverse DNS zones
192.18.in-addr.arpa
193.18.in-addr.arpa
194.18.in-addr.arpa
195.18.in-addr.arpa
196.18.in-addr.arpa
197.18.in-addr.arpa
198.18.in-addr.arpa
199.18.in-addr.arpa
200.18.in-addr.arpa
201.18.in-addr.arpa
202.18.in-addr.arpa
203.18.in-addr.arpa
204.18.in-addr.arpa
205.18.in-addr.arpa
206.18.in-addr.arpa
207.18.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010010.11000000.00000000.0000000018.192.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00010010.11000000.00000000.0000000018.192.0.0
Broadcast00010010.11111111.11111111.1111111118.255.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

18.192.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
118.192.0.0/1818.192.0.1 to 18.192.63.25418.192.63.25516,382
218.192.64.0/1818.192.64.1 to 18.192.127.25418.192.127.25516,382
318.192.128.0/1818.192.128.1 to 18.192.191.25418.192.191.25516,382
418.192.192.0/1818.192.192.1 to 18.192.255.25418.192.255.25516,382
518.193.0.0/1818.193.0.1 to 18.193.63.25418.193.63.25516,382
618.193.64.0/1818.193.64.1 to 18.193.127.25418.193.127.25516,382
718.193.128.0/1818.193.128.1 to 18.193.191.25418.193.191.25516,382
818.193.192.0/1818.193.192.1 to 18.193.255.25418.193.255.25516,382
918.194.0.0/1818.194.0.1 to 18.194.63.25418.194.63.25516,382
1018.194.64.0/1818.194.64.1 to 18.194.127.25418.194.127.25516,382
1118.194.128.0/1818.194.128.1 to 18.194.191.25418.194.191.25516,382
1218.194.192.0/1818.194.192.1 to 18.194.255.25418.194.255.25516,382
1318.195.0.0/1818.195.0.1 to 18.195.63.25418.195.63.25516,382
1418.195.64.0/1818.195.64.1 to 18.195.127.25418.195.127.25516,382
1518.195.128.0/1818.195.128.1 to 18.195.191.25418.195.191.25516,382
1618.195.192.0/1818.195.192.1 to 18.195.255.25418.195.255.25516,382
1718.196.0.0/1818.196.0.1 to 18.196.63.25418.196.63.25516,382
1818.196.64.0/1818.196.64.1 to 18.196.127.25418.196.127.25516,382
1918.196.128.0/1818.196.128.1 to 18.196.191.25418.196.191.25516,382
2018.196.192.0/1818.196.192.1 to 18.196.255.25418.196.255.25516,382
2118.197.0.0/1818.197.0.1 to 18.197.63.25418.197.63.25516,382
2218.197.64.0/1818.197.64.1 to 18.197.127.25418.197.127.25516,382
2318.197.128.0/1818.197.128.1 to 18.197.191.25418.197.191.25516,382
2418.197.192.0/1818.197.192.1 to 18.197.255.25418.197.255.25516,382
2518.198.0.0/1818.198.0.1 to 18.198.63.25418.198.63.25516,382
2618.198.64.0/1818.198.64.1 to 18.198.127.25418.198.127.25516,382
2718.198.128.0/1818.198.128.1 to 18.198.191.25418.198.191.25516,382
2818.198.192.0/1818.198.192.1 to 18.198.255.25418.198.255.25516,382
2918.199.0.0/1818.199.0.1 to 18.199.63.25418.199.63.25516,382
3018.199.64.0/1818.199.64.1 to 18.199.127.25418.199.127.25516,382
3118.199.128.0/1818.199.128.1 to 18.199.191.25418.199.191.25516,382
3218.199.192.0/1818.199.192.1 to 18.199.255.25418.199.255.25516,382
3318.200.0.0/1818.200.0.1 to 18.200.63.25418.200.63.25516,382
3418.200.64.0/1818.200.64.1 to 18.200.127.25418.200.127.25516,382
3518.200.128.0/1818.200.128.1 to 18.200.191.25418.200.191.25516,382
