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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.

Network16.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
16.0.0.0
Broadcast address
16.255.255.255
First usable
16.0.0.1
Last usable
16.255.255.254
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 10000000 · Integer 268435456 to 285212671
Reverse DNS zone
16.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010000..00000000.00000000.0000000016.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00010000..00000000.00000000.0000000016.0.0.0
Broadcast00010000..11111111.11111111.1111111116.255.255.255
Split into smaller subnets/20
/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)

16.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.0.0.0/2016.0.0.1 to 16.0.15.25416.0.15.2554,094
216.0.16.0/2016.0.16.1 to 16.0.31.25416.0.31.2554,094
316.0.32.0/2016.0.32.1 to 16.0.47.25416.0.47.2554,094
416.0.48.0/2016.0.48.1 to 16.0.63.25416.0.63.2554,094
516.0.64.0/2016.0.64.1 to 16.0.79.25416.0.79.2554,094
616.0.80.0/2016.0.80.1 to 16.0.95.25416.0.95.2554,094
716.0.96.0/2016.0.96.1 to 16.0.111.25416.0.111.2554,094
816.0.112.0/2016.0.112.1 to 16.0.127.25416.0.127.2554,094
916.0.128.0/2016.0.128.1 to 16.0.143.25416.0.143.2554,094
1016.0.144.0/2016.0.144.1 to 16.0.159.25416.0.159.2554,094
1116.0.160.0/2016.0.160.1 to 16.0.175.25416.0.175.2554,094
1216.0.176.0/2016.0.176.1 to 16.0.191.25416.0.191.2554,094
1316.0.192.0/2016.0.192.1 to 16.0.207.25416.0.207.2554,094
1416.0.208.0/2016.0.208.1 to 16.0.223.25416.0.223.2554,094
1516.0.224.0/2016.0.224.1 to 16.0.239.25416.0.239.2554,094
1616.0.240.0/2016.0.240.1 to 16.0.255.25416.0.255.2554,094
1716.1.0.0/2016.1.0.1 to 16.1.15.25416.1.15.2554,094
1816.1.16.0/2016.1.16.1 to 16.1.31.25416.1.31.2554,094
1916.1.32.0/2016.1.32.1 to 16.1.47.25416.1.47.2554,094
2016.1.48.0/2016.1.48.1 to 16.1.63.25416.1.63.2554,094
2116.1.64.0/2016.1.64.1 to 16.1.79.25416.1.79.2554,094
2216.1.80.0/2016.1.80.1 to 16.1.95.25416.1.95.2554,094
2316.1.96.0/2016.1.96.1 to 16.1.111.25416.1.111.2554,094
2416.1.112.0/2016.1.112.1 to 16.1.127.25416.1.127.2554,094
2516.1.128.0/2016.1.128.1 to 16.1.143.25416.1.143.2554,094
2616.1.144.0/2016.1.144.1 to 16.1.159.25416.1.159.2554,094
2716.1.160.0/2016.1.160.1 to 16.1.175.25416.1.175.2554,094
2816.1.176.0/2016.1.176.1 to 16.1.191.25416.1.191.2554,094
2916.1.192.0/2016.1.192.1 to 16.1.207.25416.1.207.2554,094
3016.1.208.0/2016.1.208.1 to 16.1.223.25416.1.223.2554,094
3116.1.224.0/2016.1.224.1 to 16.1.239.25416.1.239.2554,094
3216.1.240.0/2016.1.240.1 to 16.1.255.25416.1.255.2554,094
3316.2.0.0/2016.2.0.1 to 16.2.15.25416.2.15.2554,094
