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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.

Network74.178.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
74.178.0.0
Broadcast address
74.179.255.255
First usable
74.178.0.1
Last usable
74.179.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 4AB20000 · Integer 1253179392 to 1253310463
Reverse DNS zones
178.74.in-addr.arpa
179.74.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001010.10110010.00000000.0000000074.178.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01001010.10110010.00000000.0000000074.178.0.0
Broadcast01001010.10110011.11111111.1111111174.179.255.255
Split into smaller subnets/27
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

74.178.0.0/15 makes 4,096 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
174.178.0.0/2774.178.0.1 to 74.178.0.3074.178.0.3130
274.178.0.32/2774.178.0.33 to 74.178.0.6274.178.0.6330
374.178.0.64/2774.178.0.65 to 74.178.0.9474.178.0.9530
474.178.0.96/2774.178.0.97 to 74.178.0.12674.178.0.12730
574.178.0.128/2774.178.0.129 to 74.178.0.15874.178.0.15930
674.178.0.160/2774.178.0.161 to 74.178.0.19074.178.0.19130
774.178.0.192/2774.178.0.193 to 74.178.0.22274.178.0.22330
874.178.0.224/2774.178.0.225 to 74.178.0.25474.178.0.25530
974.178.1.0/2774.178.1.1 to 74.178.1.3074.178.1.3130
1074.178.1.32/2774.178.1.33 to 74.178.1.6274.178.1.6330
1174.178.1.64/2774.178.1.65 to 74.178.1.9474.178.1.9530
1274.178.1.96/2774.178.1.97 to 74.178.1.12674.178.1.12730
1374.178.1.128/2774.178.1.129 to 74.178.1.15874.178.1.15930
1474.178.1.160/2774.178.1.161 to 74.178.1.19074.178.1.19130
1574.178.1.192/2774.178.1.193 to 74.178.1.22274.178.1.22330
1674.178.1.224/2774.178.1.225 to 74.178.1.25474.178.1.25530
1774.178.2.0/2774.178.2.1 to 74.178.2.3074.178.2.3130
1874.178.2.32/2774.178.2.33 to 74.178.2.6274.178.2.6330
1974.178.2.64/2774.178.2.65 to 74.178.2.9474.178.2.9530
2074.178.2.96/2774.178.2.97 to 74.178.2.12674.178.2.12730
2174.178.2.128/2774.178.2.129 to 74.178.2.15874.178.2.15930
2274.178.2.160/2774.178.2.161 to 74.178.2.19074.178.2.19130
2374.178.2.192/2774.178.2.193 to 74.178.2.22274.178.2.22330
2474.178.2.224/2774.178.2.225 to 74.178.2.25474.178.2.25530
2574.178.3.0/2774.178.3.1 to 74.178.3.3074.178.3.3130
2674.178.3.32/2774.178.3.33 to 74.178.3.6274.178.3.6330
2774.178.3.64/2774.178.3.65 to 74.178.3.9474.178.3.9530
2874.178.3.96/2774.178.3.97 to 74.178.3.12674.178.3.12730
2974.178.3.128/2774.178.3.129 to 74.178.3.15874.178.3.15930
3074.178.3.160/2774.178.3.161 to 74.178.3.19074.178.3.19130
3174.178.3.192/2774.178.3.193 to 74.178.3.22274.178.3.22330
3274.178.3.224/2774.178.3.225 to 74.178.3.25474.178.3.25530
3374.178.4.0/2774.178.4.1 to 74.178.4.3074.178.4.3130
3474.178.4.32/2774.178.4.33 to 74.178.4.6274.178.4.6330
