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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.

Network74.3.192.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
74.3.192.0
Broadcast address
74.3.223.255
First usable
74.3.192.1
Last usable
74.3.223.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 4A03C000 · Integer 1241759744 to 1241767935
Reverse DNS zones
192.3.74.in-addr.arpa
193.3.74.in-addr.arpa
194.3.74.in-addr.arpa
195.3.74.in-addr.arpa
196.3.74.in-addr.arpa
197.3.74.in-addr.arpa
198.3.74.in-addr.arpa
199.3.74.in-addr.arpa
200.3.74.in-addr.arpa
201.3.74.in-addr.arpa
202.3.74.in-addr.arpa
203.3.74.in-addr.arpa
204.3.74.in-addr.arpa
205.3.74.in-addr.arpa
206.3.74.in-addr.arpa
207.3.74.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001010.00000011.11000000.0000000074.3.192.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01001010.00000011.11000000.0000000074.3.192.0
Broadcast01001010.00000011.11011111.1111111174.3.223.255
Split into smaller subnets/30
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

74.3.192.0/19 makes 2,048 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
174.3.192.0/3074.3.192.1 to 74.3.192.274.3.192.32
274.3.192.4/3074.3.192.5 to 74.3.192.674.3.192.72
374.3.192.8/3074.3.192.9 to 74.3.192.1074.3.192.112
474.3.192.12/3074.3.192.13 to 74.3.192.1474.3.192.152
574.3.192.16/3074.3.192.17 to 74.3.192.1874.3.192.192
674.3.192.20/3074.3.192.21 to 74.3.192.2274.3.192.232
774.3.192.24/3074.3.192.25 to 74.3.192.2674.3.192.272
874.3.192.28/3074.3.192.29 to 74.3.192.3074.3.192.312
974.3.192.32/3074.3.192.33 to 74.3.192.3474.3.192.352
1074.3.192.36/3074.3.192.37 to 74.3.192.3874.3.192.392
1174.3.192.40/3074.3.192.41 to 74.3.192.4274.3.192.432
1274.3.192.44/3074.3.192.45 to 74.3.192.4674.3.192.472
1374.3.192.48/3074.3.192.49 to 74.3.192.5074.3.192.512
1474.3.192.52/3074.3.192.53 to 74.3.192.5474.3.192.552
1574.3.192.56/3074.3.192.57 to 74.3.192.5874.3.192.592
1674.3.192.60/3074.3.192.61 to 74.3.192.6274.3.192.632
1774.3.192.64/3074.3.192.65 to 74.3.192.6674.3.192.672
1874.3.192.68/3074.3.192.69 to 74.3.192.7074.3.192.712
1974.3.192.72/3074.3.192.73 to 74.3.192.7474.3.192.752
2074.3.192.76/3074.3.192.77 to 74.3.192.7874.3.192.792
2174.3.192.80/3074.3.192.81 to 74.3.192.8274.3.192.832
2274.3.192.84/3074.3.192.85 to 74.3.192.8674.3.192.872
2374.3.192.88/3074.3.192.89 to 74.3.192.9074.3.192.912
2474.3.192.92/3074.3.192.93 to 74.3.192.9474.3.192.952
2574.3.192.96/3074.3.192.97 to 74.3.192.9874.3.192.992
2674.3.192.100/3074.3.192.101 to 74.3.192.10274.3.192.1032
2774.3.192.104/3074.3.192.105 to 74.3.192.10674.3.192.1072
2874.3.192.108/3074.3.192.109 to 74.3.192.11074.3.192.1112
