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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.

Network25.67.56.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
25.67.56.0
Broadcast address
25.67.59.255
First usable
25.67.56.1
Last usable
25.67.59.254
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 19433800 · Integer 423835648 to 423836671
Reverse DNS zones
56.67.25.in-addr.arpa
57.67.25.in-addr.arpa
58.67.25.in-addr.arpa
59.67.25.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
Address00011001.01000011.00111000.0000000025.67.56.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00011001.01000011.00111000.0000000025.67.56.0
Broadcast00011001.01000011.00111011.1111111125.67.59.255
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)

25.67.56.0/22 makes 1,024 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
125.67.56.0/3225.67.56.0 to 25.67.56.0—1
225.67.56.1/3225.67.56.1 to 25.67.56.1—1
325.67.56.2/3225.67.56.2 to 25.67.56.2—1
425.67.56.3/3225.67.56.3 to 25.67.56.3—1
525.67.56.4/3225.67.56.4 to 25.67.56.4—1
625.67.56.5/3225.67.56.5 to 25.67.56.5—1
725.67.56.6/3225.67.56.6 to 25.67.56.6—1
825.67.56.7/3225.67.56.7 to 25.67.56.7—1
925.67.56.8/3225.67.56.8 to 25.67.56.8—1
1025.67.56.9/3225.67.56.9 to 25.67.56.9—1
1125.67.56.10/3225.67.56.10 to 25.67.56.10—1
1225.67.56.11/3225.67.56.11 to 25.67.56.11—1
1325.67.56.12/3225.67.56.12 to 25.67.56.12—1
1425.67.56.13/3225.67.56.13 to 25.67.56.13—1
1525.67.56.14/3225.67.56.14 to 25.67.56.14—1
1625.67.56.15/3225.67.56.15 to 25.67.56.15—1
1725.67.56.16/3225.67.56.16 to 25.67.56.16—1
1825.67.56.17/3225.67.56.17 to 25.67.56.17—1
1925.67.56.18/3225.67.56.18 to 25.67.56.18—1
2025.67.56.19/3225.67.56.19 to 25.67.56.19—1
2125.67.56.20/3225.67.56.20 to 25.67.56.20—1
2225.67.56.21/3225.67.56.21 to 25.67.56.21—1
2325.67.56.22/3225.67.56.22 to 25.67.56.22—1
2425.67.56.23/3225.67.56.23 to 25.67.56.23—1
2525.67.56.24/3225.67.56.24 to 25.67.56.24—1
2625.67.56.25/3225.67.56.25 to 25.67.56.25—1
2725.67.56.26/3225.67.56.26 to 25.67.56.26—1
2825.67.56.27/3225.67.56.27 to 25.67.56.27—1
2925.67.56.28/3225.67.56.28 to 25.67.56.28—1
3025.67.56.29/3225.67.56.29 to 25.67.56.29—1
3125.67.56.30/3225.67.56.30 to 25.67.56.30—1
3225.67.56.31/3225.67.56.31 to 25.67.56.31—1
3325.67.56.32/3225.67.56.32 to 25.67.56.32—1
3425.67.56.33/3225.67.56.33 to 25.67.56.33—1
3525.67.56.34/3225.67.56.34 to 25.67.56.34—1
3625.67.56.35/3225.67.56.35 to 25.67.56.35—1
3725.67.56.36/3225.67.56.36 to 25.67.56.36—1
3825.67.56.37/3225.67.56.37 to 25.67.56.37—1
3925.67.56.38/3225.67.56.38 to 25.67.56.38—1
4025.67.56.39/3225.67.56.39 to 25.67.56.39—1
