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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/20
/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 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
180.0.0.0/2080.0.0.1 to 80.0.15.25480.0.15.2554,094
280.0.16.0/2080.0.16.1 to 80.0.31.25480.0.31.2554,094
380.0.32.0/2080.0.32.1 to 80.0.47.25480.0.47.2554,094
480.0.48.0/2080.0.48.1 to 80.0.63.25480.0.63.2554,094
580.0.64.0/2080.0.64.1 to 80.0.79.25480.0.79.2554,094
680.0.80.0/2080.0.80.1 to 80.0.95.25480.0.95.2554,094
780.0.96.0/2080.0.96.1 to 80.0.111.25480.0.111.2554,094
880.0.112.0/2080.0.112.1 to 80.0.127.25480.0.127.2554,094
980.0.128.0/2080.0.128.1 to 80.0.143.25480.0.143.2554,094
1080.0.144.0/2080.0.144.1 to 80.0.159.25480.0.159.2554,094
1180.0.160.0/2080.0.160.1 to 80.0.175.25480.0.175.2554,094
1280.0.176.0/2080.0.176.1 to 80.0.191.25480.0.191.2554,094
1380.0.192.0/2080.0.192.1 to 80.0.207.25480.0.207.2554,094
1480.0.208.0/2080.0.208.1 to 80.0.223.25480.0.223.2554,094
1580.0.224.0/2080.0.224.1 to 80.0.239.25480.0.239.2554,094
1680.0.240.0/2080.0.240.1 to 80.0.255.25480.0.255.2554,094
1780.1.0.0/2080.1.0.1 to 80.1.15.25480.1.15.2554,094
1880.1.16.0/2080.1.16.1 to 80.1.31.25480.1.31.2554,094
1980.1.32.0/2080.1.32.1 to 80.1.47.25480.1.47.2554,094
2080.1.48.0/2080.1.48.1 to 80.1.63.25480.1.63.2554,094
2180.1.64.0/2080.1.64.1 to 80.1.79.25480.1.79.2554,094
2280.1.80.0/2080.1.80.1 to 80.1.95.25480.1.95.2554,094
2380.1.96.0/2080.1.96.1 to 80.1.111.25480.1.111.2554,094
2480.1.112.0/2080.1.112.1 to 80.1.127.25480.1.127.2554,094
2580.1.128.0/2080.1.128.1 to 80.1.143.25480.1.143.2554,094
2680.1.144.0/2080.1.144.1 to 80.1.159.25480.1.159.2554,094
2780.1.160.0/2080.1.160.1 to 80.1.175.25480.1.175.2554,094
2880.1.176.0/2080.1.176.1 to 80.1.191.25480.1.191.2554,094
2980.1.192.0/2080.1.192.1 to 80.1.207.25480.1.207.2554,094
3080.1.208.0/2080.1.208.1 to 80.1.223.25480.1.223.2554,094
3180.1.224.0/2080.1.224.1 to 80.1.239.25480.1.239.2554,094
3280.1.240.0/2080.1.240.1 to 80.1.255.25480.1.255.2554,094
3380.2.0.0/2080.2.0.1 to 80.2.15.25480.2.15.2554,094
3480.2.16.0/2080.2.16.1 to 80.2.31.25480.2.31.2554,094
3580.2.32.0/2080.2.32.1 to 80.2.47.25480.2.47.2554,094
3680.2.48.0/2080.2.48.1 to 80.2.63.25480.2.63.2554,094
3780.2.64.0/2080.2.64.1 to 80.2.79.25480.2.79.2554,094
3880.2.80.0/2080.2.80.1 to 80.2.95.25480.2.95.2554,094
3980.2.96.0/2080.2.96.1 to 80.2.111.25480.2.111.2554,094
4080.2.112.0/2080.2.112.1 to 80.2.127.25480.2.127.2554,094
4180.2.128.0/2080.2.128.1 to 80.2.143.25480.2.143.2554,094
4280.2.144.0/2080.2.144.1 to 80.2.159.25480.2.159.2554,094
