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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.

Network51.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
51.232.0.0
Broadcast address
51.239.255.255
First usable
51.232.0.1
Last usable
51.239.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 33E80000 · Integer 870842368 to 871366655
Reverse DNS zones
232.51.in-addr.arpa
233.51.in-addr.arpa
234.51.in-addr.arpa
235.51.in-addr.arpa
236.51.in-addr.arpa
237.51.in-addr.arpa
238.51.in-addr.arpa
239.51.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110011.11101000.00000000.0000000051.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00110011.11101000.00000000.0000000051.232.0.0
Broadcast00110011.11101111.11111111.1111111151.239.255.255
Split into smaller subnets/23
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

51.232.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
151.232.0.0/2351.232.0.1 to 51.232.1.25451.232.1.255510
251.232.2.0/2351.232.2.1 to 51.232.3.25451.232.3.255510
351.232.4.0/2351.232.4.1 to 51.232.5.25451.232.5.255510
451.232.6.0/2351.232.6.1 to 51.232.7.25451.232.7.255510
551.232.8.0/2351.232.8.1 to 51.232.9.25451.232.9.255510
651.232.10.0/2351.232.10.1 to 51.232.11.25451.232.11.255510
751.232.12.0/2351.232.12.1 to 51.232.13.25451.232.13.255510
851.232.14.0/2351.232.14.1 to 51.232.15.25451.232.15.255510
951.232.16.0/2351.232.16.1 to 51.232.17.25451.232.17.255510
1051.232.18.0/2351.232.18.1 to 51.232.19.25451.232.19.255510
1151.232.20.0/2351.232.20.1 to 51.232.21.25451.232.21.255510
1251.232.22.0/2351.232.22.1 to 51.232.23.25451.232.23.255510
1351.232.24.0/2351.232.24.1 to 51.232.25.25451.232.25.255510
1451.232.26.0/2351.232.26.1 to 51.232.27.25451.232.27.255510
1551.232.28.0/2351.232.28.1 to 51.232.29.25451.232.29.255510
1651.232.30.0/2351.232.30.1 to 51.232.31.25451.232.31.255510
1751.232.32.0/2351.232.32.1 to 51.232.33.25451.232.33.255510
1851.232.34.0/2351.232.34.1 to 51.232.35.25451.232.35.255510
1951.232.36.0/2351.232.36.1 to 51.232.37.25451.232.37.255510
2051.232.38.0/2351.232.38.1 to 51.232.39.25451.232.39.255510
2151.232.40.0/2351.232.40.1 to 51.232.41.25451.232.41.255510
2251.232.42.0/2351.232.42.1 to 51.232.43.25451.232.43.255510
2351.232.44.0/2351.232.44.1 to 51.232.45.25451.232.45.255510
2451.232.46.0/2351.232.46.1 to 51.232.47.25451.232.47.255510
2551.232.48.0/2351.232.48.1 to 51.232.49.25451.232.49.255510
2651.232.50.0/2351.232.50.1 to 51.232.51.25451.232.51.255510
2751.232.52.0/2351.232.52.1 to 51.232.53.25451.232.53.255510
2851.232.54.0/2351.232.54.1 to 51.232.55.25451.232.55.255510
2951.232.56.0/2351.232.56.1 to 51.232.57.25451.232.57.255510
3051.232.58.0/2351.232.58.1 to 51.232.59.25451.232.59.255510
3151.232.60.0/2351.232.60.1 to 51.232.61.25451.232.61.255510
3251.232.62.0/2351.232.62.1 to 51.232.63.25451.232.63.255510
3351.232.64.0/2351.232.64.1 to 51.232.65.25451.232.65.255510
