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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.

Network87.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
87.128.0.0
Broadcast address
87.255.255.255
First usable
87.128.0.1
Last usable
87.255.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 57800000 · Integer 1468006400 to 1476395007
Reverse DNS zones
128.87.in-addr.arpa
129.87.in-addr.arpa
130.87.in-addr.arpa
131.87.in-addr.arpa
132.87.in-addr.arpa
133.87.in-addr.arpa
134.87.in-addr.arpa
135.87.in-addr.arpa
136.87.in-addr.arpa
137.87.in-addr.arpa
138.87.in-addr.arpa
139.87.in-addr.arpa
140.87.in-addr.arpa
141.87.in-addr.arpa
142.87.in-addr.arpa
143.87.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010111.10000000.00000000.0000000087.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01010111.10000000.00000000.0000000087.128.0.0
Broadcast01010111.11111111.11111111.1111111187.255.255.255
Split into smaller subnets/17
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

87.128.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
187.128.0.0/1787.128.0.1 to 87.128.127.25487.128.127.25532,766
287.128.128.0/1787.128.128.1 to 87.128.255.25487.128.255.25532,766
387.129.0.0/1787.129.0.1 to 87.129.127.25487.129.127.25532,766
487.129.128.0/1787.129.128.1 to 87.129.255.25487.129.255.25532,766
587.130.0.0/1787.130.0.1 to 87.130.127.25487.130.127.25532,766
687.130.128.0/1787.130.128.1 to 87.130.255.25487.130.255.25532,766
787.131.0.0/1787.131.0.1 to 87.131.127.25487.131.127.25532,766
887.131.128.0/1787.131.128.1 to 87.131.255.25487.131.255.25532,766
987.132.0.0/1787.132.0.1 to 87.132.127.25487.132.127.25532,766
1087.132.128.0/1787.132.128.1 to 87.132.255.25487.132.255.25532,766
1187.133.0.0/1787.133.0.1 to 87.133.127.25487.133.127.25532,766
1287.133.128.0/1787.133.128.1 to 87.133.255.25487.133.255.25532,766
1387.134.0.0/1787.134.0.1 to 87.134.127.25487.134.127.25532,766
1487.134.128.0/1787.134.128.1 to 87.134.255.25487.134.255.25532,766
1587.135.0.0/1787.135.0.1 to 87.135.127.25487.135.127.25532,766
1687.135.128.0/1787.135.128.1 to 87.135.255.25487.135.255.25532,766
1787.136.0.0/1787.136.0.1 to 87.136.127.25487.136.127.25532,766
1887.136.128.0/1787.136.128.1 to 87.136.255.25487.136.255.25532,766
1987.137.0.0/1787.137.0.1 to 87.137.127.25487.137.127.25532,766
2087.137.128.0/1787.137.128.1 to 87.137.255.25487.137.255.25532,766
2187.138.0.0/1787.138.0.1 to 87.138.127.25487.138.127.25532,766
2287.138.128.0/1787.138.128.1 to 87.138.255.25487.138.255.25532,766
2387.139.0.0/1787.139.0.1 to 87.139.127.25487.139.127.25532,766
2487.139.128.0/1787.139.128.1 to 87.139.255.25487.139.255.25532,766
2587.140.0.0/1787.140.0.1 to 87.140.127.25487.140.127.25532,766
2687.140.128.0/1787.140.128.1 to 87.140.255.25487.140.255.25532,766
2787.141.0.0/1787.141.0.1 to 87.141.127.25487.141.127.25532,766
2887.141.128.0/1787.141.128.1 to 87.141.255.25487.141.255.25532,766
2987.142.0.0/1787.142.0.1 to 87.142.127.25487.142.127.25532,766
3087.142.128.0/1787.142.128.1 to 87.142.255.25487.142.255.25532,766
