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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.

Network22.2.72.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
22.2.72.0
Broadcast address
22.2.75.255
First usable
22.2.72.1
Last usable
22.2.75.254
Usable hosts
1,022 (1,024 less the network and broadcast addresses)
Subnet mask
255.255.252.0
Wildcard mask
0.0.3.255 (Cisco ACLs, OSPF)
Prefix length
/22
Type
Public public
Old class
A (default /8)
As numbers
Hex 16024800 · Integer 369248256 to 369249279
Reverse DNS zones
72.2.22.in-addr.arpa
73.2.22.in-addr.arpa
74.2.22.in-addr.arpa
75.2.22.in-addr.arpa
/22 is not on a 8-bit boundary, so it takes 4 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010110.00000010.01001000.0000000022.2.72.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00010110.00000010.01001000.0000000022.2.72.0
Broadcast00010110.00000010.01001011.1111111122.2.75.255
Split into smaller subnets/32
/23 (2)/24 (4)/25 (8)/26 (16)/27 (32)/28 (64)/29 (128)/30 (256)/31 (512)/32 (1,024)

22.2.72.0/22 makes 1,024 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
122.2.72.0/3222.2.72.0 to 22.2.72.0—1
222.2.72.1/3222.2.72.1 to 22.2.72.1—1
322.2.72.2/3222.2.72.2 to 22.2.72.2—1
422.2.72.3/3222.2.72.3 to 22.2.72.3—1
522.2.72.4/3222.2.72.4 to 22.2.72.4—1
622.2.72.5/3222.2.72.5 to 22.2.72.5—1
722.2.72.6/3222.2.72.6 to 22.2.72.6—1
822.2.72.7/3222.2.72.7 to 22.2.72.7—1
922.2.72.8/3222.2.72.8 to 22.2.72.8—1
1022.2.72.9/3222.2.72.9 to 22.2.72.9—1
1122.2.72.10/3222.2.72.10 to 22.2.72.10—1
1222.2.72.11/3222.2.72.11 to 22.2.72.11—1
1322.2.72.12/3222.2.72.12 to 22.2.72.12—1
1422.2.72.13/3222.2.72.13 to 22.2.72.13—1
1522.2.72.14/3222.2.72.14 to 22.2.72.14—1
1622.2.72.15/3222.2.72.15 to 22.2.72.15—1
1722.2.72.16/3222.2.72.16 to 22.2.72.16—1
1822.2.72.17/3222.2.72.17 to 22.2.72.17—1
1922.2.72.18/3222.2.72.18 to 22.2.72.18—1
2022.2.72.19/3222.2.72.19 to 22.2.72.19—1
2122.2.72.20/3222.2.72.20 to 22.2.72.20—1
2222.2.72.21/3222.2.72.21 to 22.2.72.21—1
2322.2.72.22/3222.2.72.22 to 22.2.72.22—1
2422.2.72.23/3222.2.72.23 to 22.2.72.23—1
2522.2.72.24/3222.2.72.24 to 22.2.72.24—1
2622.2.72.25/3222.2.72.25 to 22.2.72.25—1
2722.2.72.26/3222.2.72.26 to 22.2.72.26—1
2822.2.72.27/3222.2.72.27 to 22.2.72.27—1
2922.2.72.28/3222.2.72.28 to 22.2.72.28—1
3022.2.72.29/3222.2.72.29 to 22.2.72.29—1
3122.2.72.30/3222.2.72.30 to 22.2.72.30—1
3222.2.72.31/3222.2.72.31 to 22.2.72.31—1
3322.2.72.32/3222.2.72.32 to 22.2.72.32—1
3422.2.72.33/3222.2.72.33 to 22.2.72.33—1