3618.200.192.0/1818.200.192.1 to 18.200.255.25418.200.255.25516,382
3718.201.0.0/1818.201.0.1 to 18.201.63.25418.201.63.25516,382
3818.201.64.0/1818.201.64.1 to 18.201.127.25418.201.127.25516,382
3918.201.128.0/1818.201.128.1 to 18.201.191.25418.201.191.25516,382
4018.201.192.0/1818.201.192.1 to 18.201.255.25418.201.255.25516,382
4118.202.0.0/1818.202.0.1 to 18.202.63.25418.202.63.25516,382
4218.202.64.0/1818.202.64.1 to 18.202.127.25418.202.127.25516,382
4318.202.128.0/1818.202.128.1 to 18.202.191.25418.202.191.25516,382
4418.202.192.0/1818.202.192.1 to 18.202.255.25418.202.255.25516,382
4518.203.0.0/1818.203.0.1 to 18.203.63.25418.203.63.25516,382
4618.203.64.0/1818.203.64.1 to 18.203.127.25418.203.127.25516,382
4718.203.128.0/1818.203.128.1 to 18.203.191.25418.203.191.25516,382
4818.203.192.0/1818.203.192.1 to 18.203.255.25418.203.255.25516,382
4918.204.0.0/1818.204.0.1 to 18.204.63.25418.204.63.25516,382
5018.204.64.0/1818.204.64.1 to 18.204.127.25418.204.127.25516,382
5118.204.128.0/1818.204.128.1 to 18.204.191.25418.204.191.25516,382
5218.204.192.0/1818.204.192.1 to 18.204.255.25418.204.255.25516,382
5318.205.0.0/1818.205.0.1 to 18.205.63.25418.205.63.25516,382
5418.205.64.0/1818.205.64.1 to 18.205.127.25418.205.127.25516,382
5518.205.128.0/1818.205.128.1 to 18.205.191.25418.205.191.25516,382
5618.205.192.0/1818.205.192.1 to 18.205.255.25418.205.255.25516,382
5718.206.0.0/1818.206.0.1 to 18.206.63.25418.206.63.25516,382
5818.206.64.0/1818.206.64.1 to 18.206.127.25418.206.127.25516,382
5918.206.128.0/1818.206.128.1 to 18.206.191.25418.206.191.25516,382
6018.206.192.0/1818.206.192.1 to 18.206.255.25418.206.255.25516,382
6118.207.0.0/1818.207.0.1 to 18.207.63.25418.207.63.25516,382
6218.207.64.0/1818.207.64.1 to 18.207.127.25418.207.127.25516,382
6318.207.128.0/1818.207.128.1 to 18.207.191.25418.207.191.25516,382
6418.207.192.0/1818.207.192.1 to 18.207.255.25418.207.255.25516,382
6518.208.0.0/1818.208.0.1 to 18.208.63.25418.208.63.25516,382
6618.208.64.0/1818.208.64.1 to 18.208.127.25418.208.127.25516,382
6718.208.128.0/1818.208.128.1 to 18.208.191.25418.208.191.25516,382
6818.208.192.0/1818.208.192.1 to 18.208.255.25418.208.255.25516,382
6918.209.0.0/1818.209.0.1 to 18.209.63.25418.209.63.25516,382
7018.209.64.0/1818.209.64.1 to 18.209.127.25418.209.127.25516,382
7118.209.128.0/1818.209.128.1 to 18.209.191.25418.209.191.25516,382
7218.209.192.0/1818.209.192.1 to 18.209.255.25418.209.255.25516,382
7318.210.0.0/1818.210.0.1 to 18.210.63.25418.210.63.25516,382
7418.210.64.0/1818.210.64.1 to 18.210.127.25418.210.127.25516,382
7518.210.128.0/1818.210.128.1 to 18.210.191.25418.210.191.25516,382
7618.210.192.0/1818.210.192.1 to 18.210.255.25418.210.255.25516,382
7718.211.0.0/1818.211.0.1 to 18.211.63.25418.211.63.25516,382
7818.211.64.0/1818.211.64.1 to 18.211.127.25418.211.127.25516,382
7918.211.128.0/1818.211.128.1 to 18.211.191.25418.211.191.25516,382
8018.211.192.0/1818.211.192.1 to 18.211.255.25418.211.255.25516,382
