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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.

Network33.128.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
33.128.0.0
Broadcast address
33.191.255.255
First usable
33.128.0.1
Last usable
33.191.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 21800000 · Integer 562036736 to 566231039
Reverse DNS zones
128.33.in-addr.arpa
129.33.in-addr.arpa
130.33.in-addr.arpa
131.33.in-addr.arpa
132.33.in-addr.arpa
133.33.in-addr.arpa
134.33.in-addr.arpa
135.33.in-addr.arpa
136.33.in-addr.arpa
137.33.in-addr.arpa
138.33.in-addr.arpa
139.33.in-addr.arpa
140.33.in-addr.arpa
141.33.in-addr.arpa
142.33.in-addr.arpa
143.33.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100001.10000000.00000000.0000000033.128.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00100001.10000000.00000000.0000000033.128.0.0
Broadcast00100001.10111111.11111111.1111111133.191.255.255
Split into smaller subnets/22
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

33.128.0.0/10 makes 4,096 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
133.128.0.0/2233.128.0.1 to 33.128.3.25433.128.3.2551,022
233.128.4.0/2233.128.4.1 to 33.128.7.25433.128.7.2551,022
333.128.8.0/2233.128.8.1 to 33.128.11.25433.128.11.2551,022
433.128.12.0/2233.128.12.1 to 33.128.15.25433.128.15.2551,022
533.128.16.0/2233.128.16.1 to 33.128.19.25433.128.19.2551,022
633.128.20.0/2233.128.20.1 to 33.128.23.25433.128.23.2551,022
733.128.24.0/2233.128.24.1 to 33.128.27.25433.128.27.2551,022
833.128.28.0/2233.128.28.1 to 33.128.31.25433.128.31.2551,022
933.128.32.0/2233.128.32.1 to 33.128.35.25433.128.35.2551,022
1033.128.36.0/2233.128.36.1 to 33.128.39.25433.128.39.2551,022
1133.128.40.0/2233.128.40.1 to 33.128.43.25433.128.43.2551,022
1233.128.44.0/2233.128.44.1 to 33.128.47.25433.128.47.2551,022
1333.128.48.0/2233.128.48.1 to 33.128.51.25433.128.51.2551,022
1433.128.52.0/2233.128.52.1 to 33.128.55.25433.128.55.2551,022
1533.128.56.0/2233.128.56.1 to 33.128.59.25433.128.59.2551,022
1633.128.60.0/2233.128.60.1 to 33.128.63.25433.128.63.2551,022
1733.128.64.0/2233.128.64.1 to 33.128.67.25433.128.67.2551,022
1833.128.68.0/2233.128.68.1 to 33.128.71.25433.128.71.2551,022
1933.128.72.0/2233.128.72.1 to 33.128.75.25433.128.75.2551,022
2033.128.76.0/2233.128.76.1 to 33.128.79.25433.128.79.2551,022
2133.128.80.0/2233.128.80.1 to 33.128.83.25433.128.83.2551,022
2233.128.84.0/2233.128.84.1 to 33.128.87.25433.128.87.2551,022
2333.128.88.0/2233.128.88.1 to 33.128.91.25433.128.91.2551,022
2433.128.92.0/2233.128.92.1 to 33.128.95.25433.128.95.2551,022
2533.128.96.0/2233.128.96.1 to 33.128.99.25433.128.99.2551,022
2633.128.100.0/2233.128.100.1 to 33.128.103.25433.128.103.2551,022
2733.128.104.0/2233.128.104.1 to 33.128.107.25433.128.107.2551,022
2833.128.108.0/2233.128.108.1 to 33.128.111.25433.128.111.2551,022
2933.128.112.0/2233.128.112.1 to 33.128.115.25433.128.115.2551,022
3033.128.116.0/2233.128.116.1 to 33.128.119.25433.128.119.2551,022
