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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.

Network22.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
22.166.0.0
Broadcast address
22.167.255.255
First usable
22.166.0.1
Last usable
22.167.255.254
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 16A60000 · Integer 379977728 to 380108799
Reverse DNS zones
166.22.in-addr.arpa
167.22.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
Address00010110.10100110.00000000.0000000022.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00010110.10100110.00000000.0000000022.166.0.0
Broadcast00010110.10100111.11111111.1111111122.167.255.255
Split into smaller subnets/23
/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)

22.166.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
122.166.0.0/2322.166.0.1 to 22.166.1.25422.166.1.255510
222.166.2.0/2322.166.2.1 to 22.166.3.25422.166.3.255510
322.166.4.0/2322.166.4.1 to 22.166.5.25422.166.5.255510
422.166.6.0/2322.166.6.1 to 22.166.7.25422.166.7.255510
522.166.8.0/2322.166.8.1 to 22.166.9.25422.166.9.255510
622.166.10.0/2322.166.10.1 to 22.166.11.25422.166.11.255510
722.166.12.0/2322.166.12.1 to 22.166.13.25422.166.13.255510
822.166.14.0/2322.166.14.1 to 22.166.15.25422.166.15.255510
922.166.16.0/2322.166.16.1 to 22.166.17.25422.166.17.255510
1022.166.18.0/2322.166.18.1 to 22.166.19.25422.166.19.255510
1122.166.20.0/2322.166.20.1 to 22.166.21.25422.166.21.255510
1222.166.22.0/2322.166.22.1 to 22.166.23.25422.166.23.255510
1322.166.24.0/2322.166.24.1 to 22.166.25.25422.166.25.255510
1422.166.26.0/2322.166.26.1 to 22.166.27.25422.166.27.255510
1522.166.28.0/2322.166.28.1 to 22.166.29.25422.166.29.255510
1622.166.30.0/2322.166.30.1 to 22.166.31.25422.166.31.255510
1722.166.32.0/2322.166.32.1 to 22.166.33.25422.166.33.255510
1822.166.34.0/2322.166.34.1 to 22.166.35.25422.166.35.255510
1922.166.36.0/2322.166.36.1 to 22.166.37.25422.166.37.255510
2022.166.38.0/2322.166.38.1 to 22.166.39.25422.166.39.255510
2122.166.40.0/2322.166.40.1 to 22.166.41.25422.166.41.255510
2222.166.42.0/2322.166.42.1 to 22.166.43.25422.166.43.255510
2322.166.44.0/2322.166.44.1 to 22.166.45.25422.166.45.255510
2422.166.46.0/2322.166.46.1 to 22.166.47.25422.166.47.255510
2522.166.48.0/2322.166.48.1 to 22.166.49.25422.166.49.255510
2622.166.50.0/2322.166.50.1 to 22.166.51.25422.166.51.255510
2722.166.52.0/2322.166.52.1 to 22.166.53.25422.166.53.255510
2822.166.54.0/2322.166.54.1 to 22.166.55.25422.166.55.255510
2922.166.56.0/2322.166.56.1 to 22.166.57.25422.166.57.255510
3022.166.58.0/2322.166.58.1 to 22.166.59.25422.166.59.255510
3122.166.60.0/2322.166.60.1 to 22.166.61.25422.166.61.255510
3222.166.62.0/2322.166.62.1 to 22.166.63.25422.166.63.255510
3322.166.64.0/2322.166.64.1 to 22.166.65.25422.166.65.255510
3422.166.66.0/2322.166.66.1 to 22.166.67.25422.166.67.255510
