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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.

Network43.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
43.0.0.0
Broadcast address
43.255.255.255
First usable
43.0.0.1
Last usable
43.255.255.254
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 2B000000 · Integer 721420288 to 738197503
Reverse DNS zone
43.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00101011..00000000.00000000.0000000043.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00101011..00000000.00000000.0000000043.0.0.0
Broadcast00101011..11111111.11111111.1111111143.255.255.255
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)

43.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
143.0.0.0/2043.0.0.1 to 43.0.15.25443.0.15.2554,094
243.0.16.0/2043.0.16.1 to 43.0.31.25443.0.31.2554,094
343.0.32.0/2043.0.32.1 to 43.0.47.25443.0.47.2554,094
443.0.48.0/2043.0.48.1 to 43.0.63.25443.0.63.2554,094
543.0.64.0/2043.0.64.1 to 43.0.79.25443.0.79.2554,094
643.0.80.0/2043.0.80.1 to 43.0.95.25443.0.95.2554,094
743.0.96.0/2043.0.96.1 to 43.0.111.25443.0.111.2554,094
843.0.112.0/2043.0.112.1 to 43.0.127.25443.0.127.2554,094
943.0.128.0/2043.0.128.1 to 43.0.143.25443.0.143.2554,094
1043.0.144.0/2043.0.144.1 to 43.0.159.25443.0.159.2554,094
1143.0.160.0/2043.0.160.1 to 43.0.175.25443.0.175.2554,094
1243.0.176.0/2043.0.176.1 to 43.0.191.25443.0.191.2554,094
1343.0.192.0/2043.0.192.1 to 43.0.207.25443.0.207.2554,094
1443.0.208.0/2043.0.208.1 to 43.0.223.25443.0.223.2554,094
1543.0.224.0/2043.0.224.1 to 43.0.239.25443.0.239.2554,094
1643.0.240.0/2043.0.240.1 to 43.0.255.25443.0.255.2554,094
1743.1.0.0/2043.1.0.1 to 43.1.15.25443.1.15.2554,094
1843.1.16.0/2043.1.16.1 to 43.1.31.25443.1.31.2554,094
1943.1.32.0/2043.1.32.1 to 43.1.47.25443.1.47.2554,094
2043.1.48.0/2043.1.48.1 to 43.1.63.25443.1.63.2554,094
2143.1.64.0/2043.1.64.1 to 43.1.79.25443.1.79.2554,094
2243.1.80.0/2043.1.80.1 to 43.1.95.25443.1.95.2554,094
2343.1.96.0/2043.1.96.1 to 43.1.111.25443.1.111.2554,094
2443.1.112.0/2043.1.112.1 to 43.1.127.25443.1.127.2554,094
2543.1.128.0/2043.1.128.1 to 43.1.143.25443.1.143.2554,094
2643.1.144.0/2043.1.144.1 to 43.1.159.25443.1.159.2554,094
2743.1.160.0/2043.1.160.1 to 43.1.175.25443.1.175.2554,094
2843.1.176.0/2043.1.176.1 to 43.1.191.25443.1.191.2554,094
2943.1.192.0/2043.1.192.1 to 43.1.207.25443.1.207.2554,094
3043.1.208.0/2043.1.208.1 to 43.1.223.25443.1.223.2554,094
3143.1.224.0/2043.1.224.1 to 43.1.239.25443.1.239.2554,094
3243.1.240.0/2043.1.240.1 to 43.1.255.25443.1.255.2554,094
3343.2.0.0/2043.2.0.1 to 43.2.15.25443.2.15.2554,094
3443.2.16.0/2043.2.16.1 to 43.2.31.25443.2.31.2554,094
