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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.

Network17.64.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
17.64.0.0
Broadcast address
17.95.255.255
First usable
17.64.0.1
Last usable
17.95.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 11400000 · Integer 289406976 to 291504127
Reverse DNS zones
64.17.in-addr.arpa
65.17.in-addr.arpa
66.17.in-addr.arpa
67.17.in-addr.arpa
68.17.in-addr.arpa
69.17.in-addr.arpa
70.17.in-addr.arpa
71.17.in-addr.arpa
72.17.in-addr.arpa
73.17.in-addr.arpa
74.17.in-addr.arpa
75.17.in-addr.arpa
76.17.in-addr.arpa
77.17.in-addr.arpa
78.17.in-addr.arpa
79.17.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010001.01000000.00000000.0000000017.64.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network00010001.01000000.00000000.0000000017.64.0.0
Broadcast00010001.01011111.11111111.1111111117.95.255.255
Split into smaller subnets/23
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

17.64.0.0/11 makes 4,096 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
117.64.0.0/2317.64.0.1 to 17.64.1.25417.64.1.255510
217.64.2.0/2317.64.2.1 to 17.64.3.25417.64.3.255510
317.64.4.0/2317.64.4.1 to 17.64.5.25417.64.5.255510
417.64.6.0/2317.64.6.1 to 17.64.7.25417.64.7.255510
517.64.8.0/2317.64.8.1 to 17.64.9.25417.64.9.255510
617.64.10.0/2317.64.10.1 to 17.64.11.25417.64.11.255510
717.64.12.0/2317.64.12.1 to 17.64.13.25417.64.13.255510
817.64.14.0/2317.64.14.1 to 17.64.15.25417.64.15.255510
917.64.16.0/2317.64.16.1 to 17.64.17.25417.64.17.255510
1017.64.18.0/2317.64.18.1 to 17.64.19.25417.64.19.255510
1117.64.20.0/2317.64.20.1 to 17.64.21.25417.64.21.255510
1217.64.22.0/2317.64.22.1 to 17.64.23.25417.64.23.255510
1317.64.24.0/2317.64.24.1 to 17.64.25.25417.64.25.255510
1417.64.26.0/2317.64.26.1 to 17.64.27.25417.64.27.255510
1517.64.28.0/2317.64.28.1 to 17.64.29.25417.64.29.255510
1617.64.30.0/2317.64.30.1 to 17.64.31.25417.64.31.255510
1717.64.32.0/2317.64.32.1 to 17.64.33.25417.64.33.255510
1817.64.34.0/2317.64.34.1 to 17.64.35.25417.64.35.255510
1917.64.36.0/2317.64.36.1 to 17.64.37.25417.64.37.255510
2017.64.38.0/2317.64.38.1 to 17.64.39.25417.64.39.255510
2117.64.40.0/2317.64.40.1 to 17.64.41.25417.64.41.255510
2217.64.42.0/2317.64.42.1 to 17.64.43.25417.64.43.255510
2317.64.44.0/2317.64.44.1 to 17.64.45.25417.64.45.255510
2417.64.46.0/2317.64.46.1 to 17.64.47.25417.64.47.255510
2517.64.48.0/2317.64.48.1 to 17.64.49.25417.64.49.255510
2617.64.50.0/2317.64.50.1 to 17.64.51.25417.64.51.255510
2717.64.52.0/2317.64.52.1 to 17.64.53.25417.64.53.255510
2817.64.54.0/2317.64.54.1 to 17.64.55.25417.64.55.255510
2917.64.56.0/2317.64.56.1 to 17.64.57.25417.64.57.255510
3017.64.58.0/2317.64.58.1 to 17.64.59.25417.64.59.255510
