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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.

Network91.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
91.0.0.0
Broadcast address
91.255.255.255
First usable
91.0.0.1
Last usable
91.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 5B000000 · Integer 1526726656 to 1543503871
Reverse DNS zone
91.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01011011..00000000.00000000.0000000091.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01011011..00000000.00000000.0000000091.0.0.0
Broadcast01011011..11111111.11111111.1111111191.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

91.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
191.0.0.0/1991.0.0.1 to 91.0.31.25491.0.31.2558,190
291.0.32.0/1991.0.32.1 to 91.0.63.25491.0.63.2558,190
391.0.64.0/1991.0.64.1 to 91.0.95.25491.0.95.2558,190
491.0.96.0/1991.0.96.1 to 91.0.127.25491.0.127.2558,190
591.0.128.0/1991.0.128.1 to 91.0.159.25491.0.159.2558,190
691.0.160.0/1991.0.160.1 to 91.0.191.25491.0.191.2558,190
791.0.192.0/1991.0.192.1 to 91.0.223.25491.0.223.2558,190
891.0.224.0/1991.0.224.1 to 91.0.255.25491.0.255.2558,190
991.1.0.0/1991.1.0.1 to 91.1.31.25491.1.31.2558,190
1091.1.32.0/1991.1.32.1 to 91.1.63.25491.1.63.2558,190
1191.1.64.0/1991.1.64.1 to 91.1.95.25491.1.95.2558,190
1291.1.96.0/1991.1.96.1 to 91.1.127.25491.1.127.2558,190
1391.1.128.0/1991.1.128.1 to 91.1.159.25491.1.159.2558,190
1491.1.160.0/1991.1.160.1 to 91.1.191.25491.1.191.2558,190
1591.1.192.0/1991.1.192.1 to 91.1.223.25491.1.223.2558,190
1691.1.224.0/1991.1.224.1 to 91.1.255.25491.1.255.2558,190
1791.2.0.0/1991.2.0.1 to 91.2.31.25491.2.31.2558,190
1891.2.32.0/1991.2.32.1 to 91.2.63.25491.2.63.2558,190
1991.2.64.0/1991.2.64.1 to 91.2.95.25491.2.95.2558,190
2091.2.96.0/1991.2.96.1 to 91.2.127.25491.2.127.2558,190
2191.2.128.0/1991.2.128.1 to 91.2.159.25491.2.159.2558,190
2291.2.160.0/1991.2.160.1 to 91.2.191.25491.2.191.2558,190
2391.2.192.0/1991.2.192.1 to 91.2.223.25491.2.223.2558,190
2491.2.224.0/1991.2.224.1 to 91.2.255.25491.2.255.2558,190
2591.3.0.0/1991.3.0.1 to 91.3.31.25491.3.31.2558,190
2691.3.32.0/1991.3.32.1 to 91.3.63.25491.3.63.2558,190
2791.3.64.0/1991.3.64.1 to 91.3.95.25491.3.95.2558,190
2891.3.96.0/1991.3.96.1 to 91.3.127.25491.3.127.2558,190
2991.3.128.0/1991.3.128.1 to 91.3.159.25491.3.159.2558,190
3091.3.160.0/1991.3.160.1 to 91.3.191.25491.3.191.2558,190
3191.3.192.0/1991.3.192.1 to 91.3.223.25491.3.223.2558,190
3291.3.224.0/1991.3.224.1 to 91.3.255.25491.3.255.2558,190
3391.4.0.0/1991.4.0.1 to 91.4.31.25491.4.31.2558,190
3491.4.32.0/1991.4.32.1 to 91.4.63.25491.4.63.2558,190
3591.4.64.0/1991.4.64.1 to 91.4.95.25491.4.95.2558,190
