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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.

Network28.45.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
28.45.64.0
Broadcast address
28.45.95.255
First usable
28.45.64.1
Last usable
28.45.95.254
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 1C2D4000 · Integer 472727552 to 472735743
Reverse DNS zones
64.45.28.in-addr.arpa
65.45.28.in-addr.arpa
66.45.28.in-addr.arpa
67.45.28.in-addr.arpa
68.45.28.in-addr.arpa
69.45.28.in-addr.arpa
70.45.28.in-addr.arpa
71.45.28.in-addr.arpa
72.45.28.in-addr.arpa
73.45.28.in-addr.arpa
74.45.28.in-addr.arpa
75.45.28.in-addr.arpa
76.45.28.in-addr.arpa
77.45.28.in-addr.arpa
78.45.28.in-addr.arpa
79.45.28.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
Address00011100.00101101.01000000.0000000028.45.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00011100.00101101.01000000.0000000028.45.64.0
Broadcast00011100.00101101.01011111.1111111128.45.95.255
Split into smaller subnets/31
/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)

28.45.64.0/19 makes 4,096 subnets of /31; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
128.45.64.0/3128.45.64.0 to 28.45.64.1—2
228.45.64.2/3128.45.64.2 to 28.45.64.3—2
328.45.64.4/3128.45.64.4 to 28.45.64.5—2
428.45.64.6/3128.45.64.6 to 28.45.64.7—2
528.45.64.8/3128.45.64.8 to 28.45.64.9—2
628.45.64.10/3128.45.64.10 to 28.45.64.11—2
728.45.64.12/3128.45.64.12 to 28.45.64.13—2
828.45.64.14/3128.45.64.14 to 28.45.64.15—2
928.45.64.16/3128.45.64.16 to 28.45.64.17—2
1028.45.64.18/3128.45.64.18 to 28.45.64.19—2
1128.45.64.20/3128.45.64.20 to 28.45.64.21—2
1228.45.64.22/3128.45.64.22 to 28.45.64.23—2
1328.45.64.24/3128.45.64.24 to 28.45.64.25—2
1428.45.64.26/3128.45.64.26 to 28.45.64.27—2
1528.45.64.28/3128.45.64.28 to 28.45.64.29—2
1628.45.64.30/3128.45.64.30 to 28.45.64.31—2
1728.45.64.32/3128.45.64.32 to 28.45.64.33—2
1828.45.64.34/3128.45.64.34 to 28.45.64.35—2
1928.45.64.36/3128.45.64.36 to 28.45.64.37—2
2028.45.64.38/3128.45.64.38 to 28.45.64.39—2
2128.45.64.40/3128.45.64.40 to 28.45.64.41—2
2228.45.64.42/3128.45.64.42 to 28.45.64.43—2
2328.45.64.44/3128.45.64.44 to 28.45.64.45—2
2428.45.64.46/3128.45.64.46 to 28.45.64.47—2
2528.45.64.48/3128.45.64.48 to 28.45.64.49—2
2628.45.64.50/3128.45.64.50 to 28.45.64.51—2
2728.45.64.52/3128.45.64.52 to 28.45.64.53—2
2828.45.64.54/3128.45.64.54 to 28.45.64.55—2
2928.45.64.56/3128.45.64.56 to 28.45.64.57—2
3028.45.64.58/3128.45.64.58 to 28.45.64.59—2
3128.45.64.60/3128.45.64.60 to 28.45.64.61—2
3228.45.64.62/3128.45.64.62 to 28.45.64.63—2
3328.45.64.64/3128.45.64.64 to 28.45.64.65—2
3428.45.64.66/3128.45.64.66 to 28.45.64.67—2
