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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.

Network74.3.96.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
74.3.96.0
Broadcast address
74.3.111.255
First usable
74.3.96.1
Last usable
74.3.111.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Public public
Old class
A (default /8)
As numbers
Hex 4A036000 · Integer 1241735168 to 1241739263
Reverse DNS zones
96.3.74.in-addr.arpa
97.3.74.in-addr.arpa
98.3.74.in-addr.arpa
99.3.74.in-addr.arpa
100.3.74.in-addr.arpa
101.3.74.in-addr.arpa
102.3.74.in-addr.arpa
103.3.74.in-addr.arpa
104.3.74.in-addr.arpa
105.3.74.in-addr.arpa
106.3.74.in-addr.arpa
107.3.74.in-addr.arpa
108.3.74.in-addr.arpa
109.3.74.in-addr.arpa
110.3.74.in-addr.arpa
111.3.74.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001010.00000011.01100000.0000000074.3.96.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network01001010.00000011.01100000.0000000074.3.96.0
Broadcast01001010.00000011.01101111.1111111174.3.111.255
Split into smaller subnets/29
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

74.3.96.0/20 makes 512 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
174.3.96.0/2974.3.96.1 to 74.3.96.674.3.96.76
274.3.96.8/2974.3.96.9 to 74.3.96.1474.3.96.156
374.3.96.16/2974.3.96.17 to 74.3.96.2274.3.96.236
474.3.96.24/2974.3.96.25 to 74.3.96.3074.3.96.316
574.3.96.32/2974.3.96.33 to 74.3.96.3874.3.96.396
674.3.96.40/2974.3.96.41 to 74.3.96.4674.3.96.476
774.3.96.48/2974.3.96.49 to 74.3.96.5474.3.96.556
874.3.96.56/2974.3.96.57 to 74.3.96.6274.3.96.636
974.3.96.64/2974.3.96.65 to 74.3.96.7074.3.96.716
1074.3.96.72/2974.3.96.73 to 74.3.96.7874.3.96.796
1174.3.96.80/2974.3.96.81 to 74.3.96.8674.3.96.876
1274.3.96.88/2974.3.96.89 to 74.3.96.9474.3.96.956
1374.3.96.96/2974.3.96.97 to 74.3.96.10274.3.96.1036
1474.3.96.104/2974.3.96.105 to 74.3.96.11074.3.96.1116
1574.3.96.112/2974.3.96.113 to 74.3.96.11874.3.96.1196
1674.3.96.120/2974.3.96.121 to 74.3.96.12674.3.96.1276
1774.3.96.128/2974.3.96.129 to 74.3.96.13474.3.96.1356
1874.3.96.136/2974.3.96.137 to 74.3.96.14274.3.96.1436
1974.3.96.144/2974.3.96.145 to 74.3.96.15074.3.96.1516
2074.3.96.152/2974.3.96.153 to 74.3.96.15874.3.96.1596
2174.3.96.160/2974.3.96.161 to 74.3.96.16674.3.96.1676
2274.3.96.168/2974.3.96.169 to 74.3.96.17474.3.96.1756
2374.3.96.176/2974.3.96.177 to 74.3.96.18274.3.96.1836
2474.3.96.184/2974.3.96.185 to 74.3.96.19074.3.96.1916
2574.3.96.192/2974.3.96.193 to 74.3.96.19874.3.96.1996
2674.3.96.200/2974.3.96.201 to 74.3.96.20674.3.96.2076
2774.3.96.208/2974.3.96.209 to 74.3.96.21474.3.96.2156