3574.178.4.64/2774.178.4.65 to 74.178.4.9474.178.4.9530
3674.178.4.96/2774.178.4.97 to 74.178.4.12674.178.4.12730
3774.178.4.128/2774.178.4.129 to 74.178.4.15874.178.4.15930
3874.178.4.160/2774.178.4.161 to 74.178.4.19074.178.4.19130
3974.178.4.192/2774.178.4.193 to 74.178.4.22274.178.4.22330
4074.178.4.224/2774.178.4.225 to 74.178.4.25474.178.4.25530
4174.178.5.0/2774.178.5.1 to 74.178.5.3074.178.5.3130
4274.178.5.32/2774.178.5.33 to 74.178.5.6274.178.5.6330
4374.178.5.64/2774.178.5.65 to 74.178.5.9474.178.5.9530
4474.178.5.96/2774.178.5.97 to 74.178.5.12674.178.5.12730
4574.178.5.128/2774.178.5.129 to 74.178.5.15874.178.5.15930
4674.178.5.160/2774.178.5.161 to 74.178.5.19074.178.5.19130
4774.178.5.192/2774.178.5.193 to 74.178.5.22274.178.5.22330
4874.178.5.224/2774.178.5.225 to 74.178.5.25474.178.5.25530
4974.178.6.0/2774.178.6.1 to 74.178.6.3074.178.6.3130
5074.178.6.32/2774.178.6.33 to 74.178.6.6274.178.6.6330
5174.178.6.64/2774.178.6.65 to 74.178.6.9474.178.6.9530
5274.178.6.96/2774.178.6.97 to 74.178.6.12674.178.6.12730
5374.178.6.128/2774.178.6.129 to 74.178.6.15874.178.6.15930
5474.178.6.160/2774.178.6.161 to 74.178.6.19074.178.6.19130
5574.178.6.192/2774.178.6.193 to 74.178.6.22274.178.6.22330
5674.178.6.224/2774.178.6.225 to 74.178.6.25474.178.6.25530
5774.178.7.0/2774.178.7.1 to 74.178.7.3074.178.7.3130
5874.178.7.32/2774.178.7.33 to 74.178.7.6274.178.7.6330
5974.178.7.64/2774.178.7.65 to 74.178.7.9474.178.7.9530
6074.178.7.96/2774.178.7.97 to 74.178.7.12674.178.7.12730
6174.178.7.128/2774.178.7.129 to 74.178.7.15874.178.7.15930
6274.178.7.160/2774.178.7.161 to 74.178.7.19074.178.7.19130
6374.178.7.192/2774.178.7.193 to 74.178.7.22274.178.7.22330
6474.178.7.224/2774.178.7.225 to 74.178.7.25474.178.7.25530
6574.178.8.0/2774.178.8.1 to 74.178.8.3074.178.8.3130
6674.178.8.32/2774.178.8.33 to 74.178.8.6274.178.8.6330
6774.178.8.64/2774.178.8.65 to 74.178.8.9474.178.8.9530
6874.178.8.96/2774.178.8.97 to 74.178.8.12674.178.8.12730
6974.178.8.128/2774.178.8.129 to 74.178.8.15874.178.8.15930
7074.178.8.160/2774.178.8.161 to 74.178.8.19074.178.8.19130
7174.178.8.192/2774.178.8.193 to 74.178.8.22274.178.8.22330
7274.178.8.224/2774.178.8.225 to 74.178.8.25474.178.8.25530
7374.178.9.0/2774.178.9.1 to 74.178.9.3074.178.9.3130
7474.178.9.32/2774.178.9.33 to 74.178.9.6274.178.9.6330
7574.178.9.64/2774.178.9.65 to 74.178.9.9474.178.9.9530
7674.178.9.96/2774.178.9.97 to 74.178.9.12674.178.9.12730
7774.178.9.128/2774.178.9.129 to 74.178.9.15874.178.9.15930
7874.178.9.160/2774.178.9.161 to 74.178.9.19074.178.9.19130
7974.178.9.192/2774.178.9.193 to 74.178.9.22274.178.9.22330
8074.178.9.224/2774.178.9.225 to 74.178.9.25474.178.9.25530
8174.178.10.0/2774.178.10.1 to 74.178.10.3074.178.10.3130