3522.166.68.0/2322.166.68.1 to 22.166.69.25422.166.69.255510
3622.166.70.0/2322.166.70.1 to 22.166.71.25422.166.71.255510
3722.166.72.0/2322.166.72.1 to 22.166.73.25422.166.73.255510
3822.166.74.0/2322.166.74.1 to 22.166.75.25422.166.75.255510
3922.166.76.0/2322.166.76.1 to 22.166.77.25422.166.77.255510
4022.166.78.0/2322.166.78.1 to 22.166.79.25422.166.79.255510
4122.166.80.0/2322.166.80.1 to 22.166.81.25422.166.81.255510
4222.166.82.0/2322.166.82.1 to 22.166.83.25422.166.83.255510
4322.166.84.0/2322.166.84.1 to 22.166.85.25422.166.85.255510
4422.166.86.0/2322.166.86.1 to 22.166.87.25422.166.87.255510
4522.166.88.0/2322.166.88.1 to 22.166.89.25422.166.89.255510
4622.166.90.0/2322.166.90.1 to 22.166.91.25422.166.91.255510
4722.166.92.0/2322.166.92.1 to 22.166.93.25422.166.93.255510
4822.166.94.0/2322.166.94.1 to 22.166.95.25422.166.95.255510
4922.166.96.0/2322.166.96.1 to 22.166.97.25422.166.97.255510
5022.166.98.0/2322.166.98.1 to 22.166.99.25422.166.99.255510
5122.166.100.0/2322.166.100.1 to 22.166.101.25422.166.101.255510
5222.166.102.0/2322.166.102.1 to 22.166.103.25422.166.103.255510
5322.166.104.0/2322.166.104.1 to 22.166.105.25422.166.105.255510
5422.166.106.0/2322.166.106.1 to 22.166.107.25422.166.107.255510
5522.166.108.0/2322.166.108.1 to 22.166.109.25422.166.109.255510
5622.166.110.0/2322.166.110.1 to 22.166.111.25422.166.111.255510
5722.166.112.0/2322.166.112.1 to 22.166.113.25422.166.113.255510
5822.166.114.0/2322.166.114.1 to 22.166.115.25422.166.115.255510
5922.166.116.0/2322.166.116.1 to 22.166.117.25422.166.117.255510
6022.166.118.0/2322.166.118.1 to 22.166.119.25422.166.119.255510
6122.166.120.0/2322.166.120.1 to 22.166.121.25422.166.121.255510
6222.166.122.0/2322.166.122.1 to 22.166.123.25422.166.123.255510
6322.166.124.0/2322.166.124.1 to 22.166.125.25422.166.125.255510
6422.166.126.0/2322.166.126.1 to 22.166.127.25422.166.127.255510
6522.166.128.0/2322.166.128.1 to 22.166.129.25422.166.129.255510
6622.166.130.0/2322.166.130.1 to 22.166.131.25422.166.131.255510
6722.166.132.0/2322.166.132.1 to 22.166.133.25422.166.133.255510
6822.166.134.0/2322.166.134.1 to 22.166.135.25422.166.135.255510
6922.166.136.0/2322.166.136.1 to 22.166.137.25422.166.137.255510
7022.166.138.0/2322.166.138.1 to 22.166.139.25422.166.139.255510
7122.166.140.0/2322.166.140.1 to 22.166.141.25422.166.141.255510
7222.166.142.0/2322.166.142.1 to 22.166.143.25422.166.143.255510
7322.166.144.0/2322.166.144.1 to 22.166.145.25422.166.145.255510
7422.166.146.0/2322.166.146.1 to 22.166.147.25422.166.147.255510
7522.166.148.0/2322.166.148.1 to 22.166.149.25422.166.149.255510
7622.166.150.0/2322.166.150.1 to 22.166.151.25422.166.151.255510
7722.166.152.0/2322.166.152.1 to 22.166.153.25422.166.153.255510
7822.166.154.0/2322.166.154.1 to 22.166.155.25422.166.155.255510
7922.166.156.0/2322.166.156.1 to 22.166.157.25422.166.157.255510
