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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.

Network87.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
87.0.0.0
Broadcast address
87.63.255.255
First usable
87.0.0.1
Last usable
87.63.255.254
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 57000000 · Integer 1459617792 to 1463812095
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 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
Address01010111.00000000.00000000.0000000087.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network01010111.00000000.00000000.0000000087.0.0.0
Broadcast01010111.00111111.11111111.1111111187.63.255.255
Split into smaller subnets/18
/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)

87.0.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
187.0.0.0/1887.0.0.1 to 87.0.63.25487.0.63.25516,382
287.0.64.0/1887.0.64.1 to 87.0.127.25487.0.127.25516,382
387.0.128.0/1887.0.128.1 to 87.0.191.25487.0.191.25516,382
487.0.192.0/1887.0.192.1 to 87.0.255.25487.0.255.25516,382
587.1.0.0/1887.1.0.1 to 87.1.63.25487.1.63.25516,382
687.1.64.0/1887.1.64.1 to 87.1.127.25487.1.127.25516,382
787.1.128.0/1887.1.128.1 to 87.1.191.25487.1.191.25516,382
887.1.192.0/1887.1.192.1 to 87.1.255.25487.1.255.25516,382
987.2.0.0/1887.2.0.1 to 87.2.63.25487.2.63.25516,382
1087.2.64.0/1887.2.64.1 to 87.2.127.25487.2.127.25516,382
1187.2.128.0/1887.2.128.1 to 87.2.191.25487.2.191.25516,382
1287.2.192.0/1887.2.192.1 to 87.2.255.25487.2.255.25516,382
1387.3.0.0/1887.3.0.1 to 87.3.63.25487.3.63.25516,382
1487.3.64.0/1887.3.64.1 to 87.3.127.25487.3.127.25516,382
1587.3.128.0/1887.3.128.1 to 87.3.191.25487.3.191.25516,382
1687.3.192.0/1887.3.192.1 to 87.3.255.25487.3.255.25516,382
1787.4.0.0/1887.4.0.1 to 87.4.63.25487.4.63.25516,382
1887.4.64.0/1887.4.64.1 to 87.4.127.25487.4.127.25516,382
1987.4.128.0/1887.4.128.1 to 87.4.191.25487.4.191.25516,382
2087.4.192.0/1887.4.192.1 to 87.4.255.25487.4.255.25516,382
2187.5.0.0/1887.5.0.1 to 87.5.63.25487.5.63.25516,382
2287.5.64.0/1887.5.64.1 to 87.5.127.25487.5.127.25516,382
2387.5.128.0/1887.5.128.1 to 87.5.191.25487.5.191.25516,382
2487.5.192.0/1887.5.192.1 to 87.5.255.25487.5.255.25516,382
2587.6.0.0/1887.6.0.1 to 87.6.63.25487.6.63.25516,382
2687.6.64.0/1887.6.64.1 to 87.6.127.25487.6.127.25516,382
2787.6.128.0/1887.6.128.1 to 87.6.191.25487.6.191.25516,382
2887.6.192.0/1887.6.192.1 to 87.6.255.25487.6.255.25516,382
2987.7.0.0/1887.7.0.1 to 87.7.63.25487.7.63.25516,382
3087.7.64.0/1887.7.64.1 to 87.7.127.25487.7.127.25516,382
3187.7.128.0/1887.7.128.1 to 87.7.191.25487.7.191.25516,382
3287.7.192.0/1887.7.192.1 to 87.7.255.25487.7.255.25516,382
3387.8.0.0/1887.8.0.1 to 87.8.63.25487.8.63.25516,382
3487.8.64.0/1887.8.64.1 to 87.8.127.25487.8.127.25516,382