3117.64.60.0/2317.64.60.1 to 17.64.61.25417.64.61.255510
3217.64.62.0/2317.64.62.1 to 17.64.63.25417.64.63.255510
3317.64.64.0/2317.64.64.1 to 17.64.65.25417.64.65.255510
3417.64.66.0/2317.64.66.1 to 17.64.67.25417.64.67.255510
3517.64.68.0/2317.64.68.1 to 17.64.69.25417.64.69.255510
3617.64.70.0/2317.64.70.1 to 17.64.71.25417.64.71.255510
3717.64.72.0/2317.64.72.1 to 17.64.73.25417.64.73.255510
3817.64.74.0/2317.64.74.1 to 17.64.75.25417.64.75.255510
3917.64.76.0/2317.64.76.1 to 17.64.77.25417.64.77.255510
4017.64.78.0/2317.64.78.1 to 17.64.79.25417.64.79.255510
4117.64.80.0/2317.64.80.1 to 17.64.81.25417.64.81.255510
4217.64.82.0/2317.64.82.1 to 17.64.83.25417.64.83.255510
4317.64.84.0/2317.64.84.1 to 17.64.85.25417.64.85.255510
4417.64.86.0/2317.64.86.1 to 17.64.87.25417.64.87.255510
4517.64.88.0/2317.64.88.1 to 17.64.89.25417.64.89.255510
4617.64.90.0/2317.64.90.1 to 17.64.91.25417.64.91.255510
4717.64.92.0/2317.64.92.1 to 17.64.93.25417.64.93.255510
4817.64.94.0/2317.64.94.1 to 17.64.95.25417.64.95.255510
4917.64.96.0/2317.64.96.1 to 17.64.97.25417.64.97.255510
5017.64.98.0/2317.64.98.1 to 17.64.99.25417.64.99.255510
5117.64.100.0/2317.64.100.1 to 17.64.101.25417.64.101.255510
5217.64.102.0/2317.64.102.1 to 17.64.103.25417.64.103.255510
5317.64.104.0/2317.64.104.1 to 17.64.105.25417.64.105.255510
5417.64.106.0/2317.64.106.1 to 17.64.107.25417.64.107.255510
5517.64.108.0/2317.64.108.1 to 17.64.109.25417.64.109.255510
5617.64.110.0/2317.64.110.1 to 17.64.111.25417.64.111.255510
5717.64.112.0/2317.64.112.1 to 17.64.113.25417.64.113.255510
5817.64.114.0/2317.64.114.1 to 17.64.115.25417.64.115.255510
5917.64.116.0/2317.64.116.1 to 17.64.117.25417.64.117.255510
6017.64.118.0/2317.64.118.1 to 17.64.119.25417.64.119.255510
6117.64.120.0/2317.64.120.1 to 17.64.121.25417.64.121.255510
6217.64.122.0/2317.64.122.1 to 17.64.123.25417.64.123.255510
6317.64.124.0/2317.64.124.1 to 17.64.125.25417.64.125.255510
6417.64.126.0/2317.64.126.1 to 17.64.127.25417.64.127.255510
6517.64.128.0/2317.64.128.1 to 17.64.129.25417.64.129.255510
6617.64.130.0/2317.64.130.1 to 17.64.131.25417.64.131.255510
6717.64.132.0/2317.64.132.1 to 17.64.133.25417.64.133.255510
6817.64.134.0/2317.64.134.1 to 17.64.135.25417.64.135.255510
6917.64.136.0/2317.64.136.1 to 17.64.137.25417.64.137.255510
7017.64.138.0/2317.64.138.1 to 17.64.139.25417.64.139.255510
7117.64.140.0/2317.64.140.1 to 17.64.141.25417.64.141.255510
7217.64.142.0/2317.64.142.1 to 17.64.143.25417.64.143.255510
7317.64.144.0/2317.64.144.1 to 17.64.145.25417.64.145.255510
7417.64.146.0/2317.64.146.1 to 17.64.147.25417.64.147.255510
7517.64.148.0/2317.64.148.1 to 17.64.149.25417.64.149.255510
7617.64.150.0/2317.64.150.1 to 17.64.151.25417.64.151.255510
