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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.

Network23.2.4.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
23.2.4.0
Broadcast address
23.2.7.255
First usable
23.2.4.1
Last usable
23.2.7.254
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 17020400 · Integer 386008064 to 386009087
Reverse DNS zones
4.2.23.in-addr.arpa
5.2.23.in-addr.arpa
6.2.23.in-addr.arpa
7.2.23.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
Address00010111.00000010.00000100.0000000023.2.4.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00010111.00000010.00000100.0000000023.2.4.0
Broadcast00010111.00000010.00000111.1111111123.2.7.255
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)

23.2.4.0/22 makes 1,024 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
123.2.4.0/3223.2.4.0 to 23.2.4.0—1
223.2.4.1/3223.2.4.1 to 23.2.4.1—1
323.2.4.2/3223.2.4.2 to 23.2.4.2—1
423.2.4.3/3223.2.4.3 to 23.2.4.3—1
523.2.4.4/3223.2.4.4 to 23.2.4.4—1
623.2.4.5/3223.2.4.5 to 23.2.4.5—1
723.2.4.6/3223.2.4.6 to 23.2.4.6—1
823.2.4.7/3223.2.4.7 to 23.2.4.7—1
923.2.4.8/3223.2.4.8 to 23.2.4.8—1
1023.2.4.9/3223.2.4.9 to 23.2.4.9—1
1123.2.4.10/3223.2.4.10 to 23.2.4.10—1
1223.2.4.11/3223.2.4.11 to 23.2.4.11—1
1323.2.4.12/3223.2.4.12 to 23.2.4.12—1
1423.2.4.13/3223.2.4.13 to 23.2.4.13—1
1523.2.4.14/3223.2.4.14 to 23.2.4.14—1
1623.2.4.15/3223.2.4.15 to 23.2.4.15—1
1723.2.4.16/3223.2.4.16 to 23.2.4.16—1
1823.2.4.17/3223.2.4.17 to 23.2.4.17—1
1923.2.4.18/3223.2.4.18 to 23.2.4.18—1
2023.2.4.19/3223.2.4.19 to 23.2.4.19—1
2123.2.4.20/3223.2.4.20 to 23.2.4.20—1
2223.2.4.21/3223.2.4.21 to 23.2.4.21—1
2323.2.4.22/3223.2.4.22 to 23.2.4.22—1
2423.2.4.23/3223.2.4.23 to 23.2.4.23—1
2523.2.4.24/3223.2.4.24 to 23.2.4.24—1
2623.2.4.25/3223.2.4.25 to 23.2.4.25—1
2723.2.4.26/3223.2.4.26 to 23.2.4.26—1
2823.2.4.27/3223.2.4.27 to 23.2.4.27—1
2923.2.4.28/3223.2.4.28 to 23.2.4.28—1
3023.2.4.29/3223.2.4.29 to 23.2.4.29—1
3123.2.4.30/3223.2.4.30 to 23.2.4.30—1
3223.2.4.31/3223.2.4.31 to 23.2.4.31—1
3323.2.4.32/3223.2.4.32 to 23.2.4.32—1
3423.2.4.33/3223.2.4.33 to 23.2.4.33—1
3523.2.4.34/3223.2.4.34 to 23.2.4.34—1
3623.2.4.35/3223.2.4.35 to 23.2.4.35—1
3723.2.4.36/3223.2.4.36 to 23.2.4.36—1