3587.8.128.0/1887.8.128.1 to 87.8.191.25487.8.191.25516,382
3687.8.192.0/1887.8.192.1 to 87.8.255.25487.8.255.25516,382
3787.9.0.0/1887.9.0.1 to 87.9.63.25487.9.63.25516,382
3887.9.64.0/1887.9.64.1 to 87.9.127.25487.9.127.25516,382
3987.9.128.0/1887.9.128.1 to 87.9.191.25487.9.191.25516,382
4087.9.192.0/1887.9.192.1 to 87.9.255.25487.9.255.25516,382
4187.10.0.0/1887.10.0.1 to 87.10.63.25487.10.63.25516,382
4287.10.64.0/1887.10.64.1 to 87.10.127.25487.10.127.25516,382
4387.10.128.0/1887.10.128.1 to 87.10.191.25487.10.191.25516,382
4487.10.192.0/1887.10.192.1 to 87.10.255.25487.10.255.25516,382
4587.11.0.0/1887.11.0.1 to 87.11.63.25487.11.63.25516,382
4687.11.64.0/1887.11.64.1 to 87.11.127.25487.11.127.25516,382
4787.11.128.0/1887.11.128.1 to 87.11.191.25487.11.191.25516,382
4887.11.192.0/1887.11.192.1 to 87.11.255.25487.11.255.25516,382
4987.12.0.0/1887.12.0.1 to 87.12.63.25487.12.63.25516,382
5087.12.64.0/1887.12.64.1 to 87.12.127.25487.12.127.25516,382
5187.12.128.0/1887.12.128.1 to 87.12.191.25487.12.191.25516,382
5287.12.192.0/1887.12.192.1 to 87.12.255.25487.12.255.25516,382
5387.13.0.0/1887.13.0.1 to 87.13.63.25487.13.63.25516,382
5487.13.64.0/1887.13.64.1 to 87.13.127.25487.13.127.25516,382
5587.13.128.0/1887.13.128.1 to 87.13.191.25487.13.191.25516,382
5687.13.192.0/1887.13.192.1 to 87.13.255.25487.13.255.25516,382
5787.14.0.0/1887.14.0.1 to 87.14.63.25487.14.63.25516,382
5887.14.64.0/1887.14.64.1 to 87.14.127.25487.14.127.25516,382
5987.14.128.0/1887.14.128.1 to 87.14.191.25487.14.191.25516,382
6087.14.192.0/1887.14.192.1 to 87.14.255.25487.14.255.25516,382
6187.15.0.0/1887.15.0.1 to 87.15.63.25487.15.63.25516,382
6287.15.64.0/1887.15.64.1 to 87.15.127.25487.15.127.25516,382
6387.15.128.0/1887.15.128.1 to 87.15.191.25487.15.191.25516,382
6487.15.192.0/1887.15.192.1 to 87.15.255.25487.15.255.25516,382
6587.16.0.0/1887.16.0.1 to 87.16.63.25487.16.63.25516,382
6687.16.64.0/1887.16.64.1 to 87.16.127.25487.16.127.25516,382
6787.16.128.0/1887.16.128.1 to 87.16.191.25487.16.191.25516,382
6887.16.192.0/1887.16.192.1 to 87.16.255.25487.16.255.25516,382
6987.17.0.0/1887.17.0.1 to 87.17.63.25487.17.63.25516,382
7087.17.64.0/1887.17.64.1 to 87.17.127.25487.17.127.25516,382
7187.17.128.0/1887.17.128.1 to 87.17.191.25487.17.191.25516,382
7287.17.192.0/1887.17.192.1 to 87.17.255.25487.17.255.25516,382
7387.18.0.0/1887.18.0.1 to 87.18.63.25487.18.63.25516,382
7487.18.64.0/1887.18.64.1 to 87.18.127.25487.18.127.25516,382
7587.18.128.0/1887.18.128.1 to 87.18.191.25487.18.191.25516,382
7687.18.192.0/1887.18.192.1 to 87.18.255.25487.18.255.25516,382
7787.19.0.0/1887.19.0.1 to 87.19.63.25487.19.63.25516,382
7887.19.64.0/1887.19.64.1 to 87.19.127.25487.19.127.25516,382
7987.19.128.0/1887.19.128.1 to 87.19.191.25487.19.191.25516,382