8274.178.10.32/2774.178.10.33 to 74.178.10.6274.178.10.6330
8374.178.10.64/2774.178.10.65 to 74.178.10.9474.178.10.9530
8474.178.10.96/2774.178.10.97 to 74.178.10.12674.178.10.12730
8574.178.10.128/2774.178.10.129 to 74.178.10.15874.178.10.15930
8674.178.10.160/2774.178.10.161 to 74.178.10.19074.178.10.19130
8774.178.10.192/2774.178.10.193 to 74.178.10.22274.178.10.22330
8874.178.10.224/2774.178.10.225 to 74.178.10.25474.178.10.25530
8974.178.11.0/2774.178.11.1 to 74.178.11.3074.178.11.3130
9074.178.11.32/2774.178.11.33 to 74.178.11.6274.178.11.6330
9174.178.11.64/2774.178.11.65 to 74.178.11.9474.178.11.9530
9274.178.11.96/2774.178.11.97 to 74.178.11.12674.178.11.12730
9374.178.11.128/2774.178.11.129 to 74.178.11.15874.178.11.15930
9474.178.11.160/2774.178.11.161 to 74.178.11.19074.178.11.19130
9574.178.11.192/2774.178.11.193 to 74.178.11.22274.178.11.22330
9674.178.11.224/2774.178.11.225 to 74.178.11.25474.178.11.25530
9774.178.12.0/2774.178.12.1 to 74.178.12.3074.178.12.3130
9874.178.12.32/2774.178.12.33 to 74.178.12.6274.178.12.6330
9974.178.12.64/2774.178.12.65 to 74.178.12.9474.178.12.9530
10074.178.12.96/2774.178.12.97 to 74.178.12.12674.178.12.12730
10174.178.12.128/2774.178.12.129 to 74.178.12.15874.178.12.15930
10274.178.12.160/2774.178.12.161 to 74.178.12.19074.178.12.19130
10374.178.12.192/2774.178.12.193 to 74.178.12.22274.178.12.22330
10474.178.12.224/2774.178.12.225 to 74.178.12.25474.178.12.25530
10574.178.13.0/2774.178.13.1 to 74.178.13.3074.178.13.3130
10674.178.13.32/2774.178.13.33 to 74.178.13.6274.178.13.6330
10774.178.13.64/2774.178.13.65 to 74.178.13.9474.178.13.9530
10874.178.13.96/2774.178.13.97 to 74.178.13.12674.178.13.12730
10974.178.13.128/2774.178.13.129 to 74.178.13.15874.178.13.15930
11074.178.13.160/2774.178.13.161 to 74.178.13.19074.178.13.19130
11174.178.13.192/2774.178.13.193 to 74.178.13.22274.178.13.22330
11274.178.13.224/2774.178.13.225 to 74.178.13.25474.178.13.25530
11374.178.14.0/2774.178.14.1 to 74.178.14.3074.178.14.3130
11474.178.14.32/2774.178.14.33 to 74.178.14.6274.178.14.6330
11574.178.14.64/2774.178.14.65 to 74.178.14.9474.178.14.9530
11674.178.14.96/2774.178.14.97 to 74.178.14.12674.178.14.12730
11774.178.14.128/2774.178.14.129 to 74.178.14.15874.178.14.15930
11874.178.14.160/2774.178.14.161 to 74.178.14.19074.178.14.19130
11974.178.14.192/2774.178.14.193 to 74.178.14.22274.178.14.22330
12074.178.14.224/2774.178.14.225 to 74.178.14.25474.178.14.25530
12174.178.15.0/2774.178.15.1 to 74.178.15.3074.178.15.3130
12274.178.15.32/2774.178.15.33 to 74.178.15.6274.178.15.6330
12374.178.15.64/2774.178.15.65 to 74.178.15.9474.178.15.9530
12474.178.15.96/2774.178.15.97 to 74.178.15.12674.178.15.12730
12574.178.15.128/2774.178.15.129 to 74.178.15.15874.178.15.15930