8118.212.0.0/1818.212.0.1 to 18.212.63.25418.212.63.25516,382
8218.212.64.0/1818.212.64.1 to 18.212.127.25418.212.127.25516,382
8318.212.128.0/1818.212.128.1 to 18.212.191.25418.212.191.25516,382
8418.212.192.0/1818.212.192.1 to 18.212.255.25418.212.255.25516,382
8518.213.0.0/1818.213.0.1 to 18.213.63.25418.213.63.25516,382
8618.213.64.0/1818.213.64.1 to 18.213.127.25418.213.127.25516,382
8718.213.128.0/1818.213.128.1 to 18.213.191.25418.213.191.25516,382
8818.213.192.0/1818.213.192.1 to 18.213.255.25418.213.255.25516,382
8918.214.0.0/1818.214.0.1 to 18.214.63.25418.214.63.25516,382
9018.214.64.0/1818.214.64.1 to 18.214.127.25418.214.127.25516,382
9118.214.128.0/1818.214.128.1 to 18.214.191.25418.214.191.25516,382
9218.214.192.0/1818.214.192.1 to 18.214.255.25418.214.255.25516,382
9318.215.0.0/1818.215.0.1 to 18.215.63.25418.215.63.25516,382
9418.215.64.0/1818.215.64.1 to 18.215.127.25418.215.127.25516,382
9518.215.128.0/1818.215.128.1 to 18.215.191.25418.215.191.25516,382
9618.215.192.0/1818.215.192.1 to 18.215.255.25418.215.255.25516,382
9718.216.0.0/1818.216.0.1 to 18.216.63.25418.216.63.25516,382
9818.216.64.0/1818.216.64.1 to 18.216.127.25418.216.127.25516,382
9918.216.128.0/1818.216.128.1 to 18.216.191.25418.216.191.25516,382
10018.216.192.0/1818.216.192.1 to 18.216.255.25418.216.255.25516,382
10118.217.0.0/1818.217.0.1 to 18.217.63.25418.217.63.25516,382
10218.217.64.0/1818.217.64.1 to 18.217.127.25418.217.127.25516,382
10318.217.128.0/1818.217.128.1 to 18.217.191.25418.217.191.25516,382
10418.217.192.0/1818.217.192.1 to 18.217.255.25418.217.255.25516,382
10518.218.0.0/1818.218.0.1 to 18.218.63.25418.218.63.25516,382
10618.218.64.0/1818.218.64.1 to 18.218.127.25418.218.127.25516,382
10718.218.128.0/1818.218.128.1 to 18.218.191.25418.218.191.25516,382
10818.218.192.0/1818.218.192.1 to 18.218.255.25418.218.255.25516,382
10918.219.0.0/1818.219.0.1 to 18.219.63.25418.219.63.25516,382
11018.219.64.0/1818.219.64.1 to 18.219.127.25418.219.127.25516,382
11118.219.128.0/1818.219.128.1 to 18.219.191.25418.219.191.25516,382
11218.219.192.0/1818.219.192.1 to 18.219.255.25418.219.255.25516,382
11318.220.0.0/1818.220.0.1 to 18.220.63.25418.220.63.25516,382
11418.220.64.0/1818.220.64.1 to 18.220.127.25418.220.127.25516,382
11518.220.128.0/1818.220.128.1 to 18.220.191.25418.220.191.25516,382
11618.220.192.0/1818.220.192.1 to 18.220.255.25418.220.255.25516,382
11718.221.0.0/1818.221.0.1 to 18.221.63.25418.221.63.25516,382
11818.221.64.0/1818.221.64.1 to 18.221.127.25418.221.127.25516,382
11918.221.128.0/1818.221.128.1 to 18.221.191.25418.221.191.25516,382
12018.221.192.0/1818.221.192.1 to 18.221.255.25418.221.255.25516,382
12118.222.0.0/1818.222.0.1 to 18.222.63.25418.222.63.25516,382
12218.222.64.0/1818.222.64.1 to 18.222.127.25418.222.127.25516,382
12318.222.128.0/1818.222.128.1 to 18.222.191.25418.222.191.25516,382
12418.222.192.0/1818.222.192.1 to 18.222.255.25418.222.255.25516,382
