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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.

Network84.2.32.0/21
Usable hosts2,046
Subnet mask255.255.248.0
Addresses2,048
Network address
84.2.32.0
Broadcast address
84.2.39.255
First usable
84.2.32.1
Last usable
84.2.39.254
Usable hosts
2,046 (2,048 less the network and broadcast addresses)
Subnet mask
255.255.248.0
Wildcard mask
0.0.7.255 (Cisco ACLs, OSPF)
Prefix length
/21
Type
Public public
Old class
A (default /8)
As numbers
Hex 54022000 · Integer 1409425408 to 1409427455
Reverse DNS zones
32.2.84.in-addr.arpa
33.2.84.in-addr.arpa
34.2.84.in-addr.arpa
35.2.84.in-addr.arpa
36.2.84.in-addr.arpa
37.2.84.in-addr.arpa
38.2.84.in-addr.arpa
39.2.84.in-addr.arpa
/21 is not on a 8-bit boundary, so it takes 8 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010100.00000010.00100000.0000000084.2.32.0
Subnet mask11111111.11111111.11111000.00000000255.255.248.0
Network01010100.00000010.00100000.0000000084.2.32.0
Broadcast01010100.00000010.00100111.1111111184.2.39.255
Split into smaller subnets/32
/22 (2)/23 (4)/24 (8)/25 (16)/26 (32)/27 (64)/28 (128)/29 (256)/30 (512)/31 (1,024)/32 (2,048)

84.2.32.0/21 makes 2,048 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
184.2.32.0/3284.2.32.0 to 84.2.32.0—1
284.2.32.1/3284.2.32.1 to 84.2.32.1—1
384.2.32.2/3284.2.32.2 to 84.2.32.2—1
484.2.32.3/3284.2.32.3 to 84.2.32.3—1
584.2.32.4/3284.2.32.4 to 84.2.32.4—1
684.2.32.5/3284.2.32.5 to 84.2.32.5—1
784.2.32.6/3284.2.32.6 to 84.2.32.6—1
884.2.32.7/3284.2.32.7 to 84.2.32.7—1
984.2.32.8/3284.2.32.8 to 84.2.32.8—1
1084.2.32.9/3284.2.32.9 to 84.2.32.9—1
1184.2.32.10/3284.2.32.10 to 84.2.32.10—1
1284.2.32.11/3284.2.32.11 to 84.2.32.11—1
1384.2.32.12/3284.2.32.12 to 84.2.32.12—1
1484.2.32.13/3284.2.32.13 to 84.2.32.13—1
1584.2.32.14/3284.2.32.14 to 84.2.32.14—1
1684.2.32.15/3284.2.32.15 to 84.2.32.15—1
1784.2.32.16/3284.2.32.16 to 84.2.32.16—1
1884.2.32.17/3284.2.32.17 to 84.2.32.17—1
1984.2.32.18/3284.2.32.18 to 84.2.32.18—1
2084.2.32.19/3284.2.32.19 to 84.2.32.19—1
2184.2.32.20/3284.2.32.20 to 84.2.32.20—1
2284.2.32.21/3284.2.32.21 to 84.2.32.21—1
2384.2.32.22/3284.2.32.22 to 84.2.32.22—1
2484.2.32.23/3284.2.32.23 to 84.2.32.23—1
2584.2.32.24/3284.2.32.24 to 84.2.32.24—1
2684.2.32.25/3284.2.32.25 to 84.2.32.25—1
2784.2.32.26/3284.2.32.26 to 84.2.32.26—1
2884.2.32.27/3284.2.32.27 to 84.2.32.27—1
2984.2.32.28/3284.2.32.28 to 84.2.32.28—1
3084.2.32.29/3284.2.32.29 to 84.2.32.29—1
3184.2.32.30/3284.2.32.30 to 84.2.32.30—1
