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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.

Network80.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
80.0.0.0
Broadcast address
80.127.255.255
First usable
80.0.0.1
Last usable
80.127.255.254
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 50000000 · Integer 1342177280 to 1350565887
Reverse DNS zones
0.80.in-addr.arpa
1.80.in-addr.arpa
2.80.in-addr.arpa
3.80.in-addr.arpa
4.80.in-addr.arpa
5.80.in-addr.arpa
6.80.in-addr.arpa
7.80.in-addr.arpa
8.80.in-addr.arpa
9.80.in-addr.arpa
10.80.in-addr.arpa
11.80.in-addr.arpa
12.80.in-addr.arpa
13.80.in-addr.arpa
14.80.in-addr.arpa
15.80.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
Address01010000.00000000.00000000.0000000080.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01010000.00000000.00000000.0000000080.0.0.0
Broadcast01010000.01111111.11111111.1111111180.127.255.255
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)

80.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
180.0.0.0/1980.0.0.1 to 80.0.31.25480.0.31.2558,190
280.0.32.0/1980.0.32.1 to 80.0.63.25480.0.63.2558,190
380.0.64.0/1980.0.64.1 to 80.0.95.25480.0.95.2558,190
480.0.96.0/1980.0.96.1 to 80.0.127.25480.0.127.2558,190
580.0.128.0/1980.0.128.1 to 80.0.159.25480.0.159.2558,190
680.0.160.0/1980.0.160.1 to 80.0.191.25480.0.191.2558,190
780.0.192.0/1980.0.192.1 to 80.0.223.25480.0.223.2558,190
880.0.224.0/1980.0.224.1 to 80.0.255.25480.0.255.2558,190
980.1.0.0/1980.1.0.1 to 80.1.31.25480.1.31.2558,190
1080.1.32.0/1980.1.32.1 to 80.1.63.25480.1.63.2558,190
1180.1.64.0/1980.1.64.1 to 80.1.95.25480.1.95.2558,190
1280.1.96.0/1980.1.96.1 to 80.1.127.25480.1.127.2558,190
1380.1.128.0/1980.1.128.1 to 80.1.159.25480.1.159.2558,190
1480.1.160.0/1980.1.160.1 to 80.1.191.25480.1.191.2558,190
1580.1.192.0/1980.1.192.1 to 80.1.223.25480.1.223.2558,190
1680.1.224.0/1980.1.224.1 to 80.1.255.25480.1.255.2558,190
1780.2.0.0/1980.2.0.1 to 80.2.31.25480.2.31.2558,190
1880.2.32.0/1980.2.32.1 to 80.2.63.25480.2.63.2558,190
1980.2.64.0/1980.2.64.1 to 80.2.95.25480.2.95.2558,190
2080.2.96.0/1980.2.96.1 to 80.2.127.25480.2.127.2558,190
2180.2.128.0/1980.2.128.1 to 80.2.159.25480.2.159.2558,190
2280.2.160.0/1980.2.160.1 to 80.2.191.25480.2.191.2558,190
2380.2.192.0/1980.2.192.1 to 80.2.223.25480.2.223.2558,190
2480.2.224.0/1980.2.224.1 to 80.2.255.25480.2.255.2558,190
2580.3.0.0/1980.3.0.1 to 80.3.31.25480.3.31.2558,190
2680.3.32.0/1980.3.32.1 to 80.3.63.25480.3.63.2558,190
2780.3.64.0/1980.3.64.1 to 80.3.95.25480.3.95.2558,190
2880.3.96.0/1980.3.96.1 to 80.3.127.25480.3.127.2558,190
2980.3.128.0/1980.3.128.1 to 80.3.159.25480.3.159.2558,190
3080.3.160.0/1980.3.160.1 to 80.3.191.25480.3.191.2558,190