12674.178.15.160/2774.178.15.161 to 74.178.15.19074.178.15.19130
12774.178.15.192/2774.178.15.193 to 74.178.15.22274.178.15.22330
12874.178.15.224/2774.178.15.225 to 74.178.15.25474.178.15.25530
12974.178.16.0/2774.178.16.1 to 74.178.16.3074.178.16.3130
13074.178.16.32/2774.178.16.33 to 74.178.16.6274.178.16.6330
13174.178.16.64/2774.178.16.65 to 74.178.16.9474.178.16.9530
13274.178.16.96/2774.178.16.97 to 74.178.16.12674.178.16.12730
13374.178.16.128/2774.178.16.129 to 74.178.16.15874.178.16.15930
13474.178.16.160/2774.178.16.161 to 74.178.16.19074.178.16.19130
13574.178.16.192/2774.178.16.193 to 74.178.16.22274.178.16.22330
13674.178.16.224/2774.178.16.225 to 74.178.16.25474.178.16.25530
13774.178.17.0/2774.178.17.1 to 74.178.17.3074.178.17.3130
13874.178.17.32/2774.178.17.33 to 74.178.17.6274.178.17.6330
13974.178.17.64/2774.178.17.65 to 74.178.17.9474.178.17.9530
14074.178.17.96/2774.178.17.97 to 74.178.17.12674.178.17.12730
14174.178.17.128/2774.178.17.129 to 74.178.17.15874.178.17.15930
14274.178.17.160/2774.178.17.161 to 74.178.17.19074.178.17.19130
14374.178.17.192/2774.178.17.193 to 74.178.17.22274.178.17.22330
14474.178.17.224/2774.178.17.225 to 74.178.17.25474.178.17.25530
14574.178.18.0/2774.178.18.1 to 74.178.18.3074.178.18.3130
14674.178.18.32/2774.178.18.33 to 74.178.18.6274.178.18.6330
14774.178.18.64/2774.178.18.65 to 74.178.18.9474.178.18.9530
14874.178.18.96/2774.178.18.97 to 74.178.18.12674.178.18.12730
14974.178.18.128/2774.178.18.129 to 74.178.18.15874.178.18.15930
15074.178.18.160/2774.178.18.161 to 74.178.18.19074.178.18.19130
15174.178.18.192/2774.178.18.193 to 74.178.18.22274.178.18.22330
15274.178.18.224/2774.178.18.225 to 74.178.18.25474.178.18.25530
15374.178.19.0/2774.178.19.1 to 74.178.19.3074.178.19.3130
15474.178.19.32/2774.178.19.33 to 74.178.19.6274.178.19.6330
15574.178.19.64/2774.178.19.65 to 74.178.19.9474.178.19.9530
15674.178.19.96/2774.178.19.97 to 74.178.19.12674.178.19.12730
15774.178.19.128/2774.178.19.129 to 74.178.19.15874.178.19.15930
15874.178.19.160/2774.178.19.161 to 74.178.19.19074.178.19.19130
15974.178.19.192/2774.178.19.193 to 74.178.19.22274.178.19.22330
16074.178.19.224/2774.178.19.225 to 74.178.19.25474.178.19.25530
16174.178.20.0/2774.178.20.1 to 74.178.20.3074.178.20.3130
16274.178.20.32/2774.178.20.33 to 74.178.20.6274.178.20.6330
16374.178.20.64/2774.178.20.65 to 74.178.20.9474.178.20.9530
16474.178.20.96/2774.178.20.97 to 74.178.20.12674.178.20.12730
16574.178.20.128/2774.178.20.129 to 74.178.20.15874.178.20.15930
16674.178.20.160/2774.178.20.161 to 74.178.20.19074.178.20.19130
16774.178.20.192/2774.178.20.193 to 74.178.20.22274.178.20.22330
16874.178.20.224/2774.178.20.225 to 74.178.20.25474.178.20.25530
16974.178.21.0/2774.178.21.1 to 74.178.21.3074.178.21.3130
