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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/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)

68.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
168.0.0.0/2068.0.0.1 to 68.0.15.25468.0.15.2554,094
268.0.16.0/2068.0.16.1 to 68.0.31.25468.0.31.2554,094
368.0.32.0/2068.0.32.1 to 68.0.47.25468.0.47.2554,094
468.0.48.0/2068.0.48.1 to 68.0.63.25468.0.63.2554,094
568.0.64.0/2068.0.64.1 to 68.0.79.25468.0.79.2554,094
668.0.80.0/2068.0.80.1 to 68.0.95.25468.0.95.2554,094
768.0.96.0/2068.0.96.1 to 68.0.111.25468.0.111.2554,094
868.0.112.0/2068.0.112.1 to 68.0.127.25468.0.127.2554,094
968.0.128.0/2068.0.128.1 to 68.0.143.25468.0.143.2554,094
1068.0.144.0/2068.0.144.1 to 68.0.159.25468.0.159.2554,094
1168.0.160.0/2068.0.160.1 to 68.0.175.25468.0.175.2554,094
1268.0.176.0/2068.0.176.1 to 68.0.191.25468.0.191.2554,094
1368.0.192.0/2068.0.192.1 to 68.0.207.25468.0.207.2554,094
1468.0.208.0/2068.0.208.1 to 68.0.223.25468.0.223.2554,094
1568.0.224.0/2068.0.224.1 to 68.0.239.25468.0.239.2554,094
1668.0.240.0/2068.0.240.1 to 68.0.255.25468.0.255.2554,094
1768.1.0.0/2068.1.0.1 to 68.1.15.25468.1.15.2554,094
1868.1.16.0/2068.1.16.1 to 68.1.31.25468.1.31.2554,094
1968.1.32.0/2068.1.32.1 to 68.1.47.25468.1.47.2554,094
2068.1.48.0/2068.1.48.1 to 68.1.63.25468.1.63.2554,094
2168.1.64.0/2068.1.64.1 to 68.1.79.25468.1.79.2554,094
2268.1.80.0/2068.1.80.1 to 68.1.95.25468.1.95.2554,094
2368.1.96.0/2068.1.96.1 to 68.1.111.25468.1.111.2554,094
2468.1.112.0/2068.1.112.1 to 68.1.127.25468.1.127.2554,094
2568.1.128.0/2068.1.128.1 to 68.1.143.25468.1.143.2554,094
2668.1.144.0/2068.1.144.1 to 68.1.159.25468.1.159.2554,094
2768.1.160.0/2068.1.160.1 to 68.1.175.25468.1.175.2554,094
2868.1.176.0/2068.1.176.1 to 68.1.191.25468.1.191.2554,094
2968.1.192.0/2068.1.192.1 to 68.1.207.25468.1.207.2554,094
3068.1.208.0/2068.1.208.1 to 68.1.223.25468.1.223.2554,094
3168.1.224.0/2068.1.224.1 to 68.1.239.25468.1.239.2554,094
3268.1.240.0/2068.1.240.1 to 68.1.255.25468.1.255.2554,094
3368.2.0.0/2068.2.0.1 to 68.2.15.25468.2.15.2554,094
3468.2.16.0/2068.2.16.1 to 68.2.31.25468.2.31.2554,094
3568.2.32.0/2068.2.32.1 to 68.2.47.25468.2.47.2554,094
3668.2.48.0/2068.2.48.1 to 68.2.63.25468.2.63.2554,094
3768.2.64.0/2068.2.64.1 to 68.2.79.25468.2.79.2554,094
3868.2.80.0/2068.2.80.1 to 68.2.95.25468.2.95.2554,094
3968.2.96.0/2068.2.96.1 to 68.2.111.25468.2.111.2554,094
4068.2.112.0/2068.2.112.1 to 68.2.127.25468.2.127.2554,094
4168.2.128.0/2068.2.128.1 to 68.2.143.25468.2.143.2554,094
4268.2.144.0/2068.2.144.1 to 68.2.159.25468.2.159.2554,094