3528.45.64.68/3128.45.64.68 to 28.45.64.69—2
3628.45.64.70/3128.45.64.70 to 28.45.64.71—2
3728.45.64.72/3128.45.64.72 to 28.45.64.73—2
3828.45.64.74/3128.45.64.74 to 28.45.64.75—2
3928.45.64.76/3128.45.64.76 to 28.45.64.77—2
4028.45.64.78/3128.45.64.78 to 28.45.64.79—2
4128.45.64.80/3128.45.64.80 to 28.45.64.81—2
4228.45.64.82/3128.45.64.82 to 28.45.64.83—2
4328.45.64.84/3128.45.64.84 to 28.45.64.85—2
4428.45.64.86/3128.45.64.86 to 28.45.64.87—2
4528.45.64.88/3128.45.64.88 to 28.45.64.89—2
4628.45.64.90/3128.45.64.90 to 28.45.64.91—2
4728.45.64.92/3128.45.64.92 to 28.45.64.93—2
4828.45.64.94/3128.45.64.94 to 28.45.64.95—2
4928.45.64.96/3128.45.64.96 to 28.45.64.97—2
5028.45.64.98/3128.45.64.98 to 28.45.64.99—2
5128.45.64.100/3128.45.64.100 to 28.45.64.101—2
5228.45.64.102/3128.45.64.102 to 28.45.64.103—2
5328.45.64.104/3128.45.64.104 to 28.45.64.105—2
5428.45.64.106/3128.45.64.106 to 28.45.64.107—2
5528.45.64.108/3128.45.64.108 to 28.45.64.109—2
5628.45.64.110/3128.45.64.110 to 28.45.64.111—2
5728.45.64.112/3128.45.64.112 to 28.45.64.113—2
5828.45.64.114/3128.45.64.114 to 28.45.64.115—2
5928.45.64.116/3128.45.64.116 to 28.45.64.117—2
6028.45.64.118/3128.45.64.118 to 28.45.64.119—2
6128.45.64.120/3128.45.64.120 to 28.45.64.121—2
6228.45.64.122/3128.45.64.122 to 28.45.64.123—2
6328.45.64.124/3128.45.64.124 to 28.45.64.125—2
6428.45.64.126/3128.45.64.126 to 28.45.64.127—2
6528.45.64.128/3128.45.64.128 to 28.45.64.129—2
6628.45.64.130/3128.45.64.130 to 28.45.64.131—2
6728.45.64.132/3128.45.64.132 to 28.45.64.133—2
6828.45.64.134/3128.45.64.134 to 28.45.64.135—2
6928.45.64.136/3128.45.64.136 to 28.45.64.137—2
7028.45.64.138/3128.45.64.138 to 28.45.64.139—2
7128.45.64.140/3128.45.64.140 to 28.45.64.141—2
7228.45.64.142/3128.45.64.142 to 28.45.64.143—2
7328.45.64.144/3128.45.64.144 to 28.45.64.145—2
7428.45.64.146/3128.45.64.146 to 28.45.64.147—2
7528.45.64.148/3128.45.64.148 to 28.45.64.149—2
7628.45.64.150/3128.45.64.150 to 28.45.64.151—2
7728.45.64.152/3128.45.64.152 to 28.45.64.153—2
7828.45.64.154/3128.45.64.154 to 28.45.64.155—2
7928.45.64.156/3128.45.64.156 to 28.45.64.157—2
8028.45.64.158/3128.45.64.158 to 28.45.64.159—2
8128.45.64.160/3128.45.64.160 to 28.45.64.161—2
8228.45.64.162/3128.45.64.162 to 28.45.64.163—2
8328.45.64.164/3128.45.64.164 to 28.45.64.165—2
8428.45.64.166/3128.45.64.166 to 28.45.64.167—2
8528.45.64.168/3128.45.64.168 to 28.45.64.169—2
8628.45.64.170/3128.45.64.170 to 28.45.64.171—2
8728.45.64.172/3128.45.64.172 to 28.45.64.173—2
8828.45.64.174/3128.45.64.174 to 28.45.64.175—2
8928.45.64.176/3128.45.64.176 to 28.45.64.177—2
9028.45.64.178/3128.45.64.178 to 28.45.64.179—2
