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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.

Network17.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
17.0.0.0
Broadcast address
17.255.255.255
First usable
17.0.0.1
Last usable
17.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 11000000 · Integer 285212672 to 301989887
Reverse DNS zone
17.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010001..00000000.00000000.0000000017.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00010001..00000000.00000000.0000000017.0.0.0
Broadcast00010001..11111111.11111111.1111111117.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

17.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
117.0.0.0/1617.0.0.1 to 17.0.255.25417.0.255.25565,534
217.1.0.0/1617.1.0.1 to 17.1.255.25417.1.255.25565,534
317.2.0.0/1617.2.0.1 to 17.2.255.25417.2.255.25565,534
417.3.0.0/1617.3.0.1 to 17.3.255.25417.3.255.25565,534
517.4.0.0/1617.4.0.1 to 17.4.255.25417.4.255.25565,534
617.5.0.0/1617.5.0.1 to 17.5.255.25417.5.255.25565,534
717.6.0.0/1617.6.0.1 to 17.6.255.25417.6.255.25565,534
817.7.0.0/1617.7.0.1 to 17.7.255.25417.7.255.25565,534
917.8.0.0/1617.8.0.1 to 17.8.255.25417.8.255.25565,534
1017.9.0.0/1617.9.0.1 to 17.9.255.25417.9.255.25565,534
1117.10.0.0/1617.10.0.1 to 17.10.255.25417.10.255.25565,534
1217.11.0.0/1617.11.0.1 to 17.11.255.25417.11.255.25565,534
1317.12.0.0/1617.12.0.1 to 17.12.255.25417.12.255.25565,534
1417.13.0.0/1617.13.0.1 to 17.13.255.25417.13.255.25565,534
1517.14.0.0/1617.14.0.1 to 17.14.255.25417.14.255.25565,534
1617.15.0.0/1617.15.0.1 to 17.15.255.25417.15.255.25565,534
1717.16.0.0/1617.16.0.1 to 17.16.255.25417.16.255.25565,534
1817.17.0.0/1617.17.0.1 to 17.17.255.25417.17.255.25565,534
1917.18.0.0/1617.18.0.1 to 17.18.255.25417.18.255.25565,534
2017.19.0.0/1617.19.0.1 to 17.19.255.25417.19.255.25565,534
2117.20.0.0/1617.20.0.1 to 17.20.255.25417.20.255.25565,534
2217.21.0.0/1617.21.0.1 to 17.21.255.25417.21.255.25565,534
2317.22.0.0/1617.22.0.1 to 17.22.255.25417.22.255.25565,534
2417.23.0.0/1617.23.0.1 to 17.23.255.25417.23.255.25565,534
2517.24.0.0/1617.24.0.1 to 17.24.255.25417.24.255.25565,534
2617.25.0.0/1617.25.0.1 to 17.25.255.25417.25.255.25565,534
2717.26.0.0/1617.26.0.1 to 17.26.255.25417.26.255.25565,534
2817.27.0.0/1617.27.0.1 to 17.27.255.25417.27.255.25565,534
2917.28.0.0/1617.28.0.1 to 17.28.255.25417.28.255.25565,534
3017.29.0.0/1617.29.0.1 to 17.29.255.25417.29.255.25565,534
3117.30.0.0/1617.30.0.1 to 17.30.255.25417.30.255.25565,534
3217.31.0.0/1617.31.0.1 to 17.31.255.25417.31.255.25565,534
3317.32.0.0/1617.32.0.1 to 17.32.255.25417.32.255.25565,534
3417.33.0.0/1617.33.0.1 to 17.33.255.25417.33.255.25565,534
3517.34.0.0/1617.34.0.1 to 17.34.255.25417.34.255.25565,534
3617.35.0.0/1617.35.0.1 to 17.35.255.25417.35.255.25565,534