3691.4.96.0/1991.4.96.1 to 91.4.127.25491.4.127.2558,190
3791.4.128.0/1991.4.128.1 to 91.4.159.25491.4.159.2558,190
3891.4.160.0/1991.4.160.1 to 91.4.191.25491.4.191.2558,190
3991.4.192.0/1991.4.192.1 to 91.4.223.25491.4.223.2558,190
4091.4.224.0/1991.4.224.1 to 91.4.255.25491.4.255.2558,190
4191.5.0.0/1991.5.0.1 to 91.5.31.25491.5.31.2558,190
4291.5.32.0/1991.5.32.1 to 91.5.63.25491.5.63.2558,190
4391.5.64.0/1991.5.64.1 to 91.5.95.25491.5.95.2558,190
4491.5.96.0/1991.5.96.1 to 91.5.127.25491.5.127.2558,190
4591.5.128.0/1991.5.128.1 to 91.5.159.25491.5.159.2558,190
4691.5.160.0/1991.5.160.1 to 91.5.191.25491.5.191.2558,190
4791.5.192.0/1991.5.192.1 to 91.5.223.25491.5.223.2558,190
4891.5.224.0/1991.5.224.1 to 91.5.255.25491.5.255.2558,190
4991.6.0.0/1991.6.0.1 to 91.6.31.25491.6.31.2558,190
5091.6.32.0/1991.6.32.1 to 91.6.63.25491.6.63.2558,190
5191.6.64.0/1991.6.64.1 to 91.6.95.25491.6.95.2558,190
5291.6.96.0/1991.6.96.1 to 91.6.127.25491.6.127.2558,190
5391.6.128.0/1991.6.128.1 to 91.6.159.25491.6.159.2558,190
5491.6.160.0/1991.6.160.1 to 91.6.191.25491.6.191.2558,190
5591.6.192.0/1991.6.192.1 to 91.6.223.25491.6.223.2558,190
5691.6.224.0/1991.6.224.1 to 91.6.255.25491.6.255.2558,190
5791.7.0.0/1991.7.0.1 to 91.7.31.25491.7.31.2558,190
5891.7.32.0/1991.7.32.1 to 91.7.63.25491.7.63.2558,190
5991.7.64.0/1991.7.64.1 to 91.7.95.25491.7.95.2558,190
6091.7.96.0/1991.7.96.1 to 91.7.127.25491.7.127.2558,190
6191.7.128.0/1991.7.128.1 to 91.7.159.25491.7.159.2558,190
6291.7.160.0/1991.7.160.1 to 91.7.191.25491.7.191.2558,190
6391.7.192.0/1991.7.192.1 to 91.7.223.25491.7.223.2558,190
6491.7.224.0/1991.7.224.1 to 91.7.255.25491.7.255.2558,190
6591.8.0.0/1991.8.0.1 to 91.8.31.25491.8.31.2558,190
6691.8.32.0/1991.8.32.1 to 91.8.63.25491.8.63.2558,190
6791.8.64.0/1991.8.64.1 to 91.8.95.25491.8.95.2558,190
6891.8.96.0/1991.8.96.1 to 91.8.127.25491.8.127.2558,190
6991.8.128.0/1991.8.128.1 to 91.8.159.25491.8.159.2558,190
7091.8.160.0/1991.8.160.1 to 91.8.191.25491.8.191.2558,190
7191.8.192.0/1991.8.192.1 to 91.8.223.25491.8.223.2558,190
7291.8.224.0/1991.8.224.1 to 91.8.255.25491.8.255.2558,190
7391.9.0.0/1991.9.0.1 to 91.9.31.25491.9.31.2558,190
7491.9.32.0/1991.9.32.1 to 91.9.63.25491.9.63.2558,190
7591.9.64.0/1991.9.64.1 to 91.9.95.25491.9.95.2558,190
7691.9.96.0/1991.9.96.1 to 91.9.127.25491.9.127.2558,190
7791.9.128.0/1991.9.128.1 to 91.9.159.25491.9.159.2558,190
7891.9.160.0/1991.9.160.1 to 91.9.191.25491.9.191.2558,190
7991.9.192.0/1991.9.192.1 to 91.9.223.25491.9.223.2558,190
8091.9.224.0/1991.9.224.1 to 91.9.255.25491.9.255.2558,190
8191.10.0.0/1991.10.0.1 to 91.10.31.25491.10.31.2558,190
8291.10.32.0/1991.10.32.1 to 91.10.63.25491.10.63.2558,190