7717.64.152.0/2317.64.152.1 to 17.64.153.25417.64.153.255510
7817.64.154.0/2317.64.154.1 to 17.64.155.25417.64.155.255510
7917.64.156.0/2317.64.156.1 to 17.64.157.25417.64.157.255510
8017.64.158.0/2317.64.158.1 to 17.64.159.25417.64.159.255510
8117.64.160.0/2317.64.160.1 to 17.64.161.25417.64.161.255510
8217.64.162.0/2317.64.162.1 to 17.64.163.25417.64.163.255510
8317.64.164.0/2317.64.164.1 to 17.64.165.25417.64.165.255510
8417.64.166.0/2317.64.166.1 to 17.64.167.25417.64.167.255510
8517.64.168.0/2317.64.168.1 to 17.64.169.25417.64.169.255510
8617.64.170.0/2317.64.170.1 to 17.64.171.25417.64.171.255510
8717.64.172.0/2317.64.172.1 to 17.64.173.25417.64.173.255510
8817.64.174.0/2317.64.174.1 to 17.64.175.25417.64.175.255510
8917.64.176.0/2317.64.176.1 to 17.64.177.25417.64.177.255510
9017.64.178.0/2317.64.178.1 to 17.64.179.25417.64.179.255510
9117.64.180.0/2317.64.180.1 to 17.64.181.25417.64.181.255510
9217.64.182.0/2317.64.182.1 to 17.64.183.25417.64.183.255510
9317.64.184.0/2317.64.184.1 to 17.64.185.25417.64.185.255510
9417.64.186.0/2317.64.186.1 to 17.64.187.25417.64.187.255510
9517.64.188.0/2317.64.188.1 to 17.64.189.25417.64.189.255510
9617.64.190.0/2317.64.190.1 to 17.64.191.25417.64.191.255510
9717.64.192.0/2317.64.192.1 to 17.64.193.25417.64.193.255510
9817.64.194.0/2317.64.194.1 to 17.64.195.25417.64.195.255510
9917.64.196.0/2317.64.196.1 to 17.64.197.25417.64.197.255510
10017.64.198.0/2317.64.198.1 to 17.64.199.25417.64.199.255510
10117.64.200.0/2317.64.200.1 to 17.64.201.25417.64.201.255510
10217.64.202.0/2317.64.202.1 to 17.64.203.25417.64.203.255510
10317.64.204.0/2317.64.204.1 to 17.64.205.25417.64.205.255510
10417.64.206.0/2317.64.206.1 to 17.64.207.25417.64.207.255510
10517.64.208.0/2317.64.208.1 to 17.64.209.25417.64.209.255510
10617.64.210.0/2317.64.210.1 to 17.64.211.25417.64.211.255510
10717.64.212.0/2317.64.212.1 to 17.64.213.25417.64.213.255510
10817.64.214.0/2317.64.214.1 to 17.64.215.25417.64.215.255510
10917.64.216.0/2317.64.216.1 to 17.64.217.25417.64.217.255510
11017.64.218.0/2317.64.218.1 to 17.64.219.25417.64.219.255510
11117.64.220.0/2317.64.220.1 to 17.64.221.25417.64.221.255510
11217.64.222.0/2317.64.222.1 to 17.64.223.25417.64.223.255510
11317.64.224.0/2317.64.224.1 to 17.64.225.25417.64.225.255510
11417.64.226.0/2317.64.226.1 to 17.64.227.25417.64.227.255510
11517.64.228.0/2317.64.228.1 to 17.64.229.25417.64.229.255510
11617.64.230.0/2317.64.230.1 to 17.64.231.25417.64.231.255510
11717.64.232.0/2317.64.232.1 to 17.64.233.25417.64.233.255510
11817.64.234.0/2317.64.234.1 to 17.64.235.25417.64.235.255510
11917.64.236.0/2317.64.236.1 to 17.64.237.25417.64.237.255510
12017.64.238.0/2317.64.238.1 to 17.64.239.25417.64.239.255510
12117.64.240.0/2317.64.240.1 to 17.64.241.25417.64.241.255510