2874.3.96.216/2974.3.96.217 to 74.3.96.22274.3.96.2236
2974.3.96.224/2974.3.96.225 to 74.3.96.23074.3.96.2316
3074.3.96.232/2974.3.96.233 to 74.3.96.23874.3.96.2396
3174.3.96.240/2974.3.96.241 to 74.3.96.24674.3.96.2476
3274.3.96.248/2974.3.96.249 to 74.3.96.25474.3.96.2556
3374.3.97.0/2974.3.97.1 to 74.3.97.674.3.97.76
3474.3.97.8/2974.3.97.9 to 74.3.97.1474.3.97.156
3574.3.97.16/2974.3.97.17 to 74.3.97.2274.3.97.236
3674.3.97.24/2974.3.97.25 to 74.3.97.3074.3.97.316
3774.3.97.32/2974.3.97.33 to 74.3.97.3874.3.97.396
3874.3.97.40/2974.3.97.41 to 74.3.97.4674.3.97.476
3974.3.97.48/2974.3.97.49 to 74.3.97.5474.3.97.556
4074.3.97.56/2974.3.97.57 to 74.3.97.6274.3.97.636
4174.3.97.64/2974.3.97.65 to 74.3.97.7074.3.97.716
4274.3.97.72/2974.3.97.73 to 74.3.97.7874.3.97.796
4374.3.97.80/2974.3.97.81 to 74.3.97.8674.3.97.876
4474.3.97.88/2974.3.97.89 to 74.3.97.9474.3.97.956
4574.3.97.96/2974.3.97.97 to 74.3.97.10274.3.97.1036
4674.3.97.104/2974.3.97.105 to 74.3.97.11074.3.97.1116
4774.3.97.112/2974.3.97.113 to 74.3.97.11874.3.97.1196
4874.3.97.120/2974.3.97.121 to 74.3.97.12674.3.97.1276
4974.3.97.128/2974.3.97.129 to 74.3.97.13474.3.97.1356
5074.3.97.136/2974.3.97.137 to 74.3.97.14274.3.97.1436
5174.3.97.144/2974.3.97.145 to 74.3.97.15074.3.97.1516
5274.3.97.152/2974.3.97.153 to 74.3.97.15874.3.97.1596
5374.3.97.160/2974.3.97.161 to 74.3.97.16674.3.97.1676
5474.3.97.168/2974.3.97.169 to 74.3.97.17474.3.97.1756
5574.3.97.176/2974.3.97.177 to 74.3.97.18274.3.97.1836
5674.3.97.184/2974.3.97.185 to 74.3.97.19074.3.97.1916
5774.3.97.192/2974.3.97.193 to 74.3.97.19874.3.97.1996
5874.3.97.200/2974.3.97.201 to 74.3.97.20674.3.97.2076
5974.3.97.208/2974.3.97.209 to 74.3.97.21474.3.97.2156
6074.3.97.216/2974.3.97.217 to 74.3.97.22274.3.97.2236
6174.3.97.224/2974.3.97.225 to 74.3.97.23074.3.97.2316
6274.3.97.232/2974.3.97.233 to 74.3.97.23874.3.97.2396
6374.3.97.240/2974.3.97.241 to 74.3.97.24674.3.97.2476
6474.3.97.248/2974.3.97.249 to 74.3.97.25474.3.97.2556
6574.3.98.0/2974.3.98.1 to 74.3.98.674.3.98.76
6674.3.98.8/2974.3.98.9 to 74.3.98.1474.3.98.156
6774.3.98.16/2974.3.98.17 to 74.3.98.2274.3.98.236
6874.3.98.24/2974.3.98.25 to 74.3.98.3074.3.98.316
6974.3.98.32/2974.3.98.33 to 74.3.98.3874.3.98.396
7074.3.98.40/2974.3.98.41 to 74.3.98.4674.3.98.476
7174.3.98.48/2974.3.98.49 to 74.3.98.5474.3.98.556
7274.3.98.56/2974.3.98.57 to 74.3.98.6274.3.98.636
7374.3.98.64/2974.3.98.65 to 74.3.98.7074.3.98.716
7474.3.98.72/2974.3.98.73 to 74.3.98.7874.3.98.796
7574.3.98.80/2974.3.98.81 to 74.3.98.8674.3.98.876
7674.3.98.88/2974.3.98.89 to 74.3.98.9474.3.98.956