3717.36.0.0/1617.36.0.1 to 17.36.255.25417.36.255.25565,534
3817.37.0.0/1617.37.0.1 to 17.37.255.25417.37.255.25565,534
3917.38.0.0/1617.38.0.1 to 17.38.255.25417.38.255.25565,534
4017.39.0.0/1617.39.0.1 to 17.39.255.25417.39.255.25565,534
4117.40.0.0/1617.40.0.1 to 17.40.255.25417.40.255.25565,534
4217.41.0.0/1617.41.0.1 to 17.41.255.25417.41.255.25565,534
4317.42.0.0/1617.42.0.1 to 17.42.255.25417.42.255.25565,534
4417.43.0.0/1617.43.0.1 to 17.43.255.25417.43.255.25565,534
4517.44.0.0/1617.44.0.1 to 17.44.255.25417.44.255.25565,534
4617.45.0.0/1617.45.0.1 to 17.45.255.25417.45.255.25565,534
4717.46.0.0/1617.46.0.1 to 17.46.255.25417.46.255.25565,534
4817.47.0.0/1617.47.0.1 to 17.47.255.25417.47.255.25565,534
4917.48.0.0/1617.48.0.1 to 17.48.255.25417.48.255.25565,534
5017.49.0.0/1617.49.0.1 to 17.49.255.25417.49.255.25565,534
5117.50.0.0/1617.50.0.1 to 17.50.255.25417.50.255.25565,534
5217.51.0.0/1617.51.0.1 to 17.51.255.25417.51.255.25565,534
5317.52.0.0/1617.52.0.1 to 17.52.255.25417.52.255.25565,534
5417.53.0.0/1617.53.0.1 to 17.53.255.25417.53.255.25565,534
5517.54.0.0/1617.54.0.1 to 17.54.255.25417.54.255.25565,534
5617.55.0.0/1617.55.0.1 to 17.55.255.25417.55.255.25565,534
5717.56.0.0/1617.56.0.1 to 17.56.255.25417.56.255.25565,534
5817.57.0.0/1617.57.0.1 to 17.57.255.25417.57.255.25565,534
5917.58.0.0/1617.58.0.1 to 17.58.255.25417.58.255.25565,534
6017.59.0.0/1617.59.0.1 to 17.59.255.25417.59.255.25565,534
6117.60.0.0/1617.60.0.1 to 17.60.255.25417.60.255.25565,534
6217.61.0.0/1617.61.0.1 to 17.61.255.25417.61.255.25565,534
6317.62.0.0/1617.62.0.1 to 17.62.255.25417.62.255.25565,534
6417.63.0.0/1617.63.0.1 to 17.63.255.25417.63.255.25565,534
6517.64.0.0/1617.64.0.1 to 17.64.255.25417.64.255.25565,534
6617.65.0.0/1617.65.0.1 to 17.65.255.25417.65.255.25565,534
6717.66.0.0/1617.66.0.1 to 17.66.255.25417.66.255.25565,534
6817.67.0.0/1617.67.0.1 to 17.67.255.25417.67.255.25565,534
6917.68.0.0/1617.68.0.1 to 17.68.255.25417.68.255.25565,534
7017.69.0.0/1617.69.0.1 to 17.69.255.25417.69.255.25565,534
7117.70.0.0/1617.70.0.1 to 17.70.255.25417.70.255.25565,534
7217.71.0.0/1617.71.0.1 to 17.71.255.25417.71.255.25565,534
7317.72.0.0/1617.72.0.1 to 17.72.255.25417.72.255.25565,534
7417.73.0.0/1617.73.0.1 to 17.73.255.25417.73.255.25565,534
7517.74.0.0/1617.74.0.1 to 17.74.255.25417.74.255.25565,534
7617.75.0.0/1617.75.0.1 to 17.75.255.25417.75.255.25565,534
7717.76.0.0/1617.76.0.1 to 17.76.255.25417.76.255.25565,534
7817.77.0.0/1617.77.0.1 to 17.77.255.25417.77.255.25565,534
7917.78.0.0/1617.78.0.1 to 17.78.255.25417.78.255.25565,534
8017.79.0.0/1617.79.0.1 to 17.79.255.25417.79.255.25565,534
8117.80.0.0/1617.80.0.1 to 17.80.255.25417.80.255.25565,534
8217.81.0.0/1617.81.0.1 to 17.81.255.25417.81.255.25565,534
8317.82.0.0/1617.82.0.1 to 17.82.255.25417.82.255.25565,534