3284.2.32.31/3284.2.32.31 to 84.2.32.31—1
3384.2.32.32/3284.2.32.32 to 84.2.32.32—1
3484.2.32.33/3284.2.32.33 to 84.2.32.33—1
3584.2.32.34/3284.2.32.34 to 84.2.32.34—1
3684.2.32.35/3284.2.32.35 to 84.2.32.35—1
3784.2.32.36/3284.2.32.36 to 84.2.32.36—1
3884.2.32.37/3284.2.32.37 to 84.2.32.37—1
3984.2.32.38/3284.2.32.38 to 84.2.32.38—1
4084.2.32.39/3284.2.32.39 to 84.2.32.39—1
4184.2.32.40/3284.2.32.40 to 84.2.32.40—1
4284.2.32.41/3284.2.32.41 to 84.2.32.41—1
4384.2.32.42/3284.2.32.42 to 84.2.32.42—1
4484.2.32.43/3284.2.32.43 to 84.2.32.43—1
4584.2.32.44/3284.2.32.44 to 84.2.32.44—1
4684.2.32.45/3284.2.32.45 to 84.2.32.45—1
4784.2.32.46/3284.2.32.46 to 84.2.32.46—1
4884.2.32.47/3284.2.32.47 to 84.2.32.47—1
4984.2.32.48/3284.2.32.48 to 84.2.32.48—1
5084.2.32.49/3284.2.32.49 to 84.2.32.49—1
5184.2.32.50/3284.2.32.50 to 84.2.32.50—1
5284.2.32.51/3284.2.32.51 to 84.2.32.51—1
5384.2.32.52/3284.2.32.52 to 84.2.32.52—1
5484.2.32.53/3284.2.32.53 to 84.2.32.53—1
5584.2.32.54/3284.2.32.54 to 84.2.32.54—1
5684.2.32.55/3284.2.32.55 to 84.2.32.55—1
5784.2.32.56/3284.2.32.56 to 84.2.32.56—1
5884.2.32.57/3284.2.32.57 to 84.2.32.57—1
5984.2.32.58/3284.2.32.58 to 84.2.32.58—1
6084.2.32.59/3284.2.32.59 to 84.2.32.59—1
6184.2.32.60/3284.2.32.60 to 84.2.32.60—1
6284.2.32.61/3284.2.32.61 to 84.2.32.61—1
6384.2.32.62/3284.2.32.62 to 84.2.32.62—1
6484.2.32.63/3284.2.32.63 to 84.2.32.63—1
6584.2.32.64/3284.2.32.64 to 84.2.32.64—1
6684.2.32.65/3284.2.32.65 to 84.2.32.65—1
6784.2.32.66/3284.2.32.66 to 84.2.32.66—1
6884.2.32.67/3284.2.32.67 to 84.2.32.67—1
6984.2.32.68/3284.2.32.68 to 84.2.32.68—1
7084.2.32.69/3284.2.32.69 to 84.2.32.69—1
7184.2.32.70/3284.2.32.70 to 84.2.32.70—1
7284.2.32.71/3284.2.32.71 to 84.2.32.71—1
7384.2.32.72/3284.2.32.72 to 84.2.32.72—1
7484.2.32.73/3284.2.32.73 to 84.2.32.73—1
7584.2.32.74/3284.2.32.74 to 84.2.32.74—1
7684.2.32.75/3284.2.32.75 to 84.2.32.75—1
7784.2.32.76/3284.2.32.76 to 84.2.32.76—1
7884.2.32.77/3284.2.32.77 to 84.2.32.77—1
7984.2.32.78/3284.2.32.78 to 84.2.32.78—1
8084.2.32.79/3284.2.32.79 to 84.2.32.79—1
8184.2.32.80/3284.2.32.80 to 84.2.32.80—1
8284.2.32.81/3284.2.32.81 to 84.2.32.81—1
8384.2.32.82/3284.2.32.82 to 84.2.32.82—1
8484.2.32.83/3284.2.32.83 to 84.2.32.83—1
8584.2.32.84/3284.2.32.84 to 84.2.32.84—1
8684.2.32.85/3284.2.32.85 to 84.2.32.85—1
8784.2.32.86/3284.2.32.86 to 84.2.32.86—1
8884.2.32.87/3284.2.32.87 to 84.2.32.87—1
8984.2.32.88/3284.2.32.88 to 84.2.32.88—1
9084.2.32.89/3284.2.32.89 to 84.2.32.89—1
9184.2.32.90/3284.2.32.90 to 84.2.32.90—1
9284.2.32.91/3284.2.32.91 to 84.2.32.91—1