3451.232.66.0/2351.232.66.1 to 51.232.67.25451.232.67.255510
3551.232.68.0/2351.232.68.1 to 51.232.69.25451.232.69.255510
3651.232.70.0/2351.232.70.1 to 51.232.71.25451.232.71.255510
3751.232.72.0/2351.232.72.1 to 51.232.73.25451.232.73.255510
3851.232.74.0/2351.232.74.1 to 51.232.75.25451.232.75.255510
3951.232.76.0/2351.232.76.1 to 51.232.77.25451.232.77.255510
4051.232.78.0/2351.232.78.1 to 51.232.79.25451.232.79.255510
4151.232.80.0/2351.232.80.1 to 51.232.81.25451.232.81.255510
4251.232.82.0/2351.232.82.1 to 51.232.83.25451.232.83.255510
4351.232.84.0/2351.232.84.1 to 51.232.85.25451.232.85.255510
4451.232.86.0/2351.232.86.1 to 51.232.87.25451.232.87.255510
4551.232.88.0/2351.232.88.1 to 51.232.89.25451.232.89.255510
4651.232.90.0/2351.232.90.1 to 51.232.91.25451.232.91.255510
4751.232.92.0/2351.232.92.1 to 51.232.93.25451.232.93.255510
4851.232.94.0/2351.232.94.1 to 51.232.95.25451.232.95.255510
4951.232.96.0/2351.232.96.1 to 51.232.97.25451.232.97.255510
5051.232.98.0/2351.232.98.1 to 51.232.99.25451.232.99.255510
5151.232.100.0/2351.232.100.1 to 51.232.101.25451.232.101.255510
5251.232.102.0/2351.232.102.1 to 51.232.103.25451.232.103.255510
5351.232.104.0/2351.232.104.1 to 51.232.105.25451.232.105.255510
5451.232.106.0/2351.232.106.1 to 51.232.107.25451.232.107.255510
5551.232.108.0/2351.232.108.1 to 51.232.109.25451.232.109.255510
5651.232.110.0/2351.232.110.1 to 51.232.111.25451.232.111.255510
5751.232.112.0/2351.232.112.1 to 51.232.113.25451.232.113.255510
5851.232.114.0/2351.232.114.1 to 51.232.115.25451.232.115.255510
5951.232.116.0/2351.232.116.1 to 51.232.117.25451.232.117.255510
6051.232.118.0/2351.232.118.1 to 51.232.119.25451.232.119.255510
6151.232.120.0/2351.232.120.1 to 51.232.121.25451.232.121.255510
6251.232.122.0/2351.232.122.1 to 51.232.123.25451.232.123.255510
6351.232.124.0/2351.232.124.1 to 51.232.125.25451.232.125.255510
6451.232.126.0/2351.232.126.1 to 51.232.127.25451.232.127.255510
6551.232.128.0/2351.232.128.1 to 51.232.129.25451.232.129.255510
6651.232.130.0/2351.232.130.1 to 51.232.131.25451.232.131.255510
6751.232.132.0/2351.232.132.1 to 51.232.133.25451.232.133.255510
6851.232.134.0/2351.232.134.1 to 51.232.135.25451.232.135.255510
6951.232.136.0/2351.232.136.1 to 51.232.137.25451.232.137.255510
7051.232.138.0/2351.232.138.1 to 51.232.139.25451.232.139.255510
7151.232.140.0/2351.232.140.1 to 51.232.141.25451.232.141.255510
7251.232.142.0/2351.232.142.1 to 51.232.143.25451.232.143.255510
7351.232.144.0/2351.232.144.1 to 51.232.145.25451.232.145.255510
7451.232.146.0/2351.232.146.1 to 51.232.147.25451.232.147.255510
7551.232.148.0/2351.232.148.1 to 51.232.149.25451.232.149.255510
7651.232.150.0/2351.232.150.1 to 51.232.151.25451.232.151.255510
7751.232.152.0/2351.232.152.1 to 51.232.153.25451.232.153.255510
7851.232.154.0/2351.232.154.1 to 51.232.155.25451.232.155.255510