8022.166.158.0/2322.166.158.1 to 22.166.159.25422.166.159.255510
8122.166.160.0/2322.166.160.1 to 22.166.161.25422.166.161.255510
8222.166.162.0/2322.166.162.1 to 22.166.163.25422.166.163.255510
8322.166.164.0/2322.166.164.1 to 22.166.165.25422.166.165.255510
8422.166.166.0/2322.166.166.1 to 22.166.167.25422.166.167.255510
8522.166.168.0/2322.166.168.1 to 22.166.169.25422.166.169.255510
8622.166.170.0/2322.166.170.1 to 22.166.171.25422.166.171.255510
8722.166.172.0/2322.166.172.1 to 22.166.173.25422.166.173.255510
8822.166.174.0/2322.166.174.1 to 22.166.175.25422.166.175.255510
8922.166.176.0/2322.166.176.1 to 22.166.177.25422.166.177.255510
9022.166.178.0/2322.166.178.1 to 22.166.179.25422.166.179.255510
9122.166.180.0/2322.166.180.1 to 22.166.181.25422.166.181.255510
9222.166.182.0/2322.166.182.1 to 22.166.183.25422.166.183.255510
9322.166.184.0/2322.166.184.1 to 22.166.185.25422.166.185.255510
9422.166.186.0/2322.166.186.1 to 22.166.187.25422.166.187.255510
9522.166.188.0/2322.166.188.1 to 22.166.189.25422.166.189.255510
9622.166.190.0/2322.166.190.1 to 22.166.191.25422.166.191.255510
9722.166.192.0/2322.166.192.1 to 22.166.193.25422.166.193.255510
9822.166.194.0/2322.166.194.1 to 22.166.195.25422.166.195.255510
9922.166.196.0/2322.166.196.1 to 22.166.197.25422.166.197.255510
10022.166.198.0/2322.166.198.1 to 22.166.199.25422.166.199.255510
10122.166.200.0/2322.166.200.1 to 22.166.201.25422.166.201.255510
10222.166.202.0/2322.166.202.1 to 22.166.203.25422.166.203.255510
10322.166.204.0/2322.166.204.1 to 22.166.205.25422.166.205.255510
10422.166.206.0/2322.166.206.1 to 22.166.207.25422.166.207.255510
10522.166.208.0/2322.166.208.1 to 22.166.209.25422.166.209.255510
10622.166.210.0/2322.166.210.1 to 22.166.211.25422.166.211.255510
10722.166.212.0/2322.166.212.1 to 22.166.213.25422.166.213.255510
10822.166.214.0/2322.166.214.1 to 22.166.215.25422.166.215.255510
10922.166.216.0/2322.166.216.1 to 22.166.217.25422.166.217.255510
11022.166.218.0/2322.166.218.1 to 22.166.219.25422.166.219.255510
11122.166.220.0/2322.166.220.1 to 22.166.221.25422.166.221.255510
11222.166.222.0/2322.166.222.1 to 22.166.223.25422.166.223.255510
11322.166.224.0/2322.166.224.1 to 22.166.225.25422.166.225.255510
11422.166.226.0/2322.166.226.1 to 22.166.227.25422.166.227.255510
11522.166.228.0/2322.166.228.1 to 22.166.229.25422.166.229.255510
11622.166.230.0/2322.166.230.1 to 22.166.231.25422.166.231.255510
11722.166.232.0/2322.166.232.1 to 22.166.233.25422.166.233.255510
11822.166.234.0/2322.166.234.1 to 22.166.235.25422.166.235.255510
11922.166.236.0/2322.166.236.1 to 22.166.237.25422.166.237.255510
12022.166.238.0/2322.166.238.1 to 22.166.239.25422.166.239.255510
12122.166.240.0/2322.166.240.1 to 22.166.241.25422.166.241.255510
12222.166.242.0/2322.166.242.1 to 22.166.243.25422.166.243.255510
12322.166.244.0/2322.166.244.1 to 22.166.245.25422.166.245.255510
