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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.

Network98.7.64.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
98.7.64.0
Broadcast address
98.7.79.255
First usable
98.7.64.1
Last usable
98.7.79.254
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 62074000 · Integer 1644642304 to 1644646399
Reverse DNS zones
64.7.98.in-addr.arpa
65.7.98.in-addr.arpa
66.7.98.in-addr.arpa
67.7.98.in-addr.arpa
68.7.98.in-addr.arpa
69.7.98.in-addr.arpa
70.7.98.in-addr.arpa
71.7.98.in-addr.arpa
72.7.98.in-addr.arpa
73.7.98.in-addr.arpa
74.7.98.in-addr.arpa
75.7.98.in-addr.arpa
76.7.98.in-addr.arpa
77.7.98.in-addr.arpa
78.7.98.in-addr.arpa
79.7.98.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
Address01100010.00000111.01000000.0000000098.7.64.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network01100010.00000111.01000000.0000000098.7.64.0
Broadcast01100010.00000111.01001111.1111111198.7.79.255
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)

98.7.64.0/20 makes 4,096 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
198.7.64.0/3298.7.64.0 to 98.7.64.0—1
298.7.64.1/3298.7.64.1 to 98.7.64.1—1
398.7.64.2/3298.7.64.2 to 98.7.64.2—1
498.7.64.3/3298.7.64.3 to 98.7.64.3—1
598.7.64.4/3298.7.64.4 to 98.7.64.4—1
698.7.64.5/3298.7.64.5 to 98.7.64.5—1
798.7.64.6/3298.7.64.6 to 98.7.64.6—1
898.7.64.7/3298.7.64.7 to 98.7.64.7—1
998.7.64.8/3298.7.64.8 to 98.7.64.8—1
1098.7.64.9/3298.7.64.9 to 98.7.64.9—1
1198.7.64.10/3298.7.64.10 to 98.7.64.10—1
1298.7.64.11/3298.7.64.11 to 98.7.64.11—1
1398.7.64.12/3298.7.64.12 to 98.7.64.12—1
1498.7.64.13/3298.7.64.13 to 98.7.64.13—1
1598.7.64.14/3298.7.64.14 to 98.7.64.14—1
1698.7.64.15/3298.7.64.15 to 98.7.64.15—1
1798.7.64.16/3298.7.64.16 to 98.7.64.16—1
1898.7.64.17/3298.7.64.17 to 98.7.64.17—1
1998.7.64.18/3298.7.64.18 to 98.7.64.18—1
2098.7.64.19/3298.7.64.19 to 98.7.64.19—1
2198.7.64.20/3298.7.64.20 to 98.7.64.20—1
2298.7.64.21/3298.7.64.21 to 98.7.64.21—1
2398.7.64.22/3298.7.64.22 to 98.7.64.22—1
2498.7.64.23/3298.7.64.23 to 98.7.64.23—1
2598.7.64.24/3298.7.64.24 to 98.7.64.24—1
2698.7.64.25/3298.7.64.25 to 98.7.64.25—1
2798.7.64.26/3298.7.64.26 to 98.7.64.26—1
2898.7.64.27/3298.7.64.27 to 98.7.64.27—1
2998.7.64.28/3298.7.64.28 to 98.7.64.28—1
3098.7.64.29/3298.7.64.29 to 98.7.64.29—1
3198.7.64.30/3298.7.64.30 to 98.7.64.30—1
3298.7.64.31/3298.7.64.31 to 98.7.64.31—1
3398.7.64.32/3298.7.64.32 to 98.7.64.32—1
3498.7.64.33/3298.7.64.33 to 98.7.64.33—1
