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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.

Network87.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
87.0.0.0
Broadcast address
87.127.255.255
First usable
87.0.0.1
Last usable
87.127.255.254
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 57000000 · Integer 1459617792 to 1468006399
Reverse DNS zones
0.87.in-addr.arpa
1.87.in-addr.arpa
2.87.in-addr.arpa
3.87.in-addr.arpa
4.87.in-addr.arpa
5.87.in-addr.arpa
6.87.in-addr.arpa
7.87.in-addr.arpa
8.87.in-addr.arpa
9.87.in-addr.arpa
10.87.in-addr.arpa
11.87.in-addr.arpa
12.87.in-addr.arpa
13.87.in-addr.arpa
14.87.in-addr.arpa
15.87.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
Address01010111.00000000.00000000.0000000087.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01010111.00000000.00000000.0000000087.0.0.0
Broadcast01010111.01111111.11111111.1111111187.127.255.255
Split into smaller subnets/19
/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)

87.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
187.0.0.0/1987.0.0.1 to 87.0.31.25487.0.31.2558,190
287.0.32.0/1987.0.32.1 to 87.0.63.25487.0.63.2558,190
387.0.64.0/1987.0.64.1 to 87.0.95.25487.0.95.2558,190
487.0.96.0/1987.0.96.1 to 87.0.127.25487.0.127.2558,190
587.0.128.0/1987.0.128.1 to 87.0.159.25487.0.159.2558,190
687.0.160.0/1987.0.160.1 to 87.0.191.25487.0.191.2558,190
787.0.192.0/1987.0.192.1 to 87.0.223.25487.0.223.2558,190
887.0.224.0/1987.0.224.1 to 87.0.255.25487.0.255.2558,190
987.1.0.0/1987.1.0.1 to 87.1.31.25487.1.31.2558,190
1087.1.32.0/1987.1.32.1 to 87.1.63.25487.1.63.2558,190
1187.1.64.0/1987.1.64.1 to 87.1.95.25487.1.95.2558,190
1287.1.96.0/1987.1.96.1 to 87.1.127.25487.1.127.2558,190
1387.1.128.0/1987.1.128.1 to 87.1.159.25487.1.159.2558,190
1487.1.160.0/1987.1.160.1 to 87.1.191.25487.1.191.2558,190
1587.1.192.0/1987.1.192.1 to 87.1.223.25487.1.223.2558,190
1687.1.224.0/1987.1.224.1 to 87.1.255.25487.1.255.2558,190
1787.2.0.0/1987.2.0.1 to 87.2.31.25487.2.31.2558,190
1887.2.32.0/1987.2.32.1 to 87.2.63.25487.2.63.2558,190
1987.2.64.0/1987.2.64.1 to 87.2.95.25487.2.95.2558,190
2087.2.96.0/1987.2.96.1 to 87.2.127.25487.2.127.2558,190
2187.2.128.0/1987.2.128.1 to 87.2.159.25487.2.159.2558,190
2287.2.160.0/1987.2.160.1 to 87.2.191.25487.2.191.2558,190
2387.2.192.0/1987.2.192.1 to 87.2.223.25487.2.223.2558,190
2487.2.224.0/1987.2.224.1 to 87.2.255.25487.2.255.2558,190
2587.3.0.0/1987.3.0.1 to 87.3.31.25487.3.31.2558,190
2687.3.32.0/1987.3.32.1 to 87.3.63.25487.3.63.2558,190
2787.3.64.0/1987.3.64.1 to 87.3.95.25487.3.95.2558,190
2887.3.96.0/1987.3.96.1 to 87.3.127.25487.3.127.2558,190
2987.3.128.0/1987.3.128.1 to 87.3.159.25487.3.159.2558,190
3087.3.160.0/1987.3.160.1 to 87.3.191.25487.3.191.2558,190
