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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.

Network24.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
24.0.0.0
Broadcast address
25.255.255.255
First usable
24.0.0.1
Last usable
25.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 18000000 · Integer 402653184 to 436207615
Reverse DNS zones
24.in-addr.arpa
25.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011000.00000000.00000000.0000000024.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00011000.00000000.00000000.0000000024.0.0.0
Broadcast00011001.11111111.11111111.1111111125.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

24.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
124.0.0.0/1924.0.0.1 to 24.0.31.25424.0.31.2558,190
224.0.32.0/1924.0.32.1 to 24.0.63.25424.0.63.2558,190
324.0.64.0/1924.0.64.1 to 24.0.95.25424.0.95.2558,190
424.0.96.0/1924.0.96.1 to 24.0.127.25424.0.127.2558,190
524.0.128.0/1924.0.128.1 to 24.0.159.25424.0.159.2558,190
624.0.160.0/1924.0.160.1 to 24.0.191.25424.0.191.2558,190
724.0.192.0/1924.0.192.1 to 24.0.223.25424.0.223.2558,190
824.0.224.0/1924.0.224.1 to 24.0.255.25424.0.255.2558,190
924.1.0.0/1924.1.0.1 to 24.1.31.25424.1.31.2558,190
1024.1.32.0/1924.1.32.1 to 24.1.63.25424.1.63.2558,190
1124.1.64.0/1924.1.64.1 to 24.1.95.25424.1.95.2558,190
1224.1.96.0/1924.1.96.1 to 24.1.127.25424.1.127.2558,190
1324.1.128.0/1924.1.128.1 to 24.1.159.25424.1.159.2558,190
1424.1.160.0/1924.1.160.1 to 24.1.191.25424.1.191.2558,190
1524.1.192.0/1924.1.192.1 to 24.1.223.25424.1.223.2558,190
1624.1.224.0/1924.1.224.1 to 24.1.255.25424.1.255.2558,190
1724.2.0.0/1924.2.0.1 to 24.2.31.25424.2.31.2558,190
1824.2.32.0/1924.2.32.1 to 24.2.63.25424.2.63.2558,190
1924.2.64.0/1924.2.64.1 to 24.2.95.25424.2.95.2558,190
2024.2.96.0/1924.2.96.1 to 24.2.127.25424.2.127.2558,190
2124.2.128.0/1924.2.128.1 to 24.2.159.25424.2.159.2558,190
2224.2.160.0/1924.2.160.1 to 24.2.191.25424.2.191.2558,190
2324.2.192.0/1924.2.192.1 to 24.2.223.25424.2.223.2558,190
2424.2.224.0/1924.2.224.1 to 24.2.255.25424.2.255.2558,190
2524.3.0.0/1924.3.0.1 to 24.3.31.25424.3.31.2558,190
2624.3.32.0/1924.3.32.1 to 24.3.63.25424.3.63.2558,190
2724.3.64.0/1924.3.64.1 to 24.3.95.25424.3.95.2558,190
2824.3.96.0/1924.3.96.1 to 24.3.127.25424.3.127.2558,190
2924.3.128.0/1924.3.128.1 to 24.3.159.25424.3.159.2558,190
3024.3.160.0/1924.3.160.1 to 24.3.191.25424.3.191.2558,190
3124.3.192.0/1924.3.192.1 to 24.3.223.25424.3.223.2558,190
3224.3.224.0/1924.3.224.1 to 24.3.255.25424.3.255.2558,190
3324.4.0.0/1924.4.0.1 to 24.4.31.25424.4.31.2558,190
3424.4.32.0/1924.4.32.1 to 24.4.63.25424.4.63.2558,190
3524.4.64.0/1924.4.64.1 to 24.4.95.25424.4.95.2558,190