2974.3.192.112/3074.3.192.113 to 74.3.192.11474.3.192.1152
3074.3.192.116/3074.3.192.117 to 74.3.192.11874.3.192.1192
3174.3.192.120/3074.3.192.121 to 74.3.192.12274.3.192.1232
3274.3.192.124/3074.3.192.125 to 74.3.192.12674.3.192.1272
3374.3.192.128/3074.3.192.129 to 74.3.192.13074.3.192.1312
3474.3.192.132/3074.3.192.133 to 74.3.192.13474.3.192.1352
3574.3.192.136/3074.3.192.137 to 74.3.192.13874.3.192.1392
3674.3.192.140/3074.3.192.141 to 74.3.192.14274.3.192.1432
3774.3.192.144/3074.3.192.145 to 74.3.192.14674.3.192.1472
3874.3.192.148/3074.3.192.149 to 74.3.192.15074.3.192.1512
3974.3.192.152/3074.3.192.153 to 74.3.192.15474.3.192.1552
4074.3.192.156/3074.3.192.157 to 74.3.192.15874.3.192.1592
4174.3.192.160/3074.3.192.161 to 74.3.192.16274.3.192.1632
4274.3.192.164/3074.3.192.165 to 74.3.192.16674.3.192.1672
4374.3.192.168/3074.3.192.169 to 74.3.192.17074.3.192.1712
4474.3.192.172/3074.3.192.173 to 74.3.192.17474.3.192.1752
4574.3.192.176/3074.3.192.177 to 74.3.192.17874.3.192.1792
4674.3.192.180/3074.3.192.181 to 74.3.192.18274.3.192.1832
4774.3.192.184/3074.3.192.185 to 74.3.192.18674.3.192.1872
4874.3.192.188/3074.3.192.189 to 74.3.192.19074.3.192.1912
4974.3.192.192/3074.3.192.193 to 74.3.192.19474.3.192.1952
5074.3.192.196/3074.3.192.197 to 74.3.192.19874.3.192.1992
5174.3.192.200/3074.3.192.201 to 74.3.192.20274.3.192.2032
5274.3.192.204/3074.3.192.205 to 74.3.192.20674.3.192.2072
5374.3.192.208/3074.3.192.209 to 74.3.192.21074.3.192.2112
5474.3.192.212/3074.3.192.213 to 74.3.192.21474.3.192.2152
5574.3.192.216/3074.3.192.217 to 74.3.192.21874.3.192.2192
5674.3.192.220/3074.3.192.221 to 74.3.192.22274.3.192.2232
5774.3.192.224/3074.3.192.225 to 74.3.192.22674.3.192.2272
5874.3.192.228/3074.3.192.229 to 74.3.192.23074.3.192.2312
5974.3.192.232/3074.3.192.233 to 74.3.192.23474.3.192.2352
6074.3.192.236/3074.3.192.237 to 74.3.192.23874.3.192.2392
6174.3.192.240/3074.3.192.241 to 74.3.192.24274.3.192.2432
6274.3.192.244/3074.3.192.245 to 74.3.192.24674.3.192.2472
6374.3.192.248/3074.3.192.249 to 74.3.192.25074.3.192.2512
6474.3.192.252/3074.3.192.253 to 74.3.192.25474.3.192.2552
6574.3.193.0/3074.3.193.1 to 74.3.193.274.3.193.32
6674.3.193.4/3074.3.193.5 to 74.3.193.674.3.193.72
6774.3.193.8/3074.3.193.9 to 74.3.193.1074.3.193.112
6874.3.193.12/3074.3.193.13 to 74.3.193.1474.3.193.152
6974.3.193.16/3074.3.193.17 to 74.3.193.1874.3.193.192
7074.3.193.20/3074.3.193.21 to 74.3.193.2274.3.193.232
7174.3.193.24/3074.3.193.25 to 74.3.193.2674.3.193.272
7274.3.193.28/3074.3.193.29 to 74.3.193.3074.3.193.312
7374.3.193.32/3074.3.193.33 to 74.3.193.3474.3.193.352
7474.3.193.36/3074.3.193.37 to 74.3.193.3874.3.193.392