8087.19.192.0/1887.19.192.1 to 87.19.255.25487.19.255.25516,382
8187.20.0.0/1887.20.0.1 to 87.20.63.25487.20.63.25516,382
8287.20.64.0/1887.20.64.1 to 87.20.127.25487.20.127.25516,382
8387.20.128.0/1887.20.128.1 to 87.20.191.25487.20.191.25516,382
8487.20.192.0/1887.20.192.1 to 87.20.255.25487.20.255.25516,382
8587.21.0.0/1887.21.0.1 to 87.21.63.25487.21.63.25516,382
8687.21.64.0/1887.21.64.1 to 87.21.127.25487.21.127.25516,382
8787.21.128.0/1887.21.128.1 to 87.21.191.25487.21.191.25516,382
8887.21.192.0/1887.21.192.1 to 87.21.255.25487.21.255.25516,382
8987.22.0.0/1887.22.0.1 to 87.22.63.25487.22.63.25516,382
9087.22.64.0/1887.22.64.1 to 87.22.127.25487.22.127.25516,382
9187.22.128.0/1887.22.128.1 to 87.22.191.25487.22.191.25516,382
9287.22.192.0/1887.22.192.1 to 87.22.255.25487.22.255.25516,382
9387.23.0.0/1887.23.0.1 to 87.23.63.25487.23.63.25516,382
9487.23.64.0/1887.23.64.1 to 87.23.127.25487.23.127.25516,382
9587.23.128.0/1887.23.128.1 to 87.23.191.25487.23.191.25516,382
9687.23.192.0/1887.23.192.1 to 87.23.255.25487.23.255.25516,382
9787.24.0.0/1887.24.0.1 to 87.24.63.25487.24.63.25516,382
9887.24.64.0/1887.24.64.1 to 87.24.127.25487.24.127.25516,382
9987.24.128.0/1887.24.128.1 to 87.24.191.25487.24.191.25516,382
10087.24.192.0/1887.24.192.1 to 87.24.255.25487.24.255.25516,382
10187.25.0.0/1887.25.0.1 to 87.25.63.25487.25.63.25516,382
10287.25.64.0/1887.25.64.1 to 87.25.127.25487.25.127.25516,382
10387.25.128.0/1887.25.128.1 to 87.25.191.25487.25.191.25516,382
10487.25.192.0/1887.25.192.1 to 87.25.255.25487.25.255.25516,382
10587.26.0.0/1887.26.0.1 to 87.26.63.25487.26.63.25516,382
10687.26.64.0/1887.26.64.1 to 87.26.127.25487.26.127.25516,382
10787.26.128.0/1887.26.128.1 to 87.26.191.25487.26.191.25516,382
10887.26.192.0/1887.26.192.1 to 87.26.255.25487.26.255.25516,382
10987.27.0.0/1887.27.0.1 to 87.27.63.25487.27.63.25516,382
11087.27.64.0/1887.27.64.1 to 87.27.127.25487.27.127.25516,382
11187.27.128.0/1887.27.128.1 to 87.27.191.25487.27.191.25516,382
11287.27.192.0/1887.27.192.1 to 87.27.255.25487.27.255.25516,382
11387.28.0.0/1887.28.0.1 to 87.28.63.25487.28.63.25516,382
11487.28.64.0/1887.28.64.1 to 87.28.127.25487.28.127.25516,382
11587.28.128.0/1887.28.128.1 to 87.28.191.25487.28.191.25516,382
11687.28.192.0/1887.28.192.1 to 87.28.255.25487.28.255.25516,382
11787.29.0.0/1887.29.0.1 to 87.29.63.25487.29.63.25516,382
11887.29.64.0/1887.29.64.1 to 87.29.127.25487.29.127.25516,382
11987.29.128.0/1887.29.128.1 to 87.29.191.25487.29.191.25516,382
12087.29.192.0/1887.29.192.1 to 87.29.255.25487.29.255.25516,382
12187.30.0.0/1887.30.0.1 to 87.30.63.25487.30.63.25516,382
12287.30.64.0/1887.30.64.1 to 87.30.127.25487.30.127.25516,382
12387.30.128.0/1887.30.128.1 to 87.30.191.25487.30.191.25516,382
12487.30.192.0/1887.30.192.1 to 87.30.255.25487.30.255.25516,382
