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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.

Network68.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
68.0.0.0
Broadcast address
68.127.255.255
First usable
68.0.0.1
Last usable
68.127.255.254
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 44000000 · Integer 1140850688 to 1149239295
Reverse DNS zones
0.68.in-addr.arpa
1.68.in-addr.arpa
2.68.in-addr.arpa
3.68.in-addr.arpa
4.68.in-addr.arpa
5.68.in-addr.arpa
6.68.in-addr.arpa
7.68.in-addr.arpa
8.68.in-addr.arpa
9.68.in-addr.arpa
10.68.in-addr.arpa
11.68.in-addr.arpa
12.68.in-addr.arpa
13.68.in-addr.arpa
14.68.in-addr.arpa
15.68.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
Address01000100.00000000.00000000.0000000068.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01000100.00000000.00000000.0000000068.0.0.0
Broadcast01000100.01111111.11111111.1111111168.127.255.255
Split into smaller subnets/21
/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)

68.0.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
168.0.0.0/2168.0.0.1 to 68.0.7.25468.0.7.2552,046
268.0.8.0/2168.0.8.1 to 68.0.15.25468.0.15.2552,046
368.0.16.0/2168.0.16.1 to 68.0.23.25468.0.23.2552,046
468.0.24.0/2168.0.24.1 to 68.0.31.25468.0.31.2552,046
568.0.32.0/2168.0.32.1 to 68.0.39.25468.0.39.2552,046
668.0.40.0/2168.0.40.1 to 68.0.47.25468.0.47.2552,046
768.0.48.0/2168.0.48.1 to 68.0.55.25468.0.55.2552,046
868.0.56.0/2168.0.56.1 to 68.0.63.25468.0.63.2552,046
968.0.64.0/2168.0.64.1 to 68.0.71.25468.0.71.2552,046
1068.0.72.0/2168.0.72.1 to 68.0.79.25468.0.79.2552,046
1168.0.80.0/2168.0.80.1 to 68.0.87.25468.0.87.2552,046
1268.0.88.0/2168.0.88.1 to 68.0.95.25468.0.95.2552,046
1368.0.96.0/2168.0.96.1 to 68.0.103.25468.0.103.2552,046
1468.0.104.0/2168.0.104.1 to 68.0.111.25468.0.111.2552,046
1568.0.112.0/2168.0.112.1 to 68.0.119.25468.0.119.2552,046
1668.0.120.0/2168.0.120.1 to 68.0.127.25468.0.127.2552,046
1768.0.128.0/2168.0.128.1 to 68.0.135.25468.0.135.2552,046
1868.0.136.0/2168.0.136.1 to 68.0.143.25468.0.143.2552,046
1968.0.144.0/2168.0.144.1 to 68.0.151.25468.0.151.2552,046
2068.0.152.0/2168.0.152.1 to 68.0.159.25468.0.159.2552,046
2168.0.160.0/2168.0.160.1 to 68.0.167.25468.0.167.2552,046
2268.0.168.0/2168.0.168.1 to 68.0.175.25468.0.175.2552,046
2368.0.176.0/2168.0.176.1 to 68.0.183.25468.0.183.2552,046
2468.0.184.0/2168.0.184.1 to 68.0.191.25468.0.191.2552,046
2568.0.192.0/2168.0.192.1 to 68.0.199.25468.0.199.2552,046
2668.0.200.0/2168.0.200.1 to 68.0.207.25468.0.207.2552,046
2768.0.208.0/2168.0.208.1 to 68.0.215.25468.0.215.2552,046
2868.0.216.0/2168.0.216.1 to 68.0.223.25468.0.223.2552,046