12217.64.242.0/2317.64.242.1 to 17.64.243.25417.64.243.255510
12317.64.244.0/2317.64.244.1 to 17.64.245.25417.64.245.255510
12417.64.246.0/2317.64.246.1 to 17.64.247.25417.64.247.255510
12517.64.248.0/2317.64.248.1 to 17.64.249.25417.64.249.255510
12617.64.250.0/2317.64.250.1 to 17.64.251.25417.64.251.255510
12717.64.252.0/2317.64.252.1 to 17.64.253.25417.64.253.255510
12817.64.254.0/2317.64.254.1 to 17.64.255.25417.64.255.255510
12917.65.0.0/2317.65.0.1 to 17.65.1.25417.65.1.255510
13017.65.2.0/2317.65.2.1 to 17.65.3.25417.65.3.255510
13117.65.4.0/2317.65.4.1 to 17.65.5.25417.65.5.255510
13217.65.6.0/2317.65.6.1 to 17.65.7.25417.65.7.255510
13317.65.8.0/2317.65.8.1 to 17.65.9.25417.65.9.255510
13417.65.10.0/2317.65.10.1 to 17.65.11.25417.65.11.255510
13517.65.12.0/2317.65.12.1 to 17.65.13.25417.65.13.255510
13617.65.14.0/2317.65.14.1 to 17.65.15.25417.65.15.255510
13717.65.16.0/2317.65.16.1 to 17.65.17.25417.65.17.255510
13817.65.18.0/2317.65.18.1 to 17.65.19.25417.65.19.255510
13917.65.20.0/2317.65.20.1 to 17.65.21.25417.65.21.255510
14017.65.22.0/2317.65.22.1 to 17.65.23.25417.65.23.255510
14117.65.24.0/2317.65.24.1 to 17.65.25.25417.65.25.255510
14217.65.26.0/2317.65.26.1 to 17.65.27.25417.65.27.255510
14317.65.28.0/2317.65.28.1 to 17.65.29.25417.65.29.255510
14417.65.30.0/2317.65.30.1 to 17.65.31.25417.65.31.255510
14517.65.32.0/2317.65.32.1 to 17.65.33.25417.65.33.255510
14617.65.34.0/2317.65.34.1 to 17.65.35.25417.65.35.255510
14717.65.36.0/2317.65.36.1 to 17.65.37.25417.65.37.255510
14817.65.38.0/2317.65.38.1 to 17.65.39.25417.65.39.255510
14917.65.40.0/2317.65.40.1 to 17.65.41.25417.65.41.255510
15017.65.42.0/2317.65.42.1 to 17.65.43.25417.65.43.255510
15117.65.44.0/2317.65.44.1 to 17.65.45.25417.65.45.255510
15217.65.46.0/2317.65.46.1 to 17.65.47.25417.65.47.255510
15317.65.48.0/2317.65.48.1 to 17.65.49.25417.65.49.255510
15417.65.50.0/2317.65.50.1 to 17.65.51.25417.65.51.255510
15517.65.52.0/2317.65.52.1 to 17.65.53.25417.65.53.255510
15617.65.54.0/2317.65.54.1 to 17.65.55.25417.65.55.255510
15717.65.56.0/2317.65.56.1 to 17.65.57.25417.65.57.255510
15817.65.58.0/2317.65.58.1 to 17.65.59.25417.65.59.255510
15917.65.60.0/2317.65.60.1 to 17.65.61.25417.65.61.255510
16017.65.62.0/2317.65.62.1 to 17.65.63.25417.65.63.255510
16117.65.64.0/2317.65.64.1 to 17.65.65.25417.65.65.255510
16217.65.66.0/2317.65.66.1 to 17.65.67.25417.65.67.255510
16317.65.68.0/2317.65.68.1 to 17.65.69.25417.65.69.255510
16417.65.70.0/2317.65.70.1 to 17.65.71.25417.65.71.255510
16517.65.72.0/2317.65.72.1 to 17.65.73.25417.65.73.255510
16617.65.74.0/2317.65.74.1 to 17.65.75.25417.65.75.255510
16717.65.76.0/2317.65.76.1 to 17.65.77.25417.65.77.255510
16817.65.78.0/2317.65.78.1 to 17.65.79.25417.65.79.255510