3823.2.4.37/3223.2.4.37 to 23.2.4.37—1
3923.2.4.38/3223.2.4.38 to 23.2.4.38—1
4023.2.4.39/3223.2.4.39 to 23.2.4.39—1
4123.2.4.40/3223.2.4.40 to 23.2.4.40—1
4223.2.4.41/3223.2.4.41 to 23.2.4.41—1
4323.2.4.42/3223.2.4.42 to 23.2.4.42—1
4423.2.4.43/3223.2.4.43 to 23.2.4.43—1
4523.2.4.44/3223.2.4.44 to 23.2.4.44—1
4623.2.4.45/3223.2.4.45 to 23.2.4.45—1
4723.2.4.46/3223.2.4.46 to 23.2.4.46—1
4823.2.4.47/3223.2.4.47 to 23.2.4.47—1
4923.2.4.48/3223.2.4.48 to 23.2.4.48—1
5023.2.4.49/3223.2.4.49 to 23.2.4.49—1
5123.2.4.50/3223.2.4.50 to 23.2.4.50—1
5223.2.4.51/3223.2.4.51 to 23.2.4.51—1
5323.2.4.52/3223.2.4.52 to 23.2.4.52—1
5423.2.4.53/3223.2.4.53 to 23.2.4.53—1
5523.2.4.54/3223.2.4.54 to 23.2.4.54—1
5623.2.4.55/3223.2.4.55 to 23.2.4.55—1
5723.2.4.56/3223.2.4.56 to 23.2.4.56—1
5823.2.4.57/3223.2.4.57 to 23.2.4.57—1
5923.2.4.58/3223.2.4.58 to 23.2.4.58—1
6023.2.4.59/3223.2.4.59 to 23.2.4.59—1
6123.2.4.60/3223.2.4.60 to 23.2.4.60—1
6223.2.4.61/3223.2.4.61 to 23.2.4.61—1
6323.2.4.62/3223.2.4.62 to 23.2.4.62—1
6423.2.4.63/3223.2.4.63 to 23.2.4.63—1
6523.2.4.64/3223.2.4.64 to 23.2.4.64—1
6623.2.4.65/3223.2.4.65 to 23.2.4.65—1
6723.2.4.66/3223.2.4.66 to 23.2.4.66—1
6823.2.4.67/3223.2.4.67 to 23.2.4.67—1
6923.2.4.68/3223.2.4.68 to 23.2.4.68—1
7023.2.4.69/3223.2.4.69 to 23.2.4.69—1
7123.2.4.70/3223.2.4.70 to 23.2.4.70—1
7223.2.4.71/3223.2.4.71 to 23.2.4.71—1
7323.2.4.72/3223.2.4.72 to 23.2.4.72—1
7423.2.4.73/3223.2.4.73 to 23.2.4.73—1
7523.2.4.74/3223.2.4.74 to 23.2.4.74—1
7623.2.4.75/3223.2.4.75 to 23.2.4.75—1
7723.2.4.76/3223.2.4.76 to 23.2.4.76—1
7823.2.4.77/3223.2.4.77 to 23.2.4.77—1
7923.2.4.78/3223.2.4.78 to 23.2.4.78—1
8023.2.4.79/3223.2.4.79 to 23.2.4.79—1
8123.2.4.80/3223.2.4.80 to 23.2.4.80—1
8223.2.4.81/3223.2.4.81 to 23.2.4.81—1
8323.2.4.82/3223.2.4.82 to 23.2.4.82—1
8423.2.4.83/3223.2.4.83 to 23.2.4.83—1
8523.2.4.84/3223.2.4.84 to 23.2.4.84—1
8623.2.4.85/3223.2.4.85 to 23.2.4.85—1
8723.2.4.86/3223.2.4.86 to 23.2.4.86—1
8823.2.4.87/3223.2.4.87 to 23.2.4.87—1
8923.2.4.88/3223.2.4.88 to 23.2.4.88—1
9023.2.4.89/3223.2.4.89 to 23.2.4.89—1
9123.2.4.90/3223.2.4.90 to 23.2.4.90—1
9223.2.4.91/3223.2.4.91 to 23.2.4.91—1
9323.2.4.92/3223.2.4.92 to 23.2.4.92—1
9423.2.4.93/3223.2.4.93 to 23.2.4.93—1
9523.2.4.94/3223.2.4.94 to 23.2.4.94—1
