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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.

Network96.4.16.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
96.4.16.0
Broadcast address
96.4.31.255
First usable
96.4.16.1
Last usable
96.4.31.254
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 60041000 · Integer 1610878976 to 1610883071
Reverse DNS zones
16.4.96.in-addr.arpa
17.4.96.in-addr.arpa
18.4.96.in-addr.arpa
19.4.96.in-addr.arpa
20.4.96.in-addr.arpa
21.4.96.in-addr.arpa
22.4.96.in-addr.arpa
23.4.96.in-addr.arpa
24.4.96.in-addr.arpa
25.4.96.in-addr.arpa
26.4.96.in-addr.arpa
27.4.96.in-addr.arpa
28.4.96.in-addr.arpa
29.4.96.in-addr.arpa
30.4.96.in-addr.arpa
31.4.96.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
Address01100000.00000100.00010000.0000000096.4.16.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network01100000.00000100.00010000.0000000096.4.16.0
Broadcast01100000.00000100.00011111.1111111196.4.31.255
Split into smaller subnets/32
/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)

96.4.16.0/20 makes 4,096 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
196.4.16.0/3296.4.16.0 to 96.4.16.0—1
296.4.16.1/3296.4.16.1 to 96.4.16.1—1
396.4.16.2/3296.4.16.2 to 96.4.16.2—1
496.4.16.3/3296.4.16.3 to 96.4.16.3—1
596.4.16.4/3296.4.16.4 to 96.4.16.4—1
696.4.16.5/3296.4.16.5 to 96.4.16.5—1
796.4.16.6/3296.4.16.6 to 96.4.16.6—1
896.4.16.7/3296.4.16.7 to 96.4.16.7—1
996.4.16.8/3296.4.16.8 to 96.4.16.8—1
1096.4.16.9/3296.4.16.9 to 96.4.16.9—1
1196.4.16.10/3296.4.16.10 to 96.4.16.10—1
1296.4.16.11/3296.4.16.11 to 96.4.16.11—1
1396.4.16.12/3296.4.16.12 to 96.4.16.12—1
1496.4.16.13/3296.4.16.13 to 96.4.16.13—1
1596.4.16.14/3296.4.16.14 to 96.4.16.14—1
1696.4.16.15/3296.4.16.15 to 96.4.16.15—1
1796.4.16.16/3296.4.16.16 to 96.4.16.16—1
1896.4.16.17/3296.4.16.17 to 96.4.16.17—1
1996.4.16.18/3296.4.16.18 to 96.4.16.18—1
2096.4.16.19/3296.4.16.19 to 96.4.16.19—1
2196.4.16.20/3296.4.16.20 to 96.4.16.20—1
2296.4.16.21/3296.4.16.21 to 96.4.16.21—1
2396.4.16.22/3296.4.16.22 to 96.4.16.22—1
2496.4.16.23/3296.4.16.23 to 96.4.16.23—1
2596.4.16.24/3296.4.16.24 to 96.4.16.24—1
2696.4.16.25/3296.4.16.25 to 96.4.16.25—1
2796.4.16.26/3296.4.16.26 to 96.4.16.26—1
2896.4.16.27/3296.4.16.27 to 96.4.16.27—1
2996.4.16.28/3296.4.16.28 to 96.4.16.28—1
3096.4.16.29/3296.4.16.29 to 96.4.16.29—1
3196.4.16.30/3296.4.16.30 to 96.4.16.30—1
3296.4.16.31/3296.4.16.31 to 96.4.16.31—1
3396.4.16.32/3296.4.16.32 to 96.4.16.32—1
3496.4.16.33/3296.4.16.33 to 96.4.16.33—1