8391.10.64.0/1991.10.64.1 to 91.10.95.25491.10.95.2558,190
8491.10.96.0/1991.10.96.1 to 91.10.127.25491.10.127.2558,190
8591.10.128.0/1991.10.128.1 to 91.10.159.25491.10.159.2558,190
8691.10.160.0/1991.10.160.1 to 91.10.191.25491.10.191.2558,190
8791.10.192.0/1991.10.192.1 to 91.10.223.25491.10.223.2558,190
8891.10.224.0/1991.10.224.1 to 91.10.255.25491.10.255.2558,190
8991.11.0.0/1991.11.0.1 to 91.11.31.25491.11.31.2558,190
9091.11.32.0/1991.11.32.1 to 91.11.63.25491.11.63.2558,190
9191.11.64.0/1991.11.64.1 to 91.11.95.25491.11.95.2558,190
9291.11.96.0/1991.11.96.1 to 91.11.127.25491.11.127.2558,190
9391.11.128.0/1991.11.128.1 to 91.11.159.25491.11.159.2558,190
9491.11.160.0/1991.11.160.1 to 91.11.191.25491.11.191.2558,190
9591.11.192.0/1991.11.192.1 to 91.11.223.25491.11.223.2558,190
9691.11.224.0/1991.11.224.1 to 91.11.255.25491.11.255.2558,190
9791.12.0.0/1991.12.0.1 to 91.12.31.25491.12.31.2558,190
9891.12.32.0/1991.12.32.1 to 91.12.63.25491.12.63.2558,190
9991.12.64.0/1991.12.64.1 to 91.12.95.25491.12.95.2558,190
10091.12.96.0/1991.12.96.1 to 91.12.127.25491.12.127.2558,190
10191.12.128.0/1991.12.128.1 to 91.12.159.25491.12.159.2558,190
10291.12.160.0/1991.12.160.1 to 91.12.191.25491.12.191.2558,190
10391.12.192.0/1991.12.192.1 to 91.12.223.25491.12.223.2558,190
10491.12.224.0/1991.12.224.1 to 91.12.255.25491.12.255.2558,190
10591.13.0.0/1991.13.0.1 to 91.13.31.25491.13.31.2558,190
10691.13.32.0/1991.13.32.1 to 91.13.63.25491.13.63.2558,190
10791.13.64.0/1991.13.64.1 to 91.13.95.25491.13.95.2558,190
10891.13.96.0/1991.13.96.1 to 91.13.127.25491.13.127.2558,190
10991.13.128.0/1991.13.128.1 to 91.13.159.25491.13.159.2558,190
11091.13.160.0/1991.13.160.1 to 91.13.191.25491.13.191.2558,190
11191.13.192.0/1991.13.192.1 to 91.13.223.25491.13.223.2558,190
11291.13.224.0/1991.13.224.1 to 91.13.255.25491.13.255.2558,190
11391.14.0.0/1991.14.0.1 to 91.14.31.25491.14.31.2558,190
11491.14.32.0/1991.14.32.1 to 91.14.63.25491.14.63.2558,190
11591.14.64.0/1991.14.64.1 to 91.14.95.25491.14.95.2558,190
11691.14.96.0/1991.14.96.1 to 91.14.127.25491.14.127.2558,190
11791.14.128.0/1991.14.128.1 to 91.14.159.25491.14.159.2558,190
11891.14.160.0/1991.14.160.1 to 91.14.191.25491.14.191.2558,190
11991.14.192.0/1991.14.192.1 to 91.14.223.25491.14.223.2558,190
12091.14.224.0/1991.14.224.1 to 91.14.255.25491.14.255.2558,190
12191.15.0.0/1991.15.0.1 to 91.15.31.25491.15.31.2558,190
12291.15.32.0/1991.15.32.1 to 91.15.63.25491.15.63.2558,190
12391.15.64.0/1991.15.64.1 to 91.15.95.25491.15.95.2558,190
12491.15.96.0/1991.15.96.1 to 91.15.127.25491.15.127.2558,190
12591.15.128.0/1991.15.128.1 to 91.15.159.25491.15.159.2558,190
12691.15.160.0/1991.15.160.1 to 91.15.191.25491.15.191.2558,190