3133.128.120.0/2233.128.120.1 to 33.128.123.25433.128.123.2551,022
3233.128.124.0/2233.128.124.1 to 33.128.127.25433.128.127.2551,022
3333.128.128.0/2233.128.128.1 to 33.128.131.25433.128.131.2551,022
3433.128.132.0/2233.128.132.1 to 33.128.135.25433.128.135.2551,022
3533.128.136.0/2233.128.136.1 to 33.128.139.25433.128.139.2551,022
3633.128.140.0/2233.128.140.1 to 33.128.143.25433.128.143.2551,022
3733.128.144.0/2233.128.144.1 to 33.128.147.25433.128.147.2551,022
3833.128.148.0/2233.128.148.1 to 33.128.151.25433.128.151.2551,022
3933.128.152.0/2233.128.152.1 to 33.128.155.25433.128.155.2551,022
4033.128.156.0/2233.128.156.1 to 33.128.159.25433.128.159.2551,022
4133.128.160.0/2233.128.160.1 to 33.128.163.25433.128.163.2551,022
4233.128.164.0/2233.128.164.1 to 33.128.167.25433.128.167.2551,022
4333.128.168.0/2233.128.168.1 to 33.128.171.25433.128.171.2551,022
4433.128.172.0/2233.128.172.1 to 33.128.175.25433.128.175.2551,022
4533.128.176.0/2233.128.176.1 to 33.128.179.25433.128.179.2551,022
4633.128.180.0/2233.128.180.1 to 33.128.183.25433.128.183.2551,022
4733.128.184.0/2233.128.184.1 to 33.128.187.25433.128.187.2551,022
4833.128.188.0/2233.128.188.1 to 33.128.191.25433.128.191.2551,022
4933.128.192.0/2233.128.192.1 to 33.128.195.25433.128.195.2551,022
5033.128.196.0/2233.128.196.1 to 33.128.199.25433.128.199.2551,022
5133.128.200.0/2233.128.200.1 to 33.128.203.25433.128.203.2551,022
5233.128.204.0/2233.128.204.1 to 33.128.207.25433.128.207.2551,022
5333.128.208.0/2233.128.208.1 to 33.128.211.25433.128.211.2551,022
5433.128.212.0/2233.128.212.1 to 33.128.215.25433.128.215.2551,022
5533.128.216.0/2233.128.216.1 to 33.128.219.25433.128.219.2551,022
5633.128.220.0/2233.128.220.1 to 33.128.223.25433.128.223.2551,022
5733.128.224.0/2233.128.224.1 to 33.128.227.25433.128.227.2551,022
5833.128.228.0/2233.128.228.1 to 33.128.231.25433.128.231.2551,022
5933.128.232.0/2233.128.232.1 to 33.128.235.25433.128.235.2551,022
6033.128.236.0/2233.128.236.1 to 33.128.239.25433.128.239.2551,022
6133.128.240.0/2233.128.240.1 to 33.128.243.25433.128.243.2551,022
6233.128.244.0/2233.128.244.1 to 33.128.247.25433.128.247.2551,022
6333.128.248.0/2233.128.248.1 to 33.128.251.25433.128.251.2551,022
6433.128.252.0/2233.128.252.1 to 33.128.255.25433.128.255.2551,022
6533.129.0.0/2233.129.0.1 to 33.129.3.25433.129.3.2551,022
6633.129.4.0/2233.129.4.1 to 33.129.7.25433.129.7.2551,022
6733.129.8.0/2233.129.8.1 to 33.129.11.25433.129.11.2551,022
6833.129.12.0/2233.129.12.1 to 33.129.15.25433.129.15.2551,022
6933.129.16.0/2233.129.16.1 to 33.129.19.25433.129.19.2551,022
7033.129.20.0/2233.129.20.1 to 33.129.23.25433.129.23.2551,022
7133.129.24.0/2233.129.24.1 to 33.129.27.25433.129.27.2551,022
7233.129.28.0/2233.129.28.1 to 33.129.31.25433.129.31.2551,022
7333.129.32.0/2233.129.32.1 to 33.129.35.25433.129.35.2551,022
7433.129.36.0/2233.129.36.1 to 33.129.39.25433.129.39.2551,022
7533.129.40.0/2233.129.40.1 to 33.129.43.25433.129.43.2551,022
7633.129.44.0/2233.129.44.1 to 33.129.47.25433.129.47.2551,022