3596.4.16.34/3296.4.16.34 to 96.4.16.34—1
3696.4.16.35/3296.4.16.35 to 96.4.16.35—1
3796.4.16.36/3296.4.16.36 to 96.4.16.36—1
3896.4.16.37/3296.4.16.37 to 96.4.16.37—1
3996.4.16.38/3296.4.16.38 to 96.4.16.38—1
4096.4.16.39/3296.4.16.39 to 96.4.16.39—1
4196.4.16.40/3296.4.16.40 to 96.4.16.40—1
4296.4.16.41/3296.4.16.41 to 96.4.16.41—1
4396.4.16.42/3296.4.16.42 to 96.4.16.42—1
4496.4.16.43/3296.4.16.43 to 96.4.16.43—1
4596.4.16.44/3296.4.16.44 to 96.4.16.44—1
4696.4.16.45/3296.4.16.45 to 96.4.16.45—1
4796.4.16.46/3296.4.16.46 to 96.4.16.46—1
4896.4.16.47/3296.4.16.47 to 96.4.16.47—1
4996.4.16.48/3296.4.16.48 to 96.4.16.48—1
5096.4.16.49/3296.4.16.49 to 96.4.16.49—1
5196.4.16.50/3296.4.16.50 to 96.4.16.50—1
5296.4.16.51/3296.4.16.51 to 96.4.16.51—1
5396.4.16.52/3296.4.16.52 to 96.4.16.52—1
5496.4.16.53/3296.4.16.53 to 96.4.16.53—1
5596.4.16.54/3296.4.16.54 to 96.4.16.54—1
5696.4.16.55/3296.4.16.55 to 96.4.16.55—1
5796.4.16.56/3296.4.16.56 to 96.4.16.56—1
5896.4.16.57/3296.4.16.57 to 96.4.16.57—1
5996.4.16.58/3296.4.16.58 to 96.4.16.58—1
6096.4.16.59/3296.4.16.59 to 96.4.16.59—1
6196.4.16.60/3296.4.16.60 to 96.4.16.60—1
6296.4.16.61/3296.4.16.61 to 96.4.16.61—1
6396.4.16.62/3296.4.16.62 to 96.4.16.62—1
6496.4.16.63/3296.4.16.63 to 96.4.16.63—1
6596.4.16.64/3296.4.16.64 to 96.4.16.64—1
6696.4.16.65/3296.4.16.65 to 96.4.16.65—1
6796.4.16.66/3296.4.16.66 to 96.4.16.66—1
6896.4.16.67/3296.4.16.67 to 96.4.16.67—1
6996.4.16.68/3296.4.16.68 to 96.4.16.68—1
7096.4.16.69/3296.4.16.69 to 96.4.16.69—1
7196.4.16.70/3296.4.16.70 to 96.4.16.70—1
7296.4.16.71/3296.4.16.71 to 96.4.16.71—1
7396.4.16.72/3296.4.16.72 to 96.4.16.72—1
7496.4.16.73/3296.4.16.73 to 96.4.16.73—1
7596.4.16.74/3296.4.16.74 to 96.4.16.74—1
7696.4.16.75/3296.4.16.75 to 96.4.16.75—1
7796.4.16.76/3296.4.16.76 to 96.4.16.76—1
7896.4.16.77/3296.4.16.77 to 96.4.16.77—1
7996.4.16.78/3296.4.16.78 to 96.4.16.78—1
8096.4.16.79/3296.4.16.79 to 96.4.16.79—1
8196.4.16.80/3296.4.16.80 to 96.4.16.80—1
8296.4.16.81/3296.4.16.81 to 96.4.16.81—1
8396.4.16.82/3296.4.16.82 to 96.4.16.82—1
8496.4.16.83/3296.4.16.83 to 96.4.16.83—1
8596.4.16.84/3296.4.16.84 to 96.4.16.84—1
8696.4.16.85/3296.4.16.85 to 96.4.16.85—1
8796.4.16.86/3296.4.16.86 to 96.4.16.86—1
8896.4.16.87/3296.4.16.87 to 96.4.16.87—1
8996.4.16.88/3296.4.16.88 to 96.4.16.88—1
9096.4.16.89/3296.4.16.89 to 96.4.16.89—1
9196.4.16.90/3296.4.16.90 to 96.4.16.90—1
9296.4.16.91/3296.4.16.91 to 96.4.16.91—1
9396.4.16.92/3296.4.16.92 to 96.4.16.92—1