12518.223.0.0/1818.223.0.1 to 18.223.63.25418.223.63.25516,382
12618.223.64.0/1818.223.64.1 to 18.223.127.25418.223.127.25516,382
12718.223.128.0/1818.223.128.1 to 18.223.191.25418.223.191.25516,382
12818.223.192.0/1818.223.192.1 to 18.223.255.25418.223.255.25516,382
12918.224.0.0/1818.224.0.1 to 18.224.63.25418.224.63.25516,382
13018.224.64.0/1818.224.64.1 to 18.224.127.25418.224.127.25516,382
13118.224.128.0/1818.224.128.1 to 18.224.191.25418.224.191.25516,382
13218.224.192.0/1818.224.192.1 to 18.224.255.25418.224.255.25516,382
13318.225.0.0/1818.225.0.1 to 18.225.63.25418.225.63.25516,382
13418.225.64.0/1818.225.64.1 to 18.225.127.25418.225.127.25516,382
13518.225.128.0/1818.225.128.1 to 18.225.191.25418.225.191.25516,382
13618.225.192.0/1818.225.192.1 to 18.225.255.25418.225.255.25516,382
13718.226.0.0/1818.226.0.1 to 18.226.63.25418.226.63.25516,382
13818.226.64.0/1818.226.64.1 to 18.226.127.25418.226.127.25516,382
13918.226.128.0/1818.226.128.1 to 18.226.191.25418.226.191.25516,382
14018.226.192.0/1818.226.192.1 to 18.226.255.25418.226.255.25516,382
14118.227.0.0/1818.227.0.1 to 18.227.63.25418.227.63.25516,382
14218.227.64.0/1818.227.64.1 to 18.227.127.25418.227.127.25516,382
14318.227.128.0/1818.227.128.1 to 18.227.191.25418.227.191.25516,382
14418.227.192.0/1818.227.192.1 to 18.227.255.25418.227.255.25516,382
14518.228.0.0/1818.228.0.1 to 18.228.63.25418.228.63.25516,382
14618.228.64.0/1818.228.64.1 to 18.228.127.25418.228.127.25516,382
14718.228.128.0/1818.228.128.1 to 18.228.191.25418.228.191.25516,382
14818.228.192.0/1818.228.192.1 to 18.228.255.25418.228.255.25516,382
14918.229.0.0/1818.229.0.1 to 18.229.63.25418.229.63.25516,382
15018.229.64.0/1818.229.64.1 to 18.229.127.25418.229.127.25516,382
15118.229.128.0/1818.229.128.1 to 18.229.191.25418.229.191.25516,382
15218.229.192.0/1818.229.192.1 to 18.229.255.25418.229.255.25516,382
15318.230.0.0/1818.230.0.1 to 18.230.63.25418.230.63.25516,382
15418.230.64.0/1818.230.64.1 to 18.230.127.25418.230.127.25516,382
15518.230.128.0/1818.230.128.1 to 18.230.191.25418.230.191.25516,382
15618.230.192.0/1818.230.192.1 to 18.230.255.25418.230.255.25516,382
15718.231.0.0/1818.231.0.1 to 18.231.63.25418.231.63.25516,382
15818.231.64.0/1818.231.64.1 to 18.231.127.25418.231.127.25516,382
15918.231.128.0/1818.231.128.1 to 18.231.191.25418.231.191.25516,382
16018.231.192.0/1818.231.192.1 to 18.231.255.25418.231.255.25516,382
16118.232.0.0/1818.232.0.1 to 18.232.63.25418.232.63.25516,382
16218.232.64.0/1818.232.64.1 to 18.232.127.25418.232.127.25516,382
16318.232.128.0/1818.232.128.1 to 18.232.191.25418.232.191.25516,382
16418.232.192.0/1818.232.192.1 to 18.232.255.25418.232.255.25516,382
16518.233.0.0/1818.233.0.1 to 18.233.63.25418.233.63.25516,382
16618.233.64.0/1818.233.64.1 to 18.233.127.25418.233.127.25516,382
16718.233.128.0/1818.233.128.1 to 18.233.191.25418.233.191.25516,382
16818.233.192.0/1818.233.192.1 to 18.233.255.25418.233.255.25516,382