3187.143.0.0/1787.143.0.1 to 87.143.127.25487.143.127.25532,766
3287.143.128.0/1787.143.128.1 to 87.143.255.25487.143.255.25532,766
3387.144.0.0/1787.144.0.1 to 87.144.127.25487.144.127.25532,766
3487.144.128.0/1787.144.128.1 to 87.144.255.25487.144.255.25532,766
3587.145.0.0/1787.145.0.1 to 87.145.127.25487.145.127.25532,766
3687.145.128.0/1787.145.128.1 to 87.145.255.25487.145.255.25532,766
3787.146.0.0/1787.146.0.1 to 87.146.127.25487.146.127.25532,766
3887.146.128.0/1787.146.128.1 to 87.146.255.25487.146.255.25532,766
3987.147.0.0/1787.147.0.1 to 87.147.127.25487.147.127.25532,766
4087.147.128.0/1787.147.128.1 to 87.147.255.25487.147.255.25532,766
4187.148.0.0/1787.148.0.1 to 87.148.127.25487.148.127.25532,766
4287.148.128.0/1787.148.128.1 to 87.148.255.25487.148.255.25532,766
4387.149.0.0/1787.149.0.1 to 87.149.127.25487.149.127.25532,766
4487.149.128.0/1787.149.128.1 to 87.149.255.25487.149.255.25532,766
4587.150.0.0/1787.150.0.1 to 87.150.127.25487.150.127.25532,766
4687.150.128.0/1787.150.128.1 to 87.150.255.25487.150.255.25532,766
4787.151.0.0/1787.151.0.1 to 87.151.127.25487.151.127.25532,766
4887.151.128.0/1787.151.128.1 to 87.151.255.25487.151.255.25532,766
4987.152.0.0/1787.152.0.1 to 87.152.127.25487.152.127.25532,766
5087.152.128.0/1787.152.128.1 to 87.152.255.25487.152.255.25532,766
5187.153.0.0/1787.153.0.1 to 87.153.127.25487.153.127.25532,766
5287.153.128.0/1787.153.128.1 to 87.153.255.25487.153.255.25532,766
5387.154.0.0/1787.154.0.1 to 87.154.127.25487.154.127.25532,766
5487.154.128.0/1787.154.128.1 to 87.154.255.25487.154.255.25532,766
5587.155.0.0/1787.155.0.1 to 87.155.127.25487.155.127.25532,766
5687.155.128.0/1787.155.128.1 to 87.155.255.25487.155.255.25532,766
5787.156.0.0/1787.156.0.1 to 87.156.127.25487.156.127.25532,766
5887.156.128.0/1787.156.128.1 to 87.156.255.25487.156.255.25532,766
5987.157.0.0/1787.157.0.1 to 87.157.127.25487.157.127.25532,766
6087.157.128.0/1787.157.128.1 to 87.157.255.25487.157.255.25532,766
6187.158.0.0/1787.158.0.1 to 87.158.127.25487.158.127.25532,766
6287.158.128.0/1787.158.128.1 to 87.158.255.25487.158.255.25532,766
6387.159.0.0/1787.159.0.1 to 87.159.127.25487.159.127.25532,766
6487.159.128.0/1787.159.128.1 to 87.159.255.25487.159.255.25532,766
6587.160.0.0/1787.160.0.1 to 87.160.127.25487.160.127.25532,766
6687.160.128.0/1787.160.128.1 to 87.160.255.25487.160.255.25532,766
6787.161.0.0/1787.161.0.1 to 87.161.127.25487.161.127.25532,766
6887.161.128.0/1787.161.128.1 to 87.161.255.25487.161.255.25532,766
6987.162.0.0/1787.162.0.1 to 87.162.127.25487.162.127.25532,766
7087.162.128.0/1787.162.128.1 to 87.162.255.25487.162.255.25532,766
7187.163.0.0/1787.163.0.1 to 87.163.127.25487.163.127.25532,766
7287.163.128.0/1787.163.128.1 to 87.163.255.25487.163.255.25532,766
7387.164.0.0/1787.164.0.1 to 87.164.127.25487.164.127.25532,766
7487.164.128.0/1787.164.128.1 to 87.164.255.25487.164.255.25532,766
7587.165.0.0/1787.165.0.1 to 87.165.127.25487.165.127.25532,766
7687.165.128.0/1787.165.128.1 to 87.165.255.25487.165.255.25532,766