3522.2.72.34/3222.2.72.34 to 22.2.72.34—1
3622.2.72.35/3222.2.72.35 to 22.2.72.35—1
3722.2.72.36/3222.2.72.36 to 22.2.72.36—1
3822.2.72.37/3222.2.72.37 to 22.2.72.37—1
3922.2.72.38/3222.2.72.38 to 22.2.72.38—1
4022.2.72.39/3222.2.72.39 to 22.2.72.39—1
4122.2.72.40/3222.2.72.40 to 22.2.72.40—1
4222.2.72.41/3222.2.72.41 to 22.2.72.41—1
4322.2.72.42/3222.2.72.42 to 22.2.72.42—1
4422.2.72.43/3222.2.72.43 to 22.2.72.43—1
4522.2.72.44/3222.2.72.44 to 22.2.72.44—1
4622.2.72.45/3222.2.72.45 to 22.2.72.45—1
4722.2.72.46/3222.2.72.46 to 22.2.72.46—1
4822.2.72.47/3222.2.72.47 to 22.2.72.47—1
4922.2.72.48/3222.2.72.48 to 22.2.72.48—1
5022.2.72.49/3222.2.72.49 to 22.2.72.49—1
5122.2.72.50/3222.2.72.50 to 22.2.72.50—1
5222.2.72.51/3222.2.72.51 to 22.2.72.51—1
5322.2.72.52/3222.2.72.52 to 22.2.72.52—1
5422.2.72.53/3222.2.72.53 to 22.2.72.53—1
5522.2.72.54/3222.2.72.54 to 22.2.72.54—1
5622.2.72.55/3222.2.72.55 to 22.2.72.55—1
5722.2.72.56/3222.2.72.56 to 22.2.72.56—1
5822.2.72.57/3222.2.72.57 to 22.2.72.57—1
5922.2.72.58/3222.2.72.58 to 22.2.72.58—1
6022.2.72.59/3222.2.72.59 to 22.2.72.59—1
6122.2.72.60/3222.2.72.60 to 22.2.72.60—1
6222.2.72.61/3222.2.72.61 to 22.2.72.61—1
6322.2.72.62/3222.2.72.62 to 22.2.72.62—1
6422.2.72.63/3222.2.72.63 to 22.2.72.63—1
6522.2.72.64/3222.2.72.64 to 22.2.72.64—1
6622.2.72.65/3222.2.72.65 to 22.2.72.65—1
6722.2.72.66/3222.2.72.66 to 22.2.72.66—1
6822.2.72.67/3222.2.72.67 to 22.2.72.67—1
6922.2.72.68/3222.2.72.68 to 22.2.72.68—1
7022.2.72.69/3222.2.72.69 to 22.2.72.69—1
7122.2.72.70/3222.2.72.70 to 22.2.72.70—1
7222.2.72.71/3222.2.72.71 to 22.2.72.71—1
7322.2.72.72/3222.2.72.72 to 22.2.72.72—1
7422.2.72.73/3222.2.72.73 to 22.2.72.73—1
7522.2.72.74/3222.2.72.74 to 22.2.72.74—1
7622.2.72.75/3222.2.72.75 to 22.2.72.75—1
7722.2.72.76/3222.2.72.76 to 22.2.72.76—1
7822.2.72.77/3222.2.72.77 to 22.2.72.77—1
7922.2.72.78/3222.2.72.78 to 22.2.72.78—1
8022.2.72.79/3222.2.72.79 to 22.2.72.79—1
8122.2.72.80/3222.2.72.80 to 22.2.72.80—1
8222.2.72.81/3222.2.72.81 to 22.2.72.81—1
8322.2.72.82/3222.2.72.82 to 22.2.72.82—1
8422.2.72.83/3222.2.72.83 to 22.2.72.83—1
8522.2.72.84/3222.2.72.84 to 22.2.72.84—1
8622.2.72.85/3222.2.72.85 to 22.2.72.85—1
8722.2.72.86/3222.2.72.86 to 22.2.72.86—1
8822.2.72.87/3222.2.72.87 to 22.2.72.87—1
8922.2.72.88/3222.2.72.88 to 22.2.72.88—1
9022.2.72.89/3222.2.72.89 to 22.2.72.89—1
9122.2.72.90/3222.2.72.90 to 22.2.72.90—1
9222.2.72.91/3222.2.72.91 to 22.2.72.91—1
9322.2.72.92/3222.2.72.92 to 22.2.72.92—1
9422.2.72.93/3222.2.72.93 to 22.2.72.93—1