4125.67.56.40/3225.67.56.40 to 25.67.56.40—1
4225.67.56.41/3225.67.56.41 to 25.67.56.41—1
4325.67.56.42/3225.67.56.42 to 25.67.56.42—1
4425.67.56.43/3225.67.56.43 to 25.67.56.43—1
4525.67.56.44/3225.67.56.44 to 25.67.56.44—1
4625.67.56.45/3225.67.56.45 to 25.67.56.45—1
4725.67.56.46/3225.67.56.46 to 25.67.56.46—1
4825.67.56.47/3225.67.56.47 to 25.67.56.47—1
4925.67.56.48/3225.67.56.48 to 25.67.56.48—1
5025.67.56.49/3225.67.56.49 to 25.67.56.49—1
5125.67.56.50/3225.67.56.50 to 25.67.56.50—1
5225.67.56.51/3225.67.56.51 to 25.67.56.51—1
5325.67.56.52/3225.67.56.52 to 25.67.56.52—1
5425.67.56.53/3225.67.56.53 to 25.67.56.53—1
5525.67.56.54/3225.67.56.54 to 25.67.56.54—1
5625.67.56.55/3225.67.56.55 to 25.67.56.55—1
5725.67.56.56/3225.67.56.56 to 25.67.56.56—1
5825.67.56.57/3225.67.56.57 to 25.67.56.57—1
5925.67.56.58/3225.67.56.58 to 25.67.56.58—1
6025.67.56.59/3225.67.56.59 to 25.67.56.59—1
6125.67.56.60/3225.67.56.60 to 25.67.56.60—1
6225.67.56.61/3225.67.56.61 to 25.67.56.61—1
6325.67.56.62/3225.67.56.62 to 25.67.56.62—1
6425.67.56.63/3225.67.56.63 to 25.67.56.63—1
6525.67.56.64/3225.67.56.64 to 25.67.56.64—1
6625.67.56.65/3225.67.56.65 to 25.67.56.65—1
6725.67.56.66/3225.67.56.66 to 25.67.56.66—1
6825.67.56.67/3225.67.56.67 to 25.67.56.67—1
6925.67.56.68/3225.67.56.68 to 25.67.56.68—1
7025.67.56.69/3225.67.56.69 to 25.67.56.69—1
7125.67.56.70/3225.67.56.70 to 25.67.56.70—1
7225.67.56.71/3225.67.56.71 to 25.67.56.71—1
7325.67.56.72/3225.67.56.72 to 25.67.56.72—1
7425.67.56.73/3225.67.56.73 to 25.67.56.73—1
7525.67.56.74/3225.67.56.74 to 25.67.56.74—1
7625.67.56.75/3225.67.56.75 to 25.67.56.75—1
7725.67.56.76/3225.67.56.76 to 25.67.56.76—1
7825.67.56.77/3225.67.56.77 to 25.67.56.77—1
7925.67.56.78/3225.67.56.78 to 25.67.56.78—1
8025.67.56.79/3225.67.56.79 to 25.67.56.79—1
8125.67.56.80/3225.67.56.80 to 25.67.56.80—1
8225.67.56.81/3225.67.56.81 to 25.67.56.81—1
8325.67.56.82/3225.67.56.82 to 25.67.56.82—1
8425.67.56.83/3225.67.56.83 to 25.67.56.83—1
8525.67.56.84/3225.67.56.84 to 25.67.56.84—1
8625.67.56.85/3225.67.56.85 to 25.67.56.85—1
8725.67.56.86/3225.67.56.86 to 25.67.56.86—1
8825.67.56.87/3225.67.56.87 to 25.67.56.87—1
8925.67.56.88/3225.67.56.88 to 25.67.56.88—1
9025.67.56.89/3225.67.56.89 to 25.67.56.89—1
9125.67.56.90/3225.67.56.90 to 25.67.56.90—1
9225.67.56.91/3225.67.56.91 to 25.67.56.91—1
9325.67.56.92/3225.67.56.92 to 25.67.56.92—1
9425.67.56.93/3225.67.56.93 to 25.67.56.93—1
9525.67.56.94/3225.67.56.94 to 25.67.56.94—1
9625.67.56.95/3225.67.56.95 to 25.67.56.95—1
9725.67.56.96/3225.67.56.96 to 25.67.56.96—1
9825.67.56.97/3225.67.56.97 to 25.67.56.97—1