3416.2.16.0/2016.2.16.1 to 16.2.31.25416.2.31.2554,094
3516.2.32.0/2016.2.32.1 to 16.2.47.25416.2.47.2554,094
3616.2.48.0/2016.2.48.1 to 16.2.63.25416.2.63.2554,094
3716.2.64.0/2016.2.64.1 to 16.2.79.25416.2.79.2554,094
3816.2.80.0/2016.2.80.1 to 16.2.95.25416.2.95.2554,094
3916.2.96.0/2016.2.96.1 to 16.2.111.25416.2.111.2554,094
4016.2.112.0/2016.2.112.1 to 16.2.127.25416.2.127.2554,094
4116.2.128.0/2016.2.128.1 to 16.2.143.25416.2.143.2554,094
4216.2.144.0/2016.2.144.1 to 16.2.159.25416.2.159.2554,094
4316.2.160.0/2016.2.160.1 to 16.2.175.25416.2.175.2554,094
4416.2.176.0/2016.2.176.1 to 16.2.191.25416.2.191.2554,094
4516.2.192.0/2016.2.192.1 to 16.2.207.25416.2.207.2554,094
4616.2.208.0/2016.2.208.1 to 16.2.223.25416.2.223.2554,094
4716.2.224.0/2016.2.224.1 to 16.2.239.25416.2.239.2554,094
4816.2.240.0/2016.2.240.1 to 16.2.255.25416.2.255.2554,094
4916.3.0.0/2016.3.0.1 to 16.3.15.25416.3.15.2554,094
5016.3.16.0/2016.3.16.1 to 16.3.31.25416.3.31.2554,094
5116.3.32.0/2016.3.32.1 to 16.3.47.25416.3.47.2554,094
5216.3.48.0/2016.3.48.1 to 16.3.63.25416.3.63.2554,094
5316.3.64.0/2016.3.64.1 to 16.3.79.25416.3.79.2554,094
5416.3.80.0/2016.3.80.1 to 16.3.95.25416.3.95.2554,094
5516.3.96.0/2016.3.96.1 to 16.3.111.25416.3.111.2554,094
5616.3.112.0/2016.3.112.1 to 16.3.127.25416.3.127.2554,094
5716.3.128.0/2016.3.128.1 to 16.3.143.25416.3.143.2554,094
5816.3.144.0/2016.3.144.1 to 16.3.159.25416.3.159.2554,094
5916.3.160.0/2016.3.160.1 to 16.3.175.25416.3.175.2554,094
6016.3.176.0/2016.3.176.1 to 16.3.191.25416.3.191.2554,094
6116.3.192.0/2016.3.192.1 to 16.3.207.25416.3.207.2554,094
6216.3.208.0/2016.3.208.1 to 16.3.223.25416.3.223.2554,094
6316.3.224.0/2016.3.224.1 to 16.3.239.25416.3.239.2554,094
6416.3.240.0/2016.3.240.1 to 16.3.255.25416.3.255.2554,094
6516.4.0.0/2016.4.0.1 to 16.4.15.25416.4.15.2554,094
6616.4.16.0/2016.4.16.1 to 16.4.31.25416.4.31.2554,094
6716.4.32.0/2016.4.32.1 to 16.4.47.25416.4.47.2554,094
6816.4.48.0/2016.4.48.1 to 16.4.63.25416.4.63.2554,094
6916.4.64.0/2016.4.64.1 to 16.4.79.25416.4.79.2554,094
7016.4.80.0/2016.4.80.1 to 16.4.95.25416.4.95.2554,094
7116.4.96.0/2016.4.96.1 to 16.4.111.25416.4.111.2554,094
7216.4.112.0/2016.4.112.1 to 16.4.127.25416.4.127.2554,094
7316.4.128.0/2016.4.128.1 to 16.4.143.25416.4.143.2554,094
7416.4.144.0/2016.4.144.1 to 16.4.159.25416.4.159.2554,094
7516.4.160.0/2016.4.160.1 to 16.4.175.25416.4.175.2554,094
7616.4.176.0/2016.4.176.1 to 16.4.191.25416.4.191.2554,094
7716.4.192.0/2016.4.192.1 to 16.4.207.25416.4.207.2554,094
7816.4.208.0/2016.4.208.1 to 16.4.223.25416.4.223.2554,094
7916.4.224.0/2016.4.224.1 to 16.4.239.25416.4.239.2554,094
8016.4.240.0/2016.4.240.1 to 16.4.255.25416.4.255.2554,094