3543.2.32.0/2043.2.32.1 to 43.2.47.25443.2.47.2554,094
3643.2.48.0/2043.2.48.1 to 43.2.63.25443.2.63.2554,094
3743.2.64.0/2043.2.64.1 to 43.2.79.25443.2.79.2554,094
3843.2.80.0/2043.2.80.1 to 43.2.95.25443.2.95.2554,094
3943.2.96.0/2043.2.96.1 to 43.2.111.25443.2.111.2554,094
4043.2.112.0/2043.2.112.1 to 43.2.127.25443.2.127.2554,094
4143.2.128.0/2043.2.128.1 to 43.2.143.25443.2.143.2554,094
4243.2.144.0/2043.2.144.1 to 43.2.159.25443.2.159.2554,094
4343.2.160.0/2043.2.160.1 to 43.2.175.25443.2.175.2554,094
4443.2.176.0/2043.2.176.1 to 43.2.191.25443.2.191.2554,094
4543.2.192.0/2043.2.192.1 to 43.2.207.25443.2.207.2554,094
4643.2.208.0/2043.2.208.1 to 43.2.223.25443.2.223.2554,094
4743.2.224.0/2043.2.224.1 to 43.2.239.25443.2.239.2554,094
4843.2.240.0/2043.2.240.1 to 43.2.255.25443.2.255.2554,094
4943.3.0.0/2043.3.0.1 to 43.3.15.25443.3.15.2554,094
5043.3.16.0/2043.3.16.1 to 43.3.31.25443.3.31.2554,094
5143.3.32.0/2043.3.32.1 to 43.3.47.25443.3.47.2554,094
5243.3.48.0/2043.3.48.1 to 43.3.63.25443.3.63.2554,094
5343.3.64.0/2043.3.64.1 to 43.3.79.25443.3.79.2554,094
5443.3.80.0/2043.3.80.1 to 43.3.95.25443.3.95.2554,094
5543.3.96.0/2043.3.96.1 to 43.3.111.25443.3.111.2554,094
5643.3.112.0/2043.3.112.1 to 43.3.127.25443.3.127.2554,094
5743.3.128.0/2043.3.128.1 to 43.3.143.25443.3.143.2554,094
5843.3.144.0/2043.3.144.1 to 43.3.159.25443.3.159.2554,094
5943.3.160.0/2043.3.160.1 to 43.3.175.25443.3.175.2554,094
6043.3.176.0/2043.3.176.1 to 43.3.191.25443.3.191.2554,094
6143.3.192.0/2043.3.192.1 to 43.3.207.25443.3.207.2554,094
6243.3.208.0/2043.3.208.1 to 43.3.223.25443.3.223.2554,094
6343.3.224.0/2043.3.224.1 to 43.3.239.25443.3.239.2554,094
6443.3.240.0/2043.3.240.1 to 43.3.255.25443.3.255.2554,094
6543.4.0.0/2043.4.0.1 to 43.4.15.25443.4.15.2554,094
6643.4.16.0/2043.4.16.1 to 43.4.31.25443.4.31.2554,094
6743.4.32.0/2043.4.32.1 to 43.4.47.25443.4.47.2554,094
6843.4.48.0/2043.4.48.1 to 43.4.63.25443.4.63.2554,094
6943.4.64.0/2043.4.64.1 to 43.4.79.25443.4.79.2554,094
7043.4.80.0/2043.4.80.1 to 43.4.95.25443.4.95.2554,094
7143.4.96.0/2043.4.96.1 to 43.4.111.25443.4.111.2554,094
7243.4.112.0/2043.4.112.1 to 43.4.127.25443.4.127.2554,094
7343.4.128.0/2043.4.128.1 to 43.4.143.25443.4.143.2554,094
7443.4.144.0/2043.4.144.1 to 43.4.159.25443.4.159.2554,094
7543.4.160.0/2043.4.160.1 to 43.4.175.25443.4.175.2554,094
7643.4.176.0/2043.4.176.1 to 43.4.191.25443.4.191.2554,094
7743.4.192.0/2043.4.192.1 to 43.4.207.25443.4.207.2554,094
7843.4.208.0/2043.4.208.1 to 43.4.223.25443.4.223.2554,094
7943.4.224.0/2043.4.224.1 to 43.4.239.25443.4.239.2554,094
8043.4.240.0/2043.4.240.1 to 43.4.255.25443.4.255.2554,094