2968.0.224.0/2168.0.224.1 to 68.0.231.25468.0.231.2552,046
3068.0.232.0/2168.0.232.1 to 68.0.239.25468.0.239.2552,046
3168.0.240.0/2168.0.240.1 to 68.0.247.25468.0.247.2552,046
3268.0.248.0/2168.0.248.1 to 68.0.255.25468.0.255.2552,046
3368.1.0.0/2168.1.0.1 to 68.1.7.25468.1.7.2552,046
3468.1.8.0/2168.1.8.1 to 68.1.15.25468.1.15.2552,046
3568.1.16.0/2168.1.16.1 to 68.1.23.25468.1.23.2552,046
3668.1.24.0/2168.1.24.1 to 68.1.31.25468.1.31.2552,046
3768.1.32.0/2168.1.32.1 to 68.1.39.25468.1.39.2552,046
3868.1.40.0/2168.1.40.1 to 68.1.47.25468.1.47.2552,046
3968.1.48.0/2168.1.48.1 to 68.1.55.25468.1.55.2552,046
4068.1.56.0/2168.1.56.1 to 68.1.63.25468.1.63.2552,046
4168.1.64.0/2168.1.64.1 to 68.1.71.25468.1.71.2552,046
4268.1.72.0/2168.1.72.1 to 68.1.79.25468.1.79.2552,046
4368.1.80.0/2168.1.80.1 to 68.1.87.25468.1.87.2552,046
4468.1.88.0/2168.1.88.1 to 68.1.95.25468.1.95.2552,046
4568.1.96.0/2168.1.96.1 to 68.1.103.25468.1.103.2552,046
4668.1.104.0/2168.1.104.1 to 68.1.111.25468.1.111.2552,046
4768.1.112.0/2168.1.112.1 to 68.1.119.25468.1.119.2552,046
4868.1.120.0/2168.1.120.1 to 68.1.127.25468.1.127.2552,046
4968.1.128.0/2168.1.128.1 to 68.1.135.25468.1.135.2552,046
5068.1.136.0/2168.1.136.1 to 68.1.143.25468.1.143.2552,046
5168.1.144.0/2168.1.144.1 to 68.1.151.25468.1.151.2552,046
5268.1.152.0/2168.1.152.1 to 68.1.159.25468.1.159.2552,046
5368.1.160.0/2168.1.160.1 to 68.1.167.25468.1.167.2552,046
5468.1.168.0/2168.1.168.1 to 68.1.175.25468.1.175.2552,046
5568.1.176.0/2168.1.176.1 to 68.1.183.25468.1.183.2552,046
5668.1.184.0/2168.1.184.1 to 68.1.191.25468.1.191.2552,046
5768.1.192.0/2168.1.192.1 to 68.1.199.25468.1.199.2552,046
5868.1.200.0/2168.1.200.1 to 68.1.207.25468.1.207.2552,046
5968.1.208.0/2168.1.208.1 to 68.1.215.25468.1.215.2552,046
6068.1.216.0/2168.1.216.1 to 68.1.223.25468.1.223.2552,046
6168.1.224.0/2168.1.224.1 to 68.1.231.25468.1.231.2552,046
6268.1.232.0/2168.1.232.1 to 68.1.239.25468.1.239.2552,046
6368.1.240.0/2168.1.240.1 to 68.1.247.25468.1.247.2552,046
6468.1.248.0/2168.1.248.1 to 68.1.255.25468.1.255.2552,046
6568.2.0.0/2168.2.0.1 to 68.2.7.25468.2.7.2552,046
6668.2.8.0/2168.2.8.1 to 68.2.15.25468.2.15.2552,046
6768.2.16.0/2168.2.16.1 to 68.2.23.25468.2.23.2552,046
6868.2.24.0/2168.2.24.1 to 68.2.31.25468.2.31.2552,046
6968.2.32.0/2168.2.32.1 to 68.2.39.25468.2.39.2552,046
7068.2.40.0/2168.2.40.1 to 68.2.47.25468.2.47.2552,046
7168.2.48.0/2168.2.48.1 to 68.2.55.25468.2.55.2552,046
7268.2.56.0/2168.2.56.1 to 68.2.63.25468.2.63.2552,046
7368.2.64.0/2168.2.64.1 to 68.2.71.25468.2.71.2552,046
7468.2.72.0/2168.2.72.1 to 68.2.79.25468.2.79.2552,046
7568.2.80.0/2168.2.80.1 to 68.2.87.25468.2.87.2552,046