9623.2.4.95/3223.2.4.95 to 23.2.4.95—1
9723.2.4.96/3223.2.4.96 to 23.2.4.96—1
9823.2.4.97/3223.2.4.97 to 23.2.4.97—1
9923.2.4.98/3223.2.4.98 to 23.2.4.98—1
10023.2.4.99/3223.2.4.99 to 23.2.4.99—1
10123.2.4.100/3223.2.4.100 to 23.2.4.100—1
10223.2.4.101/3223.2.4.101 to 23.2.4.101—1
10323.2.4.102/3223.2.4.102 to 23.2.4.102—1
10423.2.4.103/3223.2.4.103 to 23.2.4.103—1
10523.2.4.104/3223.2.4.104 to 23.2.4.104—1
10623.2.4.105/3223.2.4.105 to 23.2.4.105—1
10723.2.4.106/3223.2.4.106 to 23.2.4.106—1
10823.2.4.107/3223.2.4.107 to 23.2.4.107—1
10923.2.4.108/3223.2.4.108 to 23.2.4.108—1
11023.2.4.109/3223.2.4.109 to 23.2.4.109—1
11123.2.4.110/3223.2.4.110 to 23.2.4.110—1
11223.2.4.111/3223.2.4.111 to 23.2.4.111—1
11323.2.4.112/3223.2.4.112 to 23.2.4.112—1
11423.2.4.113/3223.2.4.113 to 23.2.4.113—1
11523.2.4.114/3223.2.4.114 to 23.2.4.114—1
11623.2.4.115/3223.2.4.115 to 23.2.4.115—1
11723.2.4.116/3223.2.4.116 to 23.2.4.116—1
11823.2.4.117/3223.2.4.117 to 23.2.4.117—1
11923.2.4.118/3223.2.4.118 to 23.2.4.118—1
12023.2.4.119/3223.2.4.119 to 23.2.4.119—1
12123.2.4.120/3223.2.4.120 to 23.2.4.120—1
12223.2.4.121/3223.2.4.121 to 23.2.4.121—1
12323.2.4.122/3223.2.4.122 to 23.2.4.122—1
12423.2.4.123/3223.2.4.123 to 23.2.4.123—1
12523.2.4.124/3223.2.4.124 to 23.2.4.124—1
12623.2.4.125/3223.2.4.125 to 23.2.4.125—1
12723.2.4.126/3223.2.4.126 to 23.2.4.126—1
12823.2.4.127/3223.2.4.127 to 23.2.4.127—1
12923.2.4.128/3223.2.4.128 to 23.2.4.128—1
13023.2.4.129/3223.2.4.129 to 23.2.4.129—1
13123.2.4.130/3223.2.4.130 to 23.2.4.130—1
13223.2.4.131/3223.2.4.131 to 23.2.4.131—1
13323.2.4.132/3223.2.4.132 to 23.2.4.132—1
13423.2.4.133/3223.2.4.133 to 23.2.4.133—1
13523.2.4.134/3223.2.4.134 to 23.2.4.134—1
13623.2.4.135/3223.2.4.135 to 23.2.4.135—1
13723.2.4.136/3223.2.4.136 to 23.2.4.136—1
13823.2.4.137/3223.2.4.137 to 23.2.4.137—1
13923.2.4.138/3223.2.4.138 to 23.2.4.138—1
14023.2.4.139/3223.2.4.139 to 23.2.4.139—1
14123.2.4.140/3223.2.4.140 to 23.2.4.140—1
14223.2.4.141/3223.2.4.141 to 23.2.4.141—1
14323.2.4.142/3223.2.4.142 to 23.2.4.142—1
14423.2.4.143/3223.2.4.143 to 23.2.4.143—1
14523.2.4.144/3223.2.4.144 to 23.2.4.144—1
14623.2.4.145/3223.2.4.145 to 23.2.4.145—1
14723.2.4.146/3223.2.4.146 to 23.2.4.146—1