8143.5.0.0/2043.5.0.1 to 43.5.15.25443.5.15.2554,094
8243.5.16.0/2043.5.16.1 to 43.5.31.25443.5.31.2554,094
8343.5.32.0/2043.5.32.1 to 43.5.47.25443.5.47.2554,094
8443.5.48.0/2043.5.48.1 to 43.5.63.25443.5.63.2554,094
8543.5.64.0/2043.5.64.1 to 43.5.79.25443.5.79.2554,094
8643.5.80.0/2043.5.80.1 to 43.5.95.25443.5.95.2554,094
8743.5.96.0/2043.5.96.1 to 43.5.111.25443.5.111.2554,094
8843.5.112.0/2043.5.112.1 to 43.5.127.25443.5.127.2554,094
8943.5.128.0/2043.5.128.1 to 43.5.143.25443.5.143.2554,094
9043.5.144.0/2043.5.144.1 to 43.5.159.25443.5.159.2554,094
9143.5.160.0/2043.5.160.1 to 43.5.175.25443.5.175.2554,094
9243.5.176.0/2043.5.176.1 to 43.5.191.25443.5.191.2554,094
9343.5.192.0/2043.5.192.1 to 43.5.207.25443.5.207.2554,094
9443.5.208.0/2043.5.208.1 to 43.5.223.25443.5.223.2554,094
9543.5.224.0/2043.5.224.1 to 43.5.239.25443.5.239.2554,094
9643.5.240.0/2043.5.240.1 to 43.5.255.25443.5.255.2554,094
9743.6.0.0/2043.6.0.1 to 43.6.15.25443.6.15.2554,094
9843.6.16.0/2043.6.16.1 to 43.6.31.25443.6.31.2554,094
9943.6.32.0/2043.6.32.1 to 43.6.47.25443.6.47.2554,094
10043.6.48.0/2043.6.48.1 to 43.6.63.25443.6.63.2554,094
10143.6.64.0/2043.6.64.1 to 43.6.79.25443.6.79.2554,094
10243.6.80.0/2043.6.80.1 to 43.6.95.25443.6.95.2554,094
10343.6.96.0/2043.6.96.1 to 43.6.111.25443.6.111.2554,094
10443.6.112.0/2043.6.112.1 to 43.6.127.25443.6.127.2554,094
10543.6.128.0/2043.6.128.1 to 43.6.143.25443.6.143.2554,094
10643.6.144.0/2043.6.144.1 to 43.6.159.25443.6.159.2554,094
10743.6.160.0/2043.6.160.1 to 43.6.175.25443.6.175.2554,094
10843.6.176.0/2043.6.176.1 to 43.6.191.25443.6.191.2554,094
10943.6.192.0/2043.6.192.1 to 43.6.207.25443.6.207.2554,094
11043.6.208.0/2043.6.208.1 to 43.6.223.25443.6.223.2554,094
11143.6.224.0/2043.6.224.1 to 43.6.239.25443.6.239.2554,094
11243.6.240.0/2043.6.240.1 to 43.6.255.25443.6.255.2554,094
11343.7.0.0/2043.7.0.1 to 43.7.15.25443.7.15.2554,094
11443.7.16.0/2043.7.16.1 to 43.7.31.25443.7.31.2554,094
11543.7.32.0/2043.7.32.1 to 43.7.47.25443.7.47.2554,094
11643.7.48.0/2043.7.48.1 to 43.7.63.25443.7.63.2554,094
11743.7.64.0/2043.7.64.1 to 43.7.79.25443.7.79.2554,094
11843.7.80.0/2043.7.80.1 to 43.7.95.25443.7.95.2554,094
11943.7.96.0/2043.7.96.1 to 43.7.111.25443.7.111.2554,094
12043.7.112.0/2043.7.112.1 to 43.7.127.25443.7.127.2554,094
12143.7.128.0/2043.7.128.1 to 43.7.143.25443.7.143.2554,094
12243.7.144.0/2043.7.144.1 to 43.7.159.25443.7.159.2554,094
12343.7.160.0/2043.7.160.1 to 43.7.175.25443.7.175.2554,094
12443.7.176.0/2043.7.176.1 to 43.7.191.25443.7.191.2554,094
12543.7.192.0/2043.7.192.1 to 43.7.207.25443.7.207.2554,094
12643.7.208.0/2043.7.208.1 to 43.7.223.25443.7.223.2554,094