9522.2.72.94/3222.2.72.94 to 22.2.72.94—1
9622.2.72.95/3222.2.72.95 to 22.2.72.95—1
9722.2.72.96/3222.2.72.96 to 22.2.72.96—1
9822.2.72.97/3222.2.72.97 to 22.2.72.97—1
9922.2.72.98/3222.2.72.98 to 22.2.72.98—1
10022.2.72.99/3222.2.72.99 to 22.2.72.99—1
10122.2.72.100/3222.2.72.100 to 22.2.72.100—1
10222.2.72.101/3222.2.72.101 to 22.2.72.101—1
10322.2.72.102/3222.2.72.102 to 22.2.72.102—1
10422.2.72.103/3222.2.72.103 to 22.2.72.103—1
10522.2.72.104/3222.2.72.104 to 22.2.72.104—1
10622.2.72.105/3222.2.72.105 to 22.2.72.105—1
10722.2.72.106/3222.2.72.106 to 22.2.72.106—1
10822.2.72.107/3222.2.72.107 to 22.2.72.107—1
10922.2.72.108/3222.2.72.108 to 22.2.72.108—1
11022.2.72.109/3222.2.72.109 to 22.2.72.109—1
11122.2.72.110/3222.2.72.110 to 22.2.72.110—1
11222.2.72.111/3222.2.72.111 to 22.2.72.111—1
11322.2.72.112/3222.2.72.112 to 22.2.72.112—1
11422.2.72.113/3222.2.72.113 to 22.2.72.113—1
11522.2.72.114/3222.2.72.114 to 22.2.72.114—1
11622.2.72.115/3222.2.72.115 to 22.2.72.115—1
11722.2.72.116/3222.2.72.116 to 22.2.72.116—1
11822.2.72.117/3222.2.72.117 to 22.2.72.117—1
11922.2.72.118/3222.2.72.118 to 22.2.72.118—1
12022.2.72.119/3222.2.72.119 to 22.2.72.119—1
12122.2.72.120/3222.2.72.120 to 22.2.72.120—1
12222.2.72.121/3222.2.72.121 to 22.2.72.121—1
12322.2.72.122/3222.2.72.122 to 22.2.72.122—1
12422.2.72.123/3222.2.72.123 to 22.2.72.123—1
12522.2.72.124/3222.2.72.124 to 22.2.72.124—1
12622.2.72.125/3222.2.72.125 to 22.2.72.125—1
12722.2.72.126/3222.2.72.126 to 22.2.72.126—1
12822.2.72.127/3222.2.72.127 to 22.2.72.127—1
12922.2.72.128/3222.2.72.128 to 22.2.72.128—1
13022.2.72.129/3222.2.72.129 to 22.2.72.129—1
13122.2.72.130/3222.2.72.130 to 22.2.72.130—1
13222.2.72.131/3222.2.72.131 to 22.2.72.131—1
13322.2.72.132/3222.2.72.132 to 22.2.72.132—1
13422.2.72.133/3222.2.72.133 to 22.2.72.133—1
13522.2.72.134/3222.2.72.134 to 22.2.72.134—1
13622.2.72.135/3222.2.72.135 to 22.2.72.135—1
13722.2.72.136/3222.2.72.136 to 22.2.72.136—1
13822.2.72.137/3222.2.72.137 to 22.2.72.137—1
13922.2.72.138/3222.2.72.138 to 22.2.72.138—1
14022.2.72.139/3222.2.72.139 to 22.2.72.139—1
14122.2.72.140/3222.2.72.140 to 22.2.72.140—1
14222.2.72.141/3222.2.72.141 to 22.2.72.141—1
14322.2.72.142/3222.2.72.142 to 22.2.72.142—1
14422.2.72.143/3222.2.72.143 to 22.2.72.143—1
14522.2.72.144/3222.2.72.144 to 22.2.72.144—1
14622.2.72.145/3222.2.72.145 to 22.2.72.145—1
14722.2.72.146/3222.2.72.146 to 22.2.72.146—1
14822.2.72.147/3222.2.72.147 to 22.2.72.147—1