7951.232.156.0/2351.232.156.1 to 51.232.157.25451.232.157.255510
8051.232.158.0/2351.232.158.1 to 51.232.159.25451.232.159.255510
8151.232.160.0/2351.232.160.1 to 51.232.161.25451.232.161.255510
8251.232.162.0/2351.232.162.1 to 51.232.163.25451.232.163.255510
8351.232.164.0/2351.232.164.1 to 51.232.165.25451.232.165.255510
8451.232.166.0/2351.232.166.1 to 51.232.167.25451.232.167.255510
8551.232.168.0/2351.232.168.1 to 51.232.169.25451.232.169.255510
8651.232.170.0/2351.232.170.1 to 51.232.171.25451.232.171.255510
8751.232.172.0/2351.232.172.1 to 51.232.173.25451.232.173.255510
8851.232.174.0/2351.232.174.1 to 51.232.175.25451.232.175.255510
8951.232.176.0/2351.232.176.1 to 51.232.177.25451.232.177.255510
9051.232.178.0/2351.232.178.1 to 51.232.179.25451.232.179.255510
9151.232.180.0/2351.232.180.1 to 51.232.181.25451.232.181.255510
9251.232.182.0/2351.232.182.1 to 51.232.183.25451.232.183.255510
9351.232.184.0/2351.232.184.1 to 51.232.185.25451.232.185.255510
9451.232.186.0/2351.232.186.1 to 51.232.187.25451.232.187.255510
9551.232.188.0/2351.232.188.1 to 51.232.189.25451.232.189.255510
9651.232.190.0/2351.232.190.1 to 51.232.191.25451.232.191.255510
9751.232.192.0/2351.232.192.1 to 51.232.193.25451.232.193.255510
9851.232.194.0/2351.232.194.1 to 51.232.195.25451.232.195.255510
9951.232.196.0/2351.232.196.1 to 51.232.197.25451.232.197.255510
10051.232.198.0/2351.232.198.1 to 51.232.199.25451.232.199.255510
10151.232.200.0/2351.232.200.1 to 51.232.201.25451.232.201.255510
10251.232.202.0/2351.232.202.1 to 51.232.203.25451.232.203.255510
10351.232.204.0/2351.232.204.1 to 51.232.205.25451.232.205.255510
10451.232.206.0/2351.232.206.1 to 51.232.207.25451.232.207.255510
10551.232.208.0/2351.232.208.1 to 51.232.209.25451.232.209.255510
10651.232.210.0/2351.232.210.1 to 51.232.211.25451.232.211.255510
10751.232.212.0/2351.232.212.1 to 51.232.213.25451.232.213.255510
10851.232.214.0/2351.232.214.1 to 51.232.215.25451.232.215.255510
10951.232.216.0/2351.232.216.1 to 51.232.217.25451.232.217.255510
11051.232.218.0/2351.232.218.1 to 51.232.219.25451.232.219.255510
11151.232.220.0/2351.232.220.1 to 51.232.221.25451.232.221.255510
11251.232.222.0/2351.232.222.1 to 51.232.223.25451.232.223.255510
11351.232.224.0/2351.232.224.1 to 51.232.225.25451.232.225.255510
11451.232.226.0/2351.232.226.1 to 51.232.227.25451.232.227.255510
11551.232.228.0/2351.232.228.1 to 51.232.229.25451.232.229.255510
11651.232.230.0/2351.232.230.1 to 51.232.231.25451.232.231.255510
11751.232.232.0/2351.232.232.1 to 51.232.233.25451.232.233.255510
11851.232.234.0/2351.232.234.1 to 51.232.235.25451.232.235.255510
11951.232.236.0/2351.232.236.1 to 51.232.237.25451.232.237.255510
12051.232.238.0/2351.232.238.1 to 51.232.239.25451.232.239.255510
12151.232.240.0/2351.232.240.1 to 51.232.241.25451.232.241.255510
12251.232.242.0/2351.232.242.1 to 51.232.243.25451.232.243.255510