4368.2.160.0/2068.2.160.1 to 68.2.175.25468.2.175.2554,094
4468.2.176.0/2068.2.176.1 to 68.2.191.25468.2.191.2554,094
4568.2.192.0/2068.2.192.1 to 68.2.207.25468.2.207.2554,094
4668.2.208.0/2068.2.208.1 to 68.2.223.25468.2.223.2554,094
4768.2.224.0/2068.2.224.1 to 68.2.239.25468.2.239.2554,094
4868.2.240.0/2068.2.240.1 to 68.2.255.25468.2.255.2554,094
4968.3.0.0/2068.3.0.1 to 68.3.15.25468.3.15.2554,094
5068.3.16.0/2068.3.16.1 to 68.3.31.25468.3.31.2554,094
5168.3.32.0/2068.3.32.1 to 68.3.47.25468.3.47.2554,094
5268.3.48.0/2068.3.48.1 to 68.3.63.25468.3.63.2554,094
5368.3.64.0/2068.3.64.1 to 68.3.79.25468.3.79.2554,094
5468.3.80.0/2068.3.80.1 to 68.3.95.25468.3.95.2554,094
5568.3.96.0/2068.3.96.1 to 68.3.111.25468.3.111.2554,094
5668.3.112.0/2068.3.112.1 to 68.3.127.25468.3.127.2554,094
5768.3.128.0/2068.3.128.1 to 68.3.143.25468.3.143.2554,094
5868.3.144.0/2068.3.144.1 to 68.3.159.25468.3.159.2554,094
5968.3.160.0/2068.3.160.1 to 68.3.175.25468.3.175.2554,094
6068.3.176.0/2068.3.176.1 to 68.3.191.25468.3.191.2554,094
6168.3.192.0/2068.3.192.1 to 68.3.207.25468.3.207.2554,094
6268.3.208.0/2068.3.208.1 to 68.3.223.25468.3.223.2554,094
6368.3.224.0/2068.3.224.1 to 68.3.239.25468.3.239.2554,094
6468.3.240.0/2068.3.240.1 to 68.3.255.25468.3.255.2554,094
6568.4.0.0/2068.4.0.1 to 68.4.15.25468.4.15.2554,094
6668.4.16.0/2068.4.16.1 to 68.4.31.25468.4.31.2554,094
6768.4.32.0/2068.4.32.1 to 68.4.47.25468.4.47.2554,094
6868.4.48.0/2068.4.48.1 to 68.4.63.25468.4.63.2554,094
6968.4.64.0/2068.4.64.1 to 68.4.79.25468.4.79.2554,094
7068.4.80.0/2068.4.80.1 to 68.4.95.25468.4.95.2554,094
7168.4.96.0/2068.4.96.1 to 68.4.111.25468.4.111.2554,094
7268.4.112.0/2068.4.112.1 to 68.4.127.25468.4.127.2554,094
7368.4.128.0/2068.4.128.1 to 68.4.143.25468.4.143.2554,094
7468.4.144.0/2068.4.144.1 to 68.4.159.25468.4.159.2554,094
7568.4.160.0/2068.4.160.1 to 68.4.175.25468.4.175.2554,094
7668.4.176.0/2068.4.176.1 to 68.4.191.25468.4.191.2554,094
7768.4.192.0/2068.4.192.1 to 68.4.207.25468.4.207.2554,094
7868.4.208.0/2068.4.208.1 to 68.4.223.25468.4.223.2554,094
7968.4.224.0/2068.4.224.1 to 68.4.239.25468.4.239.2554,094
8068.4.240.0/2068.4.240.1 to 68.4.255.25468.4.255.2554,094
8168.5.0.0/2068.5.0.1 to 68.5.15.25468.5.15.2554,094
8268.5.16.0/2068.5.16.1 to 68.5.31.25468.5.31.2554,094
8368.5.32.0/2068.5.32.1 to 68.5.47.25468.5.47.2554,094
8468.5.48.0/2068.5.48.1 to 68.5.63.25468.5.63.2554,094
8568.5.64.0/2068.5.64.1 to 68.5.79.25468.5.79.2554,094
8668.5.80.0/2068.5.80.1 to 68.5.95.25468.5.95.2554,094
8768.5.96.0/2068.5.96.1 to 68.5.111.25468.5.111.2554,094