7774.3.98.96/2974.3.98.97 to 74.3.98.10274.3.98.1036
7874.3.98.104/2974.3.98.105 to 74.3.98.11074.3.98.1116
7974.3.98.112/2974.3.98.113 to 74.3.98.11874.3.98.1196
8074.3.98.120/2974.3.98.121 to 74.3.98.12674.3.98.1276
8174.3.98.128/2974.3.98.129 to 74.3.98.13474.3.98.1356
8274.3.98.136/2974.3.98.137 to 74.3.98.14274.3.98.1436
8374.3.98.144/2974.3.98.145 to 74.3.98.15074.3.98.1516
8474.3.98.152/2974.3.98.153 to 74.3.98.15874.3.98.1596
8574.3.98.160/2974.3.98.161 to 74.3.98.16674.3.98.1676
8674.3.98.168/2974.3.98.169 to 74.3.98.17474.3.98.1756
8774.3.98.176/2974.3.98.177 to 74.3.98.18274.3.98.1836
8874.3.98.184/2974.3.98.185 to 74.3.98.19074.3.98.1916
8974.3.98.192/2974.3.98.193 to 74.3.98.19874.3.98.1996
9074.3.98.200/2974.3.98.201 to 74.3.98.20674.3.98.2076
9174.3.98.208/2974.3.98.209 to 74.3.98.21474.3.98.2156
9274.3.98.216/2974.3.98.217 to 74.3.98.22274.3.98.2236
9374.3.98.224/2974.3.98.225 to 74.3.98.23074.3.98.2316
9474.3.98.232/2974.3.98.233 to 74.3.98.23874.3.98.2396
9574.3.98.240/2974.3.98.241 to 74.3.98.24674.3.98.2476
9674.3.98.248/2974.3.98.249 to 74.3.98.25474.3.98.2556
9774.3.99.0/2974.3.99.1 to 74.3.99.674.3.99.76
9874.3.99.8/2974.3.99.9 to 74.3.99.1474.3.99.156
9974.3.99.16/2974.3.99.17 to 74.3.99.2274.3.99.236
10074.3.99.24/2974.3.99.25 to 74.3.99.3074.3.99.316
10174.3.99.32/2974.3.99.33 to 74.3.99.3874.3.99.396
10274.3.99.40/2974.3.99.41 to 74.3.99.4674.3.99.476
10374.3.99.48/2974.3.99.49 to 74.3.99.5474.3.99.556
10474.3.99.56/2974.3.99.57 to 74.3.99.6274.3.99.636
10574.3.99.64/2974.3.99.65 to 74.3.99.7074.3.99.716
10674.3.99.72/2974.3.99.73 to 74.3.99.7874.3.99.796
10774.3.99.80/2974.3.99.81 to 74.3.99.8674.3.99.876
10874.3.99.88/2974.3.99.89 to 74.3.99.9474.3.99.956
10974.3.99.96/2974.3.99.97 to 74.3.99.10274.3.99.1036
11074.3.99.104/2974.3.99.105 to 74.3.99.11074.3.99.1116
11174.3.99.112/2974.3.99.113 to 74.3.99.11874.3.99.1196
11274.3.99.120/2974.3.99.121 to 74.3.99.12674.3.99.1276
11374.3.99.128/2974.3.99.129 to 74.3.99.13474.3.99.1356
11474.3.99.136/2974.3.99.137 to 74.3.99.14274.3.99.1436
11574.3.99.144/2974.3.99.145 to 74.3.99.15074.3.99.1516
11674.3.99.152/2974.3.99.153 to 74.3.99.15874.3.99.1596
11774.3.99.160/2974.3.99.161 to 74.3.99.16674.3.99.1676
11874.3.99.168/2974.3.99.169 to 74.3.99.17474.3.99.1756
11974.3.99.176/2974.3.99.177 to 74.3.99.18274.3.99.1836
12074.3.99.184/2974.3.99.185 to 74.3.99.19074.3.99.1916
12174.3.99.192/2974.3.99.193 to 74.3.99.19874.3.99.1996
12274.3.99.200/2974.3.99.201 to 74.3.99.20674.3.99.2076
12374.3.99.208/2974.3.99.209 to 74.3.99.21474.3.99.2156