7574.3.193.40/3074.3.193.41 to 74.3.193.4274.3.193.432
7674.3.193.44/3074.3.193.45 to 74.3.193.4674.3.193.472
7774.3.193.48/3074.3.193.49 to 74.3.193.5074.3.193.512
7874.3.193.52/3074.3.193.53 to 74.3.193.5474.3.193.552
7974.3.193.56/3074.3.193.57 to 74.3.193.5874.3.193.592
8074.3.193.60/3074.3.193.61 to 74.3.193.6274.3.193.632
8174.3.193.64/3074.3.193.65 to 74.3.193.6674.3.193.672
8274.3.193.68/3074.3.193.69 to 74.3.193.7074.3.193.712
8374.3.193.72/3074.3.193.73 to 74.3.193.7474.3.193.752
8474.3.193.76/3074.3.193.77 to 74.3.193.7874.3.193.792
8574.3.193.80/3074.3.193.81 to 74.3.193.8274.3.193.832
8674.3.193.84/3074.3.193.85 to 74.3.193.8674.3.193.872
8774.3.193.88/3074.3.193.89 to 74.3.193.9074.3.193.912
8874.3.193.92/3074.3.193.93 to 74.3.193.9474.3.193.952
8974.3.193.96/3074.3.193.97 to 74.3.193.9874.3.193.992
9074.3.193.100/3074.3.193.101 to 74.3.193.10274.3.193.1032
9174.3.193.104/3074.3.193.105 to 74.3.193.10674.3.193.1072
9274.3.193.108/3074.3.193.109 to 74.3.193.11074.3.193.1112
9374.3.193.112/3074.3.193.113 to 74.3.193.11474.3.193.1152
9474.3.193.116/3074.3.193.117 to 74.3.193.11874.3.193.1192
9574.3.193.120/3074.3.193.121 to 74.3.193.12274.3.193.1232
9674.3.193.124/3074.3.193.125 to 74.3.193.12674.3.193.1272
9774.3.193.128/3074.3.193.129 to 74.3.193.13074.3.193.1312
9874.3.193.132/3074.3.193.133 to 74.3.193.13474.3.193.1352
9974.3.193.136/3074.3.193.137 to 74.3.193.13874.3.193.1392
10074.3.193.140/3074.3.193.141 to 74.3.193.14274.3.193.1432
10174.3.193.144/3074.3.193.145 to 74.3.193.14674.3.193.1472
10274.3.193.148/3074.3.193.149 to 74.3.193.15074.3.193.1512
10374.3.193.152/3074.3.193.153 to 74.3.193.15474.3.193.1552
10474.3.193.156/3074.3.193.157 to 74.3.193.15874.3.193.1592
10574.3.193.160/3074.3.193.161 to 74.3.193.16274.3.193.1632
10674.3.193.164/3074.3.193.165 to 74.3.193.16674.3.193.1672
10774.3.193.168/3074.3.193.169 to 74.3.193.17074.3.193.1712
10874.3.193.172/3074.3.193.173 to 74.3.193.17474.3.193.1752
10974.3.193.176/3074.3.193.177 to 74.3.193.17874.3.193.1792
11074.3.193.180/3074.3.193.181 to 74.3.193.18274.3.193.1832
11174.3.193.184/3074.3.193.185 to 74.3.193.18674.3.193.1872
11274.3.193.188/3074.3.193.189 to 74.3.193.19074.3.193.1912
11374.3.193.192/3074.3.193.193 to 74.3.193.19474.3.193.1952
11474.3.193.196/3074.3.193.197 to 74.3.193.19874.3.193.1992
11574.3.193.200/3074.3.193.201 to 74.3.193.20274.3.193.2032
11674.3.193.204/3074.3.193.205 to 74.3.193.20674.3.193.2072
11774.3.193.208/3074.3.193.209 to 74.3.193.21074.3.193.2112
11874.3.193.212/3074.3.193.213 to 74.3.193.21474.3.193.2152
11974.3.193.216/3074.3.193.217 to 74.3.193.21874.3.193.2192
12074.3.193.220/3074.3.193.221 to 74.3.193.22274.3.193.2232