8868.5.112.0/2068.5.112.1 to 68.5.127.25468.5.127.2554,094
8968.5.128.0/2068.5.128.1 to 68.5.143.25468.5.143.2554,094
9068.5.144.0/2068.5.144.1 to 68.5.159.25468.5.159.2554,094
9168.5.160.0/2068.5.160.1 to 68.5.175.25468.5.175.2554,094
9268.5.176.0/2068.5.176.1 to 68.5.191.25468.5.191.2554,094
9368.5.192.0/2068.5.192.1 to 68.5.207.25468.5.207.2554,094
9468.5.208.0/2068.5.208.1 to 68.5.223.25468.5.223.2554,094
9568.5.224.0/2068.5.224.1 to 68.5.239.25468.5.239.2554,094
9668.5.240.0/2068.5.240.1 to 68.5.255.25468.5.255.2554,094
9768.6.0.0/2068.6.0.1 to 68.6.15.25468.6.15.2554,094
9868.6.16.0/2068.6.16.1 to 68.6.31.25468.6.31.2554,094
9968.6.32.0/2068.6.32.1 to 68.6.47.25468.6.47.2554,094
10068.6.48.0/2068.6.48.1 to 68.6.63.25468.6.63.2554,094
10168.6.64.0/2068.6.64.1 to 68.6.79.25468.6.79.2554,094
10268.6.80.0/2068.6.80.1 to 68.6.95.25468.6.95.2554,094
10368.6.96.0/2068.6.96.1 to 68.6.111.25468.6.111.2554,094
10468.6.112.0/2068.6.112.1 to 68.6.127.25468.6.127.2554,094
10568.6.128.0/2068.6.128.1 to 68.6.143.25468.6.143.2554,094
10668.6.144.0/2068.6.144.1 to 68.6.159.25468.6.159.2554,094
10768.6.160.0/2068.6.160.1 to 68.6.175.25468.6.175.2554,094
10868.6.176.0/2068.6.176.1 to 68.6.191.25468.6.191.2554,094
10968.6.192.0/2068.6.192.1 to 68.6.207.25468.6.207.2554,094
11068.6.208.0/2068.6.208.1 to 68.6.223.25468.6.223.2554,094
11168.6.224.0/2068.6.224.1 to 68.6.239.25468.6.239.2554,094
11268.6.240.0/2068.6.240.1 to 68.6.255.25468.6.255.2554,094
11368.7.0.0/2068.7.0.1 to 68.7.15.25468.7.15.2554,094
11468.7.16.0/2068.7.16.1 to 68.7.31.25468.7.31.2554,094
11568.7.32.0/2068.7.32.1 to 68.7.47.25468.7.47.2554,094
11668.7.48.0/2068.7.48.1 to 68.7.63.25468.7.63.2554,094
11768.7.64.0/2068.7.64.1 to 68.7.79.25468.7.79.2554,094
11868.7.80.0/2068.7.80.1 to 68.7.95.25468.7.95.2554,094
11968.7.96.0/2068.7.96.1 to 68.7.111.25468.7.111.2554,094
12068.7.112.0/2068.7.112.1 to 68.7.127.25468.7.127.2554,094
12168.7.128.0/2068.7.128.1 to 68.7.143.25468.7.143.2554,094
12268.7.144.0/2068.7.144.1 to 68.7.159.25468.7.159.2554,094
12368.7.160.0/2068.7.160.1 to 68.7.175.25468.7.175.2554,094
12468.7.176.0/2068.7.176.1 to 68.7.191.25468.7.191.2554,094
12568.7.192.0/2068.7.192.1 to 68.7.207.25468.7.207.2554,094
12668.7.208.0/2068.7.208.1 to 68.7.223.25468.7.223.2554,094
12768.7.224.0/2068.7.224.1 to 68.7.239.25468.7.239.2554,094
12868.7.240.0/2068.7.240.1 to 68.7.255.25468.7.255.2554,094
12968.8.0.0/2068.8.0.1 to 68.8.15.25468.8.15.2554,094
13068.8.16.0/2068.8.16.1 to 68.8.31.25468.8.31.2554,094
13168.8.32.0/2068.8.32.1 to 68.8.47.25468.8.47.2554,094