7733.129.48.0/2233.129.48.1 to 33.129.51.25433.129.51.2551,022
7833.129.52.0/2233.129.52.1 to 33.129.55.25433.129.55.2551,022
7933.129.56.0/2233.129.56.1 to 33.129.59.25433.129.59.2551,022
8033.129.60.0/2233.129.60.1 to 33.129.63.25433.129.63.2551,022
8133.129.64.0/2233.129.64.1 to 33.129.67.25433.129.67.2551,022
8233.129.68.0/2233.129.68.1 to 33.129.71.25433.129.71.2551,022
8333.129.72.0/2233.129.72.1 to 33.129.75.25433.129.75.2551,022
8433.129.76.0/2233.129.76.1 to 33.129.79.25433.129.79.2551,022
8533.129.80.0/2233.129.80.1 to 33.129.83.25433.129.83.2551,022
8633.129.84.0/2233.129.84.1 to 33.129.87.25433.129.87.2551,022
8733.129.88.0/2233.129.88.1 to 33.129.91.25433.129.91.2551,022
8833.129.92.0/2233.129.92.1 to 33.129.95.25433.129.95.2551,022
8933.129.96.0/2233.129.96.1 to 33.129.99.25433.129.99.2551,022
9033.129.100.0/2233.129.100.1 to 33.129.103.25433.129.103.2551,022
9133.129.104.0/2233.129.104.1 to 33.129.107.25433.129.107.2551,022
9233.129.108.0/2233.129.108.1 to 33.129.111.25433.129.111.2551,022
9333.129.112.0/2233.129.112.1 to 33.129.115.25433.129.115.2551,022
9433.129.116.0/2233.129.116.1 to 33.129.119.25433.129.119.2551,022
9533.129.120.0/2233.129.120.1 to 33.129.123.25433.129.123.2551,022
9633.129.124.0/2233.129.124.1 to 33.129.127.25433.129.127.2551,022
9733.129.128.0/2233.129.128.1 to 33.129.131.25433.129.131.2551,022
9833.129.132.0/2233.129.132.1 to 33.129.135.25433.129.135.2551,022
9933.129.136.0/2233.129.136.1 to 33.129.139.25433.129.139.2551,022
10033.129.140.0/2233.129.140.1 to 33.129.143.25433.129.143.2551,022
10133.129.144.0/2233.129.144.1 to 33.129.147.25433.129.147.2551,022
10233.129.148.0/2233.129.148.1 to 33.129.151.25433.129.151.2551,022
10333.129.152.0/2233.129.152.1 to 33.129.155.25433.129.155.2551,022
10433.129.156.0/2233.129.156.1 to 33.129.159.25433.129.159.2551,022
10533.129.160.0/2233.129.160.1 to 33.129.163.25433.129.163.2551,022
10633.129.164.0/2233.129.164.1 to 33.129.167.25433.129.167.2551,022
10733.129.168.0/2233.129.168.1 to 33.129.171.25433.129.171.2551,022
10833.129.172.0/2233.129.172.1 to 33.129.175.25433.129.175.2551,022
10933.129.176.0/2233.129.176.1 to 33.129.179.25433.129.179.2551,022
11033.129.180.0/2233.129.180.1 to 33.129.183.25433.129.183.2551,022
11133.129.184.0/2233.129.184.1 to 33.129.187.25433.129.187.2551,022
11233.129.188.0/2233.129.188.1 to 33.129.191.25433.129.191.2551,022
11333.129.192.0/2233.129.192.1 to 33.129.195.25433.129.195.2551,022
11433.129.196.0/2233.129.196.1 to 33.129.199.25433.129.199.2551,022
11533.129.200.0/2233.129.200.1 to 33.129.203.25433.129.203.2551,022
11633.129.204.0/2233.129.204.1 to 33.129.207.25433.129.207.2551,022
11733.129.208.0/2233.129.208.1 to 33.129.211.25433.129.211.2551,022
11833.129.212.0/2233.129.212.1 to 33.129.215.25433.129.215.2551,022
11933.129.216.0/2233.129.216.1 to 33.129.219.25433.129.219.2551,022
12033.129.220.0/2233.129.220.1 to 33.129.223.25433.129.223.2551,022
12133.129.224.0/2233.129.224.1 to 33.129.227.25433.129.227.2551,022