12743.7.224.0/2043.7.224.1 to 43.7.239.25443.7.239.2554,094
12843.7.240.0/2043.7.240.1 to 43.7.255.25443.7.255.2554,094
12943.8.0.0/2043.8.0.1 to 43.8.15.25443.8.15.2554,094
13043.8.16.0/2043.8.16.1 to 43.8.31.25443.8.31.2554,094
13143.8.32.0/2043.8.32.1 to 43.8.47.25443.8.47.2554,094
13243.8.48.0/2043.8.48.1 to 43.8.63.25443.8.63.2554,094
13343.8.64.0/2043.8.64.1 to 43.8.79.25443.8.79.2554,094
13443.8.80.0/2043.8.80.1 to 43.8.95.25443.8.95.2554,094
13543.8.96.0/2043.8.96.1 to 43.8.111.25443.8.111.2554,094
13643.8.112.0/2043.8.112.1 to 43.8.127.25443.8.127.2554,094
13743.8.128.0/2043.8.128.1 to 43.8.143.25443.8.143.2554,094
13843.8.144.0/2043.8.144.1 to 43.8.159.25443.8.159.2554,094
13943.8.160.0/2043.8.160.1 to 43.8.175.25443.8.175.2554,094
14043.8.176.0/2043.8.176.1 to 43.8.191.25443.8.191.2554,094
14143.8.192.0/2043.8.192.1 to 43.8.207.25443.8.207.2554,094
14243.8.208.0/2043.8.208.1 to 43.8.223.25443.8.223.2554,094
14343.8.224.0/2043.8.224.1 to 43.8.239.25443.8.239.2554,094
14443.8.240.0/2043.8.240.1 to 43.8.255.25443.8.255.2554,094
14543.9.0.0/2043.9.0.1 to 43.9.15.25443.9.15.2554,094
14643.9.16.0/2043.9.16.1 to 43.9.31.25443.9.31.2554,094
14743.9.32.0/2043.9.32.1 to 43.9.47.25443.9.47.2554,094
14843.9.48.0/2043.9.48.1 to 43.9.63.25443.9.63.2554,094
14943.9.64.0/2043.9.64.1 to 43.9.79.25443.9.79.2554,094
15043.9.80.0/2043.9.80.1 to 43.9.95.25443.9.95.2554,094
15143.9.96.0/2043.9.96.1 to 43.9.111.25443.9.111.2554,094
15243.9.112.0/2043.9.112.1 to 43.9.127.25443.9.127.2554,094
15343.9.128.0/2043.9.128.1 to 43.9.143.25443.9.143.2554,094
15443.9.144.0/2043.9.144.1 to 43.9.159.25443.9.159.2554,094
15543.9.160.0/2043.9.160.1 to 43.9.175.25443.9.175.2554,094
15643.9.176.0/2043.9.176.1 to 43.9.191.25443.9.191.2554,094
15743.9.192.0/2043.9.192.1 to 43.9.207.25443.9.207.2554,094
15843.9.208.0/2043.9.208.1 to 43.9.223.25443.9.223.2554,094
15943.9.224.0/2043.9.224.1 to 43.9.239.25443.9.239.2554,094
16043.9.240.0/2043.9.240.1 to 43.9.255.25443.9.255.2554,094
16143.10.0.0/2043.10.0.1 to 43.10.15.25443.10.15.2554,094
16243.10.16.0/2043.10.16.1 to 43.10.31.25443.10.31.2554,094
16343.10.32.0/2043.10.32.1 to 43.10.47.25443.10.47.2554,094
16443.10.48.0/2043.10.48.1 to 43.10.63.25443.10.63.2554,094
16543.10.64.0/2043.10.64.1 to 43.10.79.25443.10.79.2554,094
16643.10.80.0/2043.10.80.1 to 43.10.95.25443.10.95.2554,094
16743.10.96.0/2043.10.96.1 to 43.10.111.25443.10.111.2554,094
16843.10.112.0/2043.10.112.1 to 43.10.127.25443.10.127.2554,094
16943.10.128.0/2043.10.128.1 to 43.10.143.25443.10.143.2554,094
17043.10.144.0/2043.10.144.1 to 43.10.159.25443.10.159.2554,094
17143.10.160.0/2043.10.160.1 to 43.10.175.25443.10.175.2554,094
