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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.

Network17.78.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
17.78.0.0
Broadcast address
17.79.255.255
First usable
17.78.0.1
Last usable
17.79.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 114E0000 · Integer 290324480 to 290455551
Reverse DNS zones
78.17.in-addr.arpa
79.17.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010001.01001110.00000000.0000000017.78.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00010001.01001110.00000000.0000000017.78.0.0
Broadcast00010001.01001111.11111111.1111111117.79.255.255
Split into smaller subnets/24
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

17.78.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
117.78.0.0/2417.78.0.1 to 17.78.0.25417.78.0.255254
217.78.1.0/2417.78.1.1 to 17.78.1.25417.78.1.255254
317.78.2.0/2417.78.2.1 to 17.78.2.25417.78.2.255254
417.78.3.0/2417.78.3.1 to 17.78.3.25417.78.3.255254
517.78.4.0/2417.78.4.1 to 17.78.4.25417.78.4.255254
617.78.5.0/2417.78.5.1 to 17.78.5.25417.78.5.255254
717.78.6.0/2417.78.6.1 to 17.78.6.25417.78.6.255254
817.78.7.0/2417.78.7.1 to 17.78.7.25417.78.7.255254
917.78.8.0/2417.78.8.1 to 17.78.8.25417.78.8.255254
1017.78.9.0/2417.78.9.1 to 17.78.9.25417.78.9.255254
1117.78.10.0/2417.78.10.1 to 17.78.10.25417.78.10.255254
1217.78.11.0/2417.78.11.1 to 17.78.11.25417.78.11.255254
1317.78.12.0/2417.78.12.1 to 17.78.12.25417.78.12.255254
1417.78.13.0/2417.78.13.1 to 17.78.13.25417.78.13.255254
1517.78.14.0/2417.78.14.1 to 17.78.14.25417.78.14.255254
1617.78.15.0/2417.78.15.1 to 17.78.15.25417.78.15.255254
1717.78.16.0/2417.78.16.1 to 17.78.16.25417.78.16.255254
1817.78.17.0/2417.78.17.1 to 17.78.17.25417.78.17.255254
1917.78.18.0/2417.78.18.1 to 17.78.18.25417.78.18.255254
2017.78.19.0/2417.78.19.1 to 17.78.19.25417.78.19.255254
2117.78.20.0/2417.78.20.1 to 17.78.20.25417.78.20.255254
2217.78.21.0/2417.78.21.1 to 17.78.21.25417.78.21.255254
2317.78.22.0/2417.78.22.1 to 17.78.22.25417.78.22.255254
2417.78.23.0/2417.78.23.1 to 17.78.23.25417.78.23.255254
2517.78.24.0/2417.78.24.1 to 17.78.24.25417.78.24.255254
2617.78.25.0/2417.78.25.1 to 17.78.25.25417.78.25.255254
2717.78.26.0/2417.78.26.1 to 17.78.26.25417.78.26.255254
2817.78.27.0/2417.78.27.1 to 17.78.27.25417.78.27.255254
2917.78.28.0/2417.78.28.1 to 17.78.28.25417.78.28.255254
3017.78.29.0/2417.78.29.1 to 17.78.29.25417.78.29.255254
3117.78.30.0/2417.78.30.1 to 17.78.30.25417.78.30.255254
3217.78.31.0/2417.78.31.1 to 17.78.31.25417.78.31.255254
3317.78.32.0/2417.78.32.1 to 17.78.32.25417.78.32.255254
3417.78.33.0/2417.78.33.1 to 17.78.33.25417.78.33.255254