12233.129.228.0/2233.129.228.1 to 33.129.231.25433.129.231.2551,022
12333.129.232.0/2233.129.232.1 to 33.129.235.25433.129.235.2551,022
12433.129.236.0/2233.129.236.1 to 33.129.239.25433.129.239.2551,022
12533.129.240.0/2233.129.240.1 to 33.129.243.25433.129.243.2551,022
12633.129.244.0/2233.129.244.1 to 33.129.247.25433.129.247.2551,022
12733.129.248.0/2233.129.248.1 to 33.129.251.25433.129.251.2551,022
12833.129.252.0/2233.129.252.1 to 33.129.255.25433.129.255.2551,022
12933.130.0.0/2233.130.0.1 to 33.130.3.25433.130.3.2551,022
13033.130.4.0/2233.130.4.1 to 33.130.7.25433.130.7.2551,022
13133.130.8.0/2233.130.8.1 to 33.130.11.25433.130.11.2551,022
13233.130.12.0/2233.130.12.1 to 33.130.15.25433.130.15.2551,022
13333.130.16.0/2233.130.16.1 to 33.130.19.25433.130.19.2551,022
13433.130.20.0/2233.130.20.1 to 33.130.23.25433.130.23.2551,022
13533.130.24.0/2233.130.24.1 to 33.130.27.25433.130.27.2551,022
13633.130.28.0/2233.130.28.1 to 33.130.31.25433.130.31.2551,022
13733.130.32.0/2233.130.32.1 to 33.130.35.25433.130.35.2551,022
13833.130.36.0/2233.130.36.1 to 33.130.39.25433.130.39.2551,022
13933.130.40.0/2233.130.40.1 to 33.130.43.25433.130.43.2551,022
14033.130.44.0/2233.130.44.1 to 33.130.47.25433.130.47.2551,022
14133.130.48.0/2233.130.48.1 to 33.130.51.25433.130.51.2551,022
14233.130.52.0/2233.130.52.1 to 33.130.55.25433.130.55.2551,022
14333.130.56.0/2233.130.56.1 to 33.130.59.25433.130.59.2551,022
14433.130.60.0/2233.130.60.1 to 33.130.63.25433.130.63.2551,022
14533.130.64.0/2233.130.64.1 to 33.130.67.25433.130.67.2551,022
14633.130.68.0/2233.130.68.1 to 33.130.71.25433.130.71.2551,022
14733.130.72.0/2233.130.72.1 to 33.130.75.25433.130.75.2551,022
14833.130.76.0/2233.130.76.1 to 33.130.79.25433.130.79.2551,022
14933.130.80.0/2233.130.80.1 to 33.130.83.25433.130.83.2551,022
15033.130.84.0/2233.130.84.1 to 33.130.87.25433.130.87.2551,022
15133.130.88.0/2233.130.88.1 to 33.130.91.25433.130.91.2551,022
15233.130.92.0/2233.130.92.1 to 33.130.95.25433.130.95.2551,022
15333.130.96.0/2233.130.96.1 to 33.130.99.25433.130.99.2551,022
15433.130.100.0/2233.130.100.1 to 33.130.103.25433.130.103.2551,022
15533.130.104.0/2233.130.104.1 to 33.130.107.25433.130.107.2551,022
15633.130.108.0/2233.130.108.1 to 33.130.111.25433.130.111.2551,022
15733.130.112.0/2233.130.112.1 to 33.130.115.25433.130.115.2551,022
15833.130.116.0/2233.130.116.1 to 33.130.119.25433.130.119.2551,022
15933.130.120.0/2233.130.120.1 to 33.130.123.25433.130.123.2551,022
16033.130.124.0/2233.130.124.1 to 33.130.127.25433.130.127.2551,022
16133.130.128.0/2233.130.128.1 to 33.130.131.25433.130.131.2551,022
16233.130.132.0/2233.130.132.1 to 33.130.135.25433.130.135.2551,022
16333.130.136.0/2233.130.136.1 to 33.130.139.25433.130.139.2551,022
16433.130.140.0/2233.130.140.1 to 33.130.143.25433.130.143.2551,022
16533.130.144.0/2233.130.144.1 to 33.130.147.25433.130.147.2551,022
16633.130.148.0/2233.130.148.1 to 33.130.151.25433.130.151.2551,022
16733.130.152.0/2233.130.152.1 to 33.130.155.25433.130.155.2551,022