3598.7.64.34/3298.7.64.34 to 98.7.64.34—1
3698.7.64.35/3298.7.64.35 to 98.7.64.35—1
3798.7.64.36/3298.7.64.36 to 98.7.64.36—1
3898.7.64.37/3298.7.64.37 to 98.7.64.37—1
3998.7.64.38/3298.7.64.38 to 98.7.64.38—1
4098.7.64.39/3298.7.64.39 to 98.7.64.39—1
4198.7.64.40/3298.7.64.40 to 98.7.64.40—1
4298.7.64.41/3298.7.64.41 to 98.7.64.41—1
4398.7.64.42/3298.7.64.42 to 98.7.64.42—1
4498.7.64.43/3298.7.64.43 to 98.7.64.43—1
4598.7.64.44/3298.7.64.44 to 98.7.64.44—1
4698.7.64.45/3298.7.64.45 to 98.7.64.45—1
4798.7.64.46/3298.7.64.46 to 98.7.64.46—1
4898.7.64.47/3298.7.64.47 to 98.7.64.47—1
4998.7.64.48/3298.7.64.48 to 98.7.64.48—1
5098.7.64.49/3298.7.64.49 to 98.7.64.49—1
5198.7.64.50/3298.7.64.50 to 98.7.64.50—1
5298.7.64.51/3298.7.64.51 to 98.7.64.51—1
5398.7.64.52/3298.7.64.52 to 98.7.64.52—1
5498.7.64.53/3298.7.64.53 to 98.7.64.53—1
5598.7.64.54/3298.7.64.54 to 98.7.64.54—1
5698.7.64.55/3298.7.64.55 to 98.7.64.55—1
5798.7.64.56/3298.7.64.56 to 98.7.64.56—1
5898.7.64.57/3298.7.64.57 to 98.7.64.57—1
5998.7.64.58/3298.7.64.58 to 98.7.64.58—1
6098.7.64.59/3298.7.64.59 to 98.7.64.59—1
6198.7.64.60/3298.7.64.60 to 98.7.64.60—1
6298.7.64.61/3298.7.64.61 to 98.7.64.61—1
6398.7.64.62/3298.7.64.62 to 98.7.64.62—1
6498.7.64.63/3298.7.64.63 to 98.7.64.63—1
6598.7.64.64/3298.7.64.64 to 98.7.64.64—1
6698.7.64.65/3298.7.64.65 to 98.7.64.65—1
6798.7.64.66/3298.7.64.66 to 98.7.64.66—1
6898.7.64.67/3298.7.64.67 to 98.7.64.67—1
6998.7.64.68/3298.7.64.68 to 98.7.64.68—1
7098.7.64.69/3298.7.64.69 to 98.7.64.69—1
7198.7.64.70/3298.7.64.70 to 98.7.64.70—1
7298.7.64.71/3298.7.64.71 to 98.7.64.71—1
7398.7.64.72/3298.7.64.72 to 98.7.64.72—1
7498.7.64.73/3298.7.64.73 to 98.7.64.73—1
7598.7.64.74/3298.7.64.74 to 98.7.64.74—1
7698.7.64.75/3298.7.64.75 to 98.7.64.75—1
7798.7.64.76/3298.7.64.76 to 98.7.64.76—1
7898.7.64.77/3298.7.64.77 to 98.7.64.77—1
7998.7.64.78/3298.7.64.78 to 98.7.64.78—1
8098.7.64.79/3298.7.64.79 to 98.7.64.79—1
8198.7.64.80/3298.7.64.80 to 98.7.64.80—1
8298.7.64.81/3298.7.64.81 to 98.7.64.81—1
8398.7.64.82/3298.7.64.82 to 98.7.64.82—1
8498.7.64.83/3298.7.64.83 to 98.7.64.83—1
8598.7.64.84/3298.7.64.84 to 98.7.64.84—1
8698.7.64.85/3298.7.64.85 to 98.7.64.85—1
8798.7.64.86/3298.7.64.86 to 98.7.64.86—1
8898.7.64.87/3298.7.64.87 to 98.7.64.87—1
8998.7.64.88/3298.7.64.88 to 98.7.64.88—1
9098.7.64.89/3298.7.64.89 to 98.7.64.89—1
9198.7.64.90/3298.7.64.90 to 98.7.64.90—1
9298.7.64.91/3298.7.64.91 to 98.7.64.91—1
9398.7.64.92/3298.7.64.92 to 98.7.64.92—1
9498.7.64.93/3298.7.64.93 to 98.7.64.93—1