8116.5.0.0/2016.5.0.1 to 16.5.15.25416.5.15.2554,094
8216.5.16.0/2016.5.16.1 to 16.5.31.25416.5.31.2554,094
8316.5.32.0/2016.5.32.1 to 16.5.47.25416.5.47.2554,094
8416.5.48.0/2016.5.48.1 to 16.5.63.25416.5.63.2554,094
8516.5.64.0/2016.5.64.1 to 16.5.79.25416.5.79.2554,094
8616.5.80.0/2016.5.80.1 to 16.5.95.25416.5.95.2554,094
8716.5.96.0/2016.5.96.1 to 16.5.111.25416.5.111.2554,094
8816.5.112.0/2016.5.112.1 to 16.5.127.25416.5.127.2554,094
8916.5.128.0/2016.5.128.1 to 16.5.143.25416.5.143.2554,094
9016.5.144.0/2016.5.144.1 to 16.5.159.25416.5.159.2554,094
9116.5.160.0/2016.5.160.1 to 16.5.175.25416.5.175.2554,094
9216.5.176.0/2016.5.176.1 to 16.5.191.25416.5.191.2554,094
9316.5.192.0/2016.5.192.1 to 16.5.207.25416.5.207.2554,094
9416.5.208.0/2016.5.208.1 to 16.5.223.25416.5.223.2554,094
9516.5.224.0/2016.5.224.1 to 16.5.239.25416.5.239.2554,094
9616.5.240.0/2016.5.240.1 to 16.5.255.25416.5.255.2554,094
9716.6.0.0/2016.6.0.1 to 16.6.15.25416.6.15.2554,094
9816.6.16.0/2016.6.16.1 to 16.6.31.25416.6.31.2554,094
9916.6.32.0/2016.6.32.1 to 16.6.47.25416.6.47.2554,094
10016.6.48.0/2016.6.48.1 to 16.6.63.25416.6.63.2554,094
10116.6.64.0/2016.6.64.1 to 16.6.79.25416.6.79.2554,094
10216.6.80.0/2016.6.80.1 to 16.6.95.25416.6.95.2554,094
10316.6.96.0/2016.6.96.1 to 16.6.111.25416.6.111.2554,094
10416.6.112.0/2016.6.112.1 to 16.6.127.25416.6.127.2554,094
10516.6.128.0/2016.6.128.1 to 16.6.143.25416.6.143.2554,094
10616.6.144.0/2016.6.144.1 to 16.6.159.25416.6.159.2554,094
10716.6.160.0/2016.6.160.1 to 16.6.175.25416.6.175.2554,094
10816.6.176.0/2016.6.176.1 to 16.6.191.25416.6.191.2554,094
10916.6.192.0/2016.6.192.1 to 16.6.207.25416.6.207.2554,094
11016.6.208.0/2016.6.208.1 to 16.6.223.25416.6.223.2554,094
11116.6.224.0/2016.6.224.1 to 16.6.239.25416.6.239.2554,094
11216.6.240.0/2016.6.240.1 to 16.6.255.25416.6.255.2554,094
11316.7.0.0/2016.7.0.1 to 16.7.15.25416.7.15.2554,094
11416.7.16.0/2016.7.16.1 to 16.7.31.25416.7.31.2554,094
11516.7.32.0/2016.7.32.1 to 16.7.47.25416.7.47.2554,094
11616.7.48.0/2016.7.48.1 to 16.7.63.25416.7.63.2554,094
11716.7.64.0/2016.7.64.1 to 16.7.79.25416.7.79.2554,094
11816.7.80.0/2016.7.80.1 to 16.7.95.25416.7.95.2554,094
11916.7.96.0/2016.7.96.1 to 16.7.111.25416.7.111.2554,094
12016.7.112.0/2016.7.112.1 to 16.7.127.25416.7.127.2554,094
12116.7.128.0/2016.7.128.1 to 16.7.143.25416.7.143.2554,094
12216.7.144.0/2016.7.144.1 to 16.7.159.25416.7.159.2554,094
12316.7.160.0/2016.7.160.1 to 16.7.175.25416.7.175.2554,094
12416.7.176.0/2016.7.176.1 to 16.7.191.25416.7.191.2554,094
12516.7.192.0/2016.7.192.1 to 16.7.207.25416.7.207.2554,094
12616.7.208.0/2016.7.208.1 to 16.7.223.25416.7.223.2554,094