4380.2.160.0/2080.2.160.1 to 80.2.175.25480.2.175.2554,094
4480.2.176.0/2080.2.176.1 to 80.2.191.25480.2.191.2554,094
4580.2.192.0/2080.2.192.1 to 80.2.207.25480.2.207.2554,094
4680.2.208.0/2080.2.208.1 to 80.2.223.25480.2.223.2554,094
4780.2.224.0/2080.2.224.1 to 80.2.239.25480.2.239.2554,094
4880.2.240.0/2080.2.240.1 to 80.2.255.25480.2.255.2554,094
4980.3.0.0/2080.3.0.1 to 80.3.15.25480.3.15.2554,094
5080.3.16.0/2080.3.16.1 to 80.3.31.25480.3.31.2554,094
5180.3.32.0/2080.3.32.1 to 80.3.47.25480.3.47.2554,094
5280.3.48.0/2080.3.48.1 to 80.3.63.25480.3.63.2554,094
5380.3.64.0/2080.3.64.1 to 80.3.79.25480.3.79.2554,094
5480.3.80.0/2080.3.80.1 to 80.3.95.25480.3.95.2554,094
5580.3.96.0/2080.3.96.1 to 80.3.111.25480.3.111.2554,094
5680.3.112.0/2080.3.112.1 to 80.3.127.25480.3.127.2554,094
5780.3.128.0/2080.3.128.1 to 80.3.143.25480.3.143.2554,094
5880.3.144.0/2080.3.144.1 to 80.3.159.25480.3.159.2554,094
5980.3.160.0/2080.3.160.1 to 80.3.175.25480.3.175.2554,094
6080.3.176.0/2080.3.176.1 to 80.3.191.25480.3.191.2554,094
6180.3.192.0/2080.3.192.1 to 80.3.207.25480.3.207.2554,094
6280.3.208.0/2080.3.208.1 to 80.3.223.25480.3.223.2554,094
6380.3.224.0/2080.3.224.1 to 80.3.239.25480.3.239.2554,094
6480.3.240.0/2080.3.240.1 to 80.3.255.25480.3.255.2554,094
6580.4.0.0/2080.4.0.1 to 80.4.15.25480.4.15.2554,094
6680.4.16.0/2080.4.16.1 to 80.4.31.25480.4.31.2554,094
6780.4.32.0/2080.4.32.1 to 80.4.47.25480.4.47.2554,094
6880.4.48.0/2080.4.48.1 to 80.4.63.25480.4.63.2554,094
6980.4.64.0/2080.4.64.1 to 80.4.79.25480.4.79.2554,094
7080.4.80.0/2080.4.80.1 to 80.4.95.25480.4.95.2554,094
7180.4.96.0/2080.4.96.1 to 80.4.111.25480.4.111.2554,094
7280.4.112.0/2080.4.112.1 to 80.4.127.25480.4.127.2554,094
7380.4.128.0/2080.4.128.1 to 80.4.143.25480.4.143.2554,094
7480.4.144.0/2080.4.144.1 to 80.4.159.25480.4.159.2554,094
7580.4.160.0/2080.4.160.1 to 80.4.175.25480.4.175.2554,094
7680.4.176.0/2080.4.176.1 to 80.4.191.25480.4.191.2554,094
7780.4.192.0/2080.4.192.1 to 80.4.207.25480.4.207.2554,094
7880.4.208.0/2080.4.208.1 to 80.4.223.25480.4.223.2554,094
7980.4.224.0/2080.4.224.1 to 80.4.239.25480.4.239.2554,094
8080.4.240.0/2080.4.240.1 to 80.4.255.25480.4.255.2554,094
8180.5.0.0/2080.5.0.1 to 80.5.15.25480.5.15.2554,094
8280.5.16.0/2080.5.16.1 to 80.5.31.25480.5.31.2554,094
8380.5.32.0/2080.5.32.1 to 80.5.47.25480.5.47.2554,094
8480.5.48.0/2080.5.48.1 to 80.5.63.25480.5.63.2554,094
8580.5.64.0/2080.5.64.1 to 80.5.79.25480.5.79.2554,094
8680.5.80.0/2080.5.80.1 to 80.5.95.25480.5.95.2554,094
8780.5.96.0/2080.5.96.1 to 80.5.111.25480.5.111.2554,094