7787.166.0.0/1787.166.0.1 to 87.166.127.25487.166.127.25532,766
7887.166.128.0/1787.166.128.1 to 87.166.255.25487.166.255.25532,766
7987.167.0.0/1787.167.0.1 to 87.167.127.25487.167.127.25532,766
8087.167.128.0/1787.167.128.1 to 87.167.255.25487.167.255.25532,766
8187.168.0.0/1787.168.0.1 to 87.168.127.25487.168.127.25532,766
8287.168.128.0/1787.168.128.1 to 87.168.255.25487.168.255.25532,766
8387.169.0.0/1787.169.0.1 to 87.169.127.25487.169.127.25532,766
8487.169.128.0/1787.169.128.1 to 87.169.255.25487.169.255.25532,766
8587.170.0.0/1787.170.0.1 to 87.170.127.25487.170.127.25532,766
8687.170.128.0/1787.170.128.1 to 87.170.255.25487.170.255.25532,766
8787.171.0.0/1787.171.0.1 to 87.171.127.25487.171.127.25532,766
8887.171.128.0/1787.171.128.1 to 87.171.255.25487.171.255.25532,766
8987.172.0.0/1787.172.0.1 to 87.172.127.25487.172.127.25532,766
9087.172.128.0/1787.172.128.1 to 87.172.255.25487.172.255.25532,766
9187.173.0.0/1787.173.0.1 to 87.173.127.25487.173.127.25532,766
9287.173.128.0/1787.173.128.1 to 87.173.255.25487.173.255.25532,766
9387.174.0.0/1787.174.0.1 to 87.174.127.25487.174.127.25532,766
9487.174.128.0/1787.174.128.1 to 87.174.255.25487.174.255.25532,766
9587.175.0.0/1787.175.0.1 to 87.175.127.25487.175.127.25532,766
9687.175.128.0/1787.175.128.1 to 87.175.255.25487.175.255.25532,766
9787.176.0.0/1787.176.0.1 to 87.176.127.25487.176.127.25532,766
9887.176.128.0/1787.176.128.1 to 87.176.255.25487.176.255.25532,766
9987.177.0.0/1787.177.0.1 to 87.177.127.25487.177.127.25532,766
10087.177.128.0/1787.177.128.1 to 87.177.255.25487.177.255.25532,766
10187.178.0.0/1787.178.0.1 to 87.178.127.25487.178.127.25532,766
10287.178.128.0/1787.178.128.1 to 87.178.255.25487.178.255.25532,766
10387.179.0.0/1787.179.0.1 to 87.179.127.25487.179.127.25532,766
10487.179.128.0/1787.179.128.1 to 87.179.255.25487.179.255.25532,766
10587.180.0.0/1787.180.0.1 to 87.180.127.25487.180.127.25532,766
10687.180.128.0/1787.180.128.1 to 87.180.255.25487.180.255.25532,766
10787.181.0.0/1787.181.0.1 to 87.181.127.25487.181.127.25532,766
10887.181.128.0/1787.181.128.1 to 87.181.255.25487.181.255.25532,766
10987.182.0.0/1787.182.0.1 to 87.182.127.25487.182.127.25532,766
11087.182.128.0/1787.182.128.1 to 87.182.255.25487.182.255.25532,766
11187.183.0.0/1787.183.0.1 to 87.183.127.25487.183.127.25532,766
11287.183.128.0/1787.183.128.1 to 87.183.255.25487.183.255.25532,766
11387.184.0.0/1787.184.0.1 to 87.184.127.25487.184.127.25532,766
11487.184.128.0/1787.184.128.1 to 87.184.255.25487.184.255.25532,766
11587.185.0.0/1787.185.0.1 to 87.185.127.25487.185.127.25532,766
11687.185.128.0/1787.185.128.1 to 87.185.255.25487.185.255.25532,766
11787.186.0.0/1787.186.0.1 to 87.186.127.25487.186.127.25532,766
11887.186.128.0/1787.186.128.1 to 87.186.255.25487.186.255.25532,766
11987.187.0.0/1787.187.0.1 to 87.187.127.25487.187.127.25532,766
12087.187.128.0/1787.187.128.1 to 87.187.255.25487.187.255.25532,766
12187.188.0.0/1787.188.0.1 to 87.188.127.25487.188.127.25532,766