14922.2.72.148/3222.2.72.148 to 22.2.72.148—1
15022.2.72.149/3222.2.72.149 to 22.2.72.149—1
15122.2.72.150/3222.2.72.150 to 22.2.72.150—1
15222.2.72.151/3222.2.72.151 to 22.2.72.151—1
15322.2.72.152/3222.2.72.152 to 22.2.72.152—1
15422.2.72.153/3222.2.72.153 to 22.2.72.153—1
15522.2.72.154/3222.2.72.154 to 22.2.72.154—1
15622.2.72.155/3222.2.72.155 to 22.2.72.155—1
15722.2.72.156/3222.2.72.156 to 22.2.72.156—1
15822.2.72.157/3222.2.72.157 to 22.2.72.157—1
15922.2.72.158/3222.2.72.158 to 22.2.72.158—1
16022.2.72.159/3222.2.72.159 to 22.2.72.159—1
16122.2.72.160/3222.2.72.160 to 22.2.72.160—1
16222.2.72.161/3222.2.72.161 to 22.2.72.161—1
16322.2.72.162/3222.2.72.162 to 22.2.72.162—1
16422.2.72.163/3222.2.72.163 to 22.2.72.163—1
16522.2.72.164/3222.2.72.164 to 22.2.72.164—1
16622.2.72.165/3222.2.72.165 to 22.2.72.165—1
16722.2.72.166/3222.2.72.166 to 22.2.72.166—1
16822.2.72.167/3222.2.72.167 to 22.2.72.167—1
16922.2.72.168/3222.2.72.168 to 22.2.72.168—1
17022.2.72.169/3222.2.72.169 to 22.2.72.169—1
17122.2.72.170/3222.2.72.170 to 22.2.72.170—1
17222.2.72.171/3222.2.72.171 to 22.2.72.171—1
17322.2.72.172/3222.2.72.172 to 22.2.72.172—1
17422.2.72.173/3222.2.72.173 to 22.2.72.173—1
17522.2.72.174/3222.2.72.174 to 22.2.72.174—1
17622.2.72.175/3222.2.72.175 to 22.2.72.175—1
17722.2.72.176/3222.2.72.176 to 22.2.72.176—1
17822.2.72.177/3222.2.72.177 to 22.2.72.177—1
17922.2.72.178/3222.2.72.178 to 22.2.72.178—1
18022.2.72.179/3222.2.72.179 to 22.2.72.179—1
18122.2.72.180/3222.2.72.180 to 22.2.72.180—1
18222.2.72.181/3222.2.72.181 to 22.2.72.181—1
18322.2.72.182/3222.2.72.182 to 22.2.72.182—1
18422.2.72.183/3222.2.72.183 to 22.2.72.183—1
18522.2.72.184/3222.2.72.184 to 22.2.72.184—1
18622.2.72.185/3222.2.72.185 to 22.2.72.185—1
18722.2.72.186/3222.2.72.186 to 22.2.72.186—1
18822.2.72.187/3222.2.72.187 to 22.2.72.187—1
18922.2.72.188/3222.2.72.188 to 22.2.72.188—1
19022.2.72.189/3222.2.72.189 to 22.2.72.189—1
19122.2.72.190/3222.2.72.190 to 22.2.72.190—1
19222.2.72.191/3222.2.72.191 to 22.2.72.191—1
19322.2.72.192/3222.2.72.192 to 22.2.72.192—1
19422.2.72.193/3222.2.72.193 to 22.2.72.193—1
19522.2.72.194/3222.2.72.194 to 22.2.72.194—1
19622.2.72.195/3222.2.72.195 to 22.2.72.195—1
19722.2.72.196/3222.2.72.196 to 22.2.72.196—1
19822.2.72.197/3222.2.72.197 to 22.2.72.197—1
19922.2.72.198/3222.2.72.198 to 22.2.72.198—1
20022.2.72.199/3222.2.72.199 to 22.2.72.199—1
20122.2.72.200/3222.2.72.200 to 22.2.72.200—1
20222.2.72.201/3222.2.72.201 to 22.2.72.201—1
20322.2.72.202/3222.2.72.202 to 22.2.72.202—1