3517.78.34.0/2417.78.34.1 to 17.78.34.25417.78.34.255254
3617.78.35.0/2417.78.35.1 to 17.78.35.25417.78.35.255254
3717.78.36.0/2417.78.36.1 to 17.78.36.25417.78.36.255254
3817.78.37.0/2417.78.37.1 to 17.78.37.25417.78.37.255254
3917.78.38.0/2417.78.38.1 to 17.78.38.25417.78.38.255254
4017.78.39.0/2417.78.39.1 to 17.78.39.25417.78.39.255254
4117.78.40.0/2417.78.40.1 to 17.78.40.25417.78.40.255254
4217.78.41.0/2417.78.41.1 to 17.78.41.25417.78.41.255254
4317.78.42.0/2417.78.42.1 to 17.78.42.25417.78.42.255254
4417.78.43.0/2417.78.43.1 to 17.78.43.25417.78.43.255254
4517.78.44.0/2417.78.44.1 to 17.78.44.25417.78.44.255254
4617.78.45.0/2417.78.45.1 to 17.78.45.25417.78.45.255254
4717.78.46.0/2417.78.46.1 to 17.78.46.25417.78.46.255254
4817.78.47.0/2417.78.47.1 to 17.78.47.25417.78.47.255254
4917.78.48.0/2417.78.48.1 to 17.78.48.25417.78.48.255254
5017.78.49.0/2417.78.49.1 to 17.78.49.25417.78.49.255254
5117.78.50.0/2417.78.50.1 to 17.78.50.25417.78.50.255254
5217.78.51.0/2417.78.51.1 to 17.78.51.25417.78.51.255254
5317.78.52.0/2417.78.52.1 to 17.78.52.25417.78.52.255254
5417.78.53.0/2417.78.53.1 to 17.78.53.25417.78.53.255254
5517.78.54.0/2417.78.54.1 to 17.78.54.25417.78.54.255254
5617.78.55.0/2417.78.55.1 to 17.78.55.25417.78.55.255254
5717.78.56.0/2417.78.56.1 to 17.78.56.25417.78.56.255254
5817.78.57.0/2417.78.57.1 to 17.78.57.25417.78.57.255254
5917.78.58.0/2417.78.58.1 to 17.78.58.25417.78.58.255254
6017.78.59.0/2417.78.59.1 to 17.78.59.25417.78.59.255254
6117.78.60.0/2417.78.60.1 to 17.78.60.25417.78.60.255254
6217.78.61.0/2417.78.61.1 to 17.78.61.25417.78.61.255254
6317.78.62.0/2417.78.62.1 to 17.78.62.25417.78.62.255254
6417.78.63.0/2417.78.63.1 to 17.78.63.25417.78.63.255254
6517.78.64.0/2417.78.64.1 to 17.78.64.25417.78.64.255254
6617.78.65.0/2417.78.65.1 to 17.78.65.25417.78.65.255254
6717.78.66.0/2417.78.66.1 to 17.78.66.25417.78.66.255254
6817.78.67.0/2417.78.67.1 to 17.78.67.25417.78.67.255254
6917.78.68.0/2417.78.68.1 to 17.78.68.25417.78.68.255254
7017.78.69.0/2417.78.69.1 to 17.78.69.25417.78.69.255254
7117.78.70.0/2417.78.70.1 to 17.78.70.25417.78.70.255254
7217.78.71.0/2417.78.71.1 to 17.78.71.25417.78.71.255254
7317.78.72.0/2417.78.72.1 to 17.78.72.25417.78.72.255254
7417.78.73.0/2417.78.73.1 to 17.78.73.25417.78.73.255254
7517.78.74.0/2417.78.74.1 to 17.78.74.25417.78.74.255254
7617.78.75.0/2417.78.75.1 to 17.78.75.25417.78.75.255254
7717.78.76.0/2417.78.76.1 to 17.78.76.25417.78.76.255254
7817.78.77.0/2417.78.77.1 to 17.78.77.25417.78.77.255254
7917.78.78.0/2417.78.78.1 to 17.78.78.25417.78.78.255254
8017.78.79.0/2417.78.79.1 to 17.78.79.25417.78.79.255254
8117.78.80.0/2417.78.80.1 to 17.78.80.25417.78.80.255254
8217.78.81.0/2417.78.81.1 to 17.78.81.25417.78.81.255254