17074.178.21.32/2774.178.21.33 to 74.178.21.6274.178.21.6330
17174.178.21.64/2774.178.21.65 to 74.178.21.9474.178.21.9530
17274.178.21.96/2774.178.21.97 to 74.178.21.12674.178.21.12730
17374.178.21.128/2774.178.21.129 to 74.178.21.15874.178.21.15930
17474.178.21.160/2774.178.21.161 to 74.178.21.19074.178.21.19130
17574.178.21.192/2774.178.21.193 to 74.178.21.22274.178.21.22330
17674.178.21.224/2774.178.21.225 to 74.178.21.25474.178.21.25530
17774.178.22.0/2774.178.22.1 to 74.178.22.3074.178.22.3130
17874.178.22.32/2774.178.22.33 to 74.178.22.6274.178.22.6330
17974.178.22.64/2774.178.22.65 to 74.178.22.9474.178.22.9530
18074.178.22.96/2774.178.22.97 to 74.178.22.12674.178.22.12730
18174.178.22.128/2774.178.22.129 to 74.178.22.15874.178.22.15930
18274.178.22.160/2774.178.22.161 to 74.178.22.19074.178.22.19130
18374.178.22.192/2774.178.22.193 to 74.178.22.22274.178.22.22330
18474.178.22.224/2774.178.22.225 to 74.178.22.25474.178.22.25530
18574.178.23.0/2774.178.23.1 to 74.178.23.3074.178.23.3130
18674.178.23.32/2774.178.23.33 to 74.178.23.6274.178.23.6330
18774.178.23.64/2774.178.23.65 to 74.178.23.9474.178.23.9530
18874.178.23.96/2774.178.23.97 to 74.178.23.12674.178.23.12730
18974.178.23.128/2774.178.23.129 to 74.178.23.15874.178.23.15930
19074.178.23.160/2774.178.23.161 to 74.178.23.19074.178.23.19130
19174.178.23.192/2774.178.23.193 to 74.178.23.22274.178.23.22330
19274.178.23.224/2774.178.23.225 to 74.178.23.25474.178.23.25530
19374.178.24.0/2774.178.24.1 to 74.178.24.3074.178.24.3130
19474.178.24.32/2774.178.24.33 to 74.178.24.6274.178.24.6330
19574.178.24.64/2774.178.24.65 to 74.178.24.9474.178.24.9530
19674.178.24.96/2774.178.24.97 to 74.178.24.12674.178.24.12730
19774.178.24.128/2774.178.24.129 to 74.178.24.15874.178.24.15930
19874.178.24.160/2774.178.24.161 to 74.178.24.19074.178.24.19130
19974.178.24.192/2774.178.24.193 to 74.178.24.22274.178.24.22330
20074.178.24.224/2774.178.24.225 to 74.178.24.25474.178.24.25530
20174.178.25.0/2774.178.25.1 to 74.178.25.3074.178.25.3130
20274.178.25.32/2774.178.25.33 to 74.178.25.6274.178.25.6330
20374.178.25.64/2774.178.25.65 to 74.178.25.9474.178.25.9530
20474.178.25.96/2774.178.25.97 to 74.178.25.12674.178.25.12730
20574.178.25.128/2774.178.25.129 to 74.178.25.15874.178.25.15930
20674.178.25.160/2774.178.25.161 to 74.178.25.19074.178.25.19130
20774.178.25.192/2774.178.25.193 to 74.178.25.22274.178.25.22330
20874.178.25.224/2774.178.25.225 to 74.178.25.25474.178.25.25530
20974.178.26.0/2774.178.26.1 to 74.178.26.3074.178.26.3130
21074.178.26.32/2774.178.26.33 to 74.178.26.6274.178.26.6330
21174.178.26.64/2774.178.26.65 to 74.178.26.9474.178.26.9530
21274.178.26.96/2774.178.26.97 to 74.178.26.12674.178.26.12730
21374.178.26.128/2774.178.26.129 to 74.178.26.15874.178.26.15930