3624.4.96.0/1924.4.96.1 to 24.4.127.25424.4.127.2558,190
3724.4.128.0/1924.4.128.1 to 24.4.159.25424.4.159.2558,190
3824.4.160.0/1924.4.160.1 to 24.4.191.25424.4.191.2558,190
3924.4.192.0/1924.4.192.1 to 24.4.223.25424.4.223.2558,190
4024.4.224.0/1924.4.224.1 to 24.4.255.25424.4.255.2558,190
4124.5.0.0/1924.5.0.1 to 24.5.31.25424.5.31.2558,190
4224.5.32.0/1924.5.32.1 to 24.5.63.25424.5.63.2558,190
4324.5.64.0/1924.5.64.1 to 24.5.95.25424.5.95.2558,190
4424.5.96.0/1924.5.96.1 to 24.5.127.25424.5.127.2558,190
4524.5.128.0/1924.5.128.1 to 24.5.159.25424.5.159.2558,190
4624.5.160.0/1924.5.160.1 to 24.5.191.25424.5.191.2558,190
4724.5.192.0/1924.5.192.1 to 24.5.223.25424.5.223.2558,190
4824.5.224.0/1924.5.224.1 to 24.5.255.25424.5.255.2558,190
4924.6.0.0/1924.6.0.1 to 24.6.31.25424.6.31.2558,190
5024.6.32.0/1924.6.32.1 to 24.6.63.25424.6.63.2558,190
5124.6.64.0/1924.6.64.1 to 24.6.95.25424.6.95.2558,190
5224.6.96.0/1924.6.96.1 to 24.6.127.25424.6.127.2558,190
5324.6.128.0/1924.6.128.1 to 24.6.159.25424.6.159.2558,190
5424.6.160.0/1924.6.160.1 to 24.6.191.25424.6.191.2558,190
5524.6.192.0/1924.6.192.1 to 24.6.223.25424.6.223.2558,190
5624.6.224.0/1924.6.224.1 to 24.6.255.25424.6.255.2558,190
5724.7.0.0/1924.7.0.1 to 24.7.31.25424.7.31.2558,190
5824.7.32.0/1924.7.32.1 to 24.7.63.25424.7.63.2558,190
5924.7.64.0/1924.7.64.1 to 24.7.95.25424.7.95.2558,190
6024.7.96.0/1924.7.96.1 to 24.7.127.25424.7.127.2558,190
6124.7.128.0/1924.7.128.1 to 24.7.159.25424.7.159.2558,190
6224.7.160.0/1924.7.160.1 to 24.7.191.25424.7.191.2558,190
6324.7.192.0/1924.7.192.1 to 24.7.223.25424.7.223.2558,190
6424.7.224.0/1924.7.224.1 to 24.7.255.25424.7.255.2558,190
6524.8.0.0/1924.8.0.1 to 24.8.31.25424.8.31.2558,190
6624.8.32.0/1924.8.32.1 to 24.8.63.25424.8.63.2558,190
6724.8.64.0/1924.8.64.1 to 24.8.95.25424.8.95.2558,190
6824.8.96.0/1924.8.96.1 to 24.8.127.25424.8.127.2558,190
6924.8.128.0/1924.8.128.1 to 24.8.159.25424.8.159.2558,190
7024.8.160.0/1924.8.160.1 to 24.8.191.25424.8.191.2558,190
7124.8.192.0/1924.8.192.1 to 24.8.223.25424.8.223.2558,190
7224.8.224.0/1924.8.224.1 to 24.8.255.25424.8.255.2558,190
7324.9.0.0/1924.9.0.1 to 24.9.31.25424.9.31.2558,190
7424.9.32.0/1924.9.32.1 to 24.9.63.25424.9.63.2558,190
7524.9.64.0/1924.9.64.1 to 24.9.95.25424.9.95.2558,190
7624.9.96.0/1924.9.96.1 to 24.9.127.25424.9.127.2558,190
7724.9.128.0/1924.9.128.1 to 24.9.159.25424.9.159.2558,190
7824.9.160.0/1924.9.160.1 to 24.9.191.25424.9.191.2558,190
7924.9.192.0/1924.9.192.1 to 24.9.223.25424.9.223.2558,190
8024.9.224.0/1924.9.224.1 to 24.9.255.25424.9.255.2558,190
8124.10.0.0/1924.10.0.1 to 24.10.31.25424.10.31.2558,190
8224.10.32.0/1924.10.32.1 to 24.10.63.25424.10.63.2558,190