8417.83.0.0/1617.83.0.1 to 17.83.255.25417.83.255.25565,534
8517.84.0.0/1617.84.0.1 to 17.84.255.25417.84.255.25565,534
8617.85.0.0/1617.85.0.1 to 17.85.255.25417.85.255.25565,534
8717.86.0.0/1617.86.0.1 to 17.86.255.25417.86.255.25565,534
8817.87.0.0/1617.87.0.1 to 17.87.255.25417.87.255.25565,534
8917.88.0.0/1617.88.0.1 to 17.88.255.25417.88.255.25565,534
9017.89.0.0/1617.89.0.1 to 17.89.255.25417.89.255.25565,534
9117.90.0.0/1617.90.0.1 to 17.90.255.25417.90.255.25565,534
9217.91.0.0/1617.91.0.1 to 17.91.255.25417.91.255.25565,534
9317.92.0.0/1617.92.0.1 to 17.92.255.25417.92.255.25565,534
9417.93.0.0/1617.93.0.1 to 17.93.255.25417.93.255.25565,534
9517.94.0.0/1617.94.0.1 to 17.94.255.25417.94.255.25565,534
9617.95.0.0/1617.95.0.1 to 17.95.255.25417.95.255.25565,534
9717.96.0.0/1617.96.0.1 to 17.96.255.25417.96.255.25565,534
9817.97.0.0/1617.97.0.1 to 17.97.255.25417.97.255.25565,534
9917.98.0.0/1617.98.0.1 to 17.98.255.25417.98.255.25565,534
10017.99.0.0/1617.99.0.1 to 17.99.255.25417.99.255.25565,534
10117.100.0.0/1617.100.0.1 to 17.100.255.25417.100.255.25565,534
10217.101.0.0/1617.101.0.1 to 17.101.255.25417.101.255.25565,534
10317.102.0.0/1617.102.0.1 to 17.102.255.25417.102.255.25565,534
10417.103.0.0/1617.103.0.1 to 17.103.255.25417.103.255.25565,534
10517.104.0.0/1617.104.0.1 to 17.104.255.25417.104.255.25565,534
10617.105.0.0/1617.105.0.1 to 17.105.255.25417.105.255.25565,534
10717.106.0.0/1617.106.0.1 to 17.106.255.25417.106.255.25565,534
10817.107.0.0/1617.107.0.1 to 17.107.255.25417.107.255.25565,534
10917.108.0.0/1617.108.0.1 to 17.108.255.25417.108.255.25565,534
11017.109.0.0/1617.109.0.1 to 17.109.255.25417.109.255.25565,534
11117.110.0.0/1617.110.0.1 to 17.110.255.25417.110.255.25565,534
11217.111.0.0/1617.111.0.1 to 17.111.255.25417.111.255.25565,534
11317.112.0.0/1617.112.0.1 to 17.112.255.25417.112.255.25565,534
11417.113.0.0/1617.113.0.1 to 17.113.255.25417.113.255.25565,534
11517.114.0.0/1617.114.0.1 to 17.114.255.25417.114.255.25565,534
11617.115.0.0/1617.115.0.1 to 17.115.255.25417.115.255.25565,534
11717.116.0.0/1617.116.0.1 to 17.116.255.25417.116.255.25565,534
11817.117.0.0/1617.117.0.1 to 17.117.255.25417.117.255.25565,534
11917.118.0.0/1617.118.0.1 to 17.118.255.25417.118.255.25565,534
12017.119.0.0/1617.119.0.1 to 17.119.255.25417.119.255.25565,534
12117.120.0.0/1617.120.0.1 to 17.120.255.25417.120.255.25565,534
12217.121.0.0/1617.121.0.1 to 17.121.255.25417.121.255.25565,534
12317.122.0.0/1617.122.0.1 to 17.122.255.25417.122.255.25565,534
12417.123.0.0/1617.123.0.1 to 17.123.255.25417.123.255.25565,534
12517.124.0.0/1617.124.0.1 to 17.124.255.25417.124.255.25565,534
12617.125.0.0/1617.125.0.1 to 17.125.255.25417.125.255.25565,534
12717.126.0.0/1617.126.0.1 to 17.126.255.25417.126.255.25565,534