12791.15.192.0/1991.15.192.1 to 91.15.223.25491.15.223.2558,190
12891.15.224.0/1991.15.224.1 to 91.15.255.25491.15.255.2558,190
12991.16.0.0/1991.16.0.1 to 91.16.31.25491.16.31.2558,190
13091.16.32.0/1991.16.32.1 to 91.16.63.25491.16.63.2558,190
13191.16.64.0/1991.16.64.1 to 91.16.95.25491.16.95.2558,190
13291.16.96.0/1991.16.96.1 to 91.16.127.25491.16.127.2558,190
13391.16.128.0/1991.16.128.1 to 91.16.159.25491.16.159.2558,190
13491.16.160.0/1991.16.160.1 to 91.16.191.25491.16.191.2558,190
13591.16.192.0/1991.16.192.1 to 91.16.223.25491.16.223.2558,190
13691.16.224.0/1991.16.224.1 to 91.16.255.25491.16.255.2558,190
13791.17.0.0/1991.17.0.1 to 91.17.31.25491.17.31.2558,190
13891.17.32.0/1991.17.32.1 to 91.17.63.25491.17.63.2558,190
13991.17.64.0/1991.17.64.1 to 91.17.95.25491.17.95.2558,190
14091.17.96.0/1991.17.96.1 to 91.17.127.25491.17.127.2558,190
14191.17.128.0/1991.17.128.1 to 91.17.159.25491.17.159.2558,190
14291.17.160.0/1991.17.160.1 to 91.17.191.25491.17.191.2558,190
14391.17.192.0/1991.17.192.1 to 91.17.223.25491.17.223.2558,190
14491.17.224.0/1991.17.224.1 to 91.17.255.25491.17.255.2558,190
14591.18.0.0/1991.18.0.1 to 91.18.31.25491.18.31.2558,190
14691.18.32.0/1991.18.32.1 to 91.18.63.25491.18.63.2558,190
14791.18.64.0/1991.18.64.1 to 91.18.95.25491.18.95.2558,190
14891.18.96.0/1991.18.96.1 to 91.18.127.25491.18.127.2558,190
14991.18.128.0/1991.18.128.1 to 91.18.159.25491.18.159.2558,190
15091.18.160.0/1991.18.160.1 to 91.18.191.25491.18.191.2558,190
15191.18.192.0/1991.18.192.1 to 91.18.223.25491.18.223.2558,190
15291.18.224.0/1991.18.224.1 to 91.18.255.25491.18.255.2558,190
15391.19.0.0/1991.19.0.1 to 91.19.31.25491.19.31.2558,190
15491.19.32.0/1991.19.32.1 to 91.19.63.25491.19.63.2558,190
15591.19.64.0/1991.19.64.1 to 91.19.95.25491.19.95.2558,190
15691.19.96.0/1991.19.96.1 to 91.19.127.25491.19.127.2558,190
15791.19.128.0/1991.19.128.1 to 91.19.159.25491.19.159.2558,190
15891.19.160.0/1991.19.160.1 to 91.19.191.25491.19.191.2558,190
15991.19.192.0/1991.19.192.1 to 91.19.223.25491.19.223.2558,190
16091.19.224.0/1991.19.224.1 to 91.19.255.25491.19.255.2558,190
16191.20.0.0/1991.20.0.1 to 91.20.31.25491.20.31.2558,190
16291.20.32.0/1991.20.32.1 to 91.20.63.25491.20.63.2558,190
16391.20.64.0/1991.20.64.1 to 91.20.95.25491.20.95.2558,190
16491.20.96.0/1991.20.96.1 to 91.20.127.25491.20.127.2558,190
16591.20.128.0/1991.20.128.1 to 91.20.159.25491.20.159.2558,190
16691.20.160.0/1991.20.160.1 to 91.20.191.25491.20.191.2558,190
16791.20.192.0/1991.20.192.1 to 91.20.223.25491.20.223.2558,190
16891.20.224.0/1991.20.224.1 to 91.20.255.25491.20.255.2558,190
16991.21.0.0/1991.21.0.1 to 91.21.31.25491.21.31.2558,190
17091.21.32.0/1991.21.32.1 to 91.21.63.25491.21.63.2558,190