3180.3.192.0/1980.3.192.1 to 80.3.223.25480.3.223.2558,190
3280.3.224.0/1980.3.224.1 to 80.3.255.25480.3.255.2558,190
3380.4.0.0/1980.4.0.1 to 80.4.31.25480.4.31.2558,190
3480.4.32.0/1980.4.32.1 to 80.4.63.25480.4.63.2558,190
3580.4.64.0/1980.4.64.1 to 80.4.95.25480.4.95.2558,190
3680.4.96.0/1980.4.96.1 to 80.4.127.25480.4.127.2558,190
3780.4.128.0/1980.4.128.1 to 80.4.159.25480.4.159.2558,190
3880.4.160.0/1980.4.160.1 to 80.4.191.25480.4.191.2558,190
3980.4.192.0/1980.4.192.1 to 80.4.223.25480.4.223.2558,190
4080.4.224.0/1980.4.224.1 to 80.4.255.25480.4.255.2558,190
4180.5.0.0/1980.5.0.1 to 80.5.31.25480.5.31.2558,190
4280.5.32.0/1980.5.32.1 to 80.5.63.25480.5.63.2558,190
4380.5.64.0/1980.5.64.1 to 80.5.95.25480.5.95.2558,190
4480.5.96.0/1980.5.96.1 to 80.5.127.25480.5.127.2558,190
4580.5.128.0/1980.5.128.1 to 80.5.159.25480.5.159.2558,190
4680.5.160.0/1980.5.160.1 to 80.5.191.25480.5.191.2558,190
4780.5.192.0/1980.5.192.1 to 80.5.223.25480.5.223.2558,190
4880.5.224.0/1980.5.224.1 to 80.5.255.25480.5.255.2558,190
4980.6.0.0/1980.6.0.1 to 80.6.31.25480.6.31.2558,190
5080.6.32.0/1980.6.32.1 to 80.6.63.25480.6.63.2558,190
5180.6.64.0/1980.6.64.1 to 80.6.95.25480.6.95.2558,190
5280.6.96.0/1980.6.96.1 to 80.6.127.25480.6.127.2558,190
5380.6.128.0/1980.6.128.1 to 80.6.159.25480.6.159.2558,190
5480.6.160.0/1980.6.160.1 to 80.6.191.25480.6.191.2558,190
5580.6.192.0/1980.6.192.1 to 80.6.223.25480.6.223.2558,190
5680.6.224.0/1980.6.224.1 to 80.6.255.25480.6.255.2558,190
5780.7.0.0/1980.7.0.1 to 80.7.31.25480.7.31.2558,190
5880.7.32.0/1980.7.32.1 to 80.7.63.25480.7.63.2558,190
5980.7.64.0/1980.7.64.1 to 80.7.95.25480.7.95.2558,190
6080.7.96.0/1980.7.96.1 to 80.7.127.25480.7.127.2558,190
6180.7.128.0/1980.7.128.1 to 80.7.159.25480.7.159.2558,190
6280.7.160.0/1980.7.160.1 to 80.7.191.25480.7.191.2558,190
6380.7.192.0/1980.7.192.1 to 80.7.223.25480.7.223.2558,190
6480.7.224.0/1980.7.224.1 to 80.7.255.25480.7.255.2558,190
6580.8.0.0/1980.8.0.1 to 80.8.31.25480.8.31.2558,190
6680.8.32.0/1980.8.32.1 to 80.8.63.25480.8.63.2558,190
6780.8.64.0/1980.8.64.1 to 80.8.95.25480.8.95.2558,190
6880.8.96.0/1980.8.96.1 to 80.8.127.25480.8.127.2558,190
6980.8.128.0/1980.8.128.1 to 80.8.159.25480.8.159.2558,190
7080.8.160.0/1980.8.160.1 to 80.8.191.25480.8.191.2558,190
7180.8.192.0/1980.8.192.1 to 80.8.223.25480.8.223.2558,190
7280.8.224.0/1980.8.224.1 to 80.8.255.25480.8.255.2558,190
7380.9.0.0/1980.9.0.1 to 80.9.31.25480.9.31.2558,190
7480.9.32.0/1980.9.32.1 to 80.9.63.25480.9.63.2558,190
7580.9.64.0/1980.9.64.1 to 80.9.95.25480.9.95.2558,190
7680.9.96.0/1980.9.96.1 to 80.9.127.25480.9.127.2558,190
7780.9.128.0/1980.9.128.1 to 80.9.159.25480.9.159.2558,190
7880.9.160.0/1980.9.160.1 to 80.9.191.25480.9.191.2558,190
7980.9.192.0/1980.9.192.1 to 80.9.223.25480.9.223.2558,190