12474.3.99.216/2974.3.99.217 to 74.3.99.22274.3.99.2236
12574.3.99.224/2974.3.99.225 to 74.3.99.23074.3.99.2316
12674.3.99.232/2974.3.99.233 to 74.3.99.23874.3.99.2396
12774.3.99.240/2974.3.99.241 to 74.3.99.24674.3.99.2476
12874.3.99.248/2974.3.99.249 to 74.3.99.25474.3.99.2556
12974.3.100.0/2974.3.100.1 to 74.3.100.674.3.100.76
13074.3.100.8/2974.3.100.9 to 74.3.100.1474.3.100.156
13174.3.100.16/2974.3.100.17 to 74.3.100.2274.3.100.236
13274.3.100.24/2974.3.100.25 to 74.3.100.3074.3.100.316
13374.3.100.32/2974.3.100.33 to 74.3.100.3874.3.100.396
13474.3.100.40/2974.3.100.41 to 74.3.100.4674.3.100.476
13574.3.100.48/2974.3.100.49 to 74.3.100.5474.3.100.556
13674.3.100.56/2974.3.100.57 to 74.3.100.6274.3.100.636
13774.3.100.64/2974.3.100.65 to 74.3.100.7074.3.100.716
13874.3.100.72/2974.3.100.73 to 74.3.100.7874.3.100.796
13974.3.100.80/2974.3.100.81 to 74.3.100.8674.3.100.876
14074.3.100.88/2974.3.100.89 to 74.3.100.9474.3.100.956
14174.3.100.96/2974.3.100.97 to 74.3.100.10274.3.100.1036
14274.3.100.104/2974.3.100.105 to 74.3.100.11074.3.100.1116
14374.3.100.112/2974.3.100.113 to 74.3.100.11874.3.100.1196
14474.3.100.120/2974.3.100.121 to 74.3.100.12674.3.100.1276
14574.3.100.128/2974.3.100.129 to 74.3.100.13474.3.100.1356
14674.3.100.136/2974.3.100.137 to 74.3.100.14274.3.100.1436
14774.3.100.144/2974.3.100.145 to 74.3.100.15074.3.100.1516
14874.3.100.152/2974.3.100.153 to 74.3.100.15874.3.100.1596
14974.3.100.160/2974.3.100.161 to 74.3.100.16674.3.100.1676
15074.3.100.168/2974.3.100.169 to 74.3.100.17474.3.100.1756
15174.3.100.176/2974.3.100.177 to 74.3.100.18274.3.100.1836
15274.3.100.184/2974.3.100.185 to 74.3.100.19074.3.100.1916
15374.3.100.192/2974.3.100.193 to 74.3.100.19874.3.100.1996
15474.3.100.200/2974.3.100.201 to 74.3.100.20674.3.100.2076
15574.3.100.208/2974.3.100.209 to 74.3.100.21474.3.100.2156
15674.3.100.216/2974.3.100.217 to 74.3.100.22274.3.100.2236
15774.3.100.224/2974.3.100.225 to 74.3.100.23074.3.100.2316
15874.3.100.232/2974.3.100.233 to 74.3.100.23874.3.100.2396
15974.3.100.240/2974.3.100.241 to 74.3.100.24674.3.100.2476
16074.3.100.248/2974.3.100.249 to 74.3.100.25474.3.100.2556
16174.3.101.0/2974.3.101.1 to 74.3.101.674.3.101.76
16274.3.101.8/2974.3.101.9 to 74.3.101.1474.3.101.156
16374.3.101.16/2974.3.101.17 to 74.3.101.2274.3.101.236
16474.3.101.24/2974.3.101.25 to 74.3.101.3074.3.101.316
16574.3.101.32/2974.3.101.33 to 74.3.101.3874.3.101.396
16674.3.101.40/2974.3.101.41 to 74.3.101.4674.3.101.476
16774.3.101.48/2974.3.101.49 to 74.3.101.5474.3.101.556
16874.3.101.56/2974.3.101.57 to 74.3.101.6274.3.101.636