16918.234.0.0/1818.234.0.1 to 18.234.63.25418.234.63.25516,382
17018.234.64.0/1818.234.64.1 to 18.234.127.25418.234.127.25516,382
17118.234.128.0/1818.234.128.1 to 18.234.191.25418.234.191.25516,382
17218.234.192.0/1818.234.192.1 to 18.234.255.25418.234.255.25516,382
17318.235.0.0/1818.235.0.1 to 18.235.63.25418.235.63.25516,382
17418.235.64.0/1818.235.64.1 to 18.235.127.25418.235.127.25516,382
17518.235.128.0/1818.235.128.1 to 18.235.191.25418.235.191.25516,382
17618.235.192.0/1818.235.192.1 to 18.235.255.25418.235.255.25516,382
17718.236.0.0/1818.236.0.1 to 18.236.63.25418.236.63.25516,382
17818.236.64.0/1818.236.64.1 to 18.236.127.25418.236.127.25516,382
17918.236.128.0/1818.236.128.1 to 18.236.191.25418.236.191.25516,382
18018.236.192.0/1818.236.192.1 to 18.236.255.25418.236.255.25516,382
18118.237.0.0/1818.237.0.1 to 18.237.63.25418.237.63.25516,382
18218.237.64.0/1818.237.64.1 to 18.237.127.25418.237.127.25516,382
18318.237.128.0/1818.237.128.1 to 18.237.191.25418.237.191.25516,382
18418.237.192.0/1818.237.192.1 to 18.237.255.25418.237.255.25516,382
18518.238.0.0/1818.238.0.1 to 18.238.63.25418.238.63.25516,382
18618.238.64.0/1818.238.64.1 to 18.238.127.25418.238.127.25516,382
18718.238.128.0/1818.238.128.1 to 18.238.191.25418.238.191.25516,382
18818.238.192.0/1818.238.192.1 to 18.238.255.25418.238.255.25516,382
18918.239.0.0/1818.239.0.1 to 18.239.63.25418.239.63.25516,382
19018.239.64.0/1818.239.64.1 to 18.239.127.25418.239.127.25516,382
19118.239.128.0/1818.239.128.1 to 18.239.191.25418.239.191.25516,382
19218.239.192.0/1818.239.192.1 to 18.239.255.25418.239.255.25516,382
19318.240.0.0/1818.240.0.1 to 18.240.63.25418.240.63.25516,382
19418.240.64.0/1818.240.64.1 to 18.240.127.25418.240.127.25516,382
19518.240.128.0/1818.240.128.1 to 18.240.191.25418.240.191.25516,382
19618.240.192.0/1818.240.192.1 to 18.240.255.25418.240.255.25516,382
19718.241.0.0/1818.241.0.1 to 18.241.63.25418.241.63.25516,382
19818.241.64.0/1818.241.64.1 to 18.241.127.25418.241.127.25516,382
19918.241.128.0/1818.241.128.1 to 18.241.191.25418.241.191.25516,382
20018.241.192.0/1818.241.192.1 to 18.241.255.25418.241.255.25516,382
20118.242.0.0/1818.242.0.1 to 18.242.63.25418.242.63.25516,382
20218.242.64.0/1818.242.64.1 to 18.242.127.25418.242.127.25516,382
20318.242.128.0/1818.242.128.1 to 18.242.191.25418.242.191.25516,382
20418.242.192.0/1818.242.192.1 to 18.242.255.25418.242.255.25516,382
20518.243.0.0/1818.243.0.1 to 18.243.63.25418.243.63.25516,382
20618.243.64.0/1818.243.64.1 to 18.243.127.25418.243.127.25516,382
20718.243.128.0/1818.243.128.1 to 18.243.191.25418.243.191.25516,382
20818.243.192.0/1818.243.192.1 to 18.243.255.25418.243.255.25516,382
20918.244.0.0/1818.244.0.1 to 18.244.63.25418.244.63.25516,382
21018.244.64.0/1818.244.64.1 to 18.244.127.25418.244.127.25516,382
21118.244.128.0/1818.244.128.1 to 18.244.191.25418.244.191.25516,382
21218.244.192.0/1818.244.192.1 to 18.244.255.25418.244.255.25516,382
21318.245.0.0/1818.245.0.1 to 18.245.63.25418.245.63.25516,382