7668.2.88.0/2168.2.88.1 to 68.2.95.25468.2.95.2552,046
7768.2.96.0/2168.2.96.1 to 68.2.103.25468.2.103.2552,046
7868.2.104.0/2168.2.104.1 to 68.2.111.25468.2.111.2552,046
7968.2.112.0/2168.2.112.1 to 68.2.119.25468.2.119.2552,046
8068.2.120.0/2168.2.120.1 to 68.2.127.25468.2.127.2552,046
8168.2.128.0/2168.2.128.1 to 68.2.135.25468.2.135.2552,046
8268.2.136.0/2168.2.136.1 to 68.2.143.25468.2.143.2552,046
8368.2.144.0/2168.2.144.1 to 68.2.151.25468.2.151.2552,046
8468.2.152.0/2168.2.152.1 to 68.2.159.25468.2.159.2552,046
8568.2.160.0/2168.2.160.1 to 68.2.167.25468.2.167.2552,046
8668.2.168.0/2168.2.168.1 to 68.2.175.25468.2.175.2552,046
8768.2.176.0/2168.2.176.1 to 68.2.183.25468.2.183.2552,046
8868.2.184.0/2168.2.184.1 to 68.2.191.25468.2.191.2552,046
8968.2.192.0/2168.2.192.1 to 68.2.199.25468.2.199.2552,046
9068.2.200.0/2168.2.200.1 to 68.2.207.25468.2.207.2552,046
9168.2.208.0/2168.2.208.1 to 68.2.215.25468.2.215.2552,046
9268.2.216.0/2168.2.216.1 to 68.2.223.25468.2.223.2552,046
9368.2.224.0/2168.2.224.1 to 68.2.231.25468.2.231.2552,046
9468.2.232.0/2168.2.232.1 to 68.2.239.25468.2.239.2552,046
9568.2.240.0/2168.2.240.1 to 68.2.247.25468.2.247.2552,046
9668.2.248.0/2168.2.248.1 to 68.2.255.25468.2.255.2552,046
9768.3.0.0/2168.3.0.1 to 68.3.7.25468.3.7.2552,046
9868.3.8.0/2168.3.8.1 to 68.3.15.25468.3.15.2552,046
9968.3.16.0/2168.3.16.1 to 68.3.23.25468.3.23.2552,046
10068.3.24.0/2168.3.24.1 to 68.3.31.25468.3.31.2552,046
10168.3.32.0/2168.3.32.1 to 68.3.39.25468.3.39.2552,046
10268.3.40.0/2168.3.40.1 to 68.3.47.25468.3.47.2552,046
10368.3.48.0/2168.3.48.1 to 68.3.55.25468.3.55.2552,046
10468.3.56.0/2168.3.56.1 to 68.3.63.25468.3.63.2552,046
10568.3.64.0/2168.3.64.1 to 68.3.71.25468.3.71.2552,046
10668.3.72.0/2168.3.72.1 to 68.3.79.25468.3.79.2552,046
10768.3.80.0/2168.3.80.1 to 68.3.87.25468.3.87.2552,046
10868.3.88.0/2168.3.88.1 to 68.3.95.25468.3.95.2552,046
10968.3.96.0/2168.3.96.1 to 68.3.103.25468.3.103.2552,046
11068.3.104.0/2168.3.104.1 to 68.3.111.25468.3.111.2552,046
11168.3.112.0/2168.3.112.1 to 68.3.119.25468.3.119.2552,046
11268.3.120.0/2168.3.120.1 to 68.3.127.25468.3.127.2552,046
11368.3.128.0/2168.3.128.1 to 68.3.135.25468.3.135.2552,046
11468.3.136.0/2168.3.136.1 to 68.3.143.25468.3.143.2552,046
11568.3.144.0/2168.3.144.1 to 68.3.151.25468.3.151.2552,046
11668.3.152.0/2168.3.152.1 to 68.3.159.25468.3.159.2552,046
11768.3.160.0/2168.3.160.1 to 68.3.167.25468.3.167.2552,046
11868.3.168.0/2168.3.168.1 to 68.3.175.25468.3.175.2552,046
11968.3.176.0/2168.3.176.1 to 68.3.183.25468.3.183.2552,046
12068.3.184.0/2168.3.184.1 to 68.3.191.25468.3.191.2552,046
12168.3.192.0/2168.3.192.1 to 68.3.199.25468.3.199.2552,046