16974.3.101.64/2974.3.101.65 to 74.3.101.7074.3.101.716
17074.3.101.72/2974.3.101.73 to 74.3.101.7874.3.101.796
17174.3.101.80/2974.3.101.81 to 74.3.101.8674.3.101.876
17274.3.101.88/2974.3.101.89 to 74.3.101.9474.3.101.956
17374.3.101.96/2974.3.101.97 to 74.3.101.10274.3.101.1036
17474.3.101.104/2974.3.101.105 to 74.3.101.11074.3.101.1116
17574.3.101.112/2974.3.101.113 to 74.3.101.11874.3.101.1196
17674.3.101.120/2974.3.101.121 to 74.3.101.12674.3.101.1276
17774.3.101.128/2974.3.101.129 to 74.3.101.13474.3.101.1356
17874.3.101.136/2974.3.101.137 to 74.3.101.14274.3.101.1436
17974.3.101.144/2974.3.101.145 to 74.3.101.15074.3.101.1516
18074.3.101.152/2974.3.101.153 to 74.3.101.15874.3.101.1596
18174.3.101.160/2974.3.101.161 to 74.3.101.16674.3.101.1676
18274.3.101.168/2974.3.101.169 to 74.3.101.17474.3.101.1756
18374.3.101.176/2974.3.101.177 to 74.3.101.18274.3.101.1836
18474.3.101.184/2974.3.101.185 to 74.3.101.19074.3.101.1916
18574.3.101.192/2974.3.101.193 to 74.3.101.19874.3.101.1996
18674.3.101.200/2974.3.101.201 to 74.3.101.20674.3.101.2076
18774.3.101.208/2974.3.101.209 to 74.3.101.21474.3.101.2156
18874.3.101.216/2974.3.101.217 to 74.3.101.22274.3.101.2236
18974.3.101.224/2974.3.101.225 to 74.3.101.23074.3.101.2316
19074.3.101.232/2974.3.101.233 to 74.3.101.23874.3.101.2396
19174.3.101.240/2974.3.101.241 to 74.3.101.24674.3.101.2476
19274.3.101.248/2974.3.101.249 to 74.3.101.25474.3.101.2556
19374.3.102.0/2974.3.102.1 to 74.3.102.674.3.102.76
19474.3.102.8/2974.3.102.9 to 74.3.102.1474.3.102.156
19574.3.102.16/2974.3.102.17 to 74.3.102.2274.3.102.236
19674.3.102.24/2974.3.102.25 to 74.3.102.3074.3.102.316
19774.3.102.32/2974.3.102.33 to 74.3.102.3874.3.102.396
19874.3.102.40/2974.3.102.41 to 74.3.102.4674.3.102.476
19974.3.102.48/2974.3.102.49 to 74.3.102.5474.3.102.556
20074.3.102.56/2974.3.102.57 to 74.3.102.6274.3.102.636
20174.3.102.64/2974.3.102.65 to 74.3.102.7074.3.102.716
20274.3.102.72/2974.3.102.73 to 74.3.102.7874.3.102.796
20374.3.102.80/2974.3.102.81 to 74.3.102.8674.3.102.876
20474.3.102.88/2974.3.102.89 to 74.3.102.9474.3.102.956
20574.3.102.96/2974.3.102.97 to 74.3.102.10274.3.102.1036
20674.3.102.104/2974.3.102.105 to 74.3.102.11074.3.102.1116
20774.3.102.112/2974.3.102.113 to 74.3.102.11874.3.102.1196
20874.3.102.120/2974.3.102.121 to 74.3.102.12674.3.102.1276
20974.3.102.128/2974.3.102.129 to 74.3.102.13474.3.102.1356
21074.3.102.136/2974.3.102.137 to 74.3.102.14274.3.102.1436
21174.3.102.144/2974.3.102.145 to 74.3.102.15074.3.102.1516
21274.3.102.152/2974.3.102.153 to 74.3.102.15874.3.102.1596
21374.3.102.160/2974.3.102.161 to 74.3.102.16674.3.102.1676