8324.10.64.0/1924.10.64.1 to 24.10.95.25424.10.95.2558,190
8424.10.96.0/1924.10.96.1 to 24.10.127.25424.10.127.2558,190
8524.10.128.0/1924.10.128.1 to 24.10.159.25424.10.159.2558,190
8624.10.160.0/1924.10.160.1 to 24.10.191.25424.10.191.2558,190
8724.10.192.0/1924.10.192.1 to 24.10.223.25424.10.223.2558,190
8824.10.224.0/1924.10.224.1 to 24.10.255.25424.10.255.2558,190
8924.11.0.0/1924.11.0.1 to 24.11.31.25424.11.31.2558,190
9024.11.32.0/1924.11.32.1 to 24.11.63.25424.11.63.2558,190
9124.11.64.0/1924.11.64.1 to 24.11.95.25424.11.95.2558,190
9224.11.96.0/1924.11.96.1 to 24.11.127.25424.11.127.2558,190
9324.11.128.0/1924.11.128.1 to 24.11.159.25424.11.159.2558,190
9424.11.160.0/1924.11.160.1 to 24.11.191.25424.11.191.2558,190
9524.11.192.0/1924.11.192.1 to 24.11.223.25424.11.223.2558,190
9624.11.224.0/1924.11.224.1 to 24.11.255.25424.11.255.2558,190
9724.12.0.0/1924.12.0.1 to 24.12.31.25424.12.31.2558,190
9824.12.32.0/1924.12.32.1 to 24.12.63.25424.12.63.2558,190
9924.12.64.0/1924.12.64.1 to 24.12.95.25424.12.95.2558,190
10024.12.96.0/1924.12.96.1 to 24.12.127.25424.12.127.2558,190
10124.12.128.0/1924.12.128.1 to 24.12.159.25424.12.159.2558,190
10224.12.160.0/1924.12.160.1 to 24.12.191.25424.12.191.2558,190
10324.12.192.0/1924.12.192.1 to 24.12.223.25424.12.223.2558,190
10424.12.224.0/1924.12.224.1 to 24.12.255.25424.12.255.2558,190
10524.13.0.0/1924.13.0.1 to 24.13.31.25424.13.31.2558,190
10624.13.32.0/1924.13.32.1 to 24.13.63.25424.13.63.2558,190
10724.13.64.0/1924.13.64.1 to 24.13.95.25424.13.95.2558,190
10824.13.96.0/1924.13.96.1 to 24.13.127.25424.13.127.2558,190
10924.13.128.0/1924.13.128.1 to 24.13.159.25424.13.159.2558,190
11024.13.160.0/1924.13.160.1 to 24.13.191.25424.13.191.2558,190
11124.13.192.0/1924.13.192.1 to 24.13.223.25424.13.223.2558,190
11224.13.224.0/1924.13.224.1 to 24.13.255.25424.13.255.2558,190
11324.14.0.0/1924.14.0.1 to 24.14.31.25424.14.31.2558,190
11424.14.32.0/1924.14.32.1 to 24.14.63.25424.14.63.2558,190
11524.14.64.0/1924.14.64.1 to 24.14.95.25424.14.95.2558,190
11624.14.96.0/1924.14.96.1 to 24.14.127.25424.14.127.2558,190
11724.14.128.0/1924.14.128.1 to 24.14.159.25424.14.159.2558,190
11824.14.160.0/1924.14.160.1 to 24.14.191.25424.14.191.2558,190
11924.14.192.0/1924.14.192.1 to 24.14.223.25424.14.223.2558,190
12024.14.224.0/1924.14.224.1 to 24.14.255.25424.14.255.2558,190
12124.15.0.0/1924.15.0.1 to 24.15.31.25424.15.31.2558,190
12224.15.32.0/1924.15.32.1 to 24.15.63.25424.15.63.2558,190
12324.15.64.0/1924.15.64.1 to 24.15.95.25424.15.95.2558,190
12424.15.96.0/1924.15.96.1 to 24.15.127.25424.15.127.2558,190
12524.15.128.0/1924.15.128.1 to 24.15.159.25424.15.159.2558,190
12624.15.160.0/1924.15.160.1 to 24.15.191.25424.15.191.2558,190