12268.3.200.0/2168.3.200.1 to 68.3.207.25468.3.207.2552,046
12368.3.208.0/2168.3.208.1 to 68.3.215.25468.3.215.2552,046
12468.3.216.0/2168.3.216.1 to 68.3.223.25468.3.223.2552,046
12568.3.224.0/2168.3.224.1 to 68.3.231.25468.3.231.2552,046
12668.3.232.0/2168.3.232.1 to 68.3.239.25468.3.239.2552,046
12768.3.240.0/2168.3.240.1 to 68.3.247.25468.3.247.2552,046
12868.3.248.0/2168.3.248.1 to 68.3.255.25468.3.255.2552,046
12968.4.0.0/2168.4.0.1 to 68.4.7.25468.4.7.2552,046
13068.4.8.0/2168.4.8.1 to 68.4.15.25468.4.15.2552,046
13168.4.16.0/2168.4.16.1 to 68.4.23.25468.4.23.2552,046
13268.4.24.0/2168.4.24.1 to 68.4.31.25468.4.31.2552,046
13368.4.32.0/2168.4.32.1 to 68.4.39.25468.4.39.2552,046
13468.4.40.0/2168.4.40.1 to 68.4.47.25468.4.47.2552,046
13568.4.48.0/2168.4.48.1 to 68.4.55.25468.4.55.2552,046
13668.4.56.0/2168.4.56.1 to 68.4.63.25468.4.63.2552,046
13768.4.64.0/2168.4.64.1 to 68.4.71.25468.4.71.2552,046
13868.4.72.0/2168.4.72.1 to 68.4.79.25468.4.79.2552,046
13968.4.80.0/2168.4.80.1 to 68.4.87.25468.4.87.2552,046
14068.4.88.0/2168.4.88.1 to 68.4.95.25468.4.95.2552,046
14168.4.96.0/2168.4.96.1 to 68.4.103.25468.4.103.2552,046
14268.4.104.0/2168.4.104.1 to 68.4.111.25468.4.111.2552,046
14368.4.112.0/2168.4.112.1 to 68.4.119.25468.4.119.2552,046
14468.4.120.0/2168.4.120.1 to 68.4.127.25468.4.127.2552,046
14568.4.128.0/2168.4.128.1 to 68.4.135.25468.4.135.2552,046
14668.4.136.0/2168.4.136.1 to 68.4.143.25468.4.143.2552,046
14768.4.144.0/2168.4.144.1 to 68.4.151.25468.4.151.2552,046
14868.4.152.0/2168.4.152.1 to 68.4.159.25468.4.159.2552,046
14968.4.160.0/2168.4.160.1 to 68.4.167.25468.4.167.2552,046
15068.4.168.0/2168.4.168.1 to 68.4.175.25468.4.175.2552,046
15168.4.176.0/2168.4.176.1 to 68.4.183.25468.4.183.2552,046
15268.4.184.0/2168.4.184.1 to 68.4.191.25468.4.191.2552,046
15368.4.192.0/2168.4.192.1 to 68.4.199.25468.4.199.2552,046
15468.4.200.0/2168.4.200.1 to 68.4.207.25468.4.207.2552,046
15568.4.208.0/2168.4.208.1 to 68.4.215.25468.4.215.2552,046
15668.4.216.0/2168.4.216.1 to 68.4.223.25468.4.223.2552,046
15768.4.224.0/2168.4.224.1 to 68.4.231.25468.4.231.2552,046
15868.4.232.0/2168.4.232.1 to 68.4.239.25468.4.239.2552,046
15968.4.240.0/2168.4.240.1 to 68.4.247.25468.4.247.2552,046
16068.4.248.0/2168.4.248.1 to 68.4.255.25468.4.255.2552,046
16168.5.0.0/2168.5.0.1 to 68.5.7.25468.5.7.2552,046
16268.5.8.0/2168.5.8.1 to 68.5.15.25468.5.15.2552,046
16368.5.16.0/2168.5.16.1 to 68.5.23.25468.5.23.2552,046
16468.5.24.0/2168.5.24.1 to 68.5.31.25468.5.31.2552,046
16568.5.32.0/2168.5.32.1 to 68.5.39.25468.5.39.2552,046
16668.5.40.0/2168.5.40.1 to 68.5.47.25468.5.47.2552,046