12174.3.193.224/3074.3.193.225 to 74.3.193.22674.3.193.2272
12274.3.193.228/3074.3.193.229 to 74.3.193.23074.3.193.2312
12374.3.193.232/3074.3.193.233 to 74.3.193.23474.3.193.2352
12474.3.193.236/3074.3.193.237 to 74.3.193.23874.3.193.2392
12574.3.193.240/3074.3.193.241 to 74.3.193.24274.3.193.2432
12674.3.193.244/3074.3.193.245 to 74.3.193.24674.3.193.2472
12774.3.193.248/3074.3.193.249 to 74.3.193.25074.3.193.2512
12874.3.193.252/3074.3.193.253 to 74.3.193.25474.3.193.2552
12974.3.194.0/3074.3.194.1 to 74.3.194.274.3.194.32
13074.3.194.4/3074.3.194.5 to 74.3.194.674.3.194.72
13174.3.194.8/3074.3.194.9 to 74.3.194.1074.3.194.112
13274.3.194.12/3074.3.194.13 to 74.3.194.1474.3.194.152
13374.3.194.16/3074.3.194.17 to 74.3.194.1874.3.194.192
13474.3.194.20/3074.3.194.21 to 74.3.194.2274.3.194.232
13574.3.194.24/3074.3.194.25 to 74.3.194.2674.3.194.272
13674.3.194.28/3074.3.194.29 to 74.3.194.3074.3.194.312
13774.3.194.32/3074.3.194.33 to 74.3.194.3474.3.194.352
13874.3.194.36/3074.3.194.37 to 74.3.194.3874.3.194.392
13974.3.194.40/3074.3.194.41 to 74.3.194.4274.3.194.432
14074.3.194.44/3074.3.194.45 to 74.3.194.4674.3.194.472
14174.3.194.48/3074.3.194.49 to 74.3.194.5074.3.194.512
14274.3.194.52/3074.3.194.53 to 74.3.194.5474.3.194.552
14374.3.194.56/3074.3.194.57 to 74.3.194.5874.3.194.592
14474.3.194.60/3074.3.194.61 to 74.3.194.6274.3.194.632
14574.3.194.64/3074.3.194.65 to 74.3.194.6674.3.194.672
14674.3.194.68/3074.3.194.69 to 74.3.194.7074.3.194.712
14774.3.194.72/3074.3.194.73 to 74.3.194.7474.3.194.752
14874.3.194.76/3074.3.194.77 to 74.3.194.7874.3.194.792
14974.3.194.80/3074.3.194.81 to 74.3.194.8274.3.194.832
15074.3.194.84/3074.3.194.85 to 74.3.194.8674.3.194.872
15174.3.194.88/3074.3.194.89 to 74.3.194.9074.3.194.912
15274.3.194.92/3074.3.194.93 to 74.3.194.9474.3.194.952
15374.3.194.96/3074.3.194.97 to 74.3.194.9874.3.194.992
15474.3.194.100/3074.3.194.101 to 74.3.194.10274.3.194.1032
15574.3.194.104/3074.3.194.105 to 74.3.194.10674.3.194.1072
15674.3.194.108/3074.3.194.109 to 74.3.194.11074.3.194.1112
15774.3.194.112/3074.3.194.113 to 74.3.194.11474.3.194.1152
15874.3.194.116/3074.3.194.117 to 74.3.194.11874.3.194.1192
15974.3.194.120/3074.3.194.121 to 74.3.194.12274.3.194.1232
16074.3.194.124/3074.3.194.125 to 74.3.194.12674.3.194.1272
16174.3.194.128/3074.3.194.129 to 74.3.194.13074.3.194.1312
16274.3.194.132/3074.3.194.133 to 74.3.194.13474.3.194.1352
16374.3.194.136/3074.3.194.137 to 74.3.194.13874.3.194.1392
16474.3.194.140/3074.3.194.141 to 74.3.194.14274.3.194.1432
16574.3.194.144/3074.3.194.145 to 74.3.194.14674.3.194.1472
16674.3.194.148/3074.3.194.149 to 74.3.194.15074.3.194.1512