8080.9.224.0/1980.9.224.1 to 80.9.255.25480.9.255.2558,190
8180.10.0.0/1980.10.0.1 to 80.10.31.25480.10.31.2558,190
8280.10.32.0/1980.10.32.1 to 80.10.63.25480.10.63.2558,190
8380.10.64.0/1980.10.64.1 to 80.10.95.25480.10.95.2558,190
8480.10.96.0/1980.10.96.1 to 80.10.127.25480.10.127.2558,190
8580.10.128.0/1980.10.128.1 to 80.10.159.25480.10.159.2558,190
8680.10.160.0/1980.10.160.1 to 80.10.191.25480.10.191.2558,190
8780.10.192.0/1980.10.192.1 to 80.10.223.25480.10.223.2558,190
8880.10.224.0/1980.10.224.1 to 80.10.255.25480.10.255.2558,190
8980.11.0.0/1980.11.0.1 to 80.11.31.25480.11.31.2558,190
9080.11.32.0/1980.11.32.1 to 80.11.63.25480.11.63.2558,190
9180.11.64.0/1980.11.64.1 to 80.11.95.25480.11.95.2558,190
9280.11.96.0/1980.11.96.1 to 80.11.127.25480.11.127.2558,190
9380.11.128.0/1980.11.128.1 to 80.11.159.25480.11.159.2558,190
9480.11.160.0/1980.11.160.1 to 80.11.191.25480.11.191.2558,190
9580.11.192.0/1980.11.192.1 to 80.11.223.25480.11.223.2558,190
9680.11.224.0/1980.11.224.1 to 80.11.255.25480.11.255.2558,190
9780.12.0.0/1980.12.0.1 to 80.12.31.25480.12.31.2558,190
9880.12.32.0/1980.12.32.1 to 80.12.63.25480.12.63.2558,190
9980.12.64.0/1980.12.64.1 to 80.12.95.25480.12.95.2558,190
10080.12.96.0/1980.12.96.1 to 80.12.127.25480.12.127.2558,190
10180.12.128.0/1980.12.128.1 to 80.12.159.25480.12.159.2558,190
10280.12.160.0/1980.12.160.1 to 80.12.191.25480.12.191.2558,190
10380.12.192.0/1980.12.192.1 to 80.12.223.25480.12.223.2558,190
10480.12.224.0/1980.12.224.1 to 80.12.255.25480.12.255.2558,190
10580.13.0.0/1980.13.0.1 to 80.13.31.25480.13.31.2558,190
10680.13.32.0/1980.13.32.1 to 80.13.63.25480.13.63.2558,190
10780.13.64.0/1980.13.64.1 to 80.13.95.25480.13.95.2558,190
10880.13.96.0/1980.13.96.1 to 80.13.127.25480.13.127.2558,190
10980.13.128.0/1980.13.128.1 to 80.13.159.25480.13.159.2558,190
11080.13.160.0/1980.13.160.1 to 80.13.191.25480.13.191.2558,190
11180.13.192.0/1980.13.192.1 to 80.13.223.25480.13.223.2558,190
11280.13.224.0/1980.13.224.1 to 80.13.255.25480.13.255.2558,190
11380.14.0.0/1980.14.0.1 to 80.14.31.25480.14.31.2558,190
11480.14.32.0/1980.14.32.1 to 80.14.63.25480.14.63.2558,190
11580.14.64.0/1980.14.64.1 to 80.14.95.25480.14.95.2558,190
11680.14.96.0/1980.14.96.1 to 80.14.127.25480.14.127.2558,190
11780.14.128.0/1980.14.128.1 to 80.14.159.25480.14.159.2558,190
11880.14.160.0/1980.14.160.1 to 80.14.191.25480.14.191.2558,190
11980.14.192.0/1980.14.192.1 to 80.14.223.25480.14.223.2558,190
12080.14.224.0/1980.14.224.1 to 80.14.255.25480.14.255.2558,190
12180.15.0.0/1980.15.0.1 to 80.15.31.25480.15.31.2558,190
12280.15.32.0/1980.15.32.1 to 80.15.63.25480.15.63.2558,190
12380.15.64.0/1980.15.64.1 to 80.15.95.25480.15.95.2558,190
12480.15.96.0/1980.15.96.1 to 80.15.127.25480.15.127.2558,190