21474.3.102.168/2974.3.102.169 to 74.3.102.17474.3.102.1756
21574.3.102.176/2974.3.102.177 to 74.3.102.18274.3.102.1836
21674.3.102.184/2974.3.102.185 to 74.3.102.19074.3.102.1916
21774.3.102.192/2974.3.102.193 to 74.3.102.19874.3.102.1996
21874.3.102.200/2974.3.102.201 to 74.3.102.20674.3.102.2076
21974.3.102.208/2974.3.102.209 to 74.3.102.21474.3.102.2156
22074.3.102.216/2974.3.102.217 to 74.3.102.22274.3.102.2236
22174.3.102.224/2974.3.102.225 to 74.3.102.23074.3.102.2316
22274.3.102.232/2974.3.102.233 to 74.3.102.23874.3.102.2396
22374.3.102.240/2974.3.102.241 to 74.3.102.24674.3.102.2476
22474.3.102.248/2974.3.102.249 to 74.3.102.25474.3.102.2556
22574.3.103.0/2974.3.103.1 to 74.3.103.674.3.103.76
22674.3.103.8/2974.3.103.9 to 74.3.103.1474.3.103.156
22774.3.103.16/2974.3.103.17 to 74.3.103.2274.3.103.236
22874.3.103.24/2974.3.103.25 to 74.3.103.3074.3.103.316
22974.3.103.32/2974.3.103.33 to 74.3.103.3874.3.103.396
23074.3.103.40/2974.3.103.41 to 74.3.103.4674.3.103.476
23174.3.103.48/2974.3.103.49 to 74.3.103.5474.3.103.556
23274.3.103.56/2974.3.103.57 to 74.3.103.6274.3.103.636
23374.3.103.64/2974.3.103.65 to 74.3.103.7074.3.103.716
23474.3.103.72/2974.3.103.73 to 74.3.103.7874.3.103.796
23574.3.103.80/2974.3.103.81 to 74.3.103.8674.3.103.876
23674.3.103.88/2974.3.103.89 to 74.3.103.9474.3.103.956
23774.3.103.96/2974.3.103.97 to 74.3.103.10274.3.103.1036
23874.3.103.104/2974.3.103.105 to 74.3.103.11074.3.103.1116
23974.3.103.112/2974.3.103.113 to 74.3.103.11874.3.103.1196
24074.3.103.120/2974.3.103.121 to 74.3.103.12674.3.103.1276
24174.3.103.128/2974.3.103.129 to 74.3.103.13474.3.103.1356
24274.3.103.136/2974.3.103.137 to 74.3.103.14274.3.103.1436
24374.3.103.144/2974.3.103.145 to 74.3.103.15074.3.103.1516
24474.3.103.152/2974.3.103.153 to 74.3.103.15874.3.103.1596
24574.3.103.160/2974.3.103.161 to 74.3.103.16674.3.103.1676
24674.3.103.168/2974.3.103.169 to 74.3.103.17474.3.103.1756
24774.3.103.176/2974.3.103.177 to 74.3.103.18274.3.103.1836
24874.3.103.184/2974.3.103.185 to 74.3.103.19074.3.103.1916
24974.3.103.192/2974.3.103.193 to 74.3.103.19874.3.103.1996
25074.3.103.200/2974.3.103.201 to 74.3.103.20674.3.103.2076
25174.3.103.208/2974.3.103.209 to 74.3.103.21474.3.103.2156
25274.3.103.216/2974.3.103.217 to 74.3.103.22274.3.103.2236
25374.3.103.224/2974.3.103.225 to 74.3.103.23074.3.103.2316
25474.3.103.232/2974.3.103.233 to 74.3.103.23874.3.103.2396
25574.3.103.240/2974.3.103.241 to 74.3.103.24674.3.103.2476
25674.3.103.248/2974.3.103.249 to 74.3.103.25474.3.103.2556

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.