12422.166.246.0/2322.166.246.1 to 22.166.247.25422.166.247.255510
12522.166.248.0/2322.166.248.1 to 22.166.249.25422.166.249.255510
12622.166.250.0/2322.166.250.1 to 22.166.251.25422.166.251.255510
12722.166.252.0/2322.166.252.1 to 22.166.253.25422.166.253.255510
12822.166.254.0/2322.166.254.1 to 22.166.255.25422.166.255.255510
12922.167.0.0/2322.167.0.1 to 22.167.1.25422.167.1.255510
13022.167.2.0/2322.167.2.1 to 22.167.3.25422.167.3.255510
13122.167.4.0/2322.167.4.1 to 22.167.5.25422.167.5.255510
13222.167.6.0/2322.167.6.1 to 22.167.7.25422.167.7.255510
13322.167.8.0/2322.167.8.1 to 22.167.9.25422.167.9.255510
13422.167.10.0/2322.167.10.1 to 22.167.11.25422.167.11.255510
13522.167.12.0/2322.167.12.1 to 22.167.13.25422.167.13.255510
13622.167.14.0/2322.167.14.1 to 22.167.15.25422.167.15.255510
13722.167.16.0/2322.167.16.1 to 22.167.17.25422.167.17.255510
13822.167.18.0/2322.167.18.1 to 22.167.19.25422.167.19.255510
13922.167.20.0/2322.167.20.1 to 22.167.21.25422.167.21.255510
14022.167.22.0/2322.167.22.1 to 22.167.23.25422.167.23.255510
14122.167.24.0/2322.167.24.1 to 22.167.25.25422.167.25.255510
14222.167.26.0/2322.167.26.1 to 22.167.27.25422.167.27.255510
14322.167.28.0/2322.167.28.1 to 22.167.29.25422.167.29.255510
14422.167.30.0/2322.167.30.1 to 22.167.31.25422.167.31.255510
14522.167.32.0/2322.167.32.1 to 22.167.33.25422.167.33.255510
14622.167.34.0/2322.167.34.1 to 22.167.35.25422.167.35.255510
14722.167.36.0/2322.167.36.1 to 22.167.37.25422.167.37.255510
14822.167.38.0/2322.167.38.1 to 22.167.39.25422.167.39.255510
14922.167.40.0/2322.167.40.1 to 22.167.41.25422.167.41.255510
15022.167.42.0/2322.167.42.1 to 22.167.43.25422.167.43.255510
15122.167.44.0/2322.167.44.1 to 22.167.45.25422.167.45.255510
15222.167.46.0/2322.167.46.1 to 22.167.47.25422.167.47.255510
15322.167.48.0/2322.167.48.1 to 22.167.49.25422.167.49.255510
15422.167.50.0/2322.167.50.1 to 22.167.51.25422.167.51.255510
15522.167.52.0/2322.167.52.1 to 22.167.53.25422.167.53.255510
15622.167.54.0/2322.167.54.1 to 22.167.55.25422.167.55.255510
15722.167.56.0/2322.167.56.1 to 22.167.57.25422.167.57.255510
15822.167.58.0/2322.167.58.1 to 22.167.59.25422.167.59.255510
15922.167.60.0/2322.167.60.1 to 22.167.61.25422.167.61.255510
16022.167.62.0/2322.167.62.1 to 22.167.63.25422.167.63.255510
16122.167.64.0/2322.167.64.1 to 22.167.65.25422.167.65.255510
16222.167.66.0/2322.167.66.1 to 22.167.67.25422.167.67.255510
16322.167.68.0/2322.167.68.1 to 22.167.69.25422.167.69.255510
16422.167.70.0/2322.167.70.1 to 22.167.71.25422.167.71.255510
16522.167.72.0/2322.167.72.1 to 22.167.73.25422.167.73.255510
16622.167.74.0/2322.167.74.1 to 22.167.75.25422.167.75.255510
16722.167.76.0/2322.167.76.1 to 22.167.77.25422.167.77.255510
16822.167.78.0/2322.167.78.1 to 22.167.79.25422.167.79.255510
16922.167.80.0/2322.167.80.1 to 22.167.81.25422.167.81.255510