16833.130.156.0/2233.130.156.1 to 33.130.159.25433.130.159.2551,022
16933.130.160.0/2233.130.160.1 to 33.130.163.25433.130.163.2551,022
17033.130.164.0/2233.130.164.1 to 33.130.167.25433.130.167.2551,022
17133.130.168.0/2233.130.168.1 to 33.130.171.25433.130.171.2551,022
17233.130.172.0/2233.130.172.1 to 33.130.175.25433.130.175.2551,022
17333.130.176.0/2233.130.176.1 to 33.130.179.25433.130.179.2551,022
17433.130.180.0/2233.130.180.1 to 33.130.183.25433.130.183.2551,022
17533.130.184.0/2233.130.184.1 to 33.130.187.25433.130.187.2551,022
17633.130.188.0/2233.130.188.1 to 33.130.191.25433.130.191.2551,022
17733.130.192.0/2233.130.192.1 to 33.130.195.25433.130.195.2551,022
17833.130.196.0/2233.130.196.1 to 33.130.199.25433.130.199.2551,022
17933.130.200.0/2233.130.200.1 to 33.130.203.25433.130.203.2551,022
18033.130.204.0/2233.130.204.1 to 33.130.207.25433.130.207.2551,022
18133.130.208.0/2233.130.208.1 to 33.130.211.25433.130.211.2551,022
18233.130.212.0/2233.130.212.1 to 33.130.215.25433.130.215.2551,022
18333.130.216.0/2233.130.216.1 to 33.130.219.25433.130.219.2551,022
18433.130.220.0/2233.130.220.1 to 33.130.223.25433.130.223.2551,022
18533.130.224.0/2233.130.224.1 to 33.130.227.25433.130.227.2551,022
18633.130.228.0/2233.130.228.1 to 33.130.231.25433.130.231.2551,022
18733.130.232.0/2233.130.232.1 to 33.130.235.25433.130.235.2551,022
18833.130.236.0/2233.130.236.1 to 33.130.239.25433.130.239.2551,022
18933.130.240.0/2233.130.240.1 to 33.130.243.25433.130.243.2551,022
19033.130.244.0/2233.130.244.1 to 33.130.247.25433.130.247.2551,022
19133.130.248.0/2233.130.248.1 to 33.130.251.25433.130.251.2551,022
19233.130.252.0/2233.130.252.1 to 33.130.255.25433.130.255.2551,022
19333.131.0.0/2233.131.0.1 to 33.131.3.25433.131.3.2551,022
19433.131.4.0/2233.131.4.1 to 33.131.7.25433.131.7.2551,022
19533.131.8.0/2233.131.8.1 to 33.131.11.25433.131.11.2551,022
19633.131.12.0/2233.131.12.1 to 33.131.15.25433.131.15.2551,022
19733.131.16.0/2233.131.16.1 to 33.131.19.25433.131.19.2551,022
19833.131.20.0/2233.131.20.1 to 33.131.23.25433.131.23.2551,022
19933.131.24.0/2233.131.24.1 to 33.131.27.25433.131.27.2551,022
20033.131.28.0/2233.131.28.1 to 33.131.31.25433.131.31.2551,022
20133.131.32.0/2233.131.32.1 to 33.131.35.25433.131.35.2551,022
20233.131.36.0/2233.131.36.1 to 33.131.39.25433.131.39.2551,022
20333.131.40.0/2233.131.40.1 to 33.131.43.25433.131.43.2551,022
20433.131.44.0/2233.131.44.1 to 33.131.47.25433.131.47.2551,022
20533.131.48.0/2233.131.48.1 to 33.131.51.25433.131.51.2551,022
20633.131.52.0/2233.131.52.1 to 33.131.55.25433.131.55.2551,022
20733.131.56.0/2233.131.56.1 to 33.131.59.25433.131.59.2551,022
20833.131.60.0/2233.131.60.1 to 33.131.63.25433.131.63.2551,022
20933.131.64.0/2233.131.64.1 to 33.131.67.25433.131.67.2551,022
21033.131.68.0/2233.131.68.1 to 33.131.71.25433.131.71.2551,022
21133.131.72.0/2233.131.72.1 to 33.131.75.25433.131.75.2551,022
21233.131.76.0/2233.131.76.1 to 33.131.79.25433.131.79.2551,022