17243.10.176.0/2043.10.176.1 to 43.10.191.25443.10.191.2554,094
17343.10.192.0/2043.10.192.1 to 43.10.207.25443.10.207.2554,094
17443.10.208.0/2043.10.208.1 to 43.10.223.25443.10.223.2554,094
17543.10.224.0/2043.10.224.1 to 43.10.239.25443.10.239.2554,094
17643.10.240.0/2043.10.240.1 to 43.10.255.25443.10.255.2554,094
17743.11.0.0/2043.11.0.1 to 43.11.15.25443.11.15.2554,094
17843.11.16.0/2043.11.16.1 to 43.11.31.25443.11.31.2554,094
17943.11.32.0/2043.11.32.1 to 43.11.47.25443.11.47.2554,094
18043.11.48.0/2043.11.48.1 to 43.11.63.25443.11.63.2554,094
18143.11.64.0/2043.11.64.1 to 43.11.79.25443.11.79.2554,094
18243.11.80.0/2043.11.80.1 to 43.11.95.25443.11.95.2554,094
18343.11.96.0/2043.11.96.1 to 43.11.111.25443.11.111.2554,094
18443.11.112.0/2043.11.112.1 to 43.11.127.25443.11.127.2554,094
18543.11.128.0/2043.11.128.1 to 43.11.143.25443.11.143.2554,094
18643.11.144.0/2043.11.144.1 to 43.11.159.25443.11.159.2554,094
18743.11.160.0/2043.11.160.1 to 43.11.175.25443.11.175.2554,094
18843.11.176.0/2043.11.176.1 to 43.11.191.25443.11.191.2554,094
18943.11.192.0/2043.11.192.1 to 43.11.207.25443.11.207.2554,094
19043.11.208.0/2043.11.208.1 to 43.11.223.25443.11.223.2554,094
19143.11.224.0/2043.11.224.1 to 43.11.239.25443.11.239.2554,094
19243.11.240.0/2043.11.240.1 to 43.11.255.25443.11.255.2554,094
19343.12.0.0/2043.12.0.1 to 43.12.15.25443.12.15.2554,094
19443.12.16.0/2043.12.16.1 to 43.12.31.25443.12.31.2554,094
19543.12.32.0/2043.12.32.1 to 43.12.47.25443.12.47.2554,094
19643.12.48.0/2043.12.48.1 to 43.12.63.25443.12.63.2554,094
19743.12.64.0/2043.12.64.1 to 43.12.79.25443.12.79.2554,094
19843.12.80.0/2043.12.80.1 to 43.12.95.25443.12.95.2554,094
19943.12.96.0/2043.12.96.1 to 43.12.111.25443.12.111.2554,094
20043.12.112.0/2043.12.112.1 to 43.12.127.25443.12.127.2554,094
20143.12.128.0/2043.12.128.1 to 43.12.143.25443.12.143.2554,094
20243.12.144.0/2043.12.144.1 to 43.12.159.25443.12.159.2554,094
20343.12.160.0/2043.12.160.1 to 43.12.175.25443.12.175.2554,094
20443.12.176.0/2043.12.176.1 to 43.12.191.25443.12.191.2554,094
20543.12.192.0/2043.12.192.1 to 43.12.207.25443.12.207.2554,094
20643.12.208.0/2043.12.208.1 to 43.12.223.25443.12.223.2554,094
20743.12.224.0/2043.12.224.1 to 43.12.239.25443.12.239.2554,094
20843.12.240.0/2043.12.240.1 to 43.12.255.25443.12.255.2554,094
20943.13.0.0/2043.13.0.1 to 43.13.15.25443.13.15.2554,094
21043.13.16.0/2043.13.16.1 to 43.13.31.25443.13.31.2554,094
21143.13.32.0/2043.13.32.1 to 43.13.47.25443.13.47.2554,094
21243.13.48.0/2043.13.48.1 to 43.13.63.25443.13.63.2554,094
21343.13.64.0/2043.13.64.1 to 43.13.79.25443.13.79.2554,094
21443.13.80.0/2043.13.80.1 to 43.13.95.25443.13.95.2554,094