12580.15.128.0/1980.15.128.1 to 80.15.159.25480.15.159.2558,190
12680.15.160.0/1980.15.160.1 to 80.15.191.25480.15.191.2558,190
12780.15.192.0/1980.15.192.1 to 80.15.223.25480.15.223.2558,190
12880.15.224.0/1980.15.224.1 to 80.15.255.25480.15.255.2558,190
12980.16.0.0/1980.16.0.1 to 80.16.31.25480.16.31.2558,190
13080.16.32.0/1980.16.32.1 to 80.16.63.25480.16.63.2558,190
13180.16.64.0/1980.16.64.1 to 80.16.95.25480.16.95.2558,190
13280.16.96.0/1980.16.96.1 to 80.16.127.25480.16.127.2558,190
13380.16.128.0/1980.16.128.1 to 80.16.159.25480.16.159.2558,190
13480.16.160.0/1980.16.160.1 to 80.16.191.25480.16.191.2558,190
13580.16.192.0/1980.16.192.1 to 80.16.223.25480.16.223.2558,190
13680.16.224.0/1980.16.224.1 to 80.16.255.25480.16.255.2558,190
13780.17.0.0/1980.17.0.1 to 80.17.31.25480.17.31.2558,190
13880.17.32.0/1980.17.32.1 to 80.17.63.25480.17.63.2558,190
13980.17.64.0/1980.17.64.1 to 80.17.95.25480.17.95.2558,190
14080.17.96.0/1980.17.96.1 to 80.17.127.25480.17.127.2558,190
14180.17.128.0/1980.17.128.1 to 80.17.159.25480.17.159.2558,190
14280.17.160.0/1980.17.160.1 to 80.17.191.25480.17.191.2558,190
14380.17.192.0/1980.17.192.1 to 80.17.223.25480.17.223.2558,190
14480.17.224.0/1980.17.224.1 to 80.17.255.25480.17.255.2558,190
14580.18.0.0/1980.18.0.1 to 80.18.31.25480.18.31.2558,190
14680.18.32.0/1980.18.32.1 to 80.18.63.25480.18.63.2558,190
14780.18.64.0/1980.18.64.1 to 80.18.95.25480.18.95.2558,190
14880.18.96.0/1980.18.96.1 to 80.18.127.25480.18.127.2558,190
14980.18.128.0/1980.18.128.1 to 80.18.159.25480.18.159.2558,190
15080.18.160.0/1980.18.160.1 to 80.18.191.25480.18.191.2558,190
15180.18.192.0/1980.18.192.1 to 80.18.223.25480.18.223.2558,190
15280.18.224.0/1980.18.224.1 to 80.18.255.25480.18.255.2558,190
15380.19.0.0/1980.19.0.1 to 80.19.31.25480.19.31.2558,190
15480.19.32.0/1980.19.32.1 to 80.19.63.25480.19.63.2558,190
15580.19.64.0/1980.19.64.1 to 80.19.95.25480.19.95.2558,190
15680.19.96.0/1980.19.96.1 to 80.19.127.25480.19.127.2558,190
15780.19.128.0/1980.19.128.1 to 80.19.159.25480.19.159.2558,190
15880.19.160.0/1980.19.160.1 to 80.19.191.25480.19.191.2558,190
15980.19.192.0/1980.19.192.1 to 80.19.223.25480.19.223.2558,190
16080.19.224.0/1980.19.224.1 to 80.19.255.25480.19.255.2558,190
16180.20.0.0/1980.20.0.1 to 80.20.31.25480.20.31.2558,190
16280.20.32.0/1980.20.32.1 to 80.20.63.25480.20.63.2558,190
16380.20.64.0/1980.20.64.1 to 80.20.95.25480.20.95.2558,190
16480.20.96.0/1980.20.96.1 to 80.20.127.25480.20.127.2558,190
16580.20.128.0/1980.20.128.1 to 80.20.159.25480.20.159.2558,190
16680.20.160.0/1980.20.160.1 to 80.20.191.25480.20.191.2558,190
16780.20.192.0/1980.20.192.1 to 80.20.223.25480.20.223.2558,190
16880.20.224.0/1980.20.224.1 to 80.20.255.25480.20.255.2558,190