3187.3.192.0/1987.3.192.1 to 87.3.223.25487.3.223.2558,190
3287.3.224.0/1987.3.224.1 to 87.3.255.25487.3.255.2558,190
3387.4.0.0/1987.4.0.1 to 87.4.31.25487.4.31.2558,190
3487.4.32.0/1987.4.32.1 to 87.4.63.25487.4.63.2558,190
3587.4.64.0/1987.4.64.1 to 87.4.95.25487.4.95.2558,190
3687.4.96.0/1987.4.96.1 to 87.4.127.25487.4.127.2558,190
3787.4.128.0/1987.4.128.1 to 87.4.159.25487.4.159.2558,190
3887.4.160.0/1987.4.160.1 to 87.4.191.25487.4.191.2558,190
3987.4.192.0/1987.4.192.1 to 87.4.223.25487.4.223.2558,190
4087.4.224.0/1987.4.224.1 to 87.4.255.25487.4.255.2558,190
4187.5.0.0/1987.5.0.1 to 87.5.31.25487.5.31.2558,190
4287.5.32.0/1987.5.32.1 to 87.5.63.25487.5.63.2558,190
4387.5.64.0/1987.5.64.1 to 87.5.95.25487.5.95.2558,190
4487.5.96.0/1987.5.96.1 to 87.5.127.25487.5.127.2558,190
4587.5.128.0/1987.5.128.1 to 87.5.159.25487.5.159.2558,190
4687.5.160.0/1987.5.160.1 to 87.5.191.25487.5.191.2558,190
4787.5.192.0/1987.5.192.1 to 87.5.223.25487.5.223.2558,190
4887.5.224.0/1987.5.224.1 to 87.5.255.25487.5.255.2558,190
4987.6.0.0/1987.6.0.1 to 87.6.31.25487.6.31.2558,190
5087.6.32.0/1987.6.32.1 to 87.6.63.25487.6.63.2558,190
5187.6.64.0/1987.6.64.1 to 87.6.95.25487.6.95.2558,190
5287.6.96.0/1987.6.96.1 to 87.6.127.25487.6.127.2558,190
5387.6.128.0/1987.6.128.1 to 87.6.159.25487.6.159.2558,190
5487.6.160.0/1987.6.160.1 to 87.6.191.25487.6.191.2558,190
5587.6.192.0/1987.6.192.1 to 87.6.223.25487.6.223.2558,190
5687.6.224.0/1987.6.224.1 to 87.6.255.25487.6.255.2558,190
5787.7.0.0/1987.7.0.1 to 87.7.31.25487.7.31.2558,190
5887.7.32.0/1987.7.32.1 to 87.7.63.25487.7.63.2558,190
5987.7.64.0/1987.7.64.1 to 87.7.95.25487.7.95.2558,190
6087.7.96.0/1987.7.96.1 to 87.7.127.25487.7.127.2558,190
6187.7.128.0/1987.7.128.1 to 87.7.159.25487.7.159.2558,190
6287.7.160.0/1987.7.160.1 to 87.7.191.25487.7.191.2558,190
6387.7.192.0/1987.7.192.1 to 87.7.223.25487.7.223.2558,190
6487.7.224.0/1987.7.224.1 to 87.7.255.25487.7.255.2558,190
6587.8.0.0/1987.8.0.1 to 87.8.31.25487.8.31.2558,190
6687.8.32.0/1987.8.32.1 to 87.8.63.25487.8.63.2558,190
6787.8.64.0/1987.8.64.1 to 87.8.95.25487.8.95.2558,190
6887.8.96.0/1987.8.96.1 to 87.8.127.25487.8.127.2558,190
6987.8.128.0/1987.8.128.1 to 87.8.159.25487.8.159.2558,190
7087.8.160.0/1987.8.160.1 to 87.8.191.25487.8.191.2558,190
7187.8.192.0/1987.8.192.1 to 87.8.223.25487.8.223.2558,190
7287.8.224.0/1987.8.224.1 to 87.8.255.25487.8.255.2558,190
7387.9.0.0/1987.9.0.1 to 87.9.31.25487.9.31.2558,190
7487.9.32.0/1987.9.32.1 to 87.9.63.25487.9.63.2558,190
7587.9.64.0/1987.9.64.1 to 87.9.95.25487.9.95.2558,190
7687.9.96.0/1987.9.96.1 to 87.9.127.25487.9.127.2558,190
7787.9.128.0/1987.9.128.1 to 87.9.159.25487.9.159.2558,190
7887.9.160.0/1987.9.160.1 to 87.9.191.25487.9.191.2558,190