12587.31.0.0/1887.31.0.1 to 87.31.63.25487.31.63.25516,382
12687.31.64.0/1887.31.64.1 to 87.31.127.25487.31.127.25516,382
12787.31.128.0/1887.31.128.1 to 87.31.191.25487.31.191.25516,382
12887.31.192.0/1887.31.192.1 to 87.31.255.25487.31.255.25516,382
12987.32.0.0/1887.32.0.1 to 87.32.63.25487.32.63.25516,382
13087.32.64.0/1887.32.64.1 to 87.32.127.25487.32.127.25516,382
13187.32.128.0/1887.32.128.1 to 87.32.191.25487.32.191.25516,382
13287.32.192.0/1887.32.192.1 to 87.32.255.25487.32.255.25516,382
13387.33.0.0/1887.33.0.1 to 87.33.63.25487.33.63.25516,382
13487.33.64.0/1887.33.64.1 to 87.33.127.25487.33.127.25516,382
13587.33.128.0/1887.33.128.1 to 87.33.191.25487.33.191.25516,382
13687.33.192.0/1887.33.192.1 to 87.33.255.25487.33.255.25516,382
13787.34.0.0/1887.34.0.1 to 87.34.63.25487.34.63.25516,382
13887.34.64.0/1887.34.64.1 to 87.34.127.25487.34.127.25516,382
13987.34.128.0/1887.34.128.1 to 87.34.191.25487.34.191.25516,382
14087.34.192.0/1887.34.192.1 to 87.34.255.25487.34.255.25516,382
14187.35.0.0/1887.35.0.1 to 87.35.63.25487.35.63.25516,382
14287.35.64.0/1887.35.64.1 to 87.35.127.25487.35.127.25516,382
14387.35.128.0/1887.35.128.1 to 87.35.191.25487.35.191.25516,382
14487.35.192.0/1887.35.192.1 to 87.35.255.25487.35.255.25516,382
14587.36.0.0/1887.36.0.1 to 87.36.63.25487.36.63.25516,382
14687.36.64.0/1887.36.64.1 to 87.36.127.25487.36.127.25516,382
14787.36.128.0/1887.36.128.1 to 87.36.191.25487.36.191.25516,382
14887.36.192.0/1887.36.192.1 to 87.36.255.25487.36.255.25516,382
14987.37.0.0/1887.37.0.1 to 87.37.63.25487.37.63.25516,382
15087.37.64.0/1887.37.64.1 to 87.37.127.25487.37.127.25516,382
15187.37.128.0/1887.37.128.1 to 87.37.191.25487.37.191.25516,382
15287.37.192.0/1887.37.192.1 to 87.37.255.25487.37.255.25516,382
15387.38.0.0/1887.38.0.1 to 87.38.63.25487.38.63.25516,382
15487.38.64.0/1887.38.64.1 to 87.38.127.25487.38.127.25516,382
15587.38.128.0/1887.38.128.1 to 87.38.191.25487.38.191.25516,382
15687.38.192.0/1887.38.192.1 to 87.38.255.25487.38.255.25516,382
15787.39.0.0/1887.39.0.1 to 87.39.63.25487.39.63.25516,382
15887.39.64.0/1887.39.64.1 to 87.39.127.25487.39.127.25516,382
15987.39.128.0/1887.39.128.1 to 87.39.191.25487.39.191.25516,382
16087.39.192.0/1887.39.192.1 to 87.39.255.25487.39.255.25516,382
16187.40.0.0/1887.40.0.1 to 87.40.63.25487.40.63.25516,382
16287.40.64.0/1887.40.64.1 to 87.40.127.25487.40.127.25516,382
16387.40.128.0/1887.40.128.1 to 87.40.191.25487.40.191.25516,382
16487.40.192.0/1887.40.192.1 to 87.40.255.25487.40.255.25516,382
16587.41.0.0/1887.41.0.1 to 87.41.63.25487.41.63.25516,382
16687.41.64.0/1887.41.64.1 to 87.41.127.25487.41.127.25516,382
16787.41.128.0/1887.41.128.1 to 87.41.191.25487.41.191.25516,382
16887.41.192.0/1887.41.192.1 to 87.41.255.25487.41.255.25516,382