9384.2.32.92/3284.2.32.92 to 84.2.32.92—1
9484.2.32.93/3284.2.32.93 to 84.2.32.93—1
9584.2.32.94/3284.2.32.94 to 84.2.32.94—1
9684.2.32.95/3284.2.32.95 to 84.2.32.95—1
9784.2.32.96/3284.2.32.96 to 84.2.32.96—1
9884.2.32.97/3284.2.32.97 to 84.2.32.97—1
9984.2.32.98/3284.2.32.98 to 84.2.32.98—1
10084.2.32.99/3284.2.32.99 to 84.2.32.99—1
10184.2.32.100/3284.2.32.100 to 84.2.32.100—1
10284.2.32.101/3284.2.32.101 to 84.2.32.101—1
10384.2.32.102/3284.2.32.102 to 84.2.32.102—1
10484.2.32.103/3284.2.32.103 to 84.2.32.103—1
10584.2.32.104/3284.2.32.104 to 84.2.32.104—1
10684.2.32.105/3284.2.32.105 to 84.2.32.105—1
10784.2.32.106/3284.2.32.106 to 84.2.32.106—1
10884.2.32.107/3284.2.32.107 to 84.2.32.107—1
10984.2.32.108/3284.2.32.108 to 84.2.32.108—1
11084.2.32.109/3284.2.32.109 to 84.2.32.109—1
11184.2.32.110/3284.2.32.110 to 84.2.32.110—1
11284.2.32.111/3284.2.32.111 to 84.2.32.111—1
11384.2.32.112/3284.2.32.112 to 84.2.32.112—1
11484.2.32.113/3284.2.32.113 to 84.2.32.113—1
11584.2.32.114/3284.2.32.114 to 84.2.32.114—1
11684.2.32.115/3284.2.32.115 to 84.2.32.115—1
11784.2.32.116/3284.2.32.116 to 84.2.32.116—1
11884.2.32.117/3284.2.32.117 to 84.2.32.117—1
11984.2.32.118/3284.2.32.118 to 84.2.32.118—1
12084.2.32.119/3284.2.32.119 to 84.2.32.119—1
12184.2.32.120/3284.2.32.120 to 84.2.32.120—1
12284.2.32.121/3284.2.32.121 to 84.2.32.121—1
12384.2.32.122/3284.2.32.122 to 84.2.32.122—1
12484.2.32.123/3284.2.32.123 to 84.2.32.123—1
12584.2.32.124/3284.2.32.124 to 84.2.32.124—1
12684.2.32.125/3284.2.32.125 to 84.2.32.125—1
12784.2.32.126/3284.2.32.126 to 84.2.32.126—1
12884.2.32.127/3284.2.32.127 to 84.2.32.127—1
12984.2.32.128/3284.2.32.128 to 84.2.32.128—1
13084.2.32.129/3284.2.32.129 to 84.2.32.129—1
13184.2.32.130/3284.2.32.130 to 84.2.32.130—1
13284.2.32.131/3284.2.32.131 to 84.2.32.131—1
13384.2.32.132/3284.2.32.132 to 84.2.32.132—1
13484.2.32.133/3284.2.32.133 to 84.2.32.133—1
13584.2.32.134/3284.2.32.134 to 84.2.32.134—1
13684.2.32.135/3284.2.32.135 to 84.2.32.135—1
13784.2.32.136/3284.2.32.136 to 84.2.32.136—1
13884.2.32.137/3284.2.32.137 to 84.2.32.137—1
13984.2.32.138/3284.2.32.138 to 84.2.32.138—1
14084.2.32.139/3284.2.32.139 to 84.2.32.139—1
14184.2.32.140/3284.2.32.140 to 84.2.32.140—1
14284.2.32.141/3284.2.32.141 to 84.2.32.141—1
14384.2.32.142/3284.2.32.142 to 84.2.32.142—1
14484.2.32.143/3284.2.32.143 to 84.2.32.143—1
14584.2.32.144/3284.2.32.144 to 84.2.32.144—1
14684.2.32.145/3284.2.32.145 to 84.2.32.145—1
14784.2.32.146/3284.2.32.146 to 84.2.32.146—1