16768.5.48.0/2168.5.48.1 to 68.5.55.25468.5.55.2552,046
16868.5.56.0/2168.5.56.1 to 68.5.63.25468.5.63.2552,046
16968.5.64.0/2168.5.64.1 to 68.5.71.25468.5.71.2552,046
17068.5.72.0/2168.5.72.1 to 68.5.79.25468.5.79.2552,046
17168.5.80.0/2168.5.80.1 to 68.5.87.25468.5.87.2552,046
17268.5.88.0/2168.5.88.1 to 68.5.95.25468.5.95.2552,046
17368.5.96.0/2168.5.96.1 to 68.5.103.25468.5.103.2552,046
17468.5.104.0/2168.5.104.1 to 68.5.111.25468.5.111.2552,046
17568.5.112.0/2168.5.112.1 to 68.5.119.25468.5.119.2552,046
17668.5.120.0/2168.5.120.1 to 68.5.127.25468.5.127.2552,046
17768.5.128.0/2168.5.128.1 to 68.5.135.25468.5.135.2552,046
17868.5.136.0/2168.5.136.1 to 68.5.143.25468.5.143.2552,046
17968.5.144.0/2168.5.144.1 to 68.5.151.25468.5.151.2552,046
18068.5.152.0/2168.5.152.1 to 68.5.159.25468.5.159.2552,046
18168.5.160.0/2168.5.160.1 to 68.5.167.25468.5.167.2552,046
18268.5.168.0/2168.5.168.1 to 68.5.175.25468.5.175.2552,046
18368.5.176.0/2168.5.176.1 to 68.5.183.25468.5.183.2552,046
18468.5.184.0/2168.5.184.1 to 68.5.191.25468.5.191.2552,046
18568.5.192.0/2168.5.192.1 to 68.5.199.25468.5.199.2552,046
18668.5.200.0/2168.5.200.1 to 68.5.207.25468.5.207.2552,046
18768.5.208.0/2168.5.208.1 to 68.5.215.25468.5.215.2552,046
18868.5.216.0/2168.5.216.1 to 68.5.223.25468.5.223.2552,046
18968.5.224.0/2168.5.224.1 to 68.5.231.25468.5.231.2552,046
19068.5.232.0/2168.5.232.1 to 68.5.239.25468.5.239.2552,046
19168.5.240.0/2168.5.240.1 to 68.5.247.25468.5.247.2552,046
19268.5.248.0/2168.5.248.1 to 68.5.255.25468.5.255.2552,046
19368.6.0.0/2168.6.0.1 to 68.6.7.25468.6.7.2552,046
19468.6.8.0/2168.6.8.1 to 68.6.15.25468.6.15.2552,046
19568.6.16.0/2168.6.16.1 to 68.6.23.25468.6.23.2552,046
19668.6.24.0/2168.6.24.1 to 68.6.31.25468.6.31.2552,046
19768.6.32.0/2168.6.32.1 to 68.6.39.25468.6.39.2552,046
19868.6.40.0/2168.6.40.1 to 68.6.47.25468.6.47.2552,046
19968.6.48.0/2168.6.48.1 to 68.6.55.25468.6.55.2552,046
20068.6.56.0/2168.6.56.1 to 68.6.63.25468.6.63.2552,046
20168.6.64.0/2168.6.64.1 to 68.6.71.25468.6.71.2552,046
20268.6.72.0/2168.6.72.1 to 68.6.79.25468.6.79.2552,046
20368.6.80.0/2168.6.80.1 to 68.6.87.25468.6.87.2552,046
20468.6.88.0/2168.6.88.1 to 68.6.95.25468.6.95.2552,046
20568.6.96.0/2168.6.96.1 to 68.6.103.25468.6.103.2552,046
20668.6.104.0/2168.6.104.1 to 68.6.111.25468.6.111.2552,046
20768.6.112.0/2168.6.112.1 to 68.6.119.25468.6.119.2552,046
20868.6.120.0/2168.6.120.1 to 68.6.127.25468.6.127.2552,046
20968.6.128.0/2168.6.128.1 to 68.6.135.25468.6.135.2552,046
21068.6.136.0/2168.6.136.1 to 68.6.143.25468.6.143.2552,046
21168.6.144.0/2168.6.144.1 to 68.6.151.25468.6.151.2552,046
21268.6.152.0/2168.6.152.1 to 68.6.159.25468.6.159.2552,046