9496.4.16.93/3296.4.16.93 to 96.4.16.93—1
9596.4.16.94/3296.4.16.94 to 96.4.16.94—1
9696.4.16.95/3296.4.16.95 to 96.4.16.95—1
9796.4.16.96/3296.4.16.96 to 96.4.16.96—1
9896.4.16.97/3296.4.16.97 to 96.4.16.97—1
9996.4.16.98/3296.4.16.98 to 96.4.16.98—1
10096.4.16.99/3296.4.16.99 to 96.4.16.99—1
10196.4.16.100/3296.4.16.100 to 96.4.16.100—1
10296.4.16.101/3296.4.16.101 to 96.4.16.101—1
10396.4.16.102/3296.4.16.102 to 96.4.16.102—1
10496.4.16.103/3296.4.16.103 to 96.4.16.103—1
10596.4.16.104/3296.4.16.104 to 96.4.16.104—1
10696.4.16.105/3296.4.16.105 to 96.4.16.105—1
10796.4.16.106/3296.4.16.106 to 96.4.16.106—1
10896.4.16.107/3296.4.16.107 to 96.4.16.107—1
10996.4.16.108/3296.4.16.108 to 96.4.16.108—1
11096.4.16.109/3296.4.16.109 to 96.4.16.109—1
11196.4.16.110/3296.4.16.110 to 96.4.16.110—1
11296.4.16.111/3296.4.16.111 to 96.4.16.111—1
11396.4.16.112/3296.4.16.112 to 96.4.16.112—1
11496.4.16.113/3296.4.16.113 to 96.4.16.113—1
11596.4.16.114/3296.4.16.114 to 96.4.16.114—1
11696.4.16.115/3296.4.16.115 to 96.4.16.115—1
11796.4.16.116/3296.4.16.116 to 96.4.16.116—1
11896.4.16.117/3296.4.16.117 to 96.4.16.117—1
11996.4.16.118/3296.4.16.118 to 96.4.16.118—1
12096.4.16.119/3296.4.16.119 to 96.4.16.119—1
12196.4.16.120/3296.4.16.120 to 96.4.16.120—1
12296.4.16.121/3296.4.16.121 to 96.4.16.121—1
12396.4.16.122/3296.4.16.122 to 96.4.16.122—1
12496.4.16.123/3296.4.16.123 to 96.4.16.123—1
12596.4.16.124/3296.4.16.124 to 96.4.16.124—1
12696.4.16.125/3296.4.16.125 to 96.4.16.125—1
12796.4.16.126/3296.4.16.126 to 96.4.16.126—1
12896.4.16.127/3296.4.16.127 to 96.4.16.127—1
12996.4.16.128/3296.4.16.128 to 96.4.16.128—1
13096.4.16.129/3296.4.16.129 to 96.4.16.129—1
13196.4.16.130/3296.4.16.130 to 96.4.16.130—1
13296.4.16.131/3296.4.16.131 to 96.4.16.131—1
13396.4.16.132/3296.4.16.132 to 96.4.16.132—1
13496.4.16.133/3296.4.16.133 to 96.4.16.133—1
13596.4.16.134/3296.4.16.134 to 96.4.16.134—1
13696.4.16.135/3296.4.16.135 to 96.4.16.135—1
13796.4.16.136/3296.4.16.136 to 96.4.16.136—1
13896.4.16.137/3296.4.16.137 to 96.4.16.137—1
13996.4.16.138/3296.4.16.138 to 96.4.16.138—1
14096.4.16.139/3296.4.16.139 to 96.4.16.139—1
14196.4.16.140/3296.4.16.140 to 96.4.16.140—1
14296.4.16.141/3296.4.16.141 to 96.4.16.141—1
14396.4.16.142/3296.4.16.142 to 96.4.16.142—1
14496.4.16.143/3296.4.16.143 to 96.4.16.143—1
14596.4.16.144/3296.4.16.144 to 96.4.16.144—1
14696.4.16.145/3296.4.16.145 to 96.4.16.145—1
14796.4.16.146/3296.4.16.146 to 96.4.16.146—1
14896.4.16.147/3296.4.16.147 to 96.4.16.147—1