17191.21.64.0/1991.21.64.1 to 91.21.95.25491.21.95.2558,190
17291.21.96.0/1991.21.96.1 to 91.21.127.25491.21.127.2558,190
17391.21.128.0/1991.21.128.1 to 91.21.159.25491.21.159.2558,190
17491.21.160.0/1991.21.160.1 to 91.21.191.25491.21.191.2558,190
17591.21.192.0/1991.21.192.1 to 91.21.223.25491.21.223.2558,190
17691.21.224.0/1991.21.224.1 to 91.21.255.25491.21.255.2558,190
17791.22.0.0/1991.22.0.1 to 91.22.31.25491.22.31.2558,190
17891.22.32.0/1991.22.32.1 to 91.22.63.25491.22.63.2558,190
17991.22.64.0/1991.22.64.1 to 91.22.95.25491.22.95.2558,190
18091.22.96.0/1991.22.96.1 to 91.22.127.25491.22.127.2558,190
18191.22.128.0/1991.22.128.1 to 91.22.159.25491.22.159.2558,190
18291.22.160.0/1991.22.160.1 to 91.22.191.25491.22.191.2558,190
18391.22.192.0/1991.22.192.1 to 91.22.223.25491.22.223.2558,190
18491.22.224.0/1991.22.224.1 to 91.22.255.25491.22.255.2558,190
18591.23.0.0/1991.23.0.1 to 91.23.31.25491.23.31.2558,190
18691.23.32.0/1991.23.32.1 to 91.23.63.25491.23.63.2558,190
18791.23.64.0/1991.23.64.1 to 91.23.95.25491.23.95.2558,190
18891.23.96.0/1991.23.96.1 to 91.23.127.25491.23.127.2558,190
18991.23.128.0/1991.23.128.1 to 91.23.159.25491.23.159.2558,190
19091.23.160.0/1991.23.160.1 to 91.23.191.25491.23.191.2558,190
19191.23.192.0/1991.23.192.1 to 91.23.223.25491.23.223.2558,190
19291.23.224.0/1991.23.224.1 to 91.23.255.25491.23.255.2558,190
19391.24.0.0/1991.24.0.1 to 91.24.31.25491.24.31.2558,190
19491.24.32.0/1991.24.32.1 to 91.24.63.25491.24.63.2558,190
19591.24.64.0/1991.24.64.1 to 91.24.95.25491.24.95.2558,190
19691.24.96.0/1991.24.96.1 to 91.24.127.25491.24.127.2558,190
19791.24.128.0/1991.24.128.1 to 91.24.159.25491.24.159.2558,190
19891.24.160.0/1991.24.160.1 to 91.24.191.25491.24.191.2558,190
19991.24.192.0/1991.24.192.1 to 91.24.223.25491.24.223.2558,190
20091.24.224.0/1991.24.224.1 to 91.24.255.25491.24.255.2558,190
20191.25.0.0/1991.25.0.1 to 91.25.31.25491.25.31.2558,190
20291.25.32.0/1991.25.32.1 to 91.25.63.25491.25.63.2558,190
20391.25.64.0/1991.25.64.1 to 91.25.95.25491.25.95.2558,190
20491.25.96.0/1991.25.96.1 to 91.25.127.25491.25.127.2558,190
20591.25.128.0/1991.25.128.1 to 91.25.159.25491.25.159.2558,190
20691.25.160.0/1991.25.160.1 to 91.25.191.25491.25.191.2558,190
20791.25.192.0/1991.25.192.1 to 91.25.223.25491.25.223.2558,190
20891.25.224.0/1991.25.224.1 to 91.25.255.25491.25.255.2558,190
20991.26.0.0/1991.26.0.1 to 91.26.31.25491.26.31.2558,190
21091.26.32.0/1991.26.32.1 to 91.26.63.25491.26.63.2558,190
21191.26.64.0/1991.26.64.1 to 91.26.95.25491.26.95.2558,190
21291.26.96.0/1991.26.96.1 to 91.26.127.25491.26.127.2558,190
21391.26.128.0/1991.26.128.1 to 91.26.159.25491.26.159.2558,190