9925.67.56.98/3225.67.56.98 to 25.67.56.98—1
10025.67.56.99/3225.67.56.99 to 25.67.56.99—1
10125.67.56.100/3225.67.56.100 to 25.67.56.100—1
10225.67.56.101/3225.67.56.101 to 25.67.56.101—1
10325.67.56.102/3225.67.56.102 to 25.67.56.102—1
10425.67.56.103/3225.67.56.103 to 25.67.56.103—1
10525.67.56.104/3225.67.56.104 to 25.67.56.104—1
10625.67.56.105/3225.67.56.105 to 25.67.56.105—1
10725.67.56.106/3225.67.56.106 to 25.67.56.106—1
10825.67.56.107/3225.67.56.107 to 25.67.56.107—1
10925.67.56.108/3225.67.56.108 to 25.67.56.108—1
11025.67.56.109/3225.67.56.109 to 25.67.56.109—1
11125.67.56.110/3225.67.56.110 to 25.67.56.110—1
11225.67.56.111/3225.67.56.111 to 25.67.56.111—1
11325.67.56.112/3225.67.56.112 to 25.67.56.112—1
11425.67.56.113/3225.67.56.113 to 25.67.56.113—1
11525.67.56.114/3225.67.56.114 to 25.67.56.114—1
11625.67.56.115/3225.67.56.115 to 25.67.56.115—1
11725.67.56.116/3225.67.56.116 to 25.67.56.116—1
11825.67.56.117/3225.67.56.117 to 25.67.56.117—1
11925.67.56.118/3225.67.56.118 to 25.67.56.118—1
12025.67.56.119/3225.67.56.119 to 25.67.56.119—1
12125.67.56.120/3225.67.56.120 to 25.67.56.120—1
12225.67.56.121/3225.67.56.121 to 25.67.56.121—1
12325.67.56.122/3225.67.56.122 to 25.67.56.122—1
12425.67.56.123/3225.67.56.123 to 25.67.56.123—1
12525.67.56.124/3225.67.56.124 to 25.67.56.124—1
12625.67.56.125/3225.67.56.125 to 25.67.56.125—1
12725.67.56.126/3225.67.56.126 to 25.67.56.126—1
12825.67.56.127/3225.67.56.127 to 25.67.56.127—1
12925.67.56.128/3225.67.56.128 to 25.67.56.128—1
13025.67.56.129/3225.67.56.129 to 25.67.56.129—1
13125.67.56.130/3225.67.56.130 to 25.67.56.130—1
13225.67.56.131/3225.67.56.131 to 25.67.56.131—1
13325.67.56.132/3225.67.56.132 to 25.67.56.132—1
13425.67.56.133/3225.67.56.133 to 25.67.56.133—1
13525.67.56.134/3225.67.56.134 to 25.67.56.134—1
13625.67.56.135/3225.67.56.135 to 25.67.56.135—1
13725.67.56.136/3225.67.56.136 to 25.67.56.136—1
13825.67.56.137/3225.67.56.137 to 25.67.56.137—1
13925.67.56.138/3225.67.56.138 to 25.67.56.138—1
14025.67.56.139/3225.67.56.139 to 25.67.56.139—1
14125.67.56.140/3225.67.56.140 to 25.67.56.140—1
14225.67.56.141/3225.67.56.141 to 25.67.56.141—1
14325.67.56.142/3225.67.56.142 to 25.67.56.142—1
14425.67.56.143/3225.67.56.143 to 25.67.56.143—1
14525.67.56.144/3225.67.56.144 to 25.67.56.144—1
14625.67.56.145/3225.67.56.145 to 25.67.56.145—1
14725.67.56.146/3225.67.56.146 to 25.67.56.146—1
14825.67.56.147/3225.67.56.147 to 25.67.56.147—1
14925.67.56.148/3225.67.56.148 to 25.67.56.148—1
15025.67.56.149/3225.67.56.149 to 25.67.56.149—1
15125.67.56.150/3225.67.56.150 to 25.67.56.150—1