13268.8.48.0/2068.8.48.1 to 68.8.63.25468.8.63.2554,094
13368.8.64.0/2068.8.64.1 to 68.8.79.25468.8.79.2554,094
13468.8.80.0/2068.8.80.1 to 68.8.95.25468.8.95.2554,094
13568.8.96.0/2068.8.96.1 to 68.8.111.25468.8.111.2554,094
13668.8.112.0/2068.8.112.1 to 68.8.127.25468.8.127.2554,094
13768.8.128.0/2068.8.128.1 to 68.8.143.25468.8.143.2554,094
13868.8.144.0/2068.8.144.1 to 68.8.159.25468.8.159.2554,094
13968.8.160.0/2068.8.160.1 to 68.8.175.25468.8.175.2554,094
14068.8.176.0/2068.8.176.1 to 68.8.191.25468.8.191.2554,094
14168.8.192.0/2068.8.192.1 to 68.8.207.25468.8.207.2554,094
14268.8.208.0/2068.8.208.1 to 68.8.223.25468.8.223.2554,094
14368.8.224.0/2068.8.224.1 to 68.8.239.25468.8.239.2554,094
14468.8.240.0/2068.8.240.1 to 68.8.255.25468.8.255.2554,094
14568.9.0.0/2068.9.0.1 to 68.9.15.25468.9.15.2554,094
14668.9.16.0/2068.9.16.1 to 68.9.31.25468.9.31.2554,094
14768.9.32.0/2068.9.32.1 to 68.9.47.25468.9.47.2554,094
14868.9.48.0/2068.9.48.1 to 68.9.63.25468.9.63.2554,094
14968.9.64.0/2068.9.64.1 to 68.9.79.25468.9.79.2554,094
15068.9.80.0/2068.9.80.1 to 68.9.95.25468.9.95.2554,094
15168.9.96.0/2068.9.96.1 to 68.9.111.25468.9.111.2554,094
15268.9.112.0/2068.9.112.1 to 68.9.127.25468.9.127.2554,094
15368.9.128.0/2068.9.128.1 to 68.9.143.25468.9.143.2554,094
15468.9.144.0/2068.9.144.1 to 68.9.159.25468.9.159.2554,094
15568.9.160.0/2068.9.160.1 to 68.9.175.25468.9.175.2554,094
15668.9.176.0/2068.9.176.1 to 68.9.191.25468.9.191.2554,094
15768.9.192.0/2068.9.192.1 to 68.9.207.25468.9.207.2554,094
15868.9.208.0/2068.9.208.1 to 68.9.223.25468.9.223.2554,094
15968.9.224.0/2068.9.224.1 to 68.9.239.25468.9.239.2554,094
16068.9.240.0/2068.9.240.1 to 68.9.255.25468.9.255.2554,094
16168.10.0.0/2068.10.0.1 to 68.10.15.25468.10.15.2554,094
16268.10.16.0/2068.10.16.1 to 68.10.31.25468.10.31.2554,094
16368.10.32.0/2068.10.32.1 to 68.10.47.25468.10.47.2554,094
16468.10.48.0/2068.10.48.1 to 68.10.63.25468.10.63.2554,094
16568.10.64.0/2068.10.64.1 to 68.10.79.25468.10.79.2554,094
16668.10.80.0/2068.10.80.1 to 68.10.95.25468.10.95.2554,094
16768.10.96.0/2068.10.96.1 to 68.10.111.25468.10.111.2554,094
16868.10.112.0/2068.10.112.1 to 68.10.127.25468.10.127.2554,094
16968.10.128.0/2068.10.128.1 to 68.10.143.25468.10.143.2554,094
17068.10.144.0/2068.10.144.1 to 68.10.159.25468.10.159.2554,094
17168.10.160.0/2068.10.160.1 to 68.10.175.25468.10.175.2554,094
17268.10.176.0/2068.10.176.1 to 68.10.191.25468.10.191.2554,094
17368.10.192.0/2068.10.192.1 to 68.10.207.25468.10.207.2554,094
17468.10.208.0/2068.10.208.1 to 68.10.223.25468.10.223.2554,094