12716.7.224.0/2016.7.224.1 to 16.7.239.25416.7.239.2554,094
12816.7.240.0/2016.7.240.1 to 16.7.255.25416.7.255.2554,094
12916.8.0.0/2016.8.0.1 to 16.8.15.25416.8.15.2554,094
13016.8.16.0/2016.8.16.1 to 16.8.31.25416.8.31.2554,094
13116.8.32.0/2016.8.32.1 to 16.8.47.25416.8.47.2554,094
13216.8.48.0/2016.8.48.1 to 16.8.63.25416.8.63.2554,094
13316.8.64.0/2016.8.64.1 to 16.8.79.25416.8.79.2554,094
13416.8.80.0/2016.8.80.1 to 16.8.95.25416.8.95.2554,094
13516.8.96.0/2016.8.96.1 to 16.8.111.25416.8.111.2554,094
13616.8.112.0/2016.8.112.1 to 16.8.127.25416.8.127.2554,094
13716.8.128.0/2016.8.128.1 to 16.8.143.25416.8.143.2554,094
13816.8.144.0/2016.8.144.1 to 16.8.159.25416.8.159.2554,094
13916.8.160.0/2016.8.160.1 to 16.8.175.25416.8.175.2554,094
14016.8.176.0/2016.8.176.1 to 16.8.191.25416.8.191.2554,094
14116.8.192.0/2016.8.192.1 to 16.8.207.25416.8.207.2554,094
14216.8.208.0/2016.8.208.1 to 16.8.223.25416.8.223.2554,094
14316.8.224.0/2016.8.224.1 to 16.8.239.25416.8.239.2554,094
14416.8.240.0/2016.8.240.1 to 16.8.255.25416.8.255.2554,094
14516.9.0.0/2016.9.0.1 to 16.9.15.25416.9.15.2554,094
14616.9.16.0/2016.9.16.1 to 16.9.31.25416.9.31.2554,094
14716.9.32.0/2016.9.32.1 to 16.9.47.25416.9.47.2554,094
14816.9.48.0/2016.9.48.1 to 16.9.63.25416.9.63.2554,094
14916.9.64.0/2016.9.64.1 to 16.9.79.25416.9.79.2554,094
15016.9.80.0/2016.9.80.1 to 16.9.95.25416.9.95.2554,094
15116.9.96.0/2016.9.96.1 to 16.9.111.25416.9.111.2554,094
15216.9.112.0/2016.9.112.1 to 16.9.127.25416.9.127.2554,094
15316.9.128.0/2016.9.128.1 to 16.9.143.25416.9.143.2554,094
15416.9.144.0/2016.9.144.1 to 16.9.159.25416.9.159.2554,094
15516.9.160.0/2016.9.160.1 to 16.9.175.25416.9.175.2554,094
15616.9.176.0/2016.9.176.1 to 16.9.191.25416.9.191.2554,094
15716.9.192.0/2016.9.192.1 to 16.9.207.25416.9.207.2554,094
15816.9.208.0/2016.9.208.1 to 16.9.223.25416.9.223.2554,094
15916.9.224.0/2016.9.224.1 to 16.9.239.25416.9.239.2554,094
16016.9.240.0/2016.9.240.1 to 16.9.255.25416.9.255.2554,094
16116.10.0.0/2016.10.0.1 to 16.10.15.25416.10.15.2554,094
16216.10.16.0/2016.10.16.1 to 16.10.31.25416.10.31.2554,094
16316.10.32.0/2016.10.32.1 to 16.10.47.25416.10.47.2554,094
16416.10.48.0/2016.10.48.1 to 16.10.63.25416.10.63.2554,094
16516.10.64.0/2016.10.64.1 to 16.10.79.25416.10.79.2554,094
16616.10.80.0/2016.10.80.1 to 16.10.95.25416.10.95.2554,094
16716.10.96.0/2016.10.96.1 to 16.10.111.25416.10.111.2554,094
16816.10.112.0/2016.10.112.1 to 16.10.127.25416.10.127.2554,094
16916.10.128.0/2016.10.128.1 to 16.10.143.25416.10.143.2554,094
17016.10.144.0/2016.10.144.1 to 16.10.159.25416.10.159.2554,094
17116.10.160.0/2016.10.160.1 to 16.10.175.25416.10.175.2554,094