12351.232.244.0/2351.232.244.1 to 51.232.245.25451.232.245.255510
12451.232.246.0/2351.232.246.1 to 51.232.247.25451.232.247.255510
12551.232.248.0/2351.232.248.1 to 51.232.249.25451.232.249.255510
12651.232.250.0/2351.232.250.1 to 51.232.251.25451.232.251.255510
12751.232.252.0/2351.232.252.1 to 51.232.253.25451.232.253.255510
12851.232.254.0/2351.232.254.1 to 51.232.255.25451.232.255.255510
12951.233.0.0/2351.233.0.1 to 51.233.1.25451.233.1.255510
13051.233.2.0/2351.233.2.1 to 51.233.3.25451.233.3.255510
13151.233.4.0/2351.233.4.1 to 51.233.5.25451.233.5.255510
13251.233.6.0/2351.233.6.1 to 51.233.7.25451.233.7.255510
13351.233.8.0/2351.233.8.1 to 51.233.9.25451.233.9.255510
13451.233.10.0/2351.233.10.1 to 51.233.11.25451.233.11.255510
13551.233.12.0/2351.233.12.1 to 51.233.13.25451.233.13.255510
13651.233.14.0/2351.233.14.1 to 51.233.15.25451.233.15.255510
13751.233.16.0/2351.233.16.1 to 51.233.17.25451.233.17.255510
13851.233.18.0/2351.233.18.1 to 51.233.19.25451.233.19.255510
13951.233.20.0/2351.233.20.1 to 51.233.21.25451.233.21.255510
14051.233.22.0/2351.233.22.1 to 51.233.23.25451.233.23.255510
14151.233.24.0/2351.233.24.1 to 51.233.25.25451.233.25.255510
14251.233.26.0/2351.233.26.1 to 51.233.27.25451.233.27.255510
14351.233.28.0/2351.233.28.1 to 51.233.29.25451.233.29.255510
14451.233.30.0/2351.233.30.1 to 51.233.31.25451.233.31.255510
14551.233.32.0/2351.233.32.1 to 51.233.33.25451.233.33.255510
14651.233.34.0/2351.233.34.1 to 51.233.35.25451.233.35.255510
14751.233.36.0/2351.233.36.1 to 51.233.37.25451.233.37.255510
14851.233.38.0/2351.233.38.1 to 51.233.39.25451.233.39.255510
14951.233.40.0/2351.233.40.1 to 51.233.41.25451.233.41.255510
15051.233.42.0/2351.233.42.1 to 51.233.43.25451.233.43.255510
15151.233.44.0/2351.233.44.1 to 51.233.45.25451.233.45.255510
15251.233.46.0/2351.233.46.1 to 51.233.47.25451.233.47.255510
15351.233.48.0/2351.233.48.1 to 51.233.49.25451.233.49.255510
15451.233.50.0/2351.233.50.1 to 51.233.51.25451.233.51.255510
15551.233.52.0/2351.233.52.1 to 51.233.53.25451.233.53.255510
15651.233.54.0/2351.233.54.1 to 51.233.55.25451.233.55.255510
15751.233.56.0/2351.233.56.1 to 51.233.57.25451.233.57.255510
15851.233.58.0/2351.233.58.1 to 51.233.59.25451.233.59.255510
15951.233.60.0/2351.233.60.1 to 51.233.61.25451.233.61.255510
16051.233.62.0/2351.233.62.1 to 51.233.63.25451.233.63.255510
16151.233.64.0/2351.233.64.1 to 51.233.65.25451.233.65.255510
16251.233.66.0/2351.233.66.1 to 51.233.67.25451.233.67.255510
16351.233.68.0/2351.233.68.1 to 51.233.69.25451.233.69.255510
16451.233.70.0/2351.233.70.1 to 51.233.71.25451.233.71.255510
16551.233.72.0/2351.233.72.1 to 51.233.73.25451.233.73.255510
16651.233.74.0/2351.233.74.1 to 51.233.75.25451.233.75.255510
16751.233.76.0/2351.233.76.1 to 51.233.77.25451.233.77.255510
16851.233.78.0/2351.233.78.1 to 51.233.79.25451.233.79.255510
16951.233.80.0/2351.233.80.1 to 51.233.81.25451.233.81.255510