8880.5.112.0/2080.5.112.1 to 80.5.127.25480.5.127.2554,094
8980.5.128.0/2080.5.128.1 to 80.5.143.25480.5.143.2554,094
9080.5.144.0/2080.5.144.1 to 80.5.159.25480.5.159.2554,094
9180.5.160.0/2080.5.160.1 to 80.5.175.25480.5.175.2554,094
9280.5.176.0/2080.5.176.1 to 80.5.191.25480.5.191.2554,094
9380.5.192.0/2080.5.192.1 to 80.5.207.25480.5.207.2554,094
9480.5.208.0/2080.5.208.1 to 80.5.223.25480.5.223.2554,094
9580.5.224.0/2080.5.224.1 to 80.5.239.25480.5.239.2554,094
9680.5.240.0/2080.5.240.1 to 80.5.255.25480.5.255.2554,094
9780.6.0.0/2080.6.0.1 to 80.6.15.25480.6.15.2554,094
9880.6.16.0/2080.6.16.1 to 80.6.31.25480.6.31.2554,094
9980.6.32.0/2080.6.32.1 to 80.6.47.25480.6.47.2554,094
10080.6.48.0/2080.6.48.1 to 80.6.63.25480.6.63.2554,094
10180.6.64.0/2080.6.64.1 to 80.6.79.25480.6.79.2554,094
10280.6.80.0/2080.6.80.1 to 80.6.95.25480.6.95.2554,094
10380.6.96.0/2080.6.96.1 to 80.6.111.25480.6.111.2554,094
10480.6.112.0/2080.6.112.1 to 80.6.127.25480.6.127.2554,094
10580.6.128.0/2080.6.128.1 to 80.6.143.25480.6.143.2554,094
10680.6.144.0/2080.6.144.1 to 80.6.159.25480.6.159.2554,094
10780.6.160.0/2080.6.160.1 to 80.6.175.25480.6.175.2554,094
10880.6.176.0/2080.6.176.1 to 80.6.191.25480.6.191.2554,094
10980.6.192.0/2080.6.192.1 to 80.6.207.25480.6.207.2554,094
11080.6.208.0/2080.6.208.1 to 80.6.223.25480.6.223.2554,094
11180.6.224.0/2080.6.224.1 to 80.6.239.25480.6.239.2554,094
11280.6.240.0/2080.6.240.1 to 80.6.255.25480.6.255.2554,094
11380.7.0.0/2080.7.0.1 to 80.7.15.25480.7.15.2554,094
11480.7.16.0/2080.7.16.1 to 80.7.31.25480.7.31.2554,094
11580.7.32.0/2080.7.32.1 to 80.7.47.25480.7.47.2554,094
11680.7.48.0/2080.7.48.1 to 80.7.63.25480.7.63.2554,094
11780.7.64.0/2080.7.64.1 to 80.7.79.25480.7.79.2554,094
11880.7.80.0/2080.7.80.1 to 80.7.95.25480.7.95.2554,094
11980.7.96.0/2080.7.96.1 to 80.7.111.25480.7.111.2554,094
12080.7.112.0/2080.7.112.1 to 80.7.127.25480.7.127.2554,094
12180.7.128.0/2080.7.128.1 to 80.7.143.25480.7.143.2554,094
12280.7.144.0/2080.7.144.1 to 80.7.159.25480.7.159.2554,094
12380.7.160.0/2080.7.160.1 to 80.7.175.25480.7.175.2554,094
12480.7.176.0/2080.7.176.1 to 80.7.191.25480.7.191.2554,094
12580.7.192.0/2080.7.192.1 to 80.7.207.25480.7.207.2554,094
12680.7.208.0/2080.7.208.1 to 80.7.223.25480.7.223.2554,094
12780.7.224.0/2080.7.224.1 to 80.7.239.25480.7.239.2554,094
12880.7.240.0/2080.7.240.1 to 80.7.255.25480.7.255.2554,094
12980.8.0.0/2080.8.0.1 to 80.8.15.25480.8.15.2554,094
13080.8.16.0/2080.8.16.1 to 80.8.31.25480.8.31.2554,094
13180.8.32.0/2080.8.32.1 to 80.8.47.25480.8.47.2554,094