9128.45.64.180/3128.45.64.180 to 28.45.64.181—2
9228.45.64.182/3128.45.64.182 to 28.45.64.183—2
9328.45.64.184/3128.45.64.184 to 28.45.64.185—2
9428.45.64.186/3128.45.64.186 to 28.45.64.187—2
9528.45.64.188/3128.45.64.188 to 28.45.64.189—2
9628.45.64.190/3128.45.64.190 to 28.45.64.191—2
9728.45.64.192/3128.45.64.192 to 28.45.64.193—2
9828.45.64.194/3128.45.64.194 to 28.45.64.195—2
9928.45.64.196/3128.45.64.196 to 28.45.64.197—2
10028.45.64.198/3128.45.64.198 to 28.45.64.199—2
10128.45.64.200/3128.45.64.200 to 28.45.64.201—2
10228.45.64.202/3128.45.64.202 to 28.45.64.203—2
10328.45.64.204/3128.45.64.204 to 28.45.64.205—2
10428.45.64.206/3128.45.64.206 to 28.45.64.207—2
10528.45.64.208/3128.45.64.208 to 28.45.64.209—2
10628.45.64.210/3128.45.64.210 to 28.45.64.211—2
10728.45.64.212/3128.45.64.212 to 28.45.64.213—2
10828.45.64.214/3128.45.64.214 to 28.45.64.215—2
10928.45.64.216/3128.45.64.216 to 28.45.64.217—2
11028.45.64.218/3128.45.64.218 to 28.45.64.219—2
11128.45.64.220/3128.45.64.220 to 28.45.64.221—2
11228.45.64.222/3128.45.64.222 to 28.45.64.223—2
11328.45.64.224/3128.45.64.224 to 28.45.64.225—2
11428.45.64.226/3128.45.64.226 to 28.45.64.227—2
11528.45.64.228/3128.45.64.228 to 28.45.64.229—2
11628.45.64.230/3128.45.64.230 to 28.45.64.231—2
11728.45.64.232/3128.45.64.232 to 28.45.64.233—2
11828.45.64.234/3128.45.64.234 to 28.45.64.235—2
11928.45.64.236/3128.45.64.236 to 28.45.64.237—2
12028.45.64.238/3128.45.64.238 to 28.45.64.239—2
12128.45.64.240/3128.45.64.240 to 28.45.64.241—2
12228.45.64.242/3128.45.64.242 to 28.45.64.243—2
12328.45.64.244/3128.45.64.244 to 28.45.64.245—2
12428.45.64.246/3128.45.64.246 to 28.45.64.247—2
12528.45.64.248/3128.45.64.248 to 28.45.64.249—2
12628.45.64.250/3128.45.64.250 to 28.45.64.251—2
12728.45.64.252/3128.45.64.252 to 28.45.64.253—2
12828.45.64.254/3128.45.64.254 to 28.45.64.255—2
12928.45.65.0/3128.45.65.0 to 28.45.65.1—2
13028.45.65.2/3128.45.65.2 to 28.45.65.3—2
13128.45.65.4/3128.45.65.4 to 28.45.65.5—2
13228.45.65.6/3128.45.65.6 to 28.45.65.7—2
13328.45.65.8/3128.45.65.8 to 28.45.65.9—2
13428.45.65.10/3128.45.65.10 to 28.45.65.11—2
13528.45.65.12/3128.45.65.12 to 28.45.65.13—2
13628.45.65.14/3128.45.65.14 to 28.45.65.15—2
13728.45.65.16/3128.45.65.16 to 28.45.65.17—2
13828.45.65.18/3128.45.65.18 to 28.45.65.19—2
13928.45.65.20/3128.45.65.20 to 28.45.65.21—2
14028.45.65.22/3128.45.65.22 to 28.45.65.23—2
14128.45.65.24/3128.45.65.24 to 28.45.65.25—2
14228.45.65.26/3128.45.65.26 to 28.45.65.27—2
14328.45.65.28/3128.45.65.28 to 28.45.65.29—2
14428.45.65.30/3128.45.65.30 to 28.45.65.31—2
14528.45.65.32/3128.45.65.32 to 28.45.65.33—2
14628.45.65.34/3128.45.65.34 to 28.45.65.35—2