12817.127.0.0/1617.127.0.1 to 17.127.255.25417.127.255.25565,534
12917.128.0.0/1617.128.0.1 to 17.128.255.25417.128.255.25565,534
13017.129.0.0/1617.129.0.1 to 17.129.255.25417.129.255.25565,534
13117.130.0.0/1617.130.0.1 to 17.130.255.25417.130.255.25565,534
13217.131.0.0/1617.131.0.1 to 17.131.255.25417.131.255.25565,534
13317.132.0.0/1617.132.0.1 to 17.132.255.25417.132.255.25565,534
13417.133.0.0/1617.133.0.1 to 17.133.255.25417.133.255.25565,534
13517.134.0.0/1617.134.0.1 to 17.134.255.25417.134.255.25565,534
13617.135.0.0/1617.135.0.1 to 17.135.255.25417.135.255.25565,534
13717.136.0.0/1617.136.0.1 to 17.136.255.25417.136.255.25565,534
13817.137.0.0/1617.137.0.1 to 17.137.255.25417.137.255.25565,534
13917.138.0.0/1617.138.0.1 to 17.138.255.25417.138.255.25565,534
14017.139.0.0/1617.139.0.1 to 17.139.255.25417.139.255.25565,534
14117.140.0.0/1617.140.0.1 to 17.140.255.25417.140.255.25565,534
14217.141.0.0/1617.141.0.1 to 17.141.255.25417.141.255.25565,534
14317.142.0.0/1617.142.0.1 to 17.142.255.25417.142.255.25565,534
14417.143.0.0/1617.143.0.1 to 17.143.255.25417.143.255.25565,534
14517.144.0.0/1617.144.0.1 to 17.144.255.25417.144.255.25565,534
14617.145.0.0/1617.145.0.1 to 17.145.255.25417.145.255.25565,534
14717.146.0.0/1617.146.0.1 to 17.146.255.25417.146.255.25565,534
14817.147.0.0/1617.147.0.1 to 17.147.255.25417.147.255.25565,534
14917.148.0.0/1617.148.0.1 to 17.148.255.25417.148.255.25565,534
15017.149.0.0/1617.149.0.1 to 17.149.255.25417.149.255.25565,534
15117.150.0.0/1617.150.0.1 to 17.150.255.25417.150.255.25565,534
15217.151.0.0/1617.151.0.1 to 17.151.255.25417.151.255.25565,534
15317.152.0.0/1617.152.0.1 to 17.152.255.25417.152.255.25565,534
15417.153.0.0/1617.153.0.1 to 17.153.255.25417.153.255.25565,534
15517.154.0.0/1617.154.0.1 to 17.154.255.25417.154.255.25565,534
15617.155.0.0/1617.155.0.1 to 17.155.255.25417.155.255.25565,534
15717.156.0.0/1617.156.0.1 to 17.156.255.25417.156.255.25565,534
15817.157.0.0/1617.157.0.1 to 17.157.255.25417.157.255.25565,534
15917.158.0.0/1617.158.0.1 to 17.158.255.25417.158.255.25565,534
16017.159.0.0/1617.159.0.1 to 17.159.255.25417.159.255.25565,534
16117.160.0.0/1617.160.0.1 to 17.160.255.25417.160.255.25565,534
16217.161.0.0/1617.161.0.1 to 17.161.255.25417.161.255.25565,534
16317.162.0.0/1617.162.0.1 to 17.162.255.25417.162.255.25565,534
16417.163.0.0/1617.163.0.1 to 17.163.255.25417.163.255.25565,534
16517.164.0.0/1617.164.0.1 to 17.164.255.25417.164.255.25565,534
16617.165.0.0/1617.165.0.1 to 17.165.255.25417.165.255.25565,534
16717.166.0.0/1617.166.0.1 to 17.166.255.25417.166.255.25565,534
16817.167.0.0/1617.167.0.1 to 17.167.255.25417.167.255.25565,534
16917.168.0.0/1617.168.0.1 to 17.168.255.25417.168.255.25565,534
17017.169.0.0/1617.169.0.1 to 17.169.255.25417.169.255.25565,534