9598.7.64.94/3298.7.64.94 to 98.7.64.94—1
9698.7.64.95/3298.7.64.95 to 98.7.64.95—1
9798.7.64.96/3298.7.64.96 to 98.7.64.96—1
9898.7.64.97/3298.7.64.97 to 98.7.64.97—1
9998.7.64.98/3298.7.64.98 to 98.7.64.98—1
10098.7.64.99/3298.7.64.99 to 98.7.64.99—1
10198.7.64.100/3298.7.64.100 to 98.7.64.100—1
10298.7.64.101/3298.7.64.101 to 98.7.64.101—1
10398.7.64.102/3298.7.64.102 to 98.7.64.102—1
10498.7.64.103/3298.7.64.103 to 98.7.64.103—1
10598.7.64.104/3298.7.64.104 to 98.7.64.104—1
10698.7.64.105/3298.7.64.105 to 98.7.64.105—1
10798.7.64.106/3298.7.64.106 to 98.7.64.106—1
10898.7.64.107/3298.7.64.107 to 98.7.64.107—1
10998.7.64.108/3298.7.64.108 to 98.7.64.108—1
11098.7.64.109/3298.7.64.109 to 98.7.64.109—1
11198.7.64.110/3298.7.64.110 to 98.7.64.110—1
11298.7.64.111/3298.7.64.111 to 98.7.64.111—1
11398.7.64.112/3298.7.64.112 to 98.7.64.112—1
11498.7.64.113/3298.7.64.113 to 98.7.64.113—1
11598.7.64.114/3298.7.64.114 to 98.7.64.114—1
11698.7.64.115/3298.7.64.115 to 98.7.64.115—1
11798.7.64.116/3298.7.64.116 to 98.7.64.116—1
11898.7.64.117/3298.7.64.117 to 98.7.64.117—1
11998.7.64.118/3298.7.64.118 to 98.7.64.118—1
12098.7.64.119/3298.7.64.119 to 98.7.64.119—1
12198.7.64.120/3298.7.64.120 to 98.7.64.120—1
12298.7.64.121/3298.7.64.121 to 98.7.64.121—1
12398.7.64.122/3298.7.64.122 to 98.7.64.122—1
12498.7.64.123/3298.7.64.123 to 98.7.64.123—1
12598.7.64.124/3298.7.64.124 to 98.7.64.124—1
12698.7.64.125/3298.7.64.125 to 98.7.64.125—1
12798.7.64.126/3298.7.64.126 to 98.7.64.126—1
12898.7.64.127/3298.7.64.127 to 98.7.64.127—1
12998.7.64.128/3298.7.64.128 to 98.7.64.128—1
13098.7.64.129/3298.7.64.129 to 98.7.64.129—1
13198.7.64.130/3298.7.64.130 to 98.7.64.130—1
13298.7.64.131/3298.7.64.131 to 98.7.64.131—1
13398.7.64.132/3298.7.64.132 to 98.7.64.132—1
13498.7.64.133/3298.7.64.133 to 98.7.64.133—1
13598.7.64.134/3298.7.64.134 to 98.7.64.134—1
13698.7.64.135/3298.7.64.135 to 98.7.64.135—1
13798.7.64.136/3298.7.64.136 to 98.7.64.136—1
13898.7.64.137/3298.7.64.137 to 98.7.64.137—1
13998.7.64.138/3298.7.64.138 to 98.7.64.138—1
14098.7.64.139/3298.7.64.139 to 98.7.64.139—1
14198.7.64.140/3298.7.64.140 to 98.7.64.140—1
14298.7.64.141/3298.7.64.141 to 98.7.64.141—1
14398.7.64.142/3298.7.64.142 to 98.7.64.142—1
14498.7.64.143/3298.7.64.143 to 98.7.64.143—1
14598.7.64.144/3298.7.64.144 to 98.7.64.144—1
14698.7.64.145/3298.7.64.145 to 98.7.64.145—1
14798.7.64.146/3298.7.64.146 to 98.7.64.146—1
14898.7.64.147/3298.7.64.147 to 98.7.64.147—1