21491.26.160.0/1991.26.160.1 to 91.26.191.25491.26.191.2558,190
21591.26.192.0/1991.26.192.1 to 91.26.223.25491.26.223.2558,190
21691.26.224.0/1991.26.224.1 to 91.26.255.25491.26.255.2558,190
21791.27.0.0/1991.27.0.1 to 91.27.31.25491.27.31.2558,190
21891.27.32.0/1991.27.32.1 to 91.27.63.25491.27.63.2558,190
21991.27.64.0/1991.27.64.1 to 91.27.95.25491.27.95.2558,190
22091.27.96.0/1991.27.96.1 to 91.27.127.25491.27.127.2558,190
22191.27.128.0/1991.27.128.1 to 91.27.159.25491.27.159.2558,190
22291.27.160.0/1991.27.160.1 to 91.27.191.25491.27.191.2558,190
22391.27.192.0/1991.27.192.1 to 91.27.223.25491.27.223.2558,190
22491.27.224.0/1991.27.224.1 to 91.27.255.25491.27.255.2558,190
22591.28.0.0/1991.28.0.1 to 91.28.31.25491.28.31.2558,190
22691.28.32.0/1991.28.32.1 to 91.28.63.25491.28.63.2558,190
22791.28.64.0/1991.28.64.1 to 91.28.95.25491.28.95.2558,190
22891.28.96.0/1991.28.96.1 to 91.28.127.25491.28.127.2558,190
22991.28.128.0/1991.28.128.1 to 91.28.159.25491.28.159.2558,190
23091.28.160.0/1991.28.160.1 to 91.28.191.25491.28.191.2558,190
23191.28.192.0/1991.28.192.1 to 91.28.223.25491.28.223.2558,190
23291.28.224.0/1991.28.224.1 to 91.28.255.25491.28.255.2558,190
23391.29.0.0/1991.29.0.1 to 91.29.31.25491.29.31.2558,190
23491.29.32.0/1991.29.32.1 to 91.29.63.25491.29.63.2558,190
23591.29.64.0/1991.29.64.1 to 91.29.95.25491.29.95.2558,190
23691.29.96.0/1991.29.96.1 to 91.29.127.25491.29.127.2558,190
23791.29.128.0/1991.29.128.1 to 91.29.159.25491.29.159.2558,190
23891.29.160.0/1991.29.160.1 to 91.29.191.25491.29.191.2558,190
23991.29.192.0/1991.29.192.1 to 91.29.223.25491.29.223.2558,190
24091.29.224.0/1991.29.224.1 to 91.29.255.25491.29.255.2558,190
24191.30.0.0/1991.30.0.1 to 91.30.31.25491.30.31.2558,190
24291.30.32.0/1991.30.32.1 to 91.30.63.25491.30.63.2558,190
24391.30.64.0/1991.30.64.1 to 91.30.95.25491.30.95.2558,190
24491.30.96.0/1991.30.96.1 to 91.30.127.25491.30.127.2558,190
24591.30.128.0/1991.30.128.1 to 91.30.159.25491.30.159.2558,190
24691.30.160.0/1991.30.160.1 to 91.30.191.25491.30.191.2558,190
24791.30.192.0/1991.30.192.1 to 91.30.223.25491.30.223.2558,190
24891.30.224.0/1991.30.224.1 to 91.30.255.25491.30.255.2558,190
24991.31.0.0/1991.31.0.1 to 91.31.31.25491.31.31.2558,190
25091.31.32.0/1991.31.32.1 to 91.31.63.25491.31.63.2558,190
25191.31.64.0/1991.31.64.1 to 91.31.95.25491.31.95.2558,190
25291.31.96.0/1991.31.96.1 to 91.31.127.25491.31.127.2558,190
25391.31.128.0/1991.31.128.1 to 91.31.159.25491.31.159.2558,190
25491.31.160.0/1991.31.160.1 to 91.31.191.25491.31.191.2558,190
25591.31.192.0/1991.31.192.1 to 91.31.223.25491.31.223.2558,190
25691.31.224.0/1991.31.224.1 to 91.31.255.25491.31.255.2558,190

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.