13280.8.48.0/2080.8.48.1 to 80.8.63.25480.8.63.2554,094
13380.8.64.0/2080.8.64.1 to 80.8.79.25480.8.79.2554,094
13480.8.80.0/2080.8.80.1 to 80.8.95.25480.8.95.2554,094
13580.8.96.0/2080.8.96.1 to 80.8.111.25480.8.111.2554,094
13680.8.112.0/2080.8.112.1 to 80.8.127.25480.8.127.2554,094
13780.8.128.0/2080.8.128.1 to 80.8.143.25480.8.143.2554,094
13880.8.144.0/2080.8.144.1 to 80.8.159.25480.8.159.2554,094
13980.8.160.0/2080.8.160.1 to 80.8.175.25480.8.175.2554,094
14080.8.176.0/2080.8.176.1 to 80.8.191.25480.8.191.2554,094
14180.8.192.0/2080.8.192.1 to 80.8.207.25480.8.207.2554,094
14280.8.208.0/2080.8.208.1 to 80.8.223.25480.8.223.2554,094
14380.8.224.0/2080.8.224.1 to 80.8.239.25480.8.239.2554,094
14480.8.240.0/2080.8.240.1 to 80.8.255.25480.8.255.2554,094
14580.9.0.0/2080.9.0.1 to 80.9.15.25480.9.15.2554,094
14680.9.16.0/2080.9.16.1 to 80.9.31.25480.9.31.2554,094
14780.9.32.0/2080.9.32.1 to 80.9.47.25480.9.47.2554,094
14880.9.48.0/2080.9.48.1 to 80.9.63.25480.9.63.2554,094
14980.9.64.0/2080.9.64.1 to 80.9.79.25480.9.79.2554,094
15080.9.80.0/2080.9.80.1 to 80.9.95.25480.9.95.2554,094
15180.9.96.0/2080.9.96.1 to 80.9.111.25480.9.111.2554,094
15280.9.112.0/2080.9.112.1 to 80.9.127.25480.9.127.2554,094
15380.9.128.0/2080.9.128.1 to 80.9.143.25480.9.143.2554,094
15480.9.144.0/2080.9.144.1 to 80.9.159.25480.9.159.2554,094
15580.9.160.0/2080.9.160.1 to 80.9.175.25480.9.175.2554,094
15680.9.176.0/2080.9.176.1 to 80.9.191.25480.9.191.2554,094
15780.9.192.0/2080.9.192.1 to 80.9.207.25480.9.207.2554,094
15880.9.208.0/2080.9.208.1 to 80.9.223.25480.9.223.2554,094
15980.9.224.0/2080.9.224.1 to 80.9.239.25480.9.239.2554,094
16080.9.240.0/2080.9.240.1 to 80.9.255.25480.9.255.2554,094
16180.10.0.0/2080.10.0.1 to 80.10.15.25480.10.15.2554,094
16280.10.16.0/2080.10.16.1 to 80.10.31.25480.10.31.2554,094
16380.10.32.0/2080.10.32.1 to 80.10.47.25480.10.47.2554,094
16480.10.48.0/2080.10.48.1 to 80.10.63.25480.10.63.2554,094
16580.10.64.0/2080.10.64.1 to 80.10.79.25480.10.79.2554,094
16680.10.80.0/2080.10.80.1 to 80.10.95.25480.10.95.2554,094
16780.10.96.0/2080.10.96.1 to 80.10.111.25480.10.111.2554,094
16880.10.112.0/2080.10.112.1 to 80.10.127.25480.10.127.2554,094
16980.10.128.0/2080.10.128.1 to 80.10.143.25480.10.143.2554,094
17080.10.144.0/2080.10.144.1 to 80.10.159.25480.10.159.2554,094
17180.10.160.0/2080.10.160.1 to 80.10.175.25480.10.175.2554,094
17280.10.176.0/2080.10.176.1 to 80.10.191.25480.10.191.2554,094
17380.10.192.0/2080.10.192.1 to 80.10.207.25480.10.207.2554,094
17480.10.208.0/2080.10.208.1 to 80.10.223.25480.10.223.2554,094