17216.10.176.0/2016.10.176.1 to 16.10.191.25416.10.191.2554,094
17316.10.192.0/2016.10.192.1 to 16.10.207.25416.10.207.2554,094
17416.10.208.0/2016.10.208.1 to 16.10.223.25416.10.223.2554,094
17516.10.224.0/2016.10.224.1 to 16.10.239.25416.10.239.2554,094
17616.10.240.0/2016.10.240.1 to 16.10.255.25416.10.255.2554,094
17716.11.0.0/2016.11.0.1 to 16.11.15.25416.11.15.2554,094
17816.11.16.0/2016.11.16.1 to 16.11.31.25416.11.31.2554,094
17916.11.32.0/2016.11.32.1 to 16.11.47.25416.11.47.2554,094
18016.11.48.0/2016.11.48.1 to 16.11.63.25416.11.63.2554,094
18116.11.64.0/2016.11.64.1 to 16.11.79.25416.11.79.2554,094
18216.11.80.0/2016.11.80.1 to 16.11.95.25416.11.95.2554,094
18316.11.96.0/2016.11.96.1 to 16.11.111.25416.11.111.2554,094
18416.11.112.0/2016.11.112.1 to 16.11.127.25416.11.127.2554,094
18516.11.128.0/2016.11.128.1 to 16.11.143.25416.11.143.2554,094
18616.11.144.0/2016.11.144.1 to 16.11.159.25416.11.159.2554,094
18716.11.160.0/2016.11.160.1 to 16.11.175.25416.11.175.2554,094
18816.11.176.0/2016.11.176.1 to 16.11.191.25416.11.191.2554,094
18916.11.192.0/2016.11.192.1 to 16.11.207.25416.11.207.2554,094
19016.11.208.0/2016.11.208.1 to 16.11.223.25416.11.223.2554,094
19116.11.224.0/2016.11.224.1 to 16.11.239.25416.11.239.2554,094
19216.11.240.0/2016.11.240.1 to 16.11.255.25416.11.255.2554,094
19316.12.0.0/2016.12.0.1 to 16.12.15.25416.12.15.2554,094
19416.12.16.0/2016.12.16.1 to 16.12.31.25416.12.31.2554,094
19516.12.32.0/2016.12.32.1 to 16.12.47.25416.12.47.2554,094
19616.12.48.0/2016.12.48.1 to 16.12.63.25416.12.63.2554,094
19716.12.64.0/2016.12.64.1 to 16.12.79.25416.12.79.2554,094
19816.12.80.0/2016.12.80.1 to 16.12.95.25416.12.95.2554,094
19916.12.96.0/2016.12.96.1 to 16.12.111.25416.12.111.2554,094
20016.12.112.0/2016.12.112.1 to 16.12.127.25416.12.127.2554,094
20116.12.128.0/2016.12.128.1 to 16.12.143.25416.12.143.2554,094
20216.12.144.0/2016.12.144.1 to 16.12.159.25416.12.159.2554,094
20316.12.160.0/2016.12.160.1 to 16.12.175.25416.12.175.2554,094
20416.12.176.0/2016.12.176.1 to 16.12.191.25416.12.191.2554,094
20516.12.192.0/2016.12.192.1 to 16.12.207.25416.12.207.2554,094
20616.12.208.0/2016.12.208.1 to 16.12.223.25416.12.223.2554,094
20716.12.224.0/2016.12.224.1 to 16.12.239.25416.12.239.2554,094
20816.12.240.0/2016.12.240.1 to 16.12.255.25416.12.255.2554,094
20916.13.0.0/2016.13.0.1 to 16.13.15.25416.13.15.2554,094
21016.13.16.0/2016.13.16.1 to 16.13.31.25416.13.31.2554,094
21116.13.32.0/2016.13.32.1 to 16.13.47.25416.13.47.2554,094
21216.13.48.0/2016.13.48.1 to 16.13.63.25416.13.63.2554,094
21316.13.64.0/2016.13.64.1 to 16.13.79.25416.13.79.2554,094
21416.13.80.0/2016.13.80.1 to 16.13.95.25416.13.95.2554,094