16980.21.0.0/1980.21.0.1 to 80.21.31.25480.21.31.2558,190
17080.21.32.0/1980.21.32.1 to 80.21.63.25480.21.63.2558,190
17180.21.64.0/1980.21.64.1 to 80.21.95.25480.21.95.2558,190
17280.21.96.0/1980.21.96.1 to 80.21.127.25480.21.127.2558,190
17380.21.128.0/1980.21.128.1 to 80.21.159.25480.21.159.2558,190
17480.21.160.0/1980.21.160.1 to 80.21.191.25480.21.191.2558,190
17580.21.192.0/1980.21.192.1 to 80.21.223.25480.21.223.2558,190
17680.21.224.0/1980.21.224.1 to 80.21.255.25480.21.255.2558,190
17780.22.0.0/1980.22.0.1 to 80.22.31.25480.22.31.2558,190
17880.22.32.0/1980.22.32.1 to 80.22.63.25480.22.63.2558,190
17980.22.64.0/1980.22.64.1 to 80.22.95.25480.22.95.2558,190
18080.22.96.0/1980.22.96.1 to 80.22.127.25480.22.127.2558,190
18180.22.128.0/1980.22.128.1 to 80.22.159.25480.22.159.2558,190
18280.22.160.0/1980.22.160.1 to 80.22.191.25480.22.191.2558,190
18380.22.192.0/1980.22.192.1 to 80.22.223.25480.22.223.2558,190
18480.22.224.0/1980.22.224.1 to 80.22.255.25480.22.255.2558,190
18580.23.0.0/1980.23.0.1 to 80.23.31.25480.23.31.2558,190
18680.23.32.0/1980.23.32.1 to 80.23.63.25480.23.63.2558,190
18780.23.64.0/1980.23.64.1 to 80.23.95.25480.23.95.2558,190
18880.23.96.0/1980.23.96.1 to 80.23.127.25480.23.127.2558,190
18980.23.128.0/1980.23.128.1 to 80.23.159.25480.23.159.2558,190
19080.23.160.0/1980.23.160.1 to 80.23.191.25480.23.191.2558,190
19180.23.192.0/1980.23.192.1 to 80.23.223.25480.23.223.2558,190
19280.23.224.0/1980.23.224.1 to 80.23.255.25480.23.255.2558,190
19380.24.0.0/1980.24.0.1 to 80.24.31.25480.24.31.2558,190
19480.24.32.0/1980.24.32.1 to 80.24.63.25480.24.63.2558,190
19580.24.64.0/1980.24.64.1 to 80.24.95.25480.24.95.2558,190
19680.24.96.0/1980.24.96.1 to 80.24.127.25480.24.127.2558,190
19780.24.128.0/1980.24.128.1 to 80.24.159.25480.24.159.2558,190
19880.24.160.0/1980.24.160.1 to 80.24.191.25480.24.191.2558,190
19980.24.192.0/1980.24.192.1 to 80.24.223.25480.24.223.2558,190
20080.24.224.0/1980.24.224.1 to 80.24.255.25480.24.255.2558,190
20180.25.0.0/1980.25.0.1 to 80.25.31.25480.25.31.2558,190
20280.25.32.0/1980.25.32.1 to 80.25.63.25480.25.63.2558,190
20380.25.64.0/1980.25.64.1 to 80.25.95.25480.25.95.2558,190
20480.25.96.0/1980.25.96.1 to 80.25.127.25480.25.127.2558,190
20580.25.128.0/1980.25.128.1 to 80.25.159.25480.25.159.2558,190
20680.25.160.0/1980.25.160.1 to 80.25.191.25480.25.191.2558,190
20780.25.192.0/1980.25.192.1 to 80.25.223.25480.25.223.2558,190
20880.25.224.0/1980.25.224.1 to 80.25.255.25480.25.255.2558,190
20980.26.0.0/1980.26.0.1 to 80.26.31.25480.26.31.2558,190
21080.26.32.0/1980.26.32.1 to 80.26.63.25480.26.63.2558,190
21180.26.64.0/1980.26.64.1 to 80.26.95.25480.26.95.2558,190
21280.26.96.0/1980.26.96.1 to 80.26.127.25480.26.127.2558,190
21380.26.128.0/1980.26.128.1 to 80.26.159.25480.26.159.2558,190