16987.42.0.0/1887.42.0.1 to 87.42.63.25487.42.63.25516,382
17087.42.64.0/1887.42.64.1 to 87.42.127.25487.42.127.25516,382
17187.42.128.0/1887.42.128.1 to 87.42.191.25487.42.191.25516,382
17287.42.192.0/1887.42.192.1 to 87.42.255.25487.42.255.25516,382
17387.43.0.0/1887.43.0.1 to 87.43.63.25487.43.63.25516,382
17487.43.64.0/1887.43.64.1 to 87.43.127.25487.43.127.25516,382
17587.43.128.0/1887.43.128.1 to 87.43.191.25487.43.191.25516,382
17687.43.192.0/1887.43.192.1 to 87.43.255.25487.43.255.25516,382
17787.44.0.0/1887.44.0.1 to 87.44.63.25487.44.63.25516,382
17887.44.64.0/1887.44.64.1 to 87.44.127.25487.44.127.25516,382
17987.44.128.0/1887.44.128.1 to 87.44.191.25487.44.191.25516,382
18087.44.192.0/1887.44.192.1 to 87.44.255.25487.44.255.25516,382
18187.45.0.0/1887.45.0.1 to 87.45.63.25487.45.63.25516,382
18287.45.64.0/1887.45.64.1 to 87.45.127.25487.45.127.25516,382
18387.45.128.0/1887.45.128.1 to 87.45.191.25487.45.191.25516,382
18487.45.192.0/1887.45.192.1 to 87.45.255.25487.45.255.25516,382
18587.46.0.0/1887.46.0.1 to 87.46.63.25487.46.63.25516,382
18687.46.64.0/1887.46.64.1 to 87.46.127.25487.46.127.25516,382
18787.46.128.0/1887.46.128.1 to 87.46.191.25487.46.191.25516,382
18887.46.192.0/1887.46.192.1 to 87.46.255.25487.46.255.25516,382
18987.47.0.0/1887.47.0.1 to 87.47.63.25487.47.63.25516,382
19087.47.64.0/1887.47.64.1 to 87.47.127.25487.47.127.25516,382
19187.47.128.0/1887.47.128.1 to 87.47.191.25487.47.191.25516,382
19287.47.192.0/1887.47.192.1 to 87.47.255.25487.47.255.25516,382
19387.48.0.0/1887.48.0.1 to 87.48.63.25487.48.63.25516,382
19487.48.64.0/1887.48.64.1 to 87.48.127.25487.48.127.25516,382
19587.48.128.0/1887.48.128.1 to 87.48.191.25487.48.191.25516,382
19687.48.192.0/1887.48.192.1 to 87.48.255.25487.48.255.25516,382
19787.49.0.0/1887.49.0.1 to 87.49.63.25487.49.63.25516,382
19887.49.64.0/1887.49.64.1 to 87.49.127.25487.49.127.25516,382
19987.49.128.0/1887.49.128.1 to 87.49.191.25487.49.191.25516,382
20087.49.192.0/1887.49.192.1 to 87.49.255.25487.49.255.25516,382
20187.50.0.0/1887.50.0.1 to 87.50.63.25487.50.63.25516,382
20287.50.64.0/1887.50.64.1 to 87.50.127.25487.50.127.25516,382
20387.50.128.0/1887.50.128.1 to 87.50.191.25487.50.191.25516,382
20487.50.192.0/1887.50.192.1 to 87.50.255.25487.50.255.25516,382
20587.51.0.0/1887.51.0.1 to 87.51.63.25487.51.63.25516,382
20687.51.64.0/1887.51.64.1 to 87.51.127.25487.51.127.25516,382
20787.51.128.0/1887.51.128.1 to 87.51.191.25487.51.191.25516,382
20887.51.192.0/1887.51.192.1 to 87.51.255.25487.51.255.25516,382
20987.52.0.0/1887.52.0.1 to 87.52.63.25487.52.63.25516,382
21087.52.64.0/1887.52.64.1 to 87.52.127.25487.52.127.25516,382
21187.52.128.0/1887.52.128.1 to 87.52.191.25487.52.191.25516,382
21287.52.192.0/1887.52.192.1 to 87.52.255.25487.52.255.25516,382
21387.53.0.0/1887.53.0.1 to 87.53.63.25487.53.63.25516,382