21516.13.96.0/2016.13.96.1 to 16.13.111.25416.13.111.2554,094
21616.13.112.0/2016.13.112.1 to 16.13.127.25416.13.127.2554,094
21716.13.128.0/2016.13.128.1 to 16.13.143.25416.13.143.2554,094
21816.13.144.0/2016.13.144.1 to 16.13.159.25416.13.159.2554,094
21916.13.160.0/2016.13.160.1 to 16.13.175.25416.13.175.2554,094
22016.13.176.0/2016.13.176.1 to 16.13.191.25416.13.191.2554,094
22116.13.192.0/2016.13.192.1 to 16.13.207.25416.13.207.2554,094
22216.13.208.0/2016.13.208.1 to 16.13.223.25416.13.223.2554,094
22316.13.224.0/2016.13.224.1 to 16.13.239.25416.13.239.2554,094
22416.13.240.0/2016.13.240.1 to 16.13.255.25416.13.255.2554,094
22516.14.0.0/2016.14.0.1 to 16.14.15.25416.14.15.2554,094
22616.14.16.0/2016.14.16.1 to 16.14.31.25416.14.31.2554,094
22716.14.32.0/2016.14.32.1 to 16.14.47.25416.14.47.2554,094
22816.14.48.0/2016.14.48.1 to 16.14.63.25416.14.63.2554,094
22916.14.64.0/2016.14.64.1 to 16.14.79.25416.14.79.2554,094
23016.14.80.0/2016.14.80.1 to 16.14.95.25416.14.95.2554,094
23116.14.96.0/2016.14.96.1 to 16.14.111.25416.14.111.2554,094
23216.14.112.0/2016.14.112.1 to 16.14.127.25416.14.127.2554,094
23316.14.128.0/2016.14.128.1 to 16.14.143.25416.14.143.2554,094
23416.14.144.0/2016.14.144.1 to 16.14.159.25416.14.159.2554,094
23516.14.160.0/2016.14.160.1 to 16.14.175.25416.14.175.2554,094
23616.14.176.0/2016.14.176.1 to 16.14.191.25416.14.191.2554,094
23716.14.192.0/2016.14.192.1 to 16.14.207.25416.14.207.2554,094
23816.14.208.0/2016.14.208.1 to 16.14.223.25416.14.223.2554,094
23916.14.224.0/2016.14.224.1 to 16.14.239.25416.14.239.2554,094
24016.14.240.0/2016.14.240.1 to 16.14.255.25416.14.255.2554,094
24116.15.0.0/2016.15.0.1 to 16.15.15.25416.15.15.2554,094
24216.15.16.0/2016.15.16.1 to 16.15.31.25416.15.31.2554,094
24316.15.32.0/2016.15.32.1 to 16.15.47.25416.15.47.2554,094
24416.15.48.0/2016.15.48.1 to 16.15.63.25416.15.63.2554,094
24516.15.64.0/2016.15.64.1 to 16.15.79.25416.15.79.2554,094
24616.15.80.0/2016.15.80.1 to 16.15.95.25416.15.95.2554,094
24716.15.96.0/2016.15.96.1 to 16.15.111.25416.15.111.2554,094
24816.15.112.0/2016.15.112.1 to 16.15.127.25416.15.127.2554,094
24916.15.128.0/2016.15.128.1 to 16.15.143.25416.15.143.2554,094
25016.15.144.0/2016.15.144.1 to 16.15.159.25416.15.159.2554,094
25116.15.160.0/2016.15.160.1 to 16.15.175.25416.15.175.2554,094
25216.15.176.0/2016.15.176.1 to 16.15.191.25416.15.191.2554,094
25316.15.192.0/2016.15.192.1 to 16.15.207.25416.15.207.2554,094
25416.15.208.0/2016.15.208.1 to 16.15.223.25416.15.223.2554,094
25516.15.224.0/2016.15.224.1 to 16.15.239.25416.15.239.2554,094
25616.15.240.0/2016.15.240.1 to 16.15.255.25416.15.255.2554,094

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.