8317.78.82.0/2417.78.82.1 to 17.78.82.25417.78.82.255254
8417.78.83.0/2417.78.83.1 to 17.78.83.25417.78.83.255254
8517.78.84.0/2417.78.84.1 to 17.78.84.25417.78.84.255254
8617.78.85.0/2417.78.85.1 to 17.78.85.25417.78.85.255254
8717.78.86.0/2417.78.86.1 to 17.78.86.25417.78.86.255254
8817.78.87.0/2417.78.87.1 to 17.78.87.25417.78.87.255254
8917.78.88.0/2417.78.88.1 to 17.78.88.25417.78.88.255254
9017.78.89.0/2417.78.89.1 to 17.78.89.25417.78.89.255254
9117.78.90.0/2417.78.90.1 to 17.78.90.25417.78.90.255254
9217.78.91.0/2417.78.91.1 to 17.78.91.25417.78.91.255254
9317.78.92.0/2417.78.92.1 to 17.78.92.25417.78.92.255254
9417.78.93.0/2417.78.93.1 to 17.78.93.25417.78.93.255254
9517.78.94.0/2417.78.94.1 to 17.78.94.25417.78.94.255254
9617.78.95.0/2417.78.95.1 to 17.78.95.25417.78.95.255254
9717.78.96.0/2417.78.96.1 to 17.78.96.25417.78.96.255254
9817.78.97.0/2417.78.97.1 to 17.78.97.25417.78.97.255254
9917.78.98.0/2417.78.98.1 to 17.78.98.25417.78.98.255254
10017.78.99.0/2417.78.99.1 to 17.78.99.25417.78.99.255254
10117.78.100.0/2417.78.100.1 to 17.78.100.25417.78.100.255254
10217.78.101.0/2417.78.101.1 to 17.78.101.25417.78.101.255254
10317.78.102.0/2417.78.102.1 to 17.78.102.25417.78.102.255254
10417.78.103.0/2417.78.103.1 to 17.78.103.25417.78.103.255254
10517.78.104.0/2417.78.104.1 to 17.78.104.25417.78.104.255254
10617.78.105.0/2417.78.105.1 to 17.78.105.25417.78.105.255254
10717.78.106.0/2417.78.106.1 to 17.78.106.25417.78.106.255254
10817.78.107.0/2417.78.107.1 to 17.78.107.25417.78.107.255254
10917.78.108.0/2417.78.108.1 to 17.78.108.25417.78.108.255254
11017.78.109.0/2417.78.109.1 to 17.78.109.25417.78.109.255254
11117.78.110.0/2417.78.110.1 to 17.78.110.25417.78.110.255254
11217.78.111.0/2417.78.111.1 to 17.78.111.25417.78.111.255254
11317.78.112.0/2417.78.112.1 to 17.78.112.25417.78.112.255254
11417.78.113.0/2417.78.113.1 to 17.78.113.25417.78.113.255254
11517.78.114.0/2417.78.114.1 to 17.78.114.25417.78.114.255254
11617.78.115.0/2417.78.115.1 to 17.78.115.25417.78.115.255254
11717.78.116.0/2417.78.116.1 to 17.78.116.25417.78.116.255254
11817.78.117.0/2417.78.117.1 to 17.78.117.25417.78.117.255254
11917.78.118.0/2417.78.118.1 to 17.78.118.25417.78.118.255254
12017.78.119.0/2417.78.119.1 to 17.78.119.25417.78.119.255254
12117.78.120.0/2417.78.120.1 to 17.78.120.25417.78.120.255254
12217.78.121.0/2417.78.121.1 to 17.78.121.25417.78.121.255254
12317.78.122.0/2417.78.122.1 to 17.78.122.25417.78.122.255254
12417.78.123.0/2417.78.123.1 to 17.78.123.25417.78.123.255254
12517.78.124.0/2417.78.124.1 to 17.78.124.25417.78.124.255254
12617.78.125.0/2417.78.125.1 to 17.78.125.25417.78.125.255254