17022.167.82.0/2322.167.82.1 to 22.167.83.25422.167.83.255510
17122.167.84.0/2322.167.84.1 to 22.167.85.25422.167.85.255510
17222.167.86.0/2322.167.86.1 to 22.167.87.25422.167.87.255510
17322.167.88.0/2322.167.88.1 to 22.167.89.25422.167.89.255510
17422.167.90.0/2322.167.90.1 to 22.167.91.25422.167.91.255510
17522.167.92.0/2322.167.92.1 to 22.167.93.25422.167.93.255510
17622.167.94.0/2322.167.94.1 to 22.167.95.25422.167.95.255510
17722.167.96.0/2322.167.96.1 to 22.167.97.25422.167.97.255510
17822.167.98.0/2322.167.98.1 to 22.167.99.25422.167.99.255510
17922.167.100.0/2322.167.100.1 to 22.167.101.25422.167.101.255510
18022.167.102.0/2322.167.102.1 to 22.167.103.25422.167.103.255510
18122.167.104.0/2322.167.104.1 to 22.167.105.25422.167.105.255510
18222.167.106.0/2322.167.106.1 to 22.167.107.25422.167.107.255510
18322.167.108.0/2322.167.108.1 to 22.167.109.25422.167.109.255510
18422.167.110.0/2322.167.110.1 to 22.167.111.25422.167.111.255510
18522.167.112.0/2322.167.112.1 to 22.167.113.25422.167.113.255510
18622.167.114.0/2322.167.114.1 to 22.167.115.25422.167.115.255510
18722.167.116.0/2322.167.116.1 to 22.167.117.25422.167.117.255510
18822.167.118.0/2322.167.118.1 to 22.167.119.25422.167.119.255510
18922.167.120.0/2322.167.120.1 to 22.167.121.25422.167.121.255510
19022.167.122.0/2322.167.122.1 to 22.167.123.25422.167.123.255510
19122.167.124.0/2322.167.124.1 to 22.167.125.25422.167.125.255510
19222.167.126.0/2322.167.126.1 to 22.167.127.25422.167.127.255510
19322.167.128.0/2322.167.128.1 to 22.167.129.25422.167.129.255510
19422.167.130.0/2322.167.130.1 to 22.167.131.25422.167.131.255510
19522.167.132.0/2322.167.132.1 to 22.167.133.25422.167.133.255510
19622.167.134.0/2322.167.134.1 to 22.167.135.25422.167.135.255510
19722.167.136.0/2322.167.136.1 to 22.167.137.25422.167.137.255510
19822.167.138.0/2322.167.138.1 to 22.167.139.25422.167.139.255510
19922.167.140.0/2322.167.140.1 to 22.167.141.25422.167.141.255510
20022.167.142.0/2322.167.142.1 to 22.167.143.25422.167.143.255510
20122.167.144.0/2322.167.144.1 to 22.167.145.25422.167.145.255510
20222.167.146.0/2322.167.146.1 to 22.167.147.25422.167.147.255510
20322.167.148.0/2322.167.148.1 to 22.167.149.25422.167.149.255510
20422.167.150.0/2322.167.150.1 to 22.167.151.25422.167.151.255510
20522.167.152.0/2322.167.152.1 to 22.167.153.25422.167.153.255510
20622.167.154.0/2322.167.154.1 to 22.167.155.25422.167.155.255510
20722.167.156.0/2322.167.156.1 to 22.167.157.25422.167.157.255510
20822.167.158.0/2322.167.158.1 to 22.167.159.25422.167.159.255510
20922.167.160.0/2322.167.160.1 to 22.167.161.25422.167.161.255510
21022.167.162.0/2322.167.162.1 to 22.167.163.25422.167.163.255510
21122.167.164.0/2322.167.164.1 to 22.167.165.25422.167.165.255510
21222.167.166.0/2322.167.166.1 to 22.167.167.25422.167.167.255510
21322.167.168.0/2322.167.168.1 to 22.167.169.25422.167.169.255510