17568.10.224.0/2068.10.224.1 to 68.10.239.25468.10.239.2554,094
17668.10.240.0/2068.10.240.1 to 68.10.255.25468.10.255.2554,094
17768.11.0.0/2068.11.0.1 to 68.11.15.25468.11.15.2554,094
17868.11.16.0/2068.11.16.1 to 68.11.31.25468.11.31.2554,094
17968.11.32.0/2068.11.32.1 to 68.11.47.25468.11.47.2554,094
18068.11.48.0/2068.11.48.1 to 68.11.63.25468.11.63.2554,094
18168.11.64.0/2068.11.64.1 to 68.11.79.25468.11.79.2554,094
18268.11.80.0/2068.11.80.1 to 68.11.95.25468.11.95.2554,094
18368.11.96.0/2068.11.96.1 to 68.11.111.25468.11.111.2554,094
18468.11.112.0/2068.11.112.1 to 68.11.127.25468.11.127.2554,094
18568.11.128.0/2068.11.128.1 to 68.11.143.25468.11.143.2554,094
18668.11.144.0/2068.11.144.1 to 68.11.159.25468.11.159.2554,094
18768.11.160.0/2068.11.160.1 to 68.11.175.25468.11.175.2554,094
18868.11.176.0/2068.11.176.1 to 68.11.191.25468.11.191.2554,094
18968.11.192.0/2068.11.192.1 to 68.11.207.25468.11.207.2554,094
19068.11.208.0/2068.11.208.1 to 68.11.223.25468.11.223.2554,094
19168.11.224.0/2068.11.224.1 to 68.11.239.25468.11.239.2554,094
19268.11.240.0/2068.11.240.1 to 68.11.255.25468.11.255.2554,094
19368.12.0.0/2068.12.0.1 to 68.12.15.25468.12.15.2554,094
19468.12.16.0/2068.12.16.1 to 68.12.31.25468.12.31.2554,094
19568.12.32.0/2068.12.32.1 to 68.12.47.25468.12.47.2554,094
19668.12.48.0/2068.12.48.1 to 68.12.63.25468.12.63.2554,094
19768.12.64.0/2068.12.64.1 to 68.12.79.25468.12.79.2554,094
19868.12.80.0/2068.12.80.1 to 68.12.95.25468.12.95.2554,094
19968.12.96.0/2068.12.96.1 to 68.12.111.25468.12.111.2554,094
20068.12.112.0/2068.12.112.1 to 68.12.127.25468.12.127.2554,094
20168.12.128.0/2068.12.128.1 to 68.12.143.25468.12.143.2554,094
20268.12.144.0/2068.12.144.1 to 68.12.159.25468.12.159.2554,094
20368.12.160.0/2068.12.160.1 to 68.12.175.25468.12.175.2554,094
20468.12.176.0/2068.12.176.1 to 68.12.191.25468.12.191.2554,094
20568.12.192.0/2068.12.192.1 to 68.12.207.25468.12.207.2554,094
20668.12.208.0/2068.12.208.1 to 68.12.223.25468.12.223.2554,094
20768.12.224.0/2068.12.224.1 to 68.12.239.25468.12.239.2554,094
20868.12.240.0/2068.12.240.1 to 68.12.255.25468.12.255.2554,094
20968.13.0.0/2068.13.0.1 to 68.13.15.25468.13.15.2554,094
21068.13.16.0/2068.13.16.1 to 68.13.31.25468.13.31.2554,094
21168.13.32.0/2068.13.32.1 to 68.13.47.25468.13.47.2554,094
21268.13.48.0/2068.13.48.1 to 68.13.63.25468.13.63.2554,094
21368.13.64.0/2068.13.64.1 to 68.13.79.25468.13.79.2554,094
21468.13.80.0/2068.13.80.1 to 68.13.95.25468.13.95.2554,094
21568.13.96.0/2068.13.96.1 to 68.13.111.25468.13.111.2554,094
21668.13.112.0/2068.13.112.1 to 68.13.127.25468.13.127.2554,094