14728.45.65.36/3128.45.65.36 to 28.45.65.37—2
14828.45.65.38/3128.45.65.38 to 28.45.65.39—2
14928.45.65.40/3128.45.65.40 to 28.45.65.41—2
15028.45.65.42/3128.45.65.42 to 28.45.65.43—2
15128.45.65.44/3128.45.65.44 to 28.45.65.45—2
15228.45.65.46/3128.45.65.46 to 28.45.65.47—2
15328.45.65.48/3128.45.65.48 to 28.45.65.49—2
15428.45.65.50/3128.45.65.50 to 28.45.65.51—2
15528.45.65.52/3128.45.65.52 to 28.45.65.53—2
15628.45.65.54/3128.45.65.54 to 28.45.65.55—2
15728.45.65.56/3128.45.65.56 to 28.45.65.57—2
15828.45.65.58/3128.45.65.58 to 28.45.65.59—2
15928.45.65.60/3128.45.65.60 to 28.45.65.61—2
16028.45.65.62/3128.45.65.62 to 28.45.65.63—2
16128.45.65.64/3128.45.65.64 to 28.45.65.65—2
16228.45.65.66/3128.45.65.66 to 28.45.65.67—2
16328.45.65.68/3128.45.65.68 to 28.45.65.69—2
16428.45.65.70/3128.45.65.70 to 28.45.65.71—2
16528.45.65.72/3128.45.65.72 to 28.45.65.73—2
16628.45.65.74/3128.45.65.74 to 28.45.65.75—2
16728.45.65.76/3128.45.65.76 to 28.45.65.77—2
16828.45.65.78/3128.45.65.78 to 28.45.65.79—2
16928.45.65.80/3128.45.65.80 to 28.45.65.81—2
17028.45.65.82/3128.45.65.82 to 28.45.65.83—2
17128.45.65.84/3128.45.65.84 to 28.45.65.85—2
17228.45.65.86/3128.45.65.86 to 28.45.65.87—2
17328.45.65.88/3128.45.65.88 to 28.45.65.89—2
17428.45.65.90/3128.45.65.90 to 28.45.65.91—2
17528.45.65.92/3128.45.65.92 to 28.45.65.93—2
17628.45.65.94/3128.45.65.94 to 28.45.65.95—2
17728.45.65.96/3128.45.65.96 to 28.45.65.97—2
17828.45.65.98/3128.45.65.98 to 28.45.65.99—2
17928.45.65.100/3128.45.65.100 to 28.45.65.101—2
18028.45.65.102/3128.45.65.102 to 28.45.65.103—2
18128.45.65.104/3128.45.65.104 to 28.45.65.105—2
18228.45.65.106/3128.45.65.106 to 28.45.65.107—2
18328.45.65.108/3128.45.65.108 to 28.45.65.109—2
18428.45.65.110/3128.45.65.110 to 28.45.65.111—2
18528.45.65.112/3128.45.65.112 to 28.45.65.113—2
18628.45.65.114/3128.45.65.114 to 28.45.65.115—2
18728.45.65.116/3128.45.65.116 to 28.45.65.117—2
18828.45.65.118/3128.45.65.118 to 28.45.65.119—2
18928.45.65.120/3128.45.65.120 to 28.45.65.121—2
19028.45.65.122/3128.45.65.122 to 28.45.65.123—2
19128.45.65.124/3128.45.65.124 to 28.45.65.125—2
19228.45.65.126/3128.45.65.126 to 28.45.65.127—2
19328.45.65.128/3128.45.65.128 to 28.45.65.129—2
19428.45.65.130/3128.45.65.130 to 28.45.65.131—2
19528.45.65.132/3128.45.65.132 to 28.45.65.133—2
19628.45.65.134/3128.45.65.134 to 28.45.65.135—2
19728.45.65.136/3128.45.65.136 to 28.45.65.137—2
19828.45.65.138/3128.45.65.138 to 28.45.65.139—2
19928.45.65.140/3128.45.65.140 to 28.45.65.141—2
20028.45.65.142/3128.45.65.142 to 28.45.65.143—2
20128.45.65.144/3128.45.65.144 to 28.45.65.145—2
20228.45.65.146/3128.45.65.146 to 28.45.65.147—2
20328.45.65.148/3128.45.65.148 to 28.45.65.149—2