17117.170.0.0/1617.170.0.1 to 17.170.255.25417.170.255.25565,534
17217.171.0.0/1617.171.0.1 to 17.171.255.25417.171.255.25565,534
17317.172.0.0/1617.172.0.1 to 17.172.255.25417.172.255.25565,534
17417.173.0.0/1617.173.0.1 to 17.173.255.25417.173.255.25565,534
17517.174.0.0/1617.174.0.1 to 17.174.255.25417.174.255.25565,534
17617.175.0.0/1617.175.0.1 to 17.175.255.25417.175.255.25565,534
17717.176.0.0/1617.176.0.1 to 17.176.255.25417.176.255.25565,534
17817.177.0.0/1617.177.0.1 to 17.177.255.25417.177.255.25565,534
17917.178.0.0/1617.178.0.1 to 17.178.255.25417.178.255.25565,534
18017.179.0.0/1617.179.0.1 to 17.179.255.25417.179.255.25565,534
18117.180.0.0/1617.180.0.1 to 17.180.255.25417.180.255.25565,534
18217.181.0.0/1617.181.0.1 to 17.181.255.25417.181.255.25565,534
18317.182.0.0/1617.182.0.1 to 17.182.255.25417.182.255.25565,534
18417.183.0.0/1617.183.0.1 to 17.183.255.25417.183.255.25565,534
18517.184.0.0/1617.184.0.1 to 17.184.255.25417.184.255.25565,534
18617.185.0.0/1617.185.0.1 to 17.185.255.25417.185.255.25565,534
18717.186.0.0/1617.186.0.1 to 17.186.255.25417.186.255.25565,534
18817.187.0.0/1617.187.0.1 to 17.187.255.25417.187.255.25565,534
18917.188.0.0/1617.188.0.1 to 17.188.255.25417.188.255.25565,534
19017.189.0.0/1617.189.0.1 to 17.189.255.25417.189.255.25565,534
19117.190.0.0/1617.190.0.1 to 17.190.255.25417.190.255.25565,534
19217.191.0.0/1617.191.0.1 to 17.191.255.25417.191.255.25565,534
19317.192.0.0/1617.192.0.1 to 17.192.255.25417.192.255.25565,534
19417.193.0.0/1617.193.0.1 to 17.193.255.25417.193.255.25565,534
19517.194.0.0/1617.194.0.1 to 17.194.255.25417.194.255.25565,534
19617.195.0.0/1617.195.0.1 to 17.195.255.25417.195.255.25565,534
19717.196.0.0/1617.196.0.1 to 17.196.255.25417.196.255.25565,534
19817.197.0.0/1617.197.0.1 to 17.197.255.25417.197.255.25565,534
19917.198.0.0/1617.198.0.1 to 17.198.255.25417.198.255.25565,534
20017.199.0.0/1617.199.0.1 to 17.199.255.25417.199.255.25565,534
20117.200.0.0/1617.200.0.1 to 17.200.255.25417.200.255.25565,534
20217.201.0.0/1617.201.0.1 to 17.201.255.25417.201.255.25565,534
20317.202.0.0/1617.202.0.1 to 17.202.255.25417.202.255.25565,534
20417.203.0.0/1617.203.0.1 to 17.203.255.25417.203.255.25565,534
20517.204.0.0/1617.204.0.1 to 17.204.255.25417.204.255.25565,534
20617.205.0.0/1617.205.0.1 to 17.205.255.25417.205.255.25565,534
20717.206.0.0/1617.206.0.1 to 17.206.255.25417.206.255.25565,534
20817.207.0.0/1617.207.0.1 to 17.207.255.25417.207.255.25565,534
20917.208.0.0/1617.208.0.1 to 17.208.255.25417.208.255.25565,534
21017.209.0.0/1617.209.0.1 to 17.209.255.25417.209.255.25565,534
21117.210.0.0/1617.210.0.1 to 17.210.255.25417.210.255.25565,534
21217.211.0.0/1617.211.0.1 to 17.211.255.25417.211.255.25565,534
21317.212.0.0/1617.212.0.1 to 17.212.255.25417.212.255.25565,534
21417.213.0.0/1617.213.0.1 to 17.213.255.25417.213.255.25565,534