7987.9.192.0/1987.9.192.1 to 87.9.223.25487.9.223.2558,190
8087.9.224.0/1987.9.224.1 to 87.9.255.25487.9.255.2558,190
8187.10.0.0/1987.10.0.1 to 87.10.31.25487.10.31.2558,190
8287.10.32.0/1987.10.32.1 to 87.10.63.25487.10.63.2558,190
8387.10.64.0/1987.10.64.1 to 87.10.95.25487.10.95.2558,190
8487.10.96.0/1987.10.96.1 to 87.10.127.25487.10.127.2558,190
8587.10.128.0/1987.10.128.1 to 87.10.159.25487.10.159.2558,190
8687.10.160.0/1987.10.160.1 to 87.10.191.25487.10.191.2558,190
8787.10.192.0/1987.10.192.1 to 87.10.223.25487.10.223.2558,190
8887.10.224.0/1987.10.224.1 to 87.10.255.25487.10.255.2558,190
8987.11.0.0/1987.11.0.1 to 87.11.31.25487.11.31.2558,190
9087.11.32.0/1987.11.32.1 to 87.11.63.25487.11.63.2558,190
9187.11.64.0/1987.11.64.1 to 87.11.95.25487.11.95.2558,190
9287.11.96.0/1987.11.96.1 to 87.11.127.25487.11.127.2558,190
9387.11.128.0/1987.11.128.1 to 87.11.159.25487.11.159.2558,190
9487.11.160.0/1987.11.160.1 to 87.11.191.25487.11.191.2558,190
9587.11.192.0/1987.11.192.1 to 87.11.223.25487.11.223.2558,190
9687.11.224.0/1987.11.224.1 to 87.11.255.25487.11.255.2558,190
9787.12.0.0/1987.12.0.1 to 87.12.31.25487.12.31.2558,190
9887.12.32.0/1987.12.32.1 to 87.12.63.25487.12.63.2558,190
9987.12.64.0/1987.12.64.1 to 87.12.95.25487.12.95.2558,190
10087.12.96.0/1987.12.96.1 to 87.12.127.25487.12.127.2558,190
10187.12.128.0/1987.12.128.1 to 87.12.159.25487.12.159.2558,190
10287.12.160.0/1987.12.160.1 to 87.12.191.25487.12.191.2558,190
10387.12.192.0/1987.12.192.1 to 87.12.223.25487.12.223.2558,190
10487.12.224.0/1987.12.224.1 to 87.12.255.25487.12.255.2558,190
10587.13.0.0/1987.13.0.1 to 87.13.31.25487.13.31.2558,190
10687.13.32.0/1987.13.32.1 to 87.13.63.25487.13.63.2558,190
10787.13.64.0/1987.13.64.1 to 87.13.95.25487.13.95.2558,190
10887.13.96.0/1987.13.96.1 to 87.13.127.25487.13.127.2558,190
10987.13.128.0/1987.13.128.1 to 87.13.159.25487.13.159.2558,190
11087.13.160.0/1987.13.160.1 to 87.13.191.25487.13.191.2558,190
11187.13.192.0/1987.13.192.1 to 87.13.223.25487.13.223.2558,190
11287.13.224.0/1987.13.224.1 to 87.13.255.25487.13.255.2558,190
11387.14.0.0/1987.14.0.1 to 87.14.31.25487.14.31.2558,190
11487.14.32.0/1987.14.32.1 to 87.14.63.25487.14.63.2558,190
11587.14.64.0/1987.14.64.1 to 87.14.95.25487.14.95.2558,190
11687.14.96.0/1987.14.96.1 to 87.14.127.25487.14.127.2558,190
11787.14.128.0/1987.14.128.1 to 87.14.159.25487.14.159.2558,190
11887.14.160.0/1987.14.160.1 to 87.14.191.25487.14.191.2558,190
11987.14.192.0/1987.14.192.1 to 87.14.223.25487.14.223.2558,190
12087.14.224.0/1987.14.224.1 to 87.14.255.25487.14.255.2558,190
12187.15.0.0/1987.15.0.1 to 87.15.31.25487.15.31.2558,190
12287.15.32.0/1987.15.32.1 to 87.15.63.25487.15.63.2558,190
12387.15.64.0/1987.15.64.1 to 87.15.95.25487.15.95.2558,190