16917.65.80.0/2317.65.80.1 to 17.65.81.25417.65.81.255510
17017.65.82.0/2317.65.82.1 to 17.65.83.25417.65.83.255510
17117.65.84.0/2317.65.84.1 to 17.65.85.25417.65.85.255510
17217.65.86.0/2317.65.86.1 to 17.65.87.25417.65.87.255510
17317.65.88.0/2317.65.88.1 to 17.65.89.25417.65.89.255510
17417.65.90.0/2317.65.90.1 to 17.65.91.25417.65.91.255510
17517.65.92.0/2317.65.92.1 to 17.65.93.25417.65.93.255510
17617.65.94.0/2317.65.94.1 to 17.65.95.25417.65.95.255510
17717.65.96.0/2317.65.96.1 to 17.65.97.25417.65.97.255510
17817.65.98.0/2317.65.98.1 to 17.65.99.25417.65.99.255510
17917.65.100.0/2317.65.100.1 to 17.65.101.25417.65.101.255510
18017.65.102.0/2317.65.102.1 to 17.65.103.25417.65.103.255510
18117.65.104.0/2317.65.104.1 to 17.65.105.25417.65.105.255510
18217.65.106.0/2317.65.106.1 to 17.65.107.25417.65.107.255510
18317.65.108.0/2317.65.108.1 to 17.65.109.25417.65.109.255510
18417.65.110.0/2317.65.110.1 to 17.65.111.25417.65.111.255510
18517.65.112.0/2317.65.112.1 to 17.65.113.25417.65.113.255510
18617.65.114.0/2317.65.114.1 to 17.65.115.25417.65.115.255510
18717.65.116.0/2317.65.116.1 to 17.65.117.25417.65.117.255510
18817.65.118.0/2317.65.118.1 to 17.65.119.25417.65.119.255510
18917.65.120.0/2317.65.120.1 to 17.65.121.25417.65.121.255510
19017.65.122.0/2317.65.122.1 to 17.65.123.25417.65.123.255510
19117.65.124.0/2317.65.124.1 to 17.65.125.25417.65.125.255510
19217.65.126.0/2317.65.126.1 to 17.65.127.25417.65.127.255510
19317.65.128.0/2317.65.128.1 to 17.65.129.25417.65.129.255510
19417.65.130.0/2317.65.130.1 to 17.65.131.25417.65.131.255510
19517.65.132.0/2317.65.132.1 to 17.65.133.25417.65.133.255510
19617.65.134.0/2317.65.134.1 to 17.65.135.25417.65.135.255510
19717.65.136.0/2317.65.136.1 to 17.65.137.25417.65.137.255510
19817.65.138.0/2317.65.138.1 to 17.65.139.25417.65.139.255510
19917.65.140.0/2317.65.140.1 to 17.65.141.25417.65.141.255510
20017.65.142.0/2317.65.142.1 to 17.65.143.25417.65.143.255510
20117.65.144.0/2317.65.144.1 to 17.65.145.25417.65.145.255510
20217.65.146.0/2317.65.146.1 to 17.65.147.25417.65.147.255510
20317.65.148.0/2317.65.148.1 to 17.65.149.25417.65.149.255510
20417.65.150.0/2317.65.150.1 to 17.65.151.25417.65.151.255510
20517.65.152.0/2317.65.152.1 to 17.65.153.25417.65.153.255510
20617.65.154.0/2317.65.154.1 to 17.65.155.25417.65.155.255510
20717.65.156.0/2317.65.156.1 to 17.65.157.25417.65.157.255510
20817.65.158.0/2317.65.158.1 to 17.65.159.25417.65.159.255510
20917.65.160.0/2317.65.160.1 to 17.65.161.25417.65.161.255510
21017.65.162.0/2317.65.162.1 to 17.65.163.25417.65.163.255510
21117.65.164.0/2317.65.164.1 to 17.65.165.25417.65.165.255510
21217.65.166.0/2317.65.166.1 to 17.65.167.25417.65.167.255510
21317.65.168.0/2317.65.168.1 to 17.65.169.25417.65.169.255510