12287.188.128.0/1787.188.128.1 to 87.188.255.25487.188.255.25532,766
12387.189.0.0/1787.189.0.1 to 87.189.127.25487.189.127.25532,766
12487.189.128.0/1787.189.128.1 to 87.189.255.25487.189.255.25532,766
12587.190.0.0/1787.190.0.1 to 87.190.127.25487.190.127.25532,766
12687.190.128.0/1787.190.128.1 to 87.190.255.25487.190.255.25532,766
12787.191.0.0/1787.191.0.1 to 87.191.127.25487.191.127.25532,766
12887.191.128.0/1787.191.128.1 to 87.191.255.25487.191.255.25532,766
12987.192.0.0/1787.192.0.1 to 87.192.127.25487.192.127.25532,766
13087.192.128.0/1787.192.128.1 to 87.192.255.25487.192.255.25532,766
13187.193.0.0/1787.193.0.1 to 87.193.127.25487.193.127.25532,766
13287.193.128.0/1787.193.128.1 to 87.193.255.25487.193.255.25532,766
13387.194.0.0/1787.194.0.1 to 87.194.127.25487.194.127.25532,766
13487.194.128.0/1787.194.128.1 to 87.194.255.25487.194.255.25532,766
13587.195.0.0/1787.195.0.1 to 87.195.127.25487.195.127.25532,766
13687.195.128.0/1787.195.128.1 to 87.195.255.25487.195.255.25532,766
13787.196.0.0/1787.196.0.1 to 87.196.127.25487.196.127.25532,766
13887.196.128.0/1787.196.128.1 to 87.196.255.25487.196.255.25532,766
13987.197.0.0/1787.197.0.1 to 87.197.127.25487.197.127.25532,766
14087.197.128.0/1787.197.128.1 to 87.197.255.25487.197.255.25532,766
14187.198.0.0/1787.198.0.1 to 87.198.127.25487.198.127.25532,766
14287.198.128.0/1787.198.128.1 to 87.198.255.25487.198.255.25532,766
14387.199.0.0/1787.199.0.1 to 87.199.127.25487.199.127.25532,766
14487.199.128.0/1787.199.128.1 to 87.199.255.25487.199.255.25532,766
14587.200.0.0/1787.200.0.1 to 87.200.127.25487.200.127.25532,766
14687.200.128.0/1787.200.128.1 to 87.200.255.25487.200.255.25532,766
14787.201.0.0/1787.201.0.1 to 87.201.127.25487.201.127.25532,766
14887.201.128.0/1787.201.128.1 to 87.201.255.25487.201.255.25532,766
14987.202.0.0/1787.202.0.1 to 87.202.127.25487.202.127.25532,766
15087.202.128.0/1787.202.128.1 to 87.202.255.25487.202.255.25532,766
15187.203.0.0/1787.203.0.1 to 87.203.127.25487.203.127.25532,766
15287.203.128.0/1787.203.128.1 to 87.203.255.25487.203.255.25532,766
15387.204.0.0/1787.204.0.1 to 87.204.127.25487.204.127.25532,766
15487.204.128.0/1787.204.128.1 to 87.204.255.25487.204.255.25532,766
15587.205.0.0/1787.205.0.1 to 87.205.127.25487.205.127.25532,766
15687.205.128.0/1787.205.128.1 to 87.205.255.25487.205.255.25532,766
15787.206.0.0/1787.206.0.1 to 87.206.127.25487.206.127.25532,766
15887.206.128.0/1787.206.128.1 to 87.206.255.25487.206.255.25532,766
15987.207.0.0/1787.207.0.1 to 87.207.127.25487.207.127.25532,766
16087.207.128.0/1787.207.128.1 to 87.207.255.25487.207.255.25532,766
16187.208.0.0/1787.208.0.1 to 87.208.127.25487.208.127.25532,766
16287.208.128.0/1787.208.128.1 to 87.208.255.25487.208.255.25532,766
16387.209.0.0/1787.209.0.1 to 87.209.127.25487.209.127.25532,766
16487.209.128.0/1787.209.128.1 to 87.209.255.25487.209.255.25532,766
16587.210.0.0/1787.210.0.1 to 87.210.127.25487.210.127.25532,766
16687.210.128.0/1787.210.128.1 to 87.210.255.25487.210.255.25532,766