12487.15.96.0/1987.15.96.1 to 87.15.127.25487.15.127.2558,190
12587.15.128.0/1987.15.128.1 to 87.15.159.25487.15.159.2558,190
12687.15.160.0/1987.15.160.1 to 87.15.191.25487.15.191.2558,190
12787.15.192.0/1987.15.192.1 to 87.15.223.25487.15.223.2558,190
12887.15.224.0/1987.15.224.1 to 87.15.255.25487.15.255.2558,190
12987.16.0.0/1987.16.0.1 to 87.16.31.25487.16.31.2558,190
13087.16.32.0/1987.16.32.1 to 87.16.63.25487.16.63.2558,190
13187.16.64.0/1987.16.64.1 to 87.16.95.25487.16.95.2558,190
13287.16.96.0/1987.16.96.1 to 87.16.127.25487.16.127.2558,190
13387.16.128.0/1987.16.128.1 to 87.16.159.25487.16.159.2558,190
13487.16.160.0/1987.16.160.1 to 87.16.191.25487.16.191.2558,190
13587.16.192.0/1987.16.192.1 to 87.16.223.25487.16.223.2558,190
13687.16.224.0/1987.16.224.1 to 87.16.255.25487.16.255.2558,190
13787.17.0.0/1987.17.0.1 to 87.17.31.25487.17.31.2558,190
13887.17.32.0/1987.17.32.1 to 87.17.63.25487.17.63.2558,190
13987.17.64.0/1987.17.64.1 to 87.17.95.25487.17.95.2558,190
14087.17.96.0/1987.17.96.1 to 87.17.127.25487.17.127.2558,190
14187.17.128.0/1987.17.128.1 to 87.17.159.25487.17.159.2558,190
14287.17.160.0/1987.17.160.1 to 87.17.191.25487.17.191.2558,190
14387.17.192.0/1987.17.192.1 to 87.17.223.25487.17.223.2558,190
14487.17.224.0/1987.17.224.1 to 87.17.255.25487.17.255.2558,190
14587.18.0.0/1987.18.0.1 to 87.18.31.25487.18.31.2558,190
14687.18.32.0/1987.18.32.1 to 87.18.63.25487.18.63.2558,190
14787.18.64.0/1987.18.64.1 to 87.18.95.25487.18.95.2558,190
14887.18.96.0/1987.18.96.1 to 87.18.127.25487.18.127.2558,190
14987.18.128.0/1987.18.128.1 to 87.18.159.25487.18.159.2558,190
15087.18.160.0/1987.18.160.1 to 87.18.191.25487.18.191.2558,190
15187.18.192.0/1987.18.192.1 to 87.18.223.25487.18.223.2558,190
15287.18.224.0/1987.18.224.1 to 87.18.255.25487.18.255.2558,190
15387.19.0.0/1987.19.0.1 to 87.19.31.25487.19.31.2558,190
15487.19.32.0/1987.19.32.1 to 87.19.63.25487.19.63.2558,190
15587.19.64.0/1987.19.64.1 to 87.19.95.25487.19.95.2558,190
15687.19.96.0/1987.19.96.1 to 87.19.127.25487.19.127.2558,190
15787.19.128.0/1987.19.128.1 to 87.19.159.25487.19.159.2558,190
15887.19.160.0/1987.19.160.1 to 87.19.191.25487.19.191.2558,190
15987.19.192.0/1987.19.192.1 to 87.19.223.25487.19.223.2558,190
16087.19.224.0/1987.19.224.1 to 87.19.255.25487.19.255.2558,190
16187.20.0.0/1987.20.0.1 to 87.20.31.25487.20.31.2558,190
16287.20.32.0/1987.20.32.1 to 87.20.63.25487.20.63.2558,190
16387.20.64.0/1987.20.64.1 to 87.20.95.25487.20.95.2558,190
16487.20.96.0/1987.20.96.1 to 87.20.127.25487.20.127.2558,190
16587.20.128.0/1987.20.128.1 to 87.20.159.25487.20.159.2558,190
16687.20.160.0/1987.20.160.1 to 87.20.191.25487.20.191.2558,190
16787.20.192.0/1987.20.192.1 to 87.20.223.25487.20.223.2558,190
16887.20.224.0/1987.20.224.1 to 87.20.255.25487.20.255.2558,190