21517.214.0.0/1617.214.0.1 to 17.214.255.25417.214.255.25565,534
21617.215.0.0/1617.215.0.1 to 17.215.255.25417.215.255.25565,534
21717.216.0.0/1617.216.0.1 to 17.216.255.25417.216.255.25565,534
21817.217.0.0/1617.217.0.1 to 17.217.255.25417.217.255.25565,534
21917.218.0.0/1617.218.0.1 to 17.218.255.25417.218.255.25565,534
22017.219.0.0/1617.219.0.1 to 17.219.255.25417.219.255.25565,534
22117.220.0.0/1617.220.0.1 to 17.220.255.25417.220.255.25565,534
22217.221.0.0/1617.221.0.1 to 17.221.255.25417.221.255.25565,534
22317.222.0.0/1617.222.0.1 to 17.222.255.25417.222.255.25565,534
22417.223.0.0/1617.223.0.1 to 17.223.255.25417.223.255.25565,534
22517.224.0.0/1617.224.0.1 to 17.224.255.25417.224.255.25565,534
22617.225.0.0/1617.225.0.1 to 17.225.255.25417.225.255.25565,534
22717.226.0.0/1617.226.0.1 to 17.226.255.25417.226.255.25565,534
22817.227.0.0/1617.227.0.1 to 17.227.255.25417.227.255.25565,534
22917.228.0.0/1617.228.0.1 to 17.228.255.25417.228.255.25565,534
23017.229.0.0/1617.229.0.1 to 17.229.255.25417.229.255.25565,534
23117.230.0.0/1617.230.0.1 to 17.230.255.25417.230.255.25565,534
23217.231.0.0/1617.231.0.1 to 17.231.255.25417.231.255.25565,534
23317.232.0.0/1617.232.0.1 to 17.232.255.25417.232.255.25565,534
23417.233.0.0/1617.233.0.1 to 17.233.255.25417.233.255.25565,534
23517.234.0.0/1617.234.0.1 to 17.234.255.25417.234.255.25565,534
23617.235.0.0/1617.235.0.1 to 17.235.255.25417.235.255.25565,534
23717.236.0.0/1617.236.0.1 to 17.236.255.25417.236.255.25565,534
23817.237.0.0/1617.237.0.1 to 17.237.255.25417.237.255.25565,534
23917.238.0.0/1617.238.0.1 to 17.238.255.25417.238.255.25565,534
24017.239.0.0/1617.239.0.1 to 17.239.255.25417.239.255.25565,534
24117.240.0.0/1617.240.0.1 to 17.240.255.25417.240.255.25565,534
24217.241.0.0/1617.241.0.1 to 17.241.255.25417.241.255.25565,534
24317.242.0.0/1617.242.0.1 to 17.242.255.25417.242.255.25565,534
24417.243.0.0/1617.243.0.1 to 17.243.255.25417.243.255.25565,534
24517.244.0.0/1617.244.0.1 to 17.244.255.25417.244.255.25565,534
24617.245.0.0/1617.245.0.1 to 17.245.255.25417.245.255.25565,534
24717.246.0.0/1617.246.0.1 to 17.246.255.25417.246.255.25565,534
24817.247.0.0/1617.247.0.1 to 17.247.255.25417.247.255.25565,534
24917.248.0.0/1617.248.0.1 to 17.248.255.25417.248.255.25565,534
25017.249.0.0/1617.249.0.1 to 17.249.255.25417.249.255.25565,534
25117.250.0.0/1617.250.0.1 to 17.250.255.25417.250.255.25565,534
25217.251.0.0/1617.251.0.1 to 17.251.255.25417.251.255.25565,534
25317.252.0.0/1617.252.0.1 to 17.252.255.25417.252.255.25565,534
25417.253.0.0/1617.253.0.1 to 17.253.255.25417.253.255.25565,534
25517.254.0.0/1617.254.0.1 to 17.254.255.25417.254.255.25565,534
25617.255.0.0/1617.255.0.1 to 17.255.255.25417.255.255.25565,534

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.