12717.78.126.0/2417.78.126.1 to 17.78.126.25417.78.126.255254
12817.78.127.0/2417.78.127.1 to 17.78.127.25417.78.127.255254
12917.78.128.0/2417.78.128.1 to 17.78.128.25417.78.128.255254
13017.78.129.0/2417.78.129.1 to 17.78.129.25417.78.129.255254
13117.78.130.0/2417.78.130.1 to 17.78.130.25417.78.130.255254
13217.78.131.0/2417.78.131.1 to 17.78.131.25417.78.131.255254
13317.78.132.0/2417.78.132.1 to 17.78.132.25417.78.132.255254
13417.78.133.0/2417.78.133.1 to 17.78.133.25417.78.133.255254
13517.78.134.0/2417.78.134.1 to 17.78.134.25417.78.134.255254
13617.78.135.0/2417.78.135.1 to 17.78.135.25417.78.135.255254
13717.78.136.0/2417.78.136.1 to 17.78.136.25417.78.136.255254
13817.78.137.0/2417.78.137.1 to 17.78.137.25417.78.137.255254
13917.78.138.0/2417.78.138.1 to 17.78.138.25417.78.138.255254
14017.78.139.0/2417.78.139.1 to 17.78.139.25417.78.139.255254
14117.78.140.0/2417.78.140.1 to 17.78.140.25417.78.140.255254
14217.78.141.0/2417.78.141.1 to 17.78.141.25417.78.141.255254
14317.78.142.0/2417.78.142.1 to 17.78.142.25417.78.142.255254
14417.78.143.0/2417.78.143.1 to 17.78.143.25417.78.143.255254
14517.78.144.0/2417.78.144.1 to 17.78.144.25417.78.144.255254
14617.78.145.0/2417.78.145.1 to 17.78.145.25417.78.145.255254
14717.78.146.0/2417.78.146.1 to 17.78.146.25417.78.146.255254
14817.78.147.0/2417.78.147.1 to 17.78.147.25417.78.147.255254
14917.78.148.0/2417.78.148.1 to 17.78.148.25417.78.148.255254
15017.78.149.0/2417.78.149.1 to 17.78.149.25417.78.149.255254
15117.78.150.0/2417.78.150.1 to 17.78.150.25417.78.150.255254
15217.78.151.0/2417.78.151.1 to 17.78.151.25417.78.151.255254
15317.78.152.0/2417.78.152.1 to 17.78.152.25417.78.152.255254
15417.78.153.0/2417.78.153.1 to 17.78.153.25417.78.153.255254
15517.78.154.0/2417.78.154.1 to 17.78.154.25417.78.154.255254
15617.78.155.0/2417.78.155.1 to 17.78.155.25417.78.155.255254
15717.78.156.0/2417.78.156.1 to 17.78.156.25417.78.156.255254
15817.78.157.0/2417.78.157.1 to 17.78.157.25417.78.157.255254
15917.78.158.0/2417.78.158.1 to 17.78.158.25417.78.158.255254
16017.78.159.0/2417.78.159.1 to 17.78.159.25417.78.159.255254
16117.78.160.0/2417.78.160.1 to 17.78.160.25417.78.160.255254
16217.78.161.0/2417.78.161.1 to 17.78.161.25417.78.161.255254
16317.78.162.0/2417.78.162.1 to 17.78.162.25417.78.162.255254
16417.78.163.0/2417.78.163.1 to 17.78.163.25417.78.163.255254
16517.78.164.0/2417.78.164.1 to 17.78.164.25417.78.164.255254
16617.78.165.0/2417.78.165.1 to 17.78.165.25417.78.165.255254
16717.78.166.0/2417.78.166.1 to 17.78.166.25417.78.166.255254
16817.78.167.0/2417.78.167.1 to 17.78.167.25417.78.167.255254
16917.78.168.0/2417.78.168.1 to 17.78.168.25417.78.168.255254
17017.78.169.0/2417.78.169.1 to 17.78.169.25417.78.169.255254