14998.7.64.148/3298.7.64.148 to 98.7.64.148—1
15098.7.64.149/3298.7.64.149 to 98.7.64.149—1
15198.7.64.150/3298.7.64.150 to 98.7.64.150—1
15298.7.64.151/3298.7.64.151 to 98.7.64.151—1
15398.7.64.152/3298.7.64.152 to 98.7.64.152—1
15498.7.64.153/3298.7.64.153 to 98.7.64.153—1
15598.7.64.154/3298.7.64.154 to 98.7.64.154—1
15698.7.64.155/3298.7.64.155 to 98.7.64.155—1
15798.7.64.156/3298.7.64.156 to 98.7.64.156—1
15898.7.64.157/3298.7.64.157 to 98.7.64.157—1
15998.7.64.158/3298.7.64.158 to 98.7.64.158—1
16098.7.64.159/3298.7.64.159 to 98.7.64.159—1
16198.7.64.160/3298.7.64.160 to 98.7.64.160—1
16298.7.64.161/3298.7.64.161 to 98.7.64.161—1
16398.7.64.162/3298.7.64.162 to 98.7.64.162—1
16498.7.64.163/3298.7.64.163 to 98.7.64.163—1
16598.7.64.164/3298.7.64.164 to 98.7.64.164—1
16698.7.64.165/3298.7.64.165 to 98.7.64.165—1
16798.7.64.166/3298.7.64.166 to 98.7.64.166—1
16898.7.64.167/3298.7.64.167 to 98.7.64.167—1
16998.7.64.168/3298.7.64.168 to 98.7.64.168—1
17098.7.64.169/3298.7.64.169 to 98.7.64.169—1
17198.7.64.170/3298.7.64.170 to 98.7.64.170—1
17298.7.64.171/3298.7.64.171 to 98.7.64.171—1
17398.7.64.172/3298.7.64.172 to 98.7.64.172—1
17498.7.64.173/3298.7.64.173 to 98.7.64.173—1
17598.7.64.174/3298.7.64.174 to 98.7.64.174—1
17698.7.64.175/3298.7.64.175 to 98.7.64.175—1
17798.7.64.176/3298.7.64.176 to 98.7.64.176—1
17898.7.64.177/3298.7.64.177 to 98.7.64.177—1
17998.7.64.178/3298.7.64.178 to 98.7.64.178—1
18098.7.64.179/3298.7.64.179 to 98.7.64.179—1
18198.7.64.180/3298.7.64.180 to 98.7.64.180—1
18298.7.64.181/3298.7.64.181 to 98.7.64.181—1
18398.7.64.182/3298.7.64.182 to 98.7.64.182—1
18498.7.64.183/3298.7.64.183 to 98.7.64.183—1
18598.7.64.184/3298.7.64.184 to 98.7.64.184—1
18698.7.64.185/3298.7.64.185 to 98.7.64.185—1
18798.7.64.186/3298.7.64.186 to 98.7.64.186—1
18898.7.64.187/3298.7.64.187 to 98.7.64.187—1
18998.7.64.188/3298.7.64.188 to 98.7.64.188—1
19098.7.64.189/3298.7.64.189 to 98.7.64.189—1
19198.7.64.190/3298.7.64.190 to 98.7.64.190—1
19298.7.64.191/3298.7.64.191 to 98.7.64.191—1
19398.7.64.192/3298.7.64.192 to 98.7.64.192—1
19498.7.64.193/3298.7.64.193 to 98.7.64.193—1
19598.7.64.194/3298.7.64.194 to 98.7.64.194—1
19698.7.64.195/3298.7.64.195 to 98.7.64.195—1
19798.7.64.196/3298.7.64.196 to 98.7.64.196—1
19898.7.64.197/3298.7.64.197 to 98.7.64.197—1
19998.7.64.198/3298.7.64.198 to 98.7.64.198—1
20098.7.64.199/3298.7.64.199 to 98.7.64.199—1
20198.7.64.200/3298.7.64.200 to 98.7.64.200—1
20298.7.64.201/3298.7.64.201 to 98.7.64.201—1
20398.7.64.202/3298.7.64.202 to 98.7.64.202—1