16774.3.194.152/3074.3.194.153 to 74.3.194.15474.3.194.1552
16874.3.194.156/3074.3.194.157 to 74.3.194.15874.3.194.1592
16974.3.194.160/3074.3.194.161 to 74.3.194.16274.3.194.1632
17074.3.194.164/3074.3.194.165 to 74.3.194.16674.3.194.1672
17174.3.194.168/3074.3.194.169 to 74.3.194.17074.3.194.1712
17274.3.194.172/3074.3.194.173 to 74.3.194.17474.3.194.1752
17374.3.194.176/3074.3.194.177 to 74.3.194.17874.3.194.1792
17474.3.194.180/3074.3.194.181 to 74.3.194.18274.3.194.1832
17574.3.194.184/3074.3.194.185 to 74.3.194.18674.3.194.1872
17674.3.194.188/3074.3.194.189 to 74.3.194.19074.3.194.1912
17774.3.194.192/3074.3.194.193 to 74.3.194.19474.3.194.1952
17874.3.194.196/3074.3.194.197 to 74.3.194.19874.3.194.1992
17974.3.194.200/3074.3.194.201 to 74.3.194.20274.3.194.2032
18074.3.194.204/3074.3.194.205 to 74.3.194.20674.3.194.2072
18174.3.194.208/3074.3.194.209 to 74.3.194.21074.3.194.2112
18274.3.194.212/3074.3.194.213 to 74.3.194.21474.3.194.2152
18374.3.194.216/3074.3.194.217 to 74.3.194.21874.3.194.2192
18474.3.194.220/3074.3.194.221 to 74.3.194.22274.3.194.2232
18574.3.194.224/3074.3.194.225 to 74.3.194.22674.3.194.2272
18674.3.194.228/3074.3.194.229 to 74.3.194.23074.3.194.2312
18774.3.194.232/3074.3.194.233 to 74.3.194.23474.3.194.2352
18874.3.194.236/3074.3.194.237 to 74.3.194.23874.3.194.2392
18974.3.194.240/3074.3.194.241 to 74.3.194.24274.3.194.2432
19074.3.194.244/3074.3.194.245 to 74.3.194.24674.3.194.2472
19174.3.194.248/3074.3.194.249 to 74.3.194.25074.3.194.2512
19274.3.194.252/3074.3.194.253 to 74.3.194.25474.3.194.2552
19374.3.195.0/3074.3.195.1 to 74.3.195.274.3.195.32
19474.3.195.4/3074.3.195.5 to 74.3.195.674.3.195.72
19574.3.195.8/3074.3.195.9 to 74.3.195.1074.3.195.112
19674.3.195.12/3074.3.195.13 to 74.3.195.1474.3.195.152
19774.3.195.16/3074.3.195.17 to 74.3.195.1874.3.195.192
19874.3.195.20/3074.3.195.21 to 74.3.195.2274.3.195.232
19974.3.195.24/3074.3.195.25 to 74.3.195.2674.3.195.272
20074.3.195.28/3074.3.195.29 to 74.3.195.3074.3.195.312
20174.3.195.32/3074.3.195.33 to 74.3.195.3474.3.195.352
20274.3.195.36/3074.3.195.37 to 74.3.195.3874.3.195.392
20374.3.195.40/3074.3.195.41 to 74.3.195.4274.3.195.432
20474.3.195.44/3074.3.195.45 to 74.3.195.4674.3.195.472
20574.3.195.48/3074.3.195.49 to 74.3.195.5074.3.195.512
20674.3.195.52/3074.3.195.53 to 74.3.195.5474.3.195.552
20774.3.195.56/3074.3.195.57 to 74.3.195.5874.3.195.592
20874.3.195.60/3074.3.195.61 to 74.3.195.6274.3.195.632
20974.3.195.64/3074.3.195.65 to 74.3.195.6674.3.195.672
21074.3.195.68/3074.3.195.69 to 74.3.195.7074.3.195.712
21174.3.195.72/3074.3.195.73 to 74.3.195.7474.3.195.752
21274.3.195.76/3074.3.195.77 to 74.3.195.7874.3.195.792