16787.211.0.0/1787.211.0.1 to 87.211.127.25487.211.127.25532,766
16887.211.128.0/1787.211.128.1 to 87.211.255.25487.211.255.25532,766
16987.212.0.0/1787.212.0.1 to 87.212.127.25487.212.127.25532,766
17087.212.128.0/1787.212.128.1 to 87.212.255.25487.212.255.25532,766
17187.213.0.0/1787.213.0.1 to 87.213.127.25487.213.127.25532,766
17287.213.128.0/1787.213.128.1 to 87.213.255.25487.213.255.25532,766
17387.214.0.0/1787.214.0.1 to 87.214.127.25487.214.127.25532,766
17487.214.128.0/1787.214.128.1 to 87.214.255.25487.214.255.25532,766
17587.215.0.0/1787.215.0.1 to 87.215.127.25487.215.127.25532,766
17687.215.128.0/1787.215.128.1 to 87.215.255.25487.215.255.25532,766
17787.216.0.0/1787.216.0.1 to 87.216.127.25487.216.127.25532,766
17887.216.128.0/1787.216.128.1 to 87.216.255.25487.216.255.25532,766
17987.217.0.0/1787.217.0.1 to 87.217.127.25487.217.127.25532,766
18087.217.128.0/1787.217.128.1 to 87.217.255.25487.217.255.25532,766
18187.218.0.0/1787.218.0.1 to 87.218.127.25487.218.127.25532,766
18287.218.128.0/1787.218.128.1 to 87.218.255.25487.218.255.25532,766
18387.219.0.0/1787.219.0.1 to 87.219.127.25487.219.127.25532,766
18487.219.128.0/1787.219.128.1 to 87.219.255.25487.219.255.25532,766
18587.220.0.0/1787.220.0.1 to 87.220.127.25487.220.127.25532,766
18687.220.128.0/1787.220.128.1 to 87.220.255.25487.220.255.25532,766
18787.221.0.0/1787.221.0.1 to 87.221.127.25487.221.127.25532,766
18887.221.128.0/1787.221.128.1 to 87.221.255.25487.221.255.25532,766
18987.222.0.0/1787.222.0.1 to 87.222.127.25487.222.127.25532,766
19087.222.128.0/1787.222.128.1 to 87.222.255.25487.222.255.25532,766
19187.223.0.0/1787.223.0.1 to 87.223.127.25487.223.127.25532,766
19287.223.128.0/1787.223.128.1 to 87.223.255.25487.223.255.25532,766
19387.224.0.0/1787.224.0.1 to 87.224.127.25487.224.127.25532,766
19487.224.128.0/1787.224.128.1 to 87.224.255.25487.224.255.25532,766
19587.225.0.0/1787.225.0.1 to 87.225.127.25487.225.127.25532,766
19687.225.128.0/1787.225.128.1 to 87.225.255.25487.225.255.25532,766
19787.226.0.0/1787.226.0.1 to 87.226.127.25487.226.127.25532,766
19887.226.128.0/1787.226.128.1 to 87.226.255.25487.226.255.25532,766
19987.227.0.0/1787.227.0.1 to 87.227.127.25487.227.127.25532,766
20087.227.128.0/1787.227.128.1 to 87.227.255.25487.227.255.25532,766
20187.228.0.0/1787.228.0.1 to 87.228.127.25487.228.127.25532,766
20287.228.128.0/1787.228.128.1 to 87.228.255.25487.228.255.25532,766
20387.229.0.0/1787.229.0.1 to 87.229.127.25487.229.127.25532,766
20487.229.128.0/1787.229.128.1 to 87.229.255.25487.229.255.25532,766
20587.230.0.0/1787.230.0.1 to 87.230.127.25487.230.127.25532,766
20687.230.128.0/1787.230.128.1 to 87.230.255.25487.230.255.25532,766
20787.231.0.0/1787.231.0.1 to 87.231.127.25487.231.127.25532,766
20887.231.128.0/1787.231.128.1 to 87.231.255.25487.231.255.25532,766
20987.232.0.0/1787.232.0.1 to 87.232.127.25487.232.127.25532,766
21087.232.128.0/1787.232.128.1 to 87.232.255.25487.232.255.25532,766
21187.233.0.0/1787.233.0.1 to 87.233.127.25487.233.127.25532,766
21287.233.128.0/1787.233.128.1 to 87.233.255.25487.233.255.25532,766