20422.2.72.203/3222.2.72.203 to 22.2.72.203—1
20522.2.72.204/3222.2.72.204 to 22.2.72.204—1
20622.2.72.205/3222.2.72.205 to 22.2.72.205—1
20722.2.72.206/3222.2.72.206 to 22.2.72.206—1
20822.2.72.207/3222.2.72.207 to 22.2.72.207—1
20922.2.72.208/3222.2.72.208 to 22.2.72.208—1
21022.2.72.209/3222.2.72.209 to 22.2.72.209—1
21122.2.72.210/3222.2.72.210 to 22.2.72.210—1
21222.2.72.211/3222.2.72.211 to 22.2.72.211—1
21322.2.72.212/3222.2.72.212 to 22.2.72.212—1
21422.2.72.213/3222.2.72.213 to 22.2.72.213—1
21522.2.72.214/3222.2.72.214 to 22.2.72.214—1
21622.2.72.215/3222.2.72.215 to 22.2.72.215—1
21722.2.72.216/3222.2.72.216 to 22.2.72.216—1
21822.2.72.217/3222.2.72.217 to 22.2.72.217—1
21922.2.72.218/3222.2.72.218 to 22.2.72.218—1
22022.2.72.219/3222.2.72.219 to 22.2.72.219—1
22122.2.72.220/3222.2.72.220 to 22.2.72.220—1
22222.2.72.221/3222.2.72.221 to 22.2.72.221—1
22322.2.72.222/3222.2.72.222 to 22.2.72.222—1
22422.2.72.223/3222.2.72.223 to 22.2.72.223—1
22522.2.72.224/3222.2.72.224 to 22.2.72.224—1
22622.2.72.225/3222.2.72.225 to 22.2.72.225—1
22722.2.72.226/3222.2.72.226 to 22.2.72.226—1
22822.2.72.227/3222.2.72.227 to 22.2.72.227—1
22922.2.72.228/3222.2.72.228 to 22.2.72.228—1
23022.2.72.229/3222.2.72.229 to 22.2.72.229—1
23122.2.72.230/3222.2.72.230 to 22.2.72.230—1
23222.2.72.231/3222.2.72.231 to 22.2.72.231—1
23322.2.72.232/3222.2.72.232 to 22.2.72.232—1
23422.2.72.233/3222.2.72.233 to 22.2.72.233—1
23522.2.72.234/3222.2.72.234 to 22.2.72.234—1
23622.2.72.235/3222.2.72.235 to 22.2.72.235—1
23722.2.72.236/3222.2.72.236 to 22.2.72.236—1
23822.2.72.237/3222.2.72.237 to 22.2.72.237—1
23922.2.72.238/3222.2.72.238 to 22.2.72.238—1
24022.2.72.239/3222.2.72.239 to 22.2.72.239—1
24122.2.72.240/3222.2.72.240 to 22.2.72.240—1
24222.2.72.241/3222.2.72.241 to 22.2.72.241—1
24322.2.72.242/3222.2.72.242 to 22.2.72.242—1
24422.2.72.243/3222.2.72.243 to 22.2.72.243—1
24522.2.72.244/3222.2.72.244 to 22.2.72.244—1
24622.2.72.245/3222.2.72.245 to 22.2.72.245—1
24722.2.72.246/3222.2.72.246 to 22.2.72.246—1
24822.2.72.247/3222.2.72.247 to 22.2.72.247—1
24922.2.72.248/3222.2.72.248 to 22.2.72.248—1
25022.2.72.249/3222.2.72.249 to 22.2.72.249—1
25122.2.72.250/3222.2.72.250 to 22.2.72.250—1
25222.2.72.251/3222.2.72.251 to 22.2.72.251—1
25322.2.72.252/3222.2.72.252 to 22.2.72.252—1
25422.2.72.253/3222.2.72.253 to 22.2.72.253—1
25522.2.72.254/3222.2.72.254 to 22.2.72.254—1
25622.2.72.255/3222.2.72.255 to 22.2.72.255—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.