15225.67.56.151/3225.67.56.151 to 25.67.56.151—1
15325.67.56.152/3225.67.56.152 to 25.67.56.152—1
15425.67.56.153/3225.67.56.153 to 25.67.56.153—1
15525.67.56.154/3225.67.56.154 to 25.67.56.154—1
15625.67.56.155/3225.67.56.155 to 25.67.56.155—1
15725.67.56.156/3225.67.56.156 to 25.67.56.156—1
15825.67.56.157/3225.67.56.157 to 25.67.56.157—1
15925.67.56.158/3225.67.56.158 to 25.67.56.158—1
16025.67.56.159/3225.67.56.159 to 25.67.56.159—1
16125.67.56.160/3225.67.56.160 to 25.67.56.160—1
16225.67.56.161/3225.67.56.161 to 25.67.56.161—1
16325.67.56.162/3225.67.56.162 to 25.67.56.162—1
16425.67.56.163/3225.67.56.163 to 25.67.56.163—1
16525.67.56.164/3225.67.56.164 to 25.67.56.164—1
16625.67.56.165/3225.67.56.165 to 25.67.56.165—1
16725.67.56.166/3225.67.56.166 to 25.67.56.166—1
16825.67.56.167/3225.67.56.167 to 25.67.56.167—1
16925.67.56.168/3225.67.56.168 to 25.67.56.168—1
17025.67.56.169/3225.67.56.169 to 25.67.56.169—1
17125.67.56.170/3225.67.56.170 to 25.67.56.170—1
17225.67.56.171/3225.67.56.171 to 25.67.56.171—1
17325.67.56.172/3225.67.56.172 to 25.67.56.172—1
17425.67.56.173/3225.67.56.173 to 25.67.56.173—1
17525.67.56.174/3225.67.56.174 to 25.67.56.174—1
17625.67.56.175/3225.67.56.175 to 25.67.56.175—1
17725.67.56.176/3225.67.56.176 to 25.67.56.176—1
17825.67.56.177/3225.67.56.177 to 25.67.56.177—1
17925.67.56.178/3225.67.56.178 to 25.67.56.178—1
18025.67.56.179/3225.67.56.179 to 25.67.56.179—1
18125.67.56.180/3225.67.56.180 to 25.67.56.180—1
18225.67.56.181/3225.67.56.181 to 25.67.56.181—1
18325.67.56.182/3225.67.56.182 to 25.67.56.182—1
18425.67.56.183/3225.67.56.183 to 25.67.56.183—1
18525.67.56.184/3225.67.56.184 to 25.67.56.184—1
18625.67.56.185/3225.67.56.185 to 25.67.56.185—1
18725.67.56.186/3225.67.56.186 to 25.67.56.186—1
18825.67.56.187/3225.67.56.187 to 25.67.56.187—1
18925.67.56.188/3225.67.56.188 to 25.67.56.188—1
19025.67.56.189/3225.67.56.189 to 25.67.56.189—1
19125.67.56.190/3225.67.56.190 to 25.67.56.190—1
19225.67.56.191/3225.67.56.191 to 25.67.56.191—1
19325.67.56.192/3225.67.56.192 to 25.67.56.192—1
19425.67.56.193/3225.67.56.193 to 25.67.56.193—1
19525.67.56.194/3225.67.56.194 to 25.67.56.194—1
19625.67.56.195/3225.67.56.195 to 25.67.56.195—1
19725.67.56.196/3225.67.56.196 to 25.67.56.196—1
19825.67.56.197/3225.67.56.197 to 25.67.56.197—1
19925.67.56.198/3225.67.56.198 to 25.67.56.198—1
20025.67.56.199/3225.67.56.199 to 25.67.56.199—1
20125.67.56.200/3225.67.56.200 to 25.67.56.200—1
20225.67.56.201/3225.67.56.201 to 25.67.56.201—1
20325.67.56.202/3225.67.56.202 to 25.67.56.202—1
20425.67.56.203/3225.67.56.203 to 25.67.56.203—1