21333.131.80.0/2233.131.80.1 to 33.131.83.25433.131.83.2551,022
21433.131.84.0/2233.131.84.1 to 33.131.87.25433.131.87.2551,022
21533.131.88.0/2233.131.88.1 to 33.131.91.25433.131.91.2551,022
21633.131.92.0/2233.131.92.1 to 33.131.95.25433.131.95.2551,022
21733.131.96.0/2233.131.96.1 to 33.131.99.25433.131.99.2551,022
21833.131.100.0/2233.131.100.1 to 33.131.103.25433.131.103.2551,022
21933.131.104.0/2233.131.104.1 to 33.131.107.25433.131.107.2551,022
22033.131.108.0/2233.131.108.1 to 33.131.111.25433.131.111.2551,022
22133.131.112.0/2233.131.112.1 to 33.131.115.25433.131.115.2551,022
22233.131.116.0/2233.131.116.1 to 33.131.119.25433.131.119.2551,022
22333.131.120.0/2233.131.120.1 to 33.131.123.25433.131.123.2551,022
22433.131.124.0/2233.131.124.1 to 33.131.127.25433.131.127.2551,022
22533.131.128.0/2233.131.128.1 to 33.131.131.25433.131.131.2551,022
22633.131.132.0/2233.131.132.1 to 33.131.135.25433.131.135.2551,022
22733.131.136.0/2233.131.136.1 to 33.131.139.25433.131.139.2551,022
22833.131.140.0/2233.131.140.1 to 33.131.143.25433.131.143.2551,022
22933.131.144.0/2233.131.144.1 to 33.131.147.25433.131.147.2551,022
23033.131.148.0/2233.131.148.1 to 33.131.151.25433.131.151.2551,022
23133.131.152.0/2233.131.152.1 to 33.131.155.25433.131.155.2551,022
23233.131.156.0/2233.131.156.1 to 33.131.159.25433.131.159.2551,022
23333.131.160.0/2233.131.160.1 to 33.131.163.25433.131.163.2551,022
23433.131.164.0/2233.131.164.1 to 33.131.167.25433.131.167.2551,022
23533.131.168.0/2233.131.168.1 to 33.131.171.25433.131.171.2551,022
23633.131.172.0/2233.131.172.1 to 33.131.175.25433.131.175.2551,022
23733.131.176.0/2233.131.176.1 to 33.131.179.25433.131.179.2551,022
23833.131.180.0/2233.131.180.1 to 33.131.183.25433.131.183.2551,022
23933.131.184.0/2233.131.184.1 to 33.131.187.25433.131.187.2551,022
24033.131.188.0/2233.131.188.1 to 33.131.191.25433.131.191.2551,022
24133.131.192.0/2233.131.192.1 to 33.131.195.25433.131.195.2551,022
24233.131.196.0/2233.131.196.1 to 33.131.199.25433.131.199.2551,022
24333.131.200.0/2233.131.200.1 to 33.131.203.25433.131.203.2551,022
24433.131.204.0/2233.131.204.1 to 33.131.207.25433.131.207.2551,022
24533.131.208.0/2233.131.208.1 to 33.131.211.25433.131.211.2551,022
24633.131.212.0/2233.131.212.1 to 33.131.215.25433.131.215.2551,022
24733.131.216.0/2233.131.216.1 to 33.131.219.25433.131.219.2551,022
24833.131.220.0/2233.131.220.1 to 33.131.223.25433.131.223.2551,022
24933.131.224.0/2233.131.224.1 to 33.131.227.25433.131.227.2551,022
25033.131.228.0/2233.131.228.1 to 33.131.231.25433.131.231.2551,022
25133.131.232.0/2233.131.232.1 to 33.131.235.25433.131.235.2551,022
25233.131.236.0/2233.131.236.1 to 33.131.239.25433.131.239.2551,022
25333.131.240.0/2233.131.240.1 to 33.131.243.25433.131.243.2551,022
25433.131.244.0/2233.131.244.1 to 33.131.247.25433.131.247.2551,022
25533.131.248.0/2233.131.248.1 to 33.131.251.25433.131.251.2551,022
25633.131.252.0/2233.131.252.1 to 33.131.255.25433.131.255.2551,022

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.