17580.10.224.0/2080.10.224.1 to 80.10.239.25480.10.239.2554,094
17680.10.240.0/2080.10.240.1 to 80.10.255.25480.10.255.2554,094
17780.11.0.0/2080.11.0.1 to 80.11.15.25480.11.15.2554,094
17880.11.16.0/2080.11.16.1 to 80.11.31.25480.11.31.2554,094
17980.11.32.0/2080.11.32.1 to 80.11.47.25480.11.47.2554,094
18080.11.48.0/2080.11.48.1 to 80.11.63.25480.11.63.2554,094
18180.11.64.0/2080.11.64.1 to 80.11.79.25480.11.79.2554,094
18280.11.80.0/2080.11.80.1 to 80.11.95.25480.11.95.2554,094
18380.11.96.0/2080.11.96.1 to 80.11.111.25480.11.111.2554,094
18480.11.112.0/2080.11.112.1 to 80.11.127.25480.11.127.2554,094
18580.11.128.0/2080.11.128.1 to 80.11.143.25480.11.143.2554,094
18680.11.144.0/2080.11.144.1 to 80.11.159.25480.11.159.2554,094
18780.11.160.0/2080.11.160.1 to 80.11.175.25480.11.175.2554,094
18880.11.176.0/2080.11.176.1 to 80.11.191.25480.11.191.2554,094
18980.11.192.0/2080.11.192.1 to 80.11.207.25480.11.207.2554,094
19080.11.208.0/2080.11.208.1 to 80.11.223.25480.11.223.2554,094
19180.11.224.0/2080.11.224.1 to 80.11.239.25480.11.239.2554,094
19280.11.240.0/2080.11.240.1 to 80.11.255.25480.11.255.2554,094
19380.12.0.0/2080.12.0.1 to 80.12.15.25480.12.15.2554,094
19480.12.16.0/2080.12.16.1 to 80.12.31.25480.12.31.2554,094
19580.12.32.0/2080.12.32.1 to 80.12.47.25480.12.47.2554,094
19680.12.48.0/2080.12.48.1 to 80.12.63.25480.12.63.2554,094
19780.12.64.0/2080.12.64.1 to 80.12.79.25480.12.79.2554,094
19880.12.80.0/2080.12.80.1 to 80.12.95.25480.12.95.2554,094
19980.12.96.0/2080.12.96.1 to 80.12.111.25480.12.111.2554,094
20080.12.112.0/2080.12.112.1 to 80.12.127.25480.12.127.2554,094
20180.12.128.0/2080.12.128.1 to 80.12.143.25480.12.143.2554,094
20280.12.144.0/2080.12.144.1 to 80.12.159.25480.12.159.2554,094
20380.12.160.0/2080.12.160.1 to 80.12.175.25480.12.175.2554,094
20480.12.176.0/2080.12.176.1 to 80.12.191.25480.12.191.2554,094
20580.12.192.0/2080.12.192.1 to 80.12.207.25480.12.207.2554,094
20680.12.208.0/2080.12.208.1 to 80.12.223.25480.12.223.2554,094
20780.12.224.0/2080.12.224.1 to 80.12.239.25480.12.239.2554,094
20880.12.240.0/2080.12.240.1 to 80.12.255.25480.12.255.2554,094
20980.13.0.0/2080.13.0.1 to 80.13.15.25480.13.15.2554,094
21080.13.16.0/2080.13.16.1 to 80.13.31.25480.13.31.2554,094
21180.13.32.0/2080.13.32.1 to 80.13.47.25480.13.47.2554,094
21280.13.48.0/2080.13.48.1 to 80.13.63.25480.13.63.2554,094
21380.13.64.0/2080.13.64.1 to 80.13.79.25480.13.79.2554,094
21480.13.80.0/2080.13.80.1 to 80.13.95.25480.13.95.2554,094
21580.13.96.0/2080.13.96.1 to 80.13.111.25480.13.111.2554,094
21680.13.112.0/2080.13.112.1 to 80.13.127.25480.13.127.2554,094