21480.26.160.0/1980.26.160.1 to 80.26.191.25480.26.191.2558,190
21580.26.192.0/1980.26.192.1 to 80.26.223.25480.26.223.2558,190
21680.26.224.0/1980.26.224.1 to 80.26.255.25480.26.255.2558,190
21780.27.0.0/1980.27.0.1 to 80.27.31.25480.27.31.2558,190
21880.27.32.0/1980.27.32.1 to 80.27.63.25480.27.63.2558,190
21980.27.64.0/1980.27.64.1 to 80.27.95.25480.27.95.2558,190
22080.27.96.0/1980.27.96.1 to 80.27.127.25480.27.127.2558,190
22180.27.128.0/1980.27.128.1 to 80.27.159.25480.27.159.2558,190
22280.27.160.0/1980.27.160.1 to 80.27.191.25480.27.191.2558,190
22380.27.192.0/1980.27.192.1 to 80.27.223.25480.27.223.2558,190
22480.27.224.0/1980.27.224.1 to 80.27.255.25480.27.255.2558,190
22580.28.0.0/1980.28.0.1 to 80.28.31.25480.28.31.2558,190
22680.28.32.0/1980.28.32.1 to 80.28.63.25480.28.63.2558,190
22780.28.64.0/1980.28.64.1 to 80.28.95.25480.28.95.2558,190
22880.28.96.0/1980.28.96.1 to 80.28.127.25480.28.127.2558,190
22980.28.128.0/1980.28.128.1 to 80.28.159.25480.28.159.2558,190
23080.28.160.0/1980.28.160.1 to 80.28.191.25480.28.191.2558,190
23180.28.192.0/1980.28.192.1 to 80.28.223.25480.28.223.2558,190
23280.28.224.0/1980.28.224.1 to 80.28.255.25480.28.255.2558,190
23380.29.0.0/1980.29.0.1 to 80.29.31.25480.29.31.2558,190
23480.29.32.0/1980.29.32.1 to 80.29.63.25480.29.63.2558,190
23580.29.64.0/1980.29.64.1 to 80.29.95.25480.29.95.2558,190
23680.29.96.0/1980.29.96.1 to 80.29.127.25480.29.127.2558,190
23780.29.128.0/1980.29.128.1 to 80.29.159.25480.29.159.2558,190
23880.29.160.0/1980.29.160.1 to 80.29.191.25480.29.191.2558,190
23980.29.192.0/1980.29.192.1 to 80.29.223.25480.29.223.2558,190
24080.29.224.0/1980.29.224.1 to 80.29.255.25480.29.255.2558,190
24180.30.0.0/1980.30.0.1 to 80.30.31.25480.30.31.2558,190
24280.30.32.0/1980.30.32.1 to 80.30.63.25480.30.63.2558,190
24380.30.64.0/1980.30.64.1 to 80.30.95.25480.30.95.2558,190
24480.30.96.0/1980.30.96.1 to 80.30.127.25480.30.127.2558,190
24580.30.128.0/1980.30.128.1 to 80.30.159.25480.30.159.2558,190
24680.30.160.0/1980.30.160.1 to 80.30.191.25480.30.191.2558,190
24780.30.192.0/1980.30.192.1 to 80.30.223.25480.30.223.2558,190
24880.30.224.0/1980.30.224.1 to 80.30.255.25480.30.255.2558,190
24980.31.0.0/1980.31.0.1 to 80.31.31.25480.31.31.2558,190
25080.31.32.0/1980.31.32.1 to 80.31.63.25480.31.63.2558,190
25180.31.64.0/1980.31.64.1 to 80.31.95.25480.31.95.2558,190
25280.31.96.0/1980.31.96.1 to 80.31.127.25480.31.127.2558,190
25380.31.128.0/1980.31.128.1 to 80.31.159.25480.31.159.2558,190
25480.31.160.0/1980.31.160.1 to 80.31.191.25480.31.191.2558,190
25580.31.192.0/1980.31.192.1 to 80.31.223.25480.31.223.2558,190
25680.31.224.0/1980.31.224.1 to 80.31.255.25480.31.255.2558,190

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.