17117.78.170.0/2417.78.170.1 to 17.78.170.25417.78.170.255254
17217.78.171.0/2417.78.171.1 to 17.78.171.25417.78.171.255254
17317.78.172.0/2417.78.172.1 to 17.78.172.25417.78.172.255254
17417.78.173.0/2417.78.173.1 to 17.78.173.25417.78.173.255254
17517.78.174.0/2417.78.174.1 to 17.78.174.25417.78.174.255254
17617.78.175.0/2417.78.175.1 to 17.78.175.25417.78.175.255254
17717.78.176.0/2417.78.176.1 to 17.78.176.25417.78.176.255254
17817.78.177.0/2417.78.177.1 to 17.78.177.25417.78.177.255254
17917.78.178.0/2417.78.178.1 to 17.78.178.25417.78.178.255254
18017.78.179.0/2417.78.179.1 to 17.78.179.25417.78.179.255254
18117.78.180.0/2417.78.180.1 to 17.78.180.25417.78.180.255254
18217.78.181.0/2417.78.181.1 to 17.78.181.25417.78.181.255254
18317.78.182.0/2417.78.182.1 to 17.78.182.25417.78.182.255254
18417.78.183.0/2417.78.183.1 to 17.78.183.25417.78.183.255254
18517.78.184.0/2417.78.184.1 to 17.78.184.25417.78.184.255254
18617.78.185.0/2417.78.185.1 to 17.78.185.25417.78.185.255254
18717.78.186.0/2417.78.186.1 to 17.78.186.25417.78.186.255254
18817.78.187.0/2417.78.187.1 to 17.78.187.25417.78.187.255254
18917.78.188.0/2417.78.188.1 to 17.78.188.25417.78.188.255254
19017.78.189.0/2417.78.189.1 to 17.78.189.25417.78.189.255254
19117.78.190.0/2417.78.190.1 to 17.78.190.25417.78.190.255254
19217.78.191.0/2417.78.191.1 to 17.78.191.25417.78.191.255254
19317.78.192.0/2417.78.192.1 to 17.78.192.25417.78.192.255254
19417.78.193.0/2417.78.193.1 to 17.78.193.25417.78.193.255254
19517.78.194.0/2417.78.194.1 to 17.78.194.25417.78.194.255254
19617.78.195.0/2417.78.195.1 to 17.78.195.25417.78.195.255254
19717.78.196.0/2417.78.196.1 to 17.78.196.25417.78.196.255254
19817.78.197.0/2417.78.197.1 to 17.78.197.25417.78.197.255254
19917.78.198.0/2417.78.198.1 to 17.78.198.25417.78.198.255254
20017.78.199.0/2417.78.199.1 to 17.78.199.25417.78.199.255254
20117.78.200.0/2417.78.200.1 to 17.78.200.25417.78.200.255254
20217.78.201.0/2417.78.201.1 to 17.78.201.25417.78.201.255254
20317.78.202.0/2417.78.202.1 to 17.78.202.25417.78.202.255254
20417.78.203.0/2417.78.203.1 to 17.78.203.25417.78.203.255254
20517.78.204.0/2417.78.204.1 to 17.78.204.25417.78.204.255254
20617.78.205.0/2417.78.205.1 to 17.78.205.25417.78.205.255254
20717.78.206.0/2417.78.206.1 to 17.78.206.25417.78.206.255254
20817.78.207.0/2417.78.207.1 to 17.78.207.25417.78.207.255254
20917.78.208.0/2417.78.208.1 to 17.78.208.25417.78.208.255254
21017.78.209.0/2417.78.209.1 to 17.78.209.25417.78.209.255254
21117.78.210.0/2417.78.210.1 to 17.78.210.25417.78.210.255254
21217.78.211.0/2417.78.211.1 to 17.78.211.25417.78.211.255254
21317.78.212.0/2417.78.212.1 to 17.78.212.25417.78.212.255254