21780.13.128.0/2080.13.128.1 to 80.13.143.25480.13.143.2554,094
21880.13.144.0/2080.13.144.1 to 80.13.159.25480.13.159.2554,094
21980.13.160.0/2080.13.160.1 to 80.13.175.25480.13.175.2554,094
22080.13.176.0/2080.13.176.1 to 80.13.191.25480.13.191.2554,094
22180.13.192.0/2080.13.192.1 to 80.13.207.25480.13.207.2554,094
22280.13.208.0/2080.13.208.1 to 80.13.223.25480.13.223.2554,094
22380.13.224.0/2080.13.224.1 to 80.13.239.25480.13.239.2554,094
22480.13.240.0/2080.13.240.1 to 80.13.255.25480.13.255.2554,094
22580.14.0.0/2080.14.0.1 to 80.14.15.25480.14.15.2554,094
22680.14.16.0/2080.14.16.1 to 80.14.31.25480.14.31.2554,094
22780.14.32.0/2080.14.32.1 to 80.14.47.25480.14.47.2554,094
22880.14.48.0/2080.14.48.1 to 80.14.63.25480.14.63.2554,094
22980.14.64.0/2080.14.64.1 to 80.14.79.25480.14.79.2554,094
23080.14.80.0/2080.14.80.1 to 80.14.95.25480.14.95.2554,094
23180.14.96.0/2080.14.96.1 to 80.14.111.25480.14.111.2554,094
23280.14.112.0/2080.14.112.1 to 80.14.127.25480.14.127.2554,094
23380.14.128.0/2080.14.128.1 to 80.14.143.25480.14.143.2554,094
23480.14.144.0/2080.14.144.1 to 80.14.159.25480.14.159.2554,094
23580.14.160.0/2080.14.160.1 to 80.14.175.25480.14.175.2554,094
23680.14.176.0/2080.14.176.1 to 80.14.191.25480.14.191.2554,094
23780.14.192.0/2080.14.192.1 to 80.14.207.25480.14.207.2554,094
23880.14.208.0/2080.14.208.1 to 80.14.223.25480.14.223.2554,094
23980.14.224.0/2080.14.224.1 to 80.14.239.25480.14.239.2554,094
24080.14.240.0/2080.14.240.1 to 80.14.255.25480.14.255.2554,094
24180.15.0.0/2080.15.0.1 to 80.15.15.25480.15.15.2554,094
24280.15.16.0/2080.15.16.1 to 80.15.31.25480.15.31.2554,094
24380.15.32.0/2080.15.32.1 to 80.15.47.25480.15.47.2554,094
24480.15.48.0/2080.15.48.1 to 80.15.63.25480.15.63.2554,094
24580.15.64.0/2080.15.64.1 to 80.15.79.25480.15.79.2554,094
24680.15.80.0/2080.15.80.1 to 80.15.95.25480.15.95.2554,094
24780.15.96.0/2080.15.96.1 to 80.15.111.25480.15.111.2554,094
24880.15.112.0/2080.15.112.1 to 80.15.127.25480.15.127.2554,094
24980.15.128.0/2080.15.128.1 to 80.15.143.25480.15.143.2554,094
25080.15.144.0/2080.15.144.1 to 80.15.159.25480.15.159.2554,094
25180.15.160.0/2080.15.160.1 to 80.15.175.25480.15.175.2554,094
25280.15.176.0/2080.15.176.1 to 80.15.191.25480.15.191.2554,094
25380.15.192.0/2080.15.192.1 to 80.15.207.25480.15.207.2554,094
25480.15.208.0/2080.15.208.1 to 80.15.223.25480.15.223.2554,094
25580.15.224.0/2080.15.224.1 to 80.15.239.25480.15.239.2554,094
25680.15.240.0/2080.15.240.1 to 80.15.255.25480.15.255.2554,094

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.