12724.15.192.0/1924.15.192.1 to 24.15.223.25424.15.223.2558,190
12824.15.224.0/1924.15.224.1 to 24.15.255.25424.15.255.2558,190
12924.16.0.0/1924.16.0.1 to 24.16.31.25424.16.31.2558,190
13024.16.32.0/1924.16.32.1 to 24.16.63.25424.16.63.2558,190
13124.16.64.0/1924.16.64.1 to 24.16.95.25424.16.95.2558,190
13224.16.96.0/1924.16.96.1 to 24.16.127.25424.16.127.2558,190
13324.16.128.0/1924.16.128.1 to 24.16.159.25424.16.159.2558,190
13424.16.160.0/1924.16.160.1 to 24.16.191.25424.16.191.2558,190
13524.16.192.0/1924.16.192.1 to 24.16.223.25424.16.223.2558,190
13624.16.224.0/1924.16.224.1 to 24.16.255.25424.16.255.2558,190
13724.17.0.0/1924.17.0.1 to 24.17.31.25424.17.31.2558,190
13824.17.32.0/1924.17.32.1 to 24.17.63.25424.17.63.2558,190
13924.17.64.0/1924.17.64.1 to 24.17.95.25424.17.95.2558,190
14024.17.96.0/1924.17.96.1 to 24.17.127.25424.17.127.2558,190
14124.17.128.0/1924.17.128.1 to 24.17.159.25424.17.159.2558,190
14224.17.160.0/1924.17.160.1 to 24.17.191.25424.17.191.2558,190
14324.17.192.0/1924.17.192.1 to 24.17.223.25424.17.223.2558,190
14424.17.224.0/1924.17.224.1 to 24.17.255.25424.17.255.2558,190
14524.18.0.0/1924.18.0.1 to 24.18.31.25424.18.31.2558,190
14624.18.32.0/1924.18.32.1 to 24.18.63.25424.18.63.2558,190
14724.18.64.0/1924.18.64.1 to 24.18.95.25424.18.95.2558,190
14824.18.96.0/1924.18.96.1 to 24.18.127.25424.18.127.2558,190
14924.18.128.0/1924.18.128.1 to 24.18.159.25424.18.159.2558,190
15024.18.160.0/1924.18.160.1 to 24.18.191.25424.18.191.2558,190
15124.18.192.0/1924.18.192.1 to 24.18.223.25424.18.223.2558,190
15224.18.224.0/1924.18.224.1 to 24.18.255.25424.18.255.2558,190
15324.19.0.0/1924.19.0.1 to 24.19.31.25424.19.31.2558,190
15424.19.32.0/1924.19.32.1 to 24.19.63.25424.19.63.2558,190
15524.19.64.0/1924.19.64.1 to 24.19.95.25424.19.95.2558,190
15624.19.96.0/1924.19.96.1 to 24.19.127.25424.19.127.2558,190
15724.19.128.0/1924.19.128.1 to 24.19.159.25424.19.159.2558,190
15824.19.160.0/1924.19.160.1 to 24.19.191.25424.19.191.2558,190
15924.19.192.0/1924.19.192.1 to 24.19.223.25424.19.223.2558,190
16024.19.224.0/1924.19.224.1 to 24.19.255.25424.19.255.2558,190
16124.20.0.0/1924.20.0.1 to 24.20.31.25424.20.31.2558,190
16224.20.32.0/1924.20.32.1 to 24.20.63.25424.20.63.2558,190
16324.20.64.0/1924.20.64.1 to 24.20.95.25424.20.95.2558,190
16424.20.96.0/1924.20.96.1 to 24.20.127.25424.20.127.2558,190
16524.20.128.0/1924.20.128.1 to 24.20.159.25424.20.159.2558,190
16624.20.160.0/1924.20.160.1 to 24.20.191.25424.20.191.2558,190
16724.20.192.0/1924.20.192.1 to 24.20.223.25424.20.223.2558,190
16824.20.224.0/1924.20.224.1 to 24.20.255.25424.20.255.2558,190
16924.21.0.0/1924.21.0.1 to 24.21.31.25424.21.31.2558,190
17024.21.32.0/1924.21.32.1 to 24.21.63.25424.21.63.2558,190