14823.2.4.147/3223.2.4.147 to 23.2.4.147—1
14923.2.4.148/3223.2.4.148 to 23.2.4.148—1
15023.2.4.149/3223.2.4.149 to 23.2.4.149—1
15123.2.4.150/3223.2.4.150 to 23.2.4.150—1
15223.2.4.151/3223.2.4.151 to 23.2.4.151—1
15323.2.4.152/3223.2.4.152 to 23.2.4.152—1
15423.2.4.153/3223.2.4.153 to 23.2.4.153—1
15523.2.4.154/3223.2.4.154 to 23.2.4.154—1
15623.2.4.155/3223.2.4.155 to 23.2.4.155—1
15723.2.4.156/3223.2.4.156 to 23.2.4.156—1
15823.2.4.157/3223.2.4.157 to 23.2.4.157—1
15923.2.4.158/3223.2.4.158 to 23.2.4.158—1
16023.2.4.159/3223.2.4.159 to 23.2.4.159—1
16123.2.4.160/3223.2.4.160 to 23.2.4.160—1
16223.2.4.161/3223.2.4.161 to 23.2.4.161—1
16323.2.4.162/3223.2.4.162 to 23.2.4.162—1
16423.2.4.163/3223.2.4.163 to 23.2.4.163—1
16523.2.4.164/3223.2.4.164 to 23.2.4.164—1
16623.2.4.165/3223.2.4.165 to 23.2.4.165—1
16723.2.4.166/3223.2.4.166 to 23.2.4.166—1
16823.2.4.167/3223.2.4.167 to 23.2.4.167—1
16923.2.4.168/3223.2.4.168 to 23.2.4.168—1
17023.2.4.169/3223.2.4.169 to 23.2.4.169—1
17123.2.4.170/3223.2.4.170 to 23.2.4.170—1
17223.2.4.171/3223.2.4.171 to 23.2.4.171—1
17323.2.4.172/3223.2.4.172 to 23.2.4.172—1
17423.2.4.173/3223.2.4.173 to 23.2.4.173—1
17523.2.4.174/3223.2.4.174 to 23.2.4.174—1
17623.2.4.175/3223.2.4.175 to 23.2.4.175—1
17723.2.4.176/3223.2.4.176 to 23.2.4.176—1
17823.2.4.177/3223.2.4.177 to 23.2.4.177—1
17923.2.4.178/3223.2.4.178 to 23.2.4.178—1
18023.2.4.179/3223.2.4.179 to 23.2.4.179—1
18123.2.4.180/3223.2.4.180 to 23.2.4.180—1
18223.2.4.181/3223.2.4.181 to 23.2.4.181—1
18323.2.4.182/3223.2.4.182 to 23.2.4.182—1
18423.2.4.183/3223.2.4.183 to 23.2.4.183—1
18523.2.4.184/3223.2.4.184 to 23.2.4.184—1
18623.2.4.185/3223.2.4.185 to 23.2.4.185—1
18723.2.4.186/3223.2.4.186 to 23.2.4.186—1
18823.2.4.187/3223.2.4.187 to 23.2.4.187—1
18923.2.4.188/3223.2.4.188 to 23.2.4.188—1
19023.2.4.189/3223.2.4.189 to 23.2.4.189—1
19123.2.4.190/3223.2.4.190 to 23.2.4.190—1
19223.2.4.191/3223.2.4.191 to 23.2.4.191—1
19323.2.4.192/3223.2.4.192 to 23.2.4.192—1
19423.2.4.193/3223.2.4.193 to 23.2.4.193—1
19523.2.4.194/3223.2.4.194 to 23.2.4.194—1
19623.2.4.195/3223.2.4.195 to 23.2.4.195—1
19723.2.4.196/3223.2.4.196 to 23.2.4.196—1
19823.2.4.197/3223.2.4.197 to 23.2.4.197—1
19923.2.4.198/3223.2.4.198 to 23.2.4.198—1