14884.2.32.147/3284.2.32.147 to 84.2.32.147—1
14984.2.32.148/3284.2.32.148 to 84.2.32.148—1
15084.2.32.149/3284.2.32.149 to 84.2.32.149—1
15184.2.32.150/3284.2.32.150 to 84.2.32.150—1
15284.2.32.151/3284.2.32.151 to 84.2.32.151—1
15384.2.32.152/3284.2.32.152 to 84.2.32.152—1
15484.2.32.153/3284.2.32.153 to 84.2.32.153—1
15584.2.32.154/3284.2.32.154 to 84.2.32.154—1
15684.2.32.155/3284.2.32.155 to 84.2.32.155—1
15784.2.32.156/3284.2.32.156 to 84.2.32.156—1
15884.2.32.157/3284.2.32.157 to 84.2.32.157—1
15984.2.32.158/3284.2.32.158 to 84.2.32.158—1
16084.2.32.159/3284.2.32.159 to 84.2.32.159—1
16184.2.32.160/3284.2.32.160 to 84.2.32.160—1
16284.2.32.161/3284.2.32.161 to 84.2.32.161—1
16384.2.32.162/3284.2.32.162 to 84.2.32.162—1
16484.2.32.163/3284.2.32.163 to 84.2.32.163—1
16584.2.32.164/3284.2.32.164 to 84.2.32.164—1
16684.2.32.165/3284.2.32.165 to 84.2.32.165—1
16784.2.32.166/3284.2.32.166 to 84.2.32.166—1
16884.2.32.167/3284.2.32.167 to 84.2.32.167—1
16984.2.32.168/3284.2.32.168 to 84.2.32.168—1
17084.2.32.169/3284.2.32.169 to 84.2.32.169—1
17184.2.32.170/3284.2.32.170 to 84.2.32.170—1
17284.2.32.171/3284.2.32.171 to 84.2.32.171—1
17384.2.32.172/3284.2.32.172 to 84.2.32.172—1
17484.2.32.173/3284.2.32.173 to 84.2.32.173—1
17584.2.32.174/3284.2.32.174 to 84.2.32.174—1
17684.2.32.175/3284.2.32.175 to 84.2.32.175—1
17784.2.32.176/3284.2.32.176 to 84.2.32.176—1
17884.2.32.177/3284.2.32.177 to 84.2.32.177—1
17984.2.32.178/3284.2.32.178 to 84.2.32.178—1
18084.2.32.179/3284.2.32.179 to 84.2.32.179—1
18184.2.32.180/3284.2.32.180 to 84.2.32.180—1
18284.2.32.181/3284.2.32.181 to 84.2.32.181—1
18384.2.32.182/3284.2.32.182 to 84.2.32.182—1
18484.2.32.183/3284.2.32.183 to 84.2.32.183—1
18584.2.32.184/3284.2.32.184 to 84.2.32.184—1
18684.2.32.185/3284.2.32.185 to 84.2.32.185—1
18784.2.32.186/3284.2.32.186 to 84.2.32.186—1
18884.2.32.187/3284.2.32.187 to 84.2.32.187—1
18984.2.32.188/3284.2.32.188 to 84.2.32.188—1
19084.2.32.189/3284.2.32.189 to 84.2.32.189—1
19184.2.32.190/3284.2.32.190 to 84.2.32.190—1
19284.2.32.191/3284.2.32.191 to 84.2.32.191—1
19384.2.32.192/3284.2.32.192 to 84.2.32.192—1
19484.2.32.193/3284.2.32.193 to 84.2.32.193—1
19584.2.32.194/3284.2.32.194 to 84.2.32.194—1
19684.2.32.195/3284.2.32.195 to 84.2.32.195—1
19784.2.32.196/3284.2.32.196 to 84.2.32.196—1
19884.2.32.197/3284.2.32.197 to 84.2.32.197—1
19984.2.32.198/3284.2.32.198 to 84.2.32.198—1
20084.2.32.199/3284.2.32.199 to 84.2.32.199—1
20184.2.32.200/3284.2.32.200 to 84.2.32.200—1
20284.2.32.201/3284.2.32.201 to 84.2.32.201—1