17124.21.64.0/1924.21.64.1 to 24.21.95.25424.21.95.2558,190
17224.21.96.0/1924.21.96.1 to 24.21.127.25424.21.127.2558,190
17324.21.128.0/1924.21.128.1 to 24.21.159.25424.21.159.2558,190
17424.21.160.0/1924.21.160.1 to 24.21.191.25424.21.191.2558,190
17524.21.192.0/1924.21.192.1 to 24.21.223.25424.21.223.2558,190
17624.21.224.0/1924.21.224.1 to 24.21.255.25424.21.255.2558,190
17724.22.0.0/1924.22.0.1 to 24.22.31.25424.22.31.2558,190
17824.22.32.0/1924.22.32.1 to 24.22.63.25424.22.63.2558,190
17924.22.64.0/1924.22.64.1 to 24.22.95.25424.22.95.2558,190
18024.22.96.0/1924.22.96.1 to 24.22.127.25424.22.127.2558,190
18124.22.128.0/1924.22.128.1 to 24.22.159.25424.22.159.2558,190
18224.22.160.0/1924.22.160.1 to 24.22.191.25424.22.191.2558,190
18324.22.192.0/1924.22.192.1 to 24.22.223.25424.22.223.2558,190
18424.22.224.0/1924.22.224.1 to 24.22.255.25424.22.255.2558,190
18524.23.0.0/1924.23.0.1 to 24.23.31.25424.23.31.2558,190
18624.23.32.0/1924.23.32.1 to 24.23.63.25424.23.63.2558,190
18724.23.64.0/1924.23.64.1 to 24.23.95.25424.23.95.2558,190
18824.23.96.0/1924.23.96.1 to 24.23.127.25424.23.127.2558,190
18924.23.128.0/1924.23.128.1 to 24.23.159.25424.23.159.2558,190
19024.23.160.0/1924.23.160.1 to 24.23.191.25424.23.191.2558,190
19124.23.192.0/1924.23.192.1 to 24.23.223.25424.23.223.2558,190
19224.23.224.0/1924.23.224.1 to 24.23.255.25424.23.255.2558,190
19324.24.0.0/1924.24.0.1 to 24.24.31.25424.24.31.2558,190
19424.24.32.0/1924.24.32.1 to 24.24.63.25424.24.63.2558,190
19524.24.64.0/1924.24.64.1 to 24.24.95.25424.24.95.2558,190
19624.24.96.0/1924.24.96.1 to 24.24.127.25424.24.127.2558,190
19724.24.128.0/1924.24.128.1 to 24.24.159.25424.24.159.2558,190
19824.24.160.0/1924.24.160.1 to 24.24.191.25424.24.191.2558,190
19924.24.192.0/1924.24.192.1 to 24.24.223.25424.24.223.2558,190
20024.24.224.0/1924.24.224.1 to 24.24.255.25424.24.255.2558,190
20124.25.0.0/1924.25.0.1 to 24.25.31.25424.25.31.2558,190
20224.25.32.0/1924.25.32.1 to 24.25.63.25424.25.63.2558,190
20324.25.64.0/1924.25.64.1 to 24.25.95.25424.25.95.2558,190
20424.25.96.0/1924.25.96.1 to 24.25.127.25424.25.127.2558,190
20524.25.128.0/1924.25.128.1 to 24.25.159.25424.25.159.2558,190
20624.25.160.0/1924.25.160.1 to 24.25.191.25424.25.191.2558,190
20724.25.192.0/1924.25.192.1 to 24.25.223.25424.25.223.2558,190
20824.25.224.0/1924.25.224.1 to 24.25.255.25424.25.255.2558,190
20924.26.0.0/1924.26.0.1 to 24.26.31.25424.26.31.2558,190
21024.26.32.0/1924.26.32.1 to 24.26.63.25424.26.63.2558,190
21124.26.64.0/1924.26.64.1 to 24.26.95.25424.26.95.2558,190
21224.26.96.0/1924.26.96.1 to 24.26.127.25424.26.127.2558,190
21324.26.128.0/1924.26.128.1 to 24.26.159.25424.26.159.2558,190