16987.21.0.0/1987.21.0.1 to 87.21.31.25487.21.31.2558,190
17087.21.32.0/1987.21.32.1 to 87.21.63.25487.21.63.2558,190
17187.21.64.0/1987.21.64.1 to 87.21.95.25487.21.95.2558,190
17287.21.96.0/1987.21.96.1 to 87.21.127.25487.21.127.2558,190
17387.21.128.0/1987.21.128.1 to 87.21.159.25487.21.159.2558,190
17487.21.160.0/1987.21.160.1 to 87.21.191.25487.21.191.2558,190
17587.21.192.0/1987.21.192.1 to 87.21.223.25487.21.223.2558,190
17687.21.224.0/1987.21.224.1 to 87.21.255.25487.21.255.2558,190
17787.22.0.0/1987.22.0.1 to 87.22.31.25487.22.31.2558,190
17887.22.32.0/1987.22.32.1 to 87.22.63.25487.22.63.2558,190
17987.22.64.0/1987.22.64.1 to 87.22.95.25487.22.95.2558,190
18087.22.96.0/1987.22.96.1 to 87.22.127.25487.22.127.2558,190
18187.22.128.0/1987.22.128.1 to 87.22.159.25487.22.159.2558,190
18287.22.160.0/1987.22.160.1 to 87.22.191.25487.22.191.2558,190
18387.22.192.0/1987.22.192.1 to 87.22.223.25487.22.223.2558,190
18487.22.224.0/1987.22.224.1 to 87.22.255.25487.22.255.2558,190
18587.23.0.0/1987.23.0.1 to 87.23.31.25487.23.31.2558,190
18687.23.32.0/1987.23.32.1 to 87.23.63.25487.23.63.2558,190
18787.23.64.0/1987.23.64.1 to 87.23.95.25487.23.95.2558,190
18887.23.96.0/1987.23.96.1 to 87.23.127.25487.23.127.2558,190
18987.23.128.0/1987.23.128.1 to 87.23.159.25487.23.159.2558,190
19087.23.160.0/1987.23.160.1 to 87.23.191.25487.23.191.2558,190
19187.23.192.0/1987.23.192.1 to 87.23.223.25487.23.223.2558,190
19287.23.224.0/1987.23.224.1 to 87.23.255.25487.23.255.2558,190
19387.24.0.0/1987.24.0.1 to 87.24.31.25487.24.31.2558,190
19487.24.32.0/1987.24.32.1 to 87.24.63.25487.24.63.2558,190
19587.24.64.0/1987.24.64.1 to 87.24.95.25487.24.95.2558,190
19687.24.96.0/1987.24.96.1 to 87.24.127.25487.24.127.2558,190
19787.24.128.0/1987.24.128.1 to 87.24.159.25487.24.159.2558,190
19887.24.160.0/1987.24.160.1 to 87.24.191.25487.24.191.2558,190
19987.24.192.0/1987.24.192.1 to 87.24.223.25487.24.223.2558,190
20087.24.224.0/1987.24.224.1 to 87.24.255.25487.24.255.2558,190
20187.25.0.0/1987.25.0.1 to 87.25.31.25487.25.31.2558,190
20287.25.32.0/1987.25.32.1 to 87.25.63.25487.25.63.2558,190
20387.25.64.0/1987.25.64.1 to 87.25.95.25487.25.95.2558,190
20487.25.96.0/1987.25.96.1 to 87.25.127.25487.25.127.2558,190
20587.25.128.0/1987.25.128.1 to 87.25.159.25487.25.159.2558,190
20687.25.160.0/1987.25.160.1 to 87.25.191.25487.25.191.2558,190
20787.25.192.0/1987.25.192.1 to 87.25.223.25487.25.223.2558,190
20887.25.224.0/1987.25.224.1 to 87.25.255.25487.25.255.2558,190
20987.26.0.0/1987.26.0.1 to 87.26.31.25487.26.31.2558,190
21087.26.32.0/1987.26.32.1 to 87.26.63.25487.26.63.2558,190
21187.26.64.0/1987.26.64.1 to 87.26.95.25487.26.95.2558,190
21287.26.96.0/1987.26.96.1 to 87.26.127.25487.26.127.2558,190