21368.6.160.0/2168.6.160.1 to 68.6.167.25468.6.167.2552,046
21468.6.168.0/2168.6.168.1 to 68.6.175.25468.6.175.2552,046
21568.6.176.0/2168.6.176.1 to 68.6.183.25468.6.183.2552,046
21668.6.184.0/2168.6.184.1 to 68.6.191.25468.6.191.2552,046
21768.6.192.0/2168.6.192.1 to 68.6.199.25468.6.199.2552,046
21868.6.200.0/2168.6.200.1 to 68.6.207.25468.6.207.2552,046
21968.6.208.0/2168.6.208.1 to 68.6.215.25468.6.215.2552,046
22068.6.216.0/2168.6.216.1 to 68.6.223.25468.6.223.2552,046
22168.6.224.0/2168.6.224.1 to 68.6.231.25468.6.231.2552,046
22268.6.232.0/2168.6.232.1 to 68.6.239.25468.6.239.2552,046
22368.6.240.0/2168.6.240.1 to 68.6.247.25468.6.247.2552,046
22468.6.248.0/2168.6.248.1 to 68.6.255.25468.6.255.2552,046
22568.7.0.0/2168.7.0.1 to 68.7.7.25468.7.7.2552,046
22668.7.8.0/2168.7.8.1 to 68.7.15.25468.7.15.2552,046
22768.7.16.0/2168.7.16.1 to 68.7.23.25468.7.23.2552,046
22868.7.24.0/2168.7.24.1 to 68.7.31.25468.7.31.2552,046
22968.7.32.0/2168.7.32.1 to 68.7.39.25468.7.39.2552,046
23068.7.40.0/2168.7.40.1 to 68.7.47.25468.7.47.2552,046
23168.7.48.0/2168.7.48.1 to 68.7.55.25468.7.55.2552,046
23268.7.56.0/2168.7.56.1 to 68.7.63.25468.7.63.2552,046
23368.7.64.0/2168.7.64.1 to 68.7.71.25468.7.71.2552,046
23468.7.72.0/2168.7.72.1 to 68.7.79.25468.7.79.2552,046
23568.7.80.0/2168.7.80.1 to 68.7.87.25468.7.87.2552,046
23668.7.88.0/2168.7.88.1 to 68.7.95.25468.7.95.2552,046
23768.7.96.0/2168.7.96.1 to 68.7.103.25468.7.103.2552,046
23868.7.104.0/2168.7.104.1 to 68.7.111.25468.7.111.2552,046
23968.7.112.0/2168.7.112.1 to 68.7.119.25468.7.119.2552,046
24068.7.120.0/2168.7.120.1 to 68.7.127.25468.7.127.2552,046
24168.7.128.0/2168.7.128.1 to 68.7.135.25468.7.135.2552,046
24268.7.136.0/2168.7.136.1 to 68.7.143.25468.7.143.2552,046
24368.7.144.0/2168.7.144.1 to 68.7.151.25468.7.151.2552,046
24468.7.152.0/2168.7.152.1 to 68.7.159.25468.7.159.2552,046
24568.7.160.0/2168.7.160.1 to 68.7.167.25468.7.167.2552,046
24668.7.168.0/2168.7.168.1 to 68.7.175.25468.7.175.2552,046
24768.7.176.0/2168.7.176.1 to 68.7.183.25468.7.183.2552,046
24868.7.184.0/2168.7.184.1 to 68.7.191.25468.7.191.2552,046
24968.7.192.0/2168.7.192.1 to 68.7.199.25468.7.199.2552,046
25068.7.200.0/2168.7.200.1 to 68.7.207.25468.7.207.2552,046
25168.7.208.0/2168.7.208.1 to 68.7.215.25468.7.215.2552,046
25268.7.216.0/2168.7.216.1 to 68.7.223.25468.7.223.2552,046
25368.7.224.0/2168.7.224.1 to 68.7.231.25468.7.231.2552,046
25468.7.232.0/2168.7.232.1 to 68.7.239.25468.7.239.2552,046
25568.7.240.0/2168.7.240.1 to 68.7.247.25468.7.247.2552,046
25668.7.248.0/2168.7.248.1 to 68.7.255.25468.7.255.2552,046

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.