20498.7.64.203/3298.7.64.203 to 98.7.64.203—1
20598.7.64.204/3298.7.64.204 to 98.7.64.204—1
20698.7.64.205/3298.7.64.205 to 98.7.64.205—1
20798.7.64.206/3298.7.64.206 to 98.7.64.206—1
20898.7.64.207/3298.7.64.207 to 98.7.64.207—1
20998.7.64.208/3298.7.64.208 to 98.7.64.208—1
21098.7.64.209/3298.7.64.209 to 98.7.64.209—1
21198.7.64.210/3298.7.64.210 to 98.7.64.210—1
21298.7.64.211/3298.7.64.211 to 98.7.64.211—1
21398.7.64.212/3298.7.64.212 to 98.7.64.212—1
21498.7.64.213/3298.7.64.213 to 98.7.64.213—1
21598.7.64.214/3298.7.64.214 to 98.7.64.214—1
21698.7.64.215/3298.7.64.215 to 98.7.64.215—1
21798.7.64.216/3298.7.64.216 to 98.7.64.216—1
21898.7.64.217/3298.7.64.217 to 98.7.64.217—1
21998.7.64.218/3298.7.64.218 to 98.7.64.218—1
22098.7.64.219/3298.7.64.219 to 98.7.64.219—1
22198.7.64.220/3298.7.64.220 to 98.7.64.220—1
22298.7.64.221/3298.7.64.221 to 98.7.64.221—1
22398.7.64.222/3298.7.64.222 to 98.7.64.222—1
22498.7.64.223/3298.7.64.223 to 98.7.64.223—1
22598.7.64.224/3298.7.64.224 to 98.7.64.224—1
22698.7.64.225/3298.7.64.225 to 98.7.64.225—1
22798.7.64.226/3298.7.64.226 to 98.7.64.226—1
22898.7.64.227/3298.7.64.227 to 98.7.64.227—1
22998.7.64.228/3298.7.64.228 to 98.7.64.228—1
23098.7.64.229/3298.7.64.229 to 98.7.64.229—1
23198.7.64.230/3298.7.64.230 to 98.7.64.230—1
23298.7.64.231/3298.7.64.231 to 98.7.64.231—1
23398.7.64.232/3298.7.64.232 to 98.7.64.232—1
23498.7.64.233/3298.7.64.233 to 98.7.64.233—1
23598.7.64.234/3298.7.64.234 to 98.7.64.234—1
23698.7.64.235/3298.7.64.235 to 98.7.64.235—1
23798.7.64.236/3298.7.64.236 to 98.7.64.236—1
23898.7.64.237/3298.7.64.237 to 98.7.64.237—1
23998.7.64.238/3298.7.64.238 to 98.7.64.238—1
24098.7.64.239/3298.7.64.239 to 98.7.64.239—1
24198.7.64.240/3298.7.64.240 to 98.7.64.240—1
24298.7.64.241/3298.7.64.241 to 98.7.64.241—1
24398.7.64.242/3298.7.64.242 to 98.7.64.242—1
24498.7.64.243/3298.7.64.243 to 98.7.64.243—1
24598.7.64.244/3298.7.64.244 to 98.7.64.244—1
24698.7.64.245/3298.7.64.245 to 98.7.64.245—1
24798.7.64.246/3298.7.64.246 to 98.7.64.246—1
24898.7.64.247/3298.7.64.247 to 98.7.64.247—1
24998.7.64.248/3298.7.64.248 to 98.7.64.248—1
25098.7.64.249/3298.7.64.249 to 98.7.64.249—1
25198.7.64.250/3298.7.64.250 to 98.7.64.250—1
25298.7.64.251/3298.7.64.251 to 98.7.64.251—1
25398.7.64.252/3298.7.64.252 to 98.7.64.252—1
25498.7.64.253/3298.7.64.253 to 98.7.64.253—1
25598.7.64.254/3298.7.64.254 to 98.7.64.254—1
25698.7.64.255/3298.7.64.255 to 98.7.64.255—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.