21417.78.213.0/2417.78.213.1 to 17.78.213.25417.78.213.255254
21517.78.214.0/2417.78.214.1 to 17.78.214.25417.78.214.255254
21617.78.215.0/2417.78.215.1 to 17.78.215.25417.78.215.255254
21717.78.216.0/2417.78.216.1 to 17.78.216.25417.78.216.255254
21817.78.217.0/2417.78.217.1 to 17.78.217.25417.78.217.255254
21917.78.218.0/2417.78.218.1 to 17.78.218.25417.78.218.255254
22017.78.219.0/2417.78.219.1 to 17.78.219.25417.78.219.255254
22117.78.220.0/2417.78.220.1 to 17.78.220.25417.78.220.255254
22217.78.221.0/2417.78.221.1 to 17.78.221.25417.78.221.255254
22317.78.222.0/2417.78.222.1 to 17.78.222.25417.78.222.255254
22417.78.223.0/2417.78.223.1 to 17.78.223.25417.78.223.255254
22517.78.224.0/2417.78.224.1 to 17.78.224.25417.78.224.255254
22617.78.225.0/2417.78.225.1 to 17.78.225.25417.78.225.255254
22717.78.226.0/2417.78.226.1 to 17.78.226.25417.78.226.255254
22817.78.227.0/2417.78.227.1 to 17.78.227.25417.78.227.255254
22917.78.228.0/2417.78.228.1 to 17.78.228.25417.78.228.255254
23017.78.229.0/2417.78.229.1 to 17.78.229.25417.78.229.255254
23117.78.230.0/2417.78.230.1 to 17.78.230.25417.78.230.255254
23217.78.231.0/2417.78.231.1 to 17.78.231.25417.78.231.255254
23317.78.232.0/2417.78.232.1 to 17.78.232.25417.78.232.255254
23417.78.233.0/2417.78.233.1 to 17.78.233.25417.78.233.255254
23517.78.234.0/2417.78.234.1 to 17.78.234.25417.78.234.255254
23617.78.235.0/2417.78.235.1 to 17.78.235.25417.78.235.255254
23717.78.236.0/2417.78.236.1 to 17.78.236.25417.78.236.255254
23817.78.237.0/2417.78.237.1 to 17.78.237.25417.78.237.255254
23917.78.238.0/2417.78.238.1 to 17.78.238.25417.78.238.255254
24017.78.239.0/2417.78.239.1 to 17.78.239.25417.78.239.255254
24117.78.240.0/2417.78.240.1 to 17.78.240.25417.78.240.255254
24217.78.241.0/2417.78.241.1 to 17.78.241.25417.78.241.255254
24317.78.242.0/2417.78.242.1 to 17.78.242.25417.78.242.255254
24417.78.243.0/2417.78.243.1 to 17.78.243.25417.78.243.255254
24517.78.244.0/2417.78.244.1 to 17.78.244.25417.78.244.255254
24617.78.245.0/2417.78.245.1 to 17.78.245.25417.78.245.255254
24717.78.246.0/2417.78.246.1 to 17.78.246.25417.78.246.255254
24817.78.247.0/2417.78.247.1 to 17.78.247.25417.78.247.255254
24917.78.248.0/2417.78.248.1 to 17.78.248.25417.78.248.255254
25017.78.249.0/2417.78.249.1 to 17.78.249.25417.78.249.255254
25117.78.250.0/2417.78.250.1 to 17.78.250.25417.78.250.255254
25217.78.251.0/2417.78.251.1 to 17.78.251.25417.78.251.255254
25317.78.252.0/2417.78.252.1 to 17.78.252.25417.78.252.255254
25417.78.253.0/2417.78.253.1 to 17.78.253.25417.78.253.255254
25517.78.254.0/2417.78.254.1 to 17.78.254.25417.78.254.255254
25617.78.255.0/2417.78.255.1 to 17.78.255.25417.78.255.255254

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.