20384.2.32.202/3284.2.32.202 to 84.2.32.202—1
20484.2.32.203/3284.2.32.203 to 84.2.32.203—1
20584.2.32.204/3284.2.32.204 to 84.2.32.204—1
20684.2.32.205/3284.2.32.205 to 84.2.32.205—1
20784.2.32.206/3284.2.32.206 to 84.2.32.206—1
20884.2.32.207/3284.2.32.207 to 84.2.32.207—1
20984.2.32.208/3284.2.32.208 to 84.2.32.208—1
21084.2.32.209/3284.2.32.209 to 84.2.32.209—1
21184.2.32.210/3284.2.32.210 to 84.2.32.210—1
21284.2.32.211/3284.2.32.211 to 84.2.32.211—1
21384.2.32.212/3284.2.32.212 to 84.2.32.212—1
21484.2.32.213/3284.2.32.213 to 84.2.32.213—1
21584.2.32.214/3284.2.32.214 to 84.2.32.214—1
21684.2.32.215/3284.2.32.215 to 84.2.32.215—1
21784.2.32.216/3284.2.32.216 to 84.2.32.216—1
21884.2.32.217/3284.2.32.217 to 84.2.32.217—1
21984.2.32.218/3284.2.32.218 to 84.2.32.218—1
22084.2.32.219/3284.2.32.219 to 84.2.32.219—1
22184.2.32.220/3284.2.32.220 to 84.2.32.220—1
22284.2.32.221/3284.2.32.221 to 84.2.32.221—1
22384.2.32.222/3284.2.32.222 to 84.2.32.222—1
22484.2.32.223/3284.2.32.223 to 84.2.32.223—1
22584.2.32.224/3284.2.32.224 to 84.2.32.224—1
22684.2.32.225/3284.2.32.225 to 84.2.32.225—1
22784.2.32.226/3284.2.32.226 to 84.2.32.226—1
22884.2.32.227/3284.2.32.227 to 84.2.32.227—1
22984.2.32.228/3284.2.32.228 to 84.2.32.228—1
23084.2.32.229/3284.2.32.229 to 84.2.32.229—1
23184.2.32.230/3284.2.32.230 to 84.2.32.230—1
23284.2.32.231/3284.2.32.231 to 84.2.32.231—1
23384.2.32.232/3284.2.32.232 to 84.2.32.232—1
23484.2.32.233/3284.2.32.233 to 84.2.32.233—1
23584.2.32.234/3284.2.32.234 to 84.2.32.234—1
23684.2.32.235/3284.2.32.235 to 84.2.32.235—1
23784.2.32.236/3284.2.32.236 to 84.2.32.236—1
23884.2.32.237/3284.2.32.237 to 84.2.32.237—1
23984.2.32.238/3284.2.32.238 to 84.2.32.238—1
24084.2.32.239/3284.2.32.239 to 84.2.32.239—1
24184.2.32.240/3284.2.32.240 to 84.2.32.240—1
24284.2.32.241/3284.2.32.241 to 84.2.32.241—1
24384.2.32.242/3284.2.32.242 to 84.2.32.242—1
24484.2.32.243/3284.2.32.243 to 84.2.32.243—1
24584.2.32.244/3284.2.32.244 to 84.2.32.244—1
24684.2.32.245/3284.2.32.245 to 84.2.32.245—1
24784.2.32.246/3284.2.32.246 to 84.2.32.246—1
24884.2.32.247/3284.2.32.247 to 84.2.32.247—1
24984.2.32.248/3284.2.32.248 to 84.2.32.248—1
25084.2.32.249/3284.2.32.249 to 84.2.32.249—1
25184.2.32.250/3284.2.32.250 to 84.2.32.250—1
25284.2.32.251/3284.2.32.251 to 84.2.32.251—1
25384.2.32.252/3284.2.32.252 to 84.2.32.252—1
25484.2.32.253/3284.2.32.253 to 84.2.32.253—1
25584.2.32.254/3284.2.32.254 to 84.2.32.254—1
25684.2.32.255/3284.2.32.255 to 84.2.32.255—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.