21387.234.0.0/1787.234.0.1 to 87.234.127.25487.234.127.25532,766
21487.234.128.0/1787.234.128.1 to 87.234.255.25487.234.255.25532,766
21587.235.0.0/1787.235.0.1 to 87.235.127.25487.235.127.25532,766
21687.235.128.0/1787.235.128.1 to 87.235.255.25487.235.255.25532,766
21787.236.0.0/1787.236.0.1 to 87.236.127.25487.236.127.25532,766
21887.236.128.0/1787.236.128.1 to 87.236.255.25487.236.255.25532,766
21987.237.0.0/1787.237.0.1 to 87.237.127.25487.237.127.25532,766
22087.237.128.0/1787.237.128.1 to 87.237.255.25487.237.255.25532,766
22187.238.0.0/1787.238.0.1 to 87.238.127.25487.238.127.25532,766
22287.238.128.0/1787.238.128.1 to 87.238.255.25487.238.255.25532,766
22387.239.0.0/1787.239.0.1 to 87.239.127.25487.239.127.25532,766
22487.239.128.0/1787.239.128.1 to 87.239.255.25487.239.255.25532,766
22587.240.0.0/1787.240.0.1 to 87.240.127.25487.240.127.25532,766
22687.240.128.0/1787.240.128.1 to 87.240.255.25487.240.255.25532,766
22787.241.0.0/1787.241.0.1 to 87.241.127.25487.241.127.25532,766
22887.241.128.0/1787.241.128.1 to 87.241.255.25487.241.255.25532,766
22987.242.0.0/1787.242.0.1 to 87.242.127.25487.242.127.25532,766
23087.242.128.0/1787.242.128.1 to 87.242.255.25487.242.255.25532,766
23187.243.0.0/1787.243.0.1 to 87.243.127.25487.243.127.25532,766
23287.243.128.0/1787.243.128.1 to 87.243.255.25487.243.255.25532,766
23387.244.0.0/1787.244.0.1 to 87.244.127.25487.244.127.25532,766
23487.244.128.0/1787.244.128.1 to 87.244.255.25487.244.255.25532,766
23587.245.0.0/1787.245.0.1 to 87.245.127.25487.245.127.25532,766
23687.245.128.0/1787.245.128.1 to 87.245.255.25487.245.255.25532,766
23787.246.0.0/1787.246.0.1 to 87.246.127.25487.246.127.25532,766
23887.246.128.0/1787.246.128.1 to 87.246.255.25487.246.255.25532,766
23987.247.0.0/1787.247.0.1 to 87.247.127.25487.247.127.25532,766
24087.247.128.0/1787.247.128.1 to 87.247.255.25487.247.255.25532,766
24187.248.0.0/1787.248.0.1 to 87.248.127.25487.248.127.25532,766
24287.248.128.0/1787.248.128.1 to 87.248.255.25487.248.255.25532,766
24387.249.0.0/1787.249.0.1 to 87.249.127.25487.249.127.25532,766
24487.249.128.0/1787.249.128.1 to 87.249.255.25487.249.255.25532,766
24587.250.0.0/1787.250.0.1 to 87.250.127.25487.250.127.25532,766
24687.250.128.0/1787.250.128.1 to 87.250.255.25487.250.255.25532,766
24787.251.0.0/1787.251.0.1 to 87.251.127.25487.251.127.25532,766
24887.251.128.0/1787.251.128.1 to 87.251.255.25487.251.255.25532,766
24987.252.0.0/1787.252.0.1 to 87.252.127.25487.252.127.25532,766
25087.252.128.0/1787.252.128.1 to 87.252.255.25487.252.255.25532,766
25187.253.0.0/1787.253.0.1 to 87.253.127.25487.253.127.25532,766
25287.253.128.0/1787.253.128.1 to 87.253.255.25487.253.255.25532,766
25387.254.0.0/1787.254.0.1 to 87.254.127.25487.254.127.25532,766
25487.254.128.0/1787.254.128.1 to 87.254.255.25487.254.255.25532,766
25587.255.0.0/1787.255.0.1 to 87.255.127.25487.255.127.25532,766
25687.255.128.0/1787.255.128.1 to 87.255.255.25487.255.255.25532,766

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.