20428.45.65.150/3128.45.65.150 to 28.45.65.151—2
20528.45.65.152/3128.45.65.152 to 28.45.65.153—2
20628.45.65.154/3128.45.65.154 to 28.45.65.155—2
20728.45.65.156/3128.45.65.156 to 28.45.65.157—2
20828.45.65.158/3128.45.65.158 to 28.45.65.159—2
20928.45.65.160/3128.45.65.160 to 28.45.65.161—2
21028.45.65.162/3128.45.65.162 to 28.45.65.163—2
21128.45.65.164/3128.45.65.164 to 28.45.65.165—2
21228.45.65.166/3128.45.65.166 to 28.45.65.167—2
21328.45.65.168/3128.45.65.168 to 28.45.65.169—2
21428.45.65.170/3128.45.65.170 to 28.45.65.171—2
21528.45.65.172/3128.45.65.172 to 28.45.65.173—2
21628.45.65.174/3128.45.65.174 to 28.45.65.175—2
21728.45.65.176/3128.45.65.176 to 28.45.65.177—2
21828.45.65.178/3128.45.65.178 to 28.45.65.179—2
21928.45.65.180/3128.45.65.180 to 28.45.65.181—2
22028.45.65.182/3128.45.65.182 to 28.45.65.183—2
22128.45.65.184/3128.45.65.184 to 28.45.65.185—2
22228.45.65.186/3128.45.65.186 to 28.45.65.187—2
22328.45.65.188/3128.45.65.188 to 28.45.65.189—2
22428.45.65.190/3128.45.65.190 to 28.45.65.191—2
22528.45.65.192/3128.45.65.192 to 28.45.65.193—2
22628.45.65.194/3128.45.65.194 to 28.45.65.195—2
22728.45.65.196/3128.45.65.196 to 28.45.65.197—2
22828.45.65.198/3128.45.65.198 to 28.45.65.199—2
22928.45.65.200/3128.45.65.200 to 28.45.65.201—2
23028.45.65.202/3128.45.65.202 to 28.45.65.203—2
23128.45.65.204/3128.45.65.204 to 28.45.65.205—2
23228.45.65.206/3128.45.65.206 to 28.45.65.207—2
23328.45.65.208/3128.45.65.208 to 28.45.65.209—2
23428.45.65.210/3128.45.65.210 to 28.45.65.211—2
23528.45.65.212/3128.45.65.212 to 28.45.65.213—2
23628.45.65.214/3128.45.65.214 to 28.45.65.215—2
23728.45.65.216/3128.45.65.216 to 28.45.65.217—2
23828.45.65.218/3128.45.65.218 to 28.45.65.219—2
23928.45.65.220/3128.45.65.220 to 28.45.65.221—2
24028.45.65.222/3128.45.65.222 to 28.45.65.223—2
24128.45.65.224/3128.45.65.224 to 28.45.65.225—2
24228.45.65.226/3128.45.65.226 to 28.45.65.227—2
24328.45.65.228/3128.45.65.228 to 28.45.65.229—2
24428.45.65.230/3128.45.65.230 to 28.45.65.231—2
24528.45.65.232/3128.45.65.232 to 28.45.65.233—2
24628.45.65.234/3128.45.65.234 to 28.45.65.235—2
24728.45.65.236/3128.45.65.236 to 28.45.65.237—2
24828.45.65.238/3128.45.65.238 to 28.45.65.239—2
24928.45.65.240/3128.45.65.240 to 28.45.65.241—2
25028.45.65.242/3128.45.65.242 to 28.45.65.243—2
25128.45.65.244/3128.45.65.244 to 28.45.65.245—2
25228.45.65.246/3128.45.65.246 to 28.45.65.247—2
25328.45.65.248/3128.45.65.248 to 28.45.65.249—2
25428.45.65.250/3128.45.65.250 to 28.45.65.251—2
25528.45.65.252/3128.45.65.252 to 28.45.65.253—2
25628.45.65.254/3128.45.65.254 to 28.45.65.255—2

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.