21417.65.170.0/2317.65.170.1 to 17.65.171.25417.65.171.255510
21517.65.172.0/2317.65.172.1 to 17.65.173.25417.65.173.255510
21617.65.174.0/2317.65.174.1 to 17.65.175.25417.65.175.255510
21717.65.176.0/2317.65.176.1 to 17.65.177.25417.65.177.255510
21817.65.178.0/2317.65.178.1 to 17.65.179.25417.65.179.255510
21917.65.180.0/2317.65.180.1 to 17.65.181.25417.65.181.255510
22017.65.182.0/2317.65.182.1 to 17.65.183.25417.65.183.255510
22117.65.184.0/2317.65.184.1 to 17.65.185.25417.65.185.255510
22217.65.186.0/2317.65.186.1 to 17.65.187.25417.65.187.255510
22317.65.188.0/2317.65.188.1 to 17.65.189.25417.65.189.255510
22417.65.190.0/2317.65.190.1 to 17.65.191.25417.65.191.255510
22517.65.192.0/2317.65.192.1 to 17.65.193.25417.65.193.255510
22617.65.194.0/2317.65.194.1 to 17.65.195.25417.65.195.255510
22717.65.196.0/2317.65.196.1 to 17.65.197.25417.65.197.255510
22817.65.198.0/2317.65.198.1 to 17.65.199.25417.65.199.255510
22917.65.200.0/2317.65.200.1 to 17.65.201.25417.65.201.255510
23017.65.202.0/2317.65.202.1 to 17.65.203.25417.65.203.255510
23117.65.204.0/2317.65.204.1 to 17.65.205.25417.65.205.255510
23217.65.206.0/2317.65.206.1 to 17.65.207.25417.65.207.255510
23317.65.208.0/2317.65.208.1 to 17.65.209.25417.65.209.255510
23417.65.210.0/2317.65.210.1 to 17.65.211.25417.65.211.255510
23517.65.212.0/2317.65.212.1 to 17.65.213.25417.65.213.255510
23617.65.214.0/2317.65.214.1 to 17.65.215.25417.65.215.255510
23717.65.216.0/2317.65.216.1 to 17.65.217.25417.65.217.255510
23817.65.218.0/2317.65.218.1 to 17.65.219.25417.65.219.255510
23917.65.220.0/2317.65.220.1 to 17.65.221.25417.65.221.255510
24017.65.222.0/2317.65.222.1 to 17.65.223.25417.65.223.255510
24117.65.224.0/2317.65.224.1 to 17.65.225.25417.65.225.255510
24217.65.226.0/2317.65.226.1 to 17.65.227.25417.65.227.255510
24317.65.228.0/2317.65.228.1 to 17.65.229.25417.65.229.255510
24417.65.230.0/2317.65.230.1 to 17.65.231.25417.65.231.255510
24517.65.232.0/2317.65.232.1 to 17.65.233.25417.65.233.255510
24617.65.234.0/2317.65.234.1 to 17.65.235.25417.65.235.255510
24717.65.236.0/2317.65.236.1 to 17.65.237.25417.65.237.255510
24817.65.238.0/2317.65.238.1 to 17.65.239.25417.65.239.255510
24917.65.240.0/2317.65.240.1 to 17.65.241.25417.65.241.255510
25017.65.242.0/2317.65.242.1 to 17.65.243.25417.65.243.255510
25117.65.244.0/2317.65.244.1 to 17.65.245.25417.65.245.255510
25217.65.246.0/2317.65.246.1 to 17.65.247.25417.65.247.255510
25317.65.248.0/2317.65.248.1 to 17.65.249.25417.65.249.255510
25417.65.250.0/2317.65.250.1 to 17.65.251.25417.65.251.255510
25517.65.252.0/2317.65.252.1 to 17.65.253.25417.65.253.255510
25617.65.254.0/2317.65.254.1 to 17.65.255.25417.65.255.255510

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.