21422.167.170.0/2322.167.170.1 to 22.167.171.25422.167.171.255510
21522.167.172.0/2322.167.172.1 to 22.167.173.25422.167.173.255510
21622.167.174.0/2322.167.174.1 to 22.167.175.25422.167.175.255510
21722.167.176.0/2322.167.176.1 to 22.167.177.25422.167.177.255510
21822.167.178.0/2322.167.178.1 to 22.167.179.25422.167.179.255510
21922.167.180.0/2322.167.180.1 to 22.167.181.25422.167.181.255510
22022.167.182.0/2322.167.182.1 to 22.167.183.25422.167.183.255510
22122.167.184.0/2322.167.184.1 to 22.167.185.25422.167.185.255510
22222.167.186.0/2322.167.186.1 to 22.167.187.25422.167.187.255510
22322.167.188.0/2322.167.188.1 to 22.167.189.25422.167.189.255510
22422.167.190.0/2322.167.190.1 to 22.167.191.25422.167.191.255510
22522.167.192.0/2322.167.192.1 to 22.167.193.25422.167.193.255510
22622.167.194.0/2322.167.194.1 to 22.167.195.25422.167.195.255510
22722.167.196.0/2322.167.196.1 to 22.167.197.25422.167.197.255510
22822.167.198.0/2322.167.198.1 to 22.167.199.25422.167.199.255510
22922.167.200.0/2322.167.200.1 to 22.167.201.25422.167.201.255510
23022.167.202.0/2322.167.202.1 to 22.167.203.25422.167.203.255510
23122.167.204.0/2322.167.204.1 to 22.167.205.25422.167.205.255510
23222.167.206.0/2322.167.206.1 to 22.167.207.25422.167.207.255510
23322.167.208.0/2322.167.208.1 to 22.167.209.25422.167.209.255510
23422.167.210.0/2322.167.210.1 to 22.167.211.25422.167.211.255510
23522.167.212.0/2322.167.212.1 to 22.167.213.25422.167.213.255510
23622.167.214.0/2322.167.214.1 to 22.167.215.25422.167.215.255510
23722.167.216.0/2322.167.216.1 to 22.167.217.25422.167.217.255510
23822.167.218.0/2322.167.218.1 to 22.167.219.25422.167.219.255510
23922.167.220.0/2322.167.220.1 to 22.167.221.25422.167.221.255510
24022.167.222.0/2322.167.222.1 to 22.167.223.25422.167.223.255510
24122.167.224.0/2322.167.224.1 to 22.167.225.25422.167.225.255510
24222.167.226.0/2322.167.226.1 to 22.167.227.25422.167.227.255510
24322.167.228.0/2322.167.228.1 to 22.167.229.25422.167.229.255510
24422.167.230.0/2322.167.230.1 to 22.167.231.25422.167.231.255510
24522.167.232.0/2322.167.232.1 to 22.167.233.25422.167.233.255510
24622.167.234.0/2322.167.234.1 to 22.167.235.25422.167.235.255510
24722.167.236.0/2322.167.236.1 to 22.167.237.25422.167.237.255510
24822.167.238.0/2322.167.238.1 to 22.167.239.25422.167.239.255510
24922.167.240.0/2322.167.240.1 to 22.167.241.25422.167.241.255510
25022.167.242.0/2322.167.242.1 to 22.167.243.25422.167.243.255510
25122.167.244.0/2322.167.244.1 to 22.167.245.25422.167.245.255510
25222.167.246.0/2322.167.246.1 to 22.167.247.25422.167.247.255510
25322.167.248.0/2322.167.248.1 to 22.167.249.25422.167.249.255510
25422.167.250.0/2322.167.250.1 to 22.167.251.25422.167.251.255510
25522.167.252.0/2322.167.252.1 to 22.167.253.25422.167.253.255510
25622.167.254.0/2322.167.254.1 to 22.167.255.25422.167.255.255510

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.