21768.13.128.0/2068.13.128.1 to 68.13.143.25468.13.143.2554,094
21868.13.144.0/2068.13.144.1 to 68.13.159.25468.13.159.2554,094
21968.13.160.0/2068.13.160.1 to 68.13.175.25468.13.175.2554,094
22068.13.176.0/2068.13.176.1 to 68.13.191.25468.13.191.2554,094
22168.13.192.0/2068.13.192.1 to 68.13.207.25468.13.207.2554,094
22268.13.208.0/2068.13.208.1 to 68.13.223.25468.13.223.2554,094
22368.13.224.0/2068.13.224.1 to 68.13.239.25468.13.239.2554,094
22468.13.240.0/2068.13.240.1 to 68.13.255.25468.13.255.2554,094
22568.14.0.0/2068.14.0.1 to 68.14.15.25468.14.15.2554,094
22668.14.16.0/2068.14.16.1 to 68.14.31.25468.14.31.2554,094
22768.14.32.0/2068.14.32.1 to 68.14.47.25468.14.47.2554,094
22868.14.48.0/2068.14.48.1 to 68.14.63.25468.14.63.2554,094
22968.14.64.0/2068.14.64.1 to 68.14.79.25468.14.79.2554,094
23068.14.80.0/2068.14.80.1 to 68.14.95.25468.14.95.2554,094
23168.14.96.0/2068.14.96.1 to 68.14.111.25468.14.111.2554,094
23268.14.112.0/2068.14.112.1 to 68.14.127.25468.14.127.2554,094
23368.14.128.0/2068.14.128.1 to 68.14.143.25468.14.143.2554,094
23468.14.144.0/2068.14.144.1 to 68.14.159.25468.14.159.2554,094
23568.14.160.0/2068.14.160.1 to 68.14.175.25468.14.175.2554,094
23668.14.176.0/2068.14.176.1 to 68.14.191.25468.14.191.2554,094
23768.14.192.0/2068.14.192.1 to 68.14.207.25468.14.207.2554,094
23868.14.208.0/2068.14.208.1 to 68.14.223.25468.14.223.2554,094
23968.14.224.0/2068.14.224.1 to 68.14.239.25468.14.239.2554,094
24068.14.240.0/2068.14.240.1 to 68.14.255.25468.14.255.2554,094
24168.15.0.0/2068.15.0.1 to 68.15.15.25468.15.15.2554,094
24268.15.16.0/2068.15.16.1 to 68.15.31.25468.15.31.2554,094
24368.15.32.0/2068.15.32.1 to 68.15.47.25468.15.47.2554,094
24468.15.48.0/2068.15.48.1 to 68.15.63.25468.15.63.2554,094
24568.15.64.0/2068.15.64.1 to 68.15.79.25468.15.79.2554,094
24668.15.80.0/2068.15.80.1 to 68.15.95.25468.15.95.2554,094
24768.15.96.0/2068.15.96.1 to 68.15.111.25468.15.111.2554,094
24868.15.112.0/2068.15.112.1 to 68.15.127.25468.15.127.2554,094
24968.15.128.0/2068.15.128.1 to 68.15.143.25468.15.143.2554,094
25068.15.144.0/2068.15.144.1 to 68.15.159.25468.15.159.2554,094
25168.15.160.0/2068.15.160.1 to 68.15.175.25468.15.175.2554,094
25268.15.176.0/2068.15.176.1 to 68.15.191.25468.15.191.2554,094
25368.15.192.0/2068.15.192.1 to 68.15.207.25468.15.207.2554,094
25468.15.208.0/2068.15.208.1 to 68.15.223.25468.15.223.2554,094
25568.15.224.0/2068.15.224.1 to 68.15.239.25468.15.239.2554,094
25668.15.240.0/2068.15.240.1 to 68.15.255.25468.15.255.2554,094

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.