21543.13.96.0/2043.13.96.1 to 43.13.111.25443.13.111.2554,094
21643.13.112.0/2043.13.112.1 to 43.13.127.25443.13.127.2554,094
21743.13.128.0/2043.13.128.1 to 43.13.143.25443.13.143.2554,094
21843.13.144.0/2043.13.144.1 to 43.13.159.25443.13.159.2554,094
21943.13.160.0/2043.13.160.1 to 43.13.175.25443.13.175.2554,094
22043.13.176.0/2043.13.176.1 to 43.13.191.25443.13.191.2554,094
22143.13.192.0/2043.13.192.1 to 43.13.207.25443.13.207.2554,094
22243.13.208.0/2043.13.208.1 to 43.13.223.25443.13.223.2554,094
22343.13.224.0/2043.13.224.1 to 43.13.239.25443.13.239.2554,094
22443.13.240.0/2043.13.240.1 to 43.13.255.25443.13.255.2554,094
22543.14.0.0/2043.14.0.1 to 43.14.15.25443.14.15.2554,094
22643.14.16.0/2043.14.16.1 to 43.14.31.25443.14.31.2554,094
22743.14.32.0/2043.14.32.1 to 43.14.47.25443.14.47.2554,094
22843.14.48.0/2043.14.48.1 to 43.14.63.25443.14.63.2554,094
22943.14.64.0/2043.14.64.1 to 43.14.79.25443.14.79.2554,094
23043.14.80.0/2043.14.80.1 to 43.14.95.25443.14.95.2554,094
23143.14.96.0/2043.14.96.1 to 43.14.111.25443.14.111.2554,094
23243.14.112.0/2043.14.112.1 to 43.14.127.25443.14.127.2554,094
23343.14.128.0/2043.14.128.1 to 43.14.143.25443.14.143.2554,094
23443.14.144.0/2043.14.144.1 to 43.14.159.25443.14.159.2554,094
23543.14.160.0/2043.14.160.1 to 43.14.175.25443.14.175.2554,094
23643.14.176.0/2043.14.176.1 to 43.14.191.25443.14.191.2554,094
23743.14.192.0/2043.14.192.1 to 43.14.207.25443.14.207.2554,094
23843.14.208.0/2043.14.208.1 to 43.14.223.25443.14.223.2554,094
23943.14.224.0/2043.14.224.1 to 43.14.239.25443.14.239.2554,094
24043.14.240.0/2043.14.240.1 to 43.14.255.25443.14.255.2554,094
24143.15.0.0/2043.15.0.1 to 43.15.15.25443.15.15.2554,094
24243.15.16.0/2043.15.16.1 to 43.15.31.25443.15.31.2554,094
24343.15.32.0/2043.15.32.1 to 43.15.47.25443.15.47.2554,094
24443.15.48.0/2043.15.48.1 to 43.15.63.25443.15.63.2554,094
24543.15.64.0/2043.15.64.1 to 43.15.79.25443.15.79.2554,094
24643.15.80.0/2043.15.80.1 to 43.15.95.25443.15.95.2554,094
24743.15.96.0/2043.15.96.1 to 43.15.111.25443.15.111.2554,094
24843.15.112.0/2043.15.112.1 to 43.15.127.25443.15.127.2554,094
24943.15.128.0/2043.15.128.1 to 43.15.143.25443.15.143.2554,094
25043.15.144.0/2043.15.144.1 to 43.15.159.25443.15.159.2554,094
25143.15.160.0/2043.15.160.1 to 43.15.175.25443.15.175.2554,094
25243.15.176.0/2043.15.176.1 to 43.15.191.25443.15.191.2554,094
25343.15.192.0/2043.15.192.1 to 43.15.207.25443.15.207.2554,094
25443.15.208.0/2043.15.208.1 to 43.15.223.25443.15.223.2554,094
25543.15.224.0/2043.15.224.1 to 43.15.239.25443.15.239.2554,094
25643.15.240.0/2043.15.240.1 to 43.15.255.25443.15.255.2554,094

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.