17051.233.82.0/2351.233.82.1 to 51.233.83.25451.233.83.255510
17151.233.84.0/2351.233.84.1 to 51.233.85.25451.233.85.255510
17251.233.86.0/2351.233.86.1 to 51.233.87.25451.233.87.255510
17351.233.88.0/2351.233.88.1 to 51.233.89.25451.233.89.255510
17451.233.90.0/2351.233.90.1 to 51.233.91.25451.233.91.255510
17551.233.92.0/2351.233.92.1 to 51.233.93.25451.233.93.255510
17651.233.94.0/2351.233.94.1 to 51.233.95.25451.233.95.255510
17751.233.96.0/2351.233.96.1 to 51.233.97.25451.233.97.255510
17851.233.98.0/2351.233.98.1 to 51.233.99.25451.233.99.255510
17951.233.100.0/2351.233.100.1 to 51.233.101.25451.233.101.255510
18051.233.102.0/2351.233.102.1 to 51.233.103.25451.233.103.255510
18151.233.104.0/2351.233.104.1 to 51.233.105.25451.233.105.255510
18251.233.106.0/2351.233.106.1 to 51.233.107.25451.233.107.255510
18351.233.108.0/2351.233.108.1 to 51.233.109.25451.233.109.255510
18451.233.110.0/2351.233.110.1 to 51.233.111.25451.233.111.255510
18551.233.112.0/2351.233.112.1 to 51.233.113.25451.233.113.255510
18651.233.114.0/2351.233.114.1 to 51.233.115.25451.233.115.255510
18751.233.116.0/2351.233.116.1 to 51.233.117.25451.233.117.255510
18851.233.118.0/2351.233.118.1 to 51.233.119.25451.233.119.255510
18951.233.120.0/2351.233.120.1 to 51.233.121.25451.233.121.255510
19051.233.122.0/2351.233.122.1 to 51.233.123.25451.233.123.255510
19151.233.124.0/2351.233.124.1 to 51.233.125.25451.233.125.255510
19251.233.126.0/2351.233.126.1 to 51.233.127.25451.233.127.255510
19351.233.128.0/2351.233.128.1 to 51.233.129.25451.233.129.255510
19451.233.130.0/2351.233.130.1 to 51.233.131.25451.233.131.255510
19551.233.132.0/2351.233.132.1 to 51.233.133.25451.233.133.255510
19651.233.134.0/2351.233.134.1 to 51.233.135.25451.233.135.255510
19751.233.136.0/2351.233.136.1 to 51.233.137.25451.233.137.255510
19851.233.138.0/2351.233.138.1 to 51.233.139.25451.233.139.255510
19951.233.140.0/2351.233.140.1 to 51.233.141.25451.233.141.255510
20051.233.142.0/2351.233.142.1 to 51.233.143.25451.233.143.255510
20151.233.144.0/2351.233.144.1 to 51.233.145.25451.233.145.255510
20251.233.146.0/2351.233.146.1 to 51.233.147.25451.233.147.255510
20351.233.148.0/2351.233.148.1 to 51.233.149.25451.233.149.255510
20451.233.150.0/2351.233.150.1 to 51.233.151.25451.233.151.255510
20551.233.152.0/2351.233.152.1 to 51.233.153.25451.233.153.255510
20651.233.154.0/2351.233.154.1 to 51.233.155.25451.233.155.255510
20751.233.156.0/2351.233.156.1 to 51.233.157.25451.233.157.255510
20851.233.158.0/2351.233.158.1 to 51.233.159.25451.233.159.255510
20951.233.160.0/2351.233.160.1 to 51.233.161.25451.233.161.255510
21051.233.162.0/2351.233.162.1 to 51.233.163.25451.233.163.255510
21151.233.164.0/2351.233.164.1 to 51.233.165.25451.233.165.255510
21251.233.166.0/2351.233.166.1 to 51.233.167.25451.233.167.255510
21351.233.168.0/2351.233.168.1 to 51.233.169.25451.233.169.255510