21374.3.195.80/3074.3.195.81 to 74.3.195.8274.3.195.832
21474.3.195.84/3074.3.195.85 to 74.3.195.8674.3.195.872
21574.3.195.88/3074.3.195.89 to 74.3.195.9074.3.195.912
21674.3.195.92/3074.3.195.93 to 74.3.195.9474.3.195.952
21774.3.195.96/3074.3.195.97 to 74.3.195.9874.3.195.992
21874.3.195.100/3074.3.195.101 to 74.3.195.10274.3.195.1032
21974.3.195.104/3074.3.195.105 to 74.3.195.10674.3.195.1072
22074.3.195.108/3074.3.195.109 to 74.3.195.11074.3.195.1112
22174.3.195.112/3074.3.195.113 to 74.3.195.11474.3.195.1152
22274.3.195.116/3074.3.195.117 to 74.3.195.11874.3.195.1192
22374.3.195.120/3074.3.195.121 to 74.3.195.12274.3.195.1232
22474.3.195.124/3074.3.195.125 to 74.3.195.12674.3.195.1272
22574.3.195.128/3074.3.195.129 to 74.3.195.13074.3.195.1312
22674.3.195.132/3074.3.195.133 to 74.3.195.13474.3.195.1352
22774.3.195.136/3074.3.195.137 to 74.3.195.13874.3.195.1392
22874.3.195.140/3074.3.195.141 to 74.3.195.14274.3.195.1432
22974.3.195.144/3074.3.195.145 to 74.3.195.14674.3.195.1472
23074.3.195.148/3074.3.195.149 to 74.3.195.15074.3.195.1512
23174.3.195.152/3074.3.195.153 to 74.3.195.15474.3.195.1552
23274.3.195.156/3074.3.195.157 to 74.3.195.15874.3.195.1592
23374.3.195.160/3074.3.195.161 to 74.3.195.16274.3.195.1632
23474.3.195.164/3074.3.195.165 to 74.3.195.16674.3.195.1672
23574.3.195.168/3074.3.195.169 to 74.3.195.17074.3.195.1712
23674.3.195.172/3074.3.195.173 to 74.3.195.17474.3.195.1752
23774.3.195.176/3074.3.195.177 to 74.3.195.17874.3.195.1792
23874.3.195.180/3074.3.195.181 to 74.3.195.18274.3.195.1832
23974.3.195.184/3074.3.195.185 to 74.3.195.18674.3.195.1872
24074.3.195.188/3074.3.195.189 to 74.3.195.19074.3.195.1912
24174.3.195.192/3074.3.195.193 to 74.3.195.19474.3.195.1952
24274.3.195.196/3074.3.195.197 to 74.3.195.19874.3.195.1992
24374.3.195.200/3074.3.195.201 to 74.3.195.20274.3.195.2032
24474.3.195.204/3074.3.195.205 to 74.3.195.20674.3.195.2072
24574.3.195.208/3074.3.195.209 to 74.3.195.21074.3.195.2112
24674.3.195.212/3074.3.195.213 to 74.3.195.21474.3.195.2152
24774.3.195.216/3074.3.195.217 to 74.3.195.21874.3.195.2192
24874.3.195.220/3074.3.195.221 to 74.3.195.22274.3.195.2232
24974.3.195.224/3074.3.195.225 to 74.3.195.22674.3.195.2272
25074.3.195.228/3074.3.195.229 to 74.3.195.23074.3.195.2312
25174.3.195.232/3074.3.195.233 to 74.3.195.23474.3.195.2352
25274.3.195.236/3074.3.195.237 to 74.3.195.23874.3.195.2392
25374.3.195.240/3074.3.195.241 to 74.3.195.24274.3.195.2432
25474.3.195.244/3074.3.195.245 to 74.3.195.24674.3.195.2472
25574.3.195.248/3074.3.195.249 to 74.3.195.25074.3.195.2512
25674.3.195.252/3074.3.195.253 to 74.3.195.25474.3.195.2552

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.