14996.4.16.148/3296.4.16.148 to 96.4.16.148—1
15096.4.16.149/3296.4.16.149 to 96.4.16.149—1
15196.4.16.150/3296.4.16.150 to 96.4.16.150—1
15296.4.16.151/3296.4.16.151 to 96.4.16.151—1
15396.4.16.152/3296.4.16.152 to 96.4.16.152—1
15496.4.16.153/3296.4.16.153 to 96.4.16.153—1
15596.4.16.154/3296.4.16.154 to 96.4.16.154—1
15696.4.16.155/3296.4.16.155 to 96.4.16.155—1
15796.4.16.156/3296.4.16.156 to 96.4.16.156—1
15896.4.16.157/3296.4.16.157 to 96.4.16.157—1
15996.4.16.158/3296.4.16.158 to 96.4.16.158—1
16096.4.16.159/3296.4.16.159 to 96.4.16.159—1
16196.4.16.160/3296.4.16.160 to 96.4.16.160—1
16296.4.16.161/3296.4.16.161 to 96.4.16.161—1
16396.4.16.162/3296.4.16.162 to 96.4.16.162—1
16496.4.16.163/3296.4.16.163 to 96.4.16.163—1
16596.4.16.164/3296.4.16.164 to 96.4.16.164—1
16696.4.16.165/3296.4.16.165 to 96.4.16.165—1
16796.4.16.166/3296.4.16.166 to 96.4.16.166—1
16896.4.16.167/3296.4.16.167 to 96.4.16.167—1
16996.4.16.168/3296.4.16.168 to 96.4.16.168—1
17096.4.16.169/3296.4.16.169 to 96.4.16.169—1
17196.4.16.170/3296.4.16.170 to 96.4.16.170—1
17296.4.16.171/3296.4.16.171 to 96.4.16.171—1
17396.4.16.172/3296.4.16.172 to 96.4.16.172—1
17496.4.16.173/3296.4.16.173 to 96.4.16.173—1
17596.4.16.174/3296.4.16.174 to 96.4.16.174—1
17696.4.16.175/3296.4.16.175 to 96.4.16.175—1
17796.4.16.176/3296.4.16.176 to 96.4.16.176—1
17896.4.16.177/3296.4.16.177 to 96.4.16.177—1
17996.4.16.178/3296.4.16.178 to 96.4.16.178—1
18096.4.16.179/3296.4.16.179 to 96.4.16.179—1
18196.4.16.180/3296.4.16.180 to 96.4.16.180—1
18296.4.16.181/3296.4.16.181 to 96.4.16.181—1
18396.4.16.182/3296.4.16.182 to 96.4.16.182—1
18496.4.16.183/3296.4.16.183 to 96.4.16.183—1
18596.4.16.184/3296.4.16.184 to 96.4.16.184—1
18696.4.16.185/3296.4.16.185 to 96.4.16.185—1
18796.4.16.186/3296.4.16.186 to 96.4.16.186—1
18896.4.16.187/3296.4.16.187 to 96.4.16.187—1
18996.4.16.188/3296.4.16.188 to 96.4.16.188—1
19096.4.16.189/3296.4.16.189 to 96.4.16.189—1
19196.4.16.190/3296.4.16.190 to 96.4.16.190—1
19296.4.16.191/3296.4.16.191 to 96.4.16.191—1
19396.4.16.192/3296.4.16.192 to 96.4.16.192—1
19496.4.16.193/3296.4.16.193 to 96.4.16.193—1
19596.4.16.194/3296.4.16.194 to 96.4.16.194—1
19696.4.16.195/3296.4.16.195 to 96.4.16.195—1
19796.4.16.196/3296.4.16.196 to 96.4.16.196—1
19896.4.16.197/3296.4.16.197 to 96.4.16.197—1
19996.4.16.198/3296.4.16.198 to 96.4.16.198—1
20096.4.16.199/3296.4.16.199 to 96.4.16.199—1
20196.4.16.200/3296.4.16.200 to 96.4.16.200—1
20296.4.16.201/3296.4.16.201 to 96.4.16.201—1
20396.4.16.202/3296.4.16.202 to 96.4.16.202—1