21487.53.64.0/1887.53.64.1 to 87.53.127.25487.53.127.25516,382
21587.53.128.0/1887.53.128.1 to 87.53.191.25487.53.191.25516,382
21687.53.192.0/1887.53.192.1 to 87.53.255.25487.53.255.25516,382
21787.54.0.0/1887.54.0.1 to 87.54.63.25487.54.63.25516,382
21887.54.64.0/1887.54.64.1 to 87.54.127.25487.54.127.25516,382
21987.54.128.0/1887.54.128.1 to 87.54.191.25487.54.191.25516,382
22087.54.192.0/1887.54.192.1 to 87.54.255.25487.54.255.25516,382
22187.55.0.0/1887.55.0.1 to 87.55.63.25487.55.63.25516,382
22287.55.64.0/1887.55.64.1 to 87.55.127.25487.55.127.25516,382
22387.55.128.0/1887.55.128.1 to 87.55.191.25487.55.191.25516,382
22487.55.192.0/1887.55.192.1 to 87.55.255.25487.55.255.25516,382
22587.56.0.0/1887.56.0.1 to 87.56.63.25487.56.63.25516,382
22687.56.64.0/1887.56.64.1 to 87.56.127.25487.56.127.25516,382
22787.56.128.0/1887.56.128.1 to 87.56.191.25487.56.191.25516,382
22887.56.192.0/1887.56.192.1 to 87.56.255.25487.56.255.25516,382
22987.57.0.0/1887.57.0.1 to 87.57.63.25487.57.63.25516,382
23087.57.64.0/1887.57.64.1 to 87.57.127.25487.57.127.25516,382
23187.57.128.0/1887.57.128.1 to 87.57.191.25487.57.191.25516,382
23287.57.192.0/1887.57.192.1 to 87.57.255.25487.57.255.25516,382
23387.58.0.0/1887.58.0.1 to 87.58.63.25487.58.63.25516,382
23487.58.64.0/1887.58.64.1 to 87.58.127.25487.58.127.25516,382
23587.58.128.0/1887.58.128.1 to 87.58.191.25487.58.191.25516,382
23687.58.192.0/1887.58.192.1 to 87.58.255.25487.58.255.25516,382
23787.59.0.0/1887.59.0.1 to 87.59.63.25487.59.63.25516,382
23887.59.64.0/1887.59.64.1 to 87.59.127.25487.59.127.25516,382
23987.59.128.0/1887.59.128.1 to 87.59.191.25487.59.191.25516,382
24087.59.192.0/1887.59.192.1 to 87.59.255.25487.59.255.25516,382
24187.60.0.0/1887.60.0.1 to 87.60.63.25487.60.63.25516,382
24287.60.64.0/1887.60.64.1 to 87.60.127.25487.60.127.25516,382
24387.60.128.0/1887.60.128.1 to 87.60.191.25487.60.191.25516,382
24487.60.192.0/1887.60.192.1 to 87.60.255.25487.60.255.25516,382
24587.61.0.0/1887.61.0.1 to 87.61.63.25487.61.63.25516,382
24687.61.64.0/1887.61.64.1 to 87.61.127.25487.61.127.25516,382
24787.61.128.0/1887.61.128.1 to 87.61.191.25487.61.191.25516,382
24887.61.192.0/1887.61.192.1 to 87.61.255.25487.61.255.25516,382
24987.62.0.0/1887.62.0.1 to 87.62.63.25487.62.63.25516,382
25087.62.64.0/1887.62.64.1 to 87.62.127.25487.62.127.25516,382
25187.62.128.0/1887.62.128.1 to 87.62.191.25487.62.191.25516,382
25287.62.192.0/1887.62.192.1 to 87.62.255.25487.62.255.25516,382
25387.63.0.0/1887.63.0.1 to 87.63.63.25487.63.63.25516,382
25487.63.64.0/1887.63.64.1 to 87.63.127.25487.63.127.25516,382
25587.63.128.0/1887.63.128.1 to 87.63.191.25487.63.191.25516,382
25687.63.192.0/1887.63.192.1 to 87.63.255.25487.63.255.25516,382

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.