21474.178.26.160/2774.178.26.161 to 74.178.26.19074.178.26.19130
21574.178.26.192/2774.178.26.193 to 74.178.26.22274.178.26.22330
21674.178.26.224/2774.178.26.225 to 74.178.26.25474.178.26.25530
21774.178.27.0/2774.178.27.1 to 74.178.27.3074.178.27.3130
21874.178.27.32/2774.178.27.33 to 74.178.27.6274.178.27.6330
21974.178.27.64/2774.178.27.65 to 74.178.27.9474.178.27.9530
22074.178.27.96/2774.178.27.97 to 74.178.27.12674.178.27.12730
22174.178.27.128/2774.178.27.129 to 74.178.27.15874.178.27.15930
22274.178.27.160/2774.178.27.161 to 74.178.27.19074.178.27.19130
22374.178.27.192/2774.178.27.193 to 74.178.27.22274.178.27.22330
22474.178.27.224/2774.178.27.225 to 74.178.27.25474.178.27.25530
22574.178.28.0/2774.178.28.1 to 74.178.28.3074.178.28.3130
22674.178.28.32/2774.178.28.33 to 74.178.28.6274.178.28.6330
22774.178.28.64/2774.178.28.65 to 74.178.28.9474.178.28.9530
22874.178.28.96/2774.178.28.97 to 74.178.28.12674.178.28.12730
22974.178.28.128/2774.178.28.129 to 74.178.28.15874.178.28.15930
23074.178.28.160/2774.178.28.161 to 74.178.28.19074.178.28.19130
23174.178.28.192/2774.178.28.193 to 74.178.28.22274.178.28.22330
23274.178.28.224/2774.178.28.225 to 74.178.28.25474.178.28.25530
23374.178.29.0/2774.178.29.1 to 74.178.29.3074.178.29.3130
23474.178.29.32/2774.178.29.33 to 74.178.29.6274.178.29.6330
23574.178.29.64/2774.178.29.65 to 74.178.29.9474.178.29.9530
23674.178.29.96/2774.178.29.97 to 74.178.29.12674.178.29.12730
23774.178.29.128/2774.178.29.129 to 74.178.29.15874.178.29.15930
23874.178.29.160/2774.178.29.161 to 74.178.29.19074.178.29.19130
23974.178.29.192/2774.178.29.193 to 74.178.29.22274.178.29.22330
24074.178.29.224/2774.178.29.225 to 74.178.29.25474.178.29.25530
24174.178.30.0/2774.178.30.1 to 74.178.30.3074.178.30.3130
24274.178.30.32/2774.178.30.33 to 74.178.30.6274.178.30.6330
24374.178.30.64/2774.178.30.65 to 74.178.30.9474.178.30.9530
24474.178.30.96/2774.178.30.97 to 74.178.30.12674.178.30.12730
24574.178.30.128/2774.178.30.129 to 74.178.30.15874.178.30.15930
24674.178.30.160/2774.178.30.161 to 74.178.30.19074.178.30.19130
24774.178.30.192/2774.178.30.193 to 74.178.30.22274.178.30.22330
24874.178.30.224/2774.178.30.225 to 74.178.30.25474.178.30.25530
24974.178.31.0/2774.178.31.1 to 74.178.31.3074.178.31.3130
25074.178.31.32/2774.178.31.33 to 74.178.31.6274.178.31.6330
25174.178.31.64/2774.178.31.65 to 74.178.31.9474.178.31.9530
25274.178.31.96/2774.178.31.97 to 74.178.31.12674.178.31.12730
25374.178.31.128/2774.178.31.129 to 74.178.31.15874.178.31.15930
25474.178.31.160/2774.178.31.161 to 74.178.31.19074.178.31.19130
25574.178.31.192/2774.178.31.193 to 74.178.31.22274.178.31.22330
25674.178.31.224/2774.178.31.225 to 74.178.31.25474.178.31.25530

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.