21387.26.128.0/1987.26.128.1 to 87.26.159.25487.26.159.2558,190
21487.26.160.0/1987.26.160.1 to 87.26.191.25487.26.191.2558,190
21587.26.192.0/1987.26.192.1 to 87.26.223.25487.26.223.2558,190
21687.26.224.0/1987.26.224.1 to 87.26.255.25487.26.255.2558,190
21787.27.0.0/1987.27.0.1 to 87.27.31.25487.27.31.2558,190
21887.27.32.0/1987.27.32.1 to 87.27.63.25487.27.63.2558,190
21987.27.64.0/1987.27.64.1 to 87.27.95.25487.27.95.2558,190
22087.27.96.0/1987.27.96.1 to 87.27.127.25487.27.127.2558,190
22187.27.128.0/1987.27.128.1 to 87.27.159.25487.27.159.2558,190
22287.27.160.0/1987.27.160.1 to 87.27.191.25487.27.191.2558,190
22387.27.192.0/1987.27.192.1 to 87.27.223.25487.27.223.2558,190
22487.27.224.0/1987.27.224.1 to 87.27.255.25487.27.255.2558,190
22587.28.0.0/1987.28.0.1 to 87.28.31.25487.28.31.2558,190
22687.28.32.0/1987.28.32.1 to 87.28.63.25487.28.63.2558,190
22787.28.64.0/1987.28.64.1 to 87.28.95.25487.28.95.2558,190
22887.28.96.0/1987.28.96.1 to 87.28.127.25487.28.127.2558,190
22987.28.128.0/1987.28.128.1 to 87.28.159.25487.28.159.2558,190
23087.28.160.0/1987.28.160.1 to 87.28.191.25487.28.191.2558,190
23187.28.192.0/1987.28.192.1 to 87.28.223.25487.28.223.2558,190
23287.28.224.0/1987.28.224.1 to 87.28.255.25487.28.255.2558,190
23387.29.0.0/1987.29.0.1 to 87.29.31.25487.29.31.2558,190
23487.29.32.0/1987.29.32.1 to 87.29.63.25487.29.63.2558,190
23587.29.64.0/1987.29.64.1 to 87.29.95.25487.29.95.2558,190
23687.29.96.0/1987.29.96.1 to 87.29.127.25487.29.127.2558,190
23787.29.128.0/1987.29.128.1 to 87.29.159.25487.29.159.2558,190
23887.29.160.0/1987.29.160.1 to 87.29.191.25487.29.191.2558,190
23987.29.192.0/1987.29.192.1 to 87.29.223.25487.29.223.2558,190
24087.29.224.0/1987.29.224.1 to 87.29.255.25487.29.255.2558,190
24187.30.0.0/1987.30.0.1 to 87.30.31.25487.30.31.2558,190
24287.30.32.0/1987.30.32.1 to 87.30.63.25487.30.63.2558,190
24387.30.64.0/1987.30.64.1 to 87.30.95.25487.30.95.2558,190
24487.30.96.0/1987.30.96.1 to 87.30.127.25487.30.127.2558,190
24587.30.128.0/1987.30.128.1 to 87.30.159.25487.30.159.2558,190
24687.30.160.0/1987.30.160.1 to 87.30.191.25487.30.191.2558,190
24787.30.192.0/1987.30.192.1 to 87.30.223.25487.30.223.2558,190
24887.30.224.0/1987.30.224.1 to 87.30.255.25487.30.255.2558,190
24987.31.0.0/1987.31.0.1 to 87.31.31.25487.31.31.2558,190
25087.31.32.0/1987.31.32.1 to 87.31.63.25487.31.63.2558,190
25187.31.64.0/1987.31.64.1 to 87.31.95.25487.31.95.2558,190
25287.31.96.0/1987.31.96.1 to 87.31.127.25487.31.127.2558,190
25387.31.128.0/1987.31.128.1 to 87.31.159.25487.31.159.2558,190
25487.31.160.0/1987.31.160.1 to 87.31.191.25487.31.191.2558,190
25587.31.192.0/1987.31.192.1 to 87.31.223.25487.31.223.2558,190
25687.31.224.0/1987.31.224.1 to 87.31.255.25487.31.255.2558,190

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.