20525.67.56.204/3225.67.56.204 to 25.67.56.204—1
20625.67.56.205/3225.67.56.205 to 25.67.56.205—1
20725.67.56.206/3225.67.56.206 to 25.67.56.206—1
20825.67.56.207/3225.67.56.207 to 25.67.56.207—1
20925.67.56.208/3225.67.56.208 to 25.67.56.208—1
21025.67.56.209/3225.67.56.209 to 25.67.56.209—1
21125.67.56.210/3225.67.56.210 to 25.67.56.210—1
21225.67.56.211/3225.67.56.211 to 25.67.56.211—1
21325.67.56.212/3225.67.56.212 to 25.67.56.212—1
21425.67.56.213/3225.67.56.213 to 25.67.56.213—1
21525.67.56.214/3225.67.56.214 to 25.67.56.214—1
21625.67.56.215/3225.67.56.215 to 25.67.56.215—1
21725.67.56.216/3225.67.56.216 to 25.67.56.216—1
21825.67.56.217/3225.67.56.217 to 25.67.56.217—1
21925.67.56.218/3225.67.56.218 to 25.67.56.218—1
22025.67.56.219/3225.67.56.219 to 25.67.56.219—1
22125.67.56.220/3225.67.56.220 to 25.67.56.220—1
22225.67.56.221/3225.67.56.221 to 25.67.56.221—1
22325.67.56.222/3225.67.56.222 to 25.67.56.222—1
22425.67.56.223/3225.67.56.223 to 25.67.56.223—1
22525.67.56.224/3225.67.56.224 to 25.67.56.224—1
22625.67.56.225/3225.67.56.225 to 25.67.56.225—1
22725.67.56.226/3225.67.56.226 to 25.67.56.226—1
22825.67.56.227/3225.67.56.227 to 25.67.56.227—1
22925.67.56.228/3225.67.56.228 to 25.67.56.228—1
23025.67.56.229/3225.67.56.229 to 25.67.56.229—1
23125.67.56.230/3225.67.56.230 to 25.67.56.230—1
23225.67.56.231/3225.67.56.231 to 25.67.56.231—1
23325.67.56.232/3225.67.56.232 to 25.67.56.232—1
23425.67.56.233/3225.67.56.233 to 25.67.56.233—1
23525.67.56.234/3225.67.56.234 to 25.67.56.234—1
23625.67.56.235/3225.67.56.235 to 25.67.56.235—1
23725.67.56.236/3225.67.56.236 to 25.67.56.236—1
23825.67.56.237/3225.67.56.237 to 25.67.56.237—1
23925.67.56.238/3225.67.56.238 to 25.67.56.238—1
24025.67.56.239/3225.67.56.239 to 25.67.56.239—1
24125.67.56.240/3225.67.56.240 to 25.67.56.240—1
24225.67.56.241/3225.67.56.241 to 25.67.56.241—1
24325.67.56.242/3225.67.56.242 to 25.67.56.242—1
24425.67.56.243/3225.67.56.243 to 25.67.56.243—1
24525.67.56.244/3225.67.56.244 to 25.67.56.244—1
24625.67.56.245/3225.67.56.245 to 25.67.56.245—1
24725.67.56.246/3225.67.56.246 to 25.67.56.246—1
24825.67.56.247/3225.67.56.247 to 25.67.56.247—1
24925.67.56.248/3225.67.56.248 to 25.67.56.248—1
25025.67.56.249/3225.67.56.249 to 25.67.56.249—1
25125.67.56.250/3225.67.56.250 to 25.67.56.250—1
25225.67.56.251/3225.67.56.251 to 25.67.56.251—1
25325.67.56.252/3225.67.56.252 to 25.67.56.252—1
25425.67.56.253/3225.67.56.253 to 25.67.56.253—1
25525.67.56.254/3225.67.56.254 to 25.67.56.254—1
25625.67.56.255/3225.67.56.255 to 25.67.56.255—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.