20496.4.16.203/3296.4.16.203 to 96.4.16.203—1
20596.4.16.204/3296.4.16.204 to 96.4.16.204—1
20696.4.16.205/3296.4.16.205 to 96.4.16.205—1
20796.4.16.206/3296.4.16.206 to 96.4.16.206—1
20896.4.16.207/3296.4.16.207 to 96.4.16.207—1
20996.4.16.208/3296.4.16.208 to 96.4.16.208—1
21096.4.16.209/3296.4.16.209 to 96.4.16.209—1
21196.4.16.210/3296.4.16.210 to 96.4.16.210—1
21296.4.16.211/3296.4.16.211 to 96.4.16.211—1
21396.4.16.212/3296.4.16.212 to 96.4.16.212—1
21496.4.16.213/3296.4.16.213 to 96.4.16.213—1
21596.4.16.214/3296.4.16.214 to 96.4.16.214—1
21696.4.16.215/3296.4.16.215 to 96.4.16.215—1
21796.4.16.216/3296.4.16.216 to 96.4.16.216—1
21896.4.16.217/3296.4.16.217 to 96.4.16.217—1
21996.4.16.218/3296.4.16.218 to 96.4.16.218—1
22096.4.16.219/3296.4.16.219 to 96.4.16.219—1
22196.4.16.220/3296.4.16.220 to 96.4.16.220—1
22296.4.16.221/3296.4.16.221 to 96.4.16.221—1
22396.4.16.222/3296.4.16.222 to 96.4.16.222—1
22496.4.16.223/3296.4.16.223 to 96.4.16.223—1
22596.4.16.224/3296.4.16.224 to 96.4.16.224—1
22696.4.16.225/3296.4.16.225 to 96.4.16.225—1
22796.4.16.226/3296.4.16.226 to 96.4.16.226—1
22896.4.16.227/3296.4.16.227 to 96.4.16.227—1
22996.4.16.228/3296.4.16.228 to 96.4.16.228—1
23096.4.16.229/3296.4.16.229 to 96.4.16.229—1
23196.4.16.230/3296.4.16.230 to 96.4.16.230—1
23296.4.16.231/3296.4.16.231 to 96.4.16.231—1
23396.4.16.232/3296.4.16.232 to 96.4.16.232—1
23496.4.16.233/3296.4.16.233 to 96.4.16.233—1
23596.4.16.234/3296.4.16.234 to 96.4.16.234—1
23696.4.16.235/3296.4.16.235 to 96.4.16.235—1
23796.4.16.236/3296.4.16.236 to 96.4.16.236—1
23896.4.16.237/3296.4.16.237 to 96.4.16.237—1
23996.4.16.238/3296.4.16.238 to 96.4.16.238—1
24096.4.16.239/3296.4.16.239 to 96.4.16.239—1
24196.4.16.240/3296.4.16.240 to 96.4.16.240—1
24296.4.16.241/3296.4.16.241 to 96.4.16.241—1
24396.4.16.242/3296.4.16.242 to 96.4.16.242—1
24496.4.16.243/3296.4.16.243 to 96.4.16.243—1
24596.4.16.244/3296.4.16.244 to 96.4.16.244—1
24696.4.16.245/3296.4.16.245 to 96.4.16.245—1
24796.4.16.246/3296.4.16.246 to 96.4.16.246—1
24896.4.16.247/3296.4.16.247 to 96.4.16.247—1
24996.4.16.248/3296.4.16.248 to 96.4.16.248—1
25096.4.16.249/3296.4.16.249 to 96.4.16.249—1
25196.4.16.250/3296.4.16.250 to 96.4.16.250—1
25296.4.16.251/3296.4.16.251 to 96.4.16.251—1
25396.4.16.252/3296.4.16.252 to 96.4.16.252—1
25496.4.16.253/3296.4.16.253 to 96.4.16.253—1
25596.4.16.254/3296.4.16.254 to 96.4.16.254—1
25696.4.16.255/3296.4.16.255 to 96.4.16.255—1

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.