21451.233.170.0/2351.233.170.1 to 51.233.171.25451.233.171.255510
21551.233.172.0/2351.233.172.1 to 51.233.173.25451.233.173.255510
21651.233.174.0/2351.233.174.1 to 51.233.175.25451.233.175.255510
21751.233.176.0/2351.233.176.1 to 51.233.177.25451.233.177.255510
21851.233.178.0/2351.233.178.1 to 51.233.179.25451.233.179.255510
21951.233.180.0/2351.233.180.1 to 51.233.181.25451.233.181.255510
22051.233.182.0/2351.233.182.1 to 51.233.183.25451.233.183.255510
22151.233.184.0/2351.233.184.1 to 51.233.185.25451.233.185.255510
22251.233.186.0/2351.233.186.1 to 51.233.187.25451.233.187.255510
22351.233.188.0/2351.233.188.1 to 51.233.189.25451.233.189.255510
22451.233.190.0/2351.233.190.1 to 51.233.191.25451.233.191.255510
22551.233.192.0/2351.233.192.1 to 51.233.193.25451.233.193.255510
22651.233.194.0/2351.233.194.1 to 51.233.195.25451.233.195.255510
22751.233.196.0/2351.233.196.1 to 51.233.197.25451.233.197.255510
22851.233.198.0/2351.233.198.1 to 51.233.199.25451.233.199.255510
22951.233.200.0/2351.233.200.1 to 51.233.201.25451.233.201.255510
23051.233.202.0/2351.233.202.1 to 51.233.203.25451.233.203.255510
23151.233.204.0/2351.233.204.1 to 51.233.205.25451.233.205.255510
23251.233.206.0/2351.233.206.1 to 51.233.207.25451.233.207.255510
23351.233.208.0/2351.233.208.1 to 51.233.209.25451.233.209.255510
23451.233.210.0/2351.233.210.1 to 51.233.211.25451.233.211.255510
23551.233.212.0/2351.233.212.1 to 51.233.213.25451.233.213.255510
23651.233.214.0/2351.233.214.1 to 51.233.215.25451.233.215.255510
23751.233.216.0/2351.233.216.1 to 51.233.217.25451.233.217.255510
23851.233.218.0/2351.233.218.1 to 51.233.219.25451.233.219.255510
23951.233.220.0/2351.233.220.1 to 51.233.221.25451.233.221.255510
24051.233.222.0/2351.233.222.1 to 51.233.223.25451.233.223.255510
24151.233.224.0/2351.233.224.1 to 51.233.225.25451.233.225.255510
24251.233.226.0/2351.233.226.1 to 51.233.227.25451.233.227.255510
24351.233.228.0/2351.233.228.1 to 51.233.229.25451.233.229.255510
24451.233.230.0/2351.233.230.1 to 51.233.231.25451.233.231.255510
24551.233.232.0/2351.233.232.1 to 51.233.233.25451.233.233.255510
24651.233.234.0/2351.233.234.1 to 51.233.235.25451.233.235.255510
24751.233.236.0/2351.233.236.1 to 51.233.237.25451.233.237.255510
24851.233.238.0/2351.233.238.1 to 51.233.239.25451.233.239.255510
24951.233.240.0/2351.233.240.1 to 51.233.241.25451.233.241.255510
25051.233.242.0/2351.233.242.1 to 51.233.243.25451.233.243.255510
25151.233.244.0/2351.233.244.1 to 51.233.245.25451.233.245.255510
25251.233.246.0/2351.233.246.1 to 51.233.247.25451.233.247.255510
25351.233.248.0/2351.233.248.1 to 51.233.249.25451.233.249.255510
25451.233.250.0/2351.233.250.1 to 51.233.251.25451.233.251.255510
25551.233.252.0/2351.233.252.1 to 51.233.253.25451.233.253.255510
25651.233.254.0/2351.233.254.1 to 51.233.255.25451.233.255.255510

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.