21418.245.64.0/1818.245.64.1 to 18.245.127.25418.245.127.25516,382
21518.245.128.0/1818.245.128.1 to 18.245.191.25418.245.191.25516,382
21618.245.192.0/1818.245.192.1 to 18.245.255.25418.245.255.25516,382
21718.246.0.0/1818.246.0.1 to 18.246.63.25418.246.63.25516,382
21818.246.64.0/1818.246.64.1 to 18.246.127.25418.246.127.25516,382
21918.246.128.0/1818.246.128.1 to 18.246.191.25418.246.191.25516,382
22018.246.192.0/1818.246.192.1 to 18.246.255.25418.246.255.25516,382
22118.247.0.0/1818.247.0.1 to 18.247.63.25418.247.63.25516,382
22218.247.64.0/1818.247.64.1 to 18.247.127.25418.247.127.25516,382
22318.247.128.0/1818.247.128.1 to 18.247.191.25418.247.191.25516,382
22418.247.192.0/1818.247.192.1 to 18.247.255.25418.247.255.25516,382
22518.248.0.0/1818.248.0.1 to 18.248.63.25418.248.63.25516,382
22618.248.64.0/1818.248.64.1 to 18.248.127.25418.248.127.25516,382
22718.248.128.0/1818.248.128.1 to 18.248.191.25418.248.191.25516,382
22818.248.192.0/1818.248.192.1 to 18.248.255.25418.248.255.25516,382
22918.249.0.0/1818.249.0.1 to 18.249.63.25418.249.63.25516,382
23018.249.64.0/1818.249.64.1 to 18.249.127.25418.249.127.25516,382
23118.249.128.0/1818.249.128.1 to 18.249.191.25418.249.191.25516,382
23218.249.192.0/1818.249.192.1 to 18.249.255.25418.249.255.25516,382
23318.250.0.0/1818.250.0.1 to 18.250.63.25418.250.63.25516,382
23418.250.64.0/1818.250.64.1 to 18.250.127.25418.250.127.25516,382
23518.250.128.0/1818.250.128.1 to 18.250.191.25418.250.191.25516,382
23618.250.192.0/1818.250.192.1 to 18.250.255.25418.250.255.25516,382
23718.251.0.0/1818.251.0.1 to 18.251.63.25418.251.63.25516,382
23818.251.64.0/1818.251.64.1 to 18.251.127.25418.251.127.25516,382
23918.251.128.0/1818.251.128.1 to 18.251.191.25418.251.191.25516,382
24018.251.192.0/1818.251.192.1 to 18.251.255.25418.251.255.25516,382
24118.252.0.0/1818.252.0.1 to 18.252.63.25418.252.63.25516,382
24218.252.64.0/1818.252.64.1 to 18.252.127.25418.252.127.25516,382
24318.252.128.0/1818.252.128.1 to 18.252.191.25418.252.191.25516,382
24418.252.192.0/1818.252.192.1 to 18.252.255.25418.252.255.25516,382
24518.253.0.0/1818.253.0.1 to 18.253.63.25418.253.63.25516,382
24618.253.64.0/1818.253.64.1 to 18.253.127.25418.253.127.25516,382
24718.253.128.0/1818.253.128.1 to 18.253.191.25418.253.191.25516,382
24818.253.192.0/1818.253.192.1 to 18.253.255.25418.253.255.25516,382
24918.254.0.0/1818.254.0.1 to 18.254.63.25418.254.63.25516,382
25018.254.64.0/1818.254.64.1 to 18.254.127.25418.254.127.25516,382
25118.254.128.0/1818.254.128.1 to 18.254.191.25418.254.191.25516,382
25218.254.192.0/1818.254.192.1 to 18.254.255.25418.254.255.25516,382
25318.255.0.0/1818.255.0.1 to 18.255.63.25418.255.63.25516,382
25418.255.64.0/1818.255.64.1 to 18.255.127.25418.255.127.25516,382
25518.255.128.0/1818.255.128.1 to 18.255.191.25418.255.191.25516,382
25618.255.192.0/1818.255.192.1 to 18.255.255.25418.255.255.25516,382

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.