21424.26.160.0/1924.26.160.1 to 24.26.191.25424.26.191.2558,190
21524.26.192.0/1924.26.192.1 to 24.26.223.25424.26.223.2558,190
21624.26.224.0/1924.26.224.1 to 24.26.255.25424.26.255.2558,190
21724.27.0.0/1924.27.0.1 to 24.27.31.25424.27.31.2558,190
21824.27.32.0/1924.27.32.1 to 24.27.63.25424.27.63.2558,190
21924.27.64.0/1924.27.64.1 to 24.27.95.25424.27.95.2558,190
22024.27.96.0/1924.27.96.1 to 24.27.127.25424.27.127.2558,190
22124.27.128.0/1924.27.128.1 to 24.27.159.25424.27.159.2558,190
22224.27.160.0/1924.27.160.1 to 24.27.191.25424.27.191.2558,190
22324.27.192.0/1924.27.192.1 to 24.27.223.25424.27.223.2558,190
22424.27.224.0/1924.27.224.1 to 24.27.255.25424.27.255.2558,190
22524.28.0.0/1924.28.0.1 to 24.28.31.25424.28.31.2558,190
22624.28.32.0/1924.28.32.1 to 24.28.63.25424.28.63.2558,190
22724.28.64.0/1924.28.64.1 to 24.28.95.25424.28.95.2558,190
22824.28.96.0/1924.28.96.1 to 24.28.127.25424.28.127.2558,190
22924.28.128.0/1924.28.128.1 to 24.28.159.25424.28.159.2558,190
23024.28.160.0/1924.28.160.1 to 24.28.191.25424.28.191.2558,190
23124.28.192.0/1924.28.192.1 to 24.28.223.25424.28.223.2558,190
23224.28.224.0/1924.28.224.1 to 24.28.255.25424.28.255.2558,190
23324.29.0.0/1924.29.0.1 to 24.29.31.25424.29.31.2558,190
23424.29.32.0/1924.29.32.1 to 24.29.63.25424.29.63.2558,190
23524.29.64.0/1924.29.64.1 to 24.29.95.25424.29.95.2558,190
23624.29.96.0/1924.29.96.1 to 24.29.127.25424.29.127.2558,190
23724.29.128.0/1924.29.128.1 to 24.29.159.25424.29.159.2558,190
23824.29.160.0/1924.29.160.1 to 24.29.191.25424.29.191.2558,190
23924.29.192.0/1924.29.192.1 to 24.29.223.25424.29.223.2558,190
24024.29.224.0/1924.29.224.1 to 24.29.255.25424.29.255.2558,190
24124.30.0.0/1924.30.0.1 to 24.30.31.25424.30.31.2558,190
24224.30.32.0/1924.30.32.1 to 24.30.63.25424.30.63.2558,190
24324.30.64.0/1924.30.64.1 to 24.30.95.25424.30.95.2558,190
24424.30.96.0/1924.30.96.1 to 24.30.127.25424.30.127.2558,190
24524.30.128.0/1924.30.128.1 to 24.30.159.25424.30.159.2558,190
24624.30.160.0/1924.30.160.1 to 24.30.191.25424.30.191.2558,190
24724.30.192.0/1924.30.192.1 to 24.30.223.25424.30.223.2558,190
24824.30.224.0/1924.30.224.1 to 24.30.255.25424.30.255.2558,190
24924.31.0.0/1924.31.0.1 to 24.31.31.25424.31.31.2558,190
25024.31.32.0/1924.31.32.1 to 24.31.63.25424.31.63.2558,190
25124.31.64.0/1924.31.64.1 to 24.31.95.25424.31.95.2558,190
25224.31.96.0/1924.31.96.1 to 24.31.127.25424.31.127.2558,190
25324.31.128.0/1924.31.128.1 to 24.31.159.25424.31.159.2558,190
25424.31.160.0/1924.31.160.1 to 24.31.191.25424.31.191.2558,190
25524.31.192.0/1924.31.192.1 to 24.31.223.25424.31.223.2558,190
25624.31.224.0/1924.31.224.1 to 24.31.255.25424.31.255.2558,190

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.