20023.2.4.199/3223.2.4.199 to 23.2.4.199—1
20123.2.4.200/3223.2.4.200 to 23.2.4.200—1
20223.2.4.201/3223.2.4.201 to 23.2.4.201—1
20323.2.4.202/3223.2.4.202 to 23.2.4.202—1
20423.2.4.203/3223.2.4.203 to 23.2.4.203—1
20523.2.4.204/3223.2.4.204 to 23.2.4.204—1
20623.2.4.205/3223.2.4.205 to 23.2.4.205—1
20723.2.4.206/3223.2.4.206 to 23.2.4.206—1
20823.2.4.207/3223.2.4.207 to 23.2.4.207—1
20923.2.4.208/3223.2.4.208 to 23.2.4.208—1
21023.2.4.209/3223.2.4.209 to 23.2.4.209—1
21123.2.4.210/3223.2.4.210 to 23.2.4.210—1
21223.2.4.211/3223.2.4.211 to 23.2.4.211—1
21323.2.4.212/3223.2.4.212 to 23.2.4.212—1
21423.2.4.213/3223.2.4.213 to 23.2.4.213—1
21523.2.4.214/3223.2.4.214 to 23.2.4.214—1
21623.2.4.215/3223.2.4.215 to 23.2.4.215—1
21723.2.4.216/3223.2.4.216 to 23.2.4.216—1
21823.2.4.217/3223.2.4.217 to 23.2.4.217—1
21923.2.4.218/3223.2.4.218 to 23.2.4.218—1
22023.2.4.219/3223.2.4.219 to 23.2.4.219—1
22123.2.4.220/3223.2.4.220 to 23.2.4.220—1
22223.2.4.221/3223.2.4.221 to 23.2.4.221—1
22323.2.4.222/3223.2.4.222 to 23.2.4.222—1
22423.2.4.223/3223.2.4.223 to 23.2.4.223—1
22523.2.4.224/3223.2.4.224 to 23.2.4.224—1
22623.2.4.225/3223.2.4.225 to 23.2.4.225—1
22723.2.4.226/3223.2.4.226 to 23.2.4.226—1
22823.2.4.227/3223.2.4.227 to 23.2.4.227—1
22923.2.4.228/3223.2.4.228 to 23.2.4.228—1
23023.2.4.229/3223.2.4.229 to 23.2.4.229—1
23123.2.4.230/3223.2.4.230 to 23.2.4.230—1
23223.2.4.231/3223.2.4.231 to 23.2.4.231—1
23323.2.4.232/3223.2.4.232 to 23.2.4.232—1
23423.2.4.233/3223.2.4.233 to 23.2.4.233—1
23523.2.4.234/3223.2.4.234 to 23.2.4.234—1
23623.2.4.235/3223.2.4.235 to 23.2.4.235—1
23723.2.4.236/3223.2.4.236 to 23.2.4.236—1
23823.2.4.237/3223.2.4.237 to 23.2.4.237—1
23923.2.4.238/3223.2.4.238 to 23.2.4.238—1
24023.2.4.239/3223.2.4.239 to 23.2.4.239—1
24123.2.4.240/3223.2.4.240 to 23.2.4.240—1
24223.2.4.241/3223.2.4.241 to 23.2.4.241—1
24323.2.4.242/3223.2.4.242 to 23.2.4.242—1
24423.2.4.243/3223.2.4.243 to 23.2.4.243—1
24523.2.4.244/3223.2.4.244 to 23.2.4.244—1
24623.2.4.245/3223.2.4.245 to 23.2.4.245—1
24723.2.4.246/3223.2.4.246 to 23.2.4.246—1
24823.2.4.247/3223.2.4.247 to 23.2.4.247—1
24923.2.4.248/3223.2.4.248 to 23.2.4.248—1
25023.2.4.249/3223.2.4.249 to 23.2.4.249—1
25123.2.4.250/3223.2.4.250 to 23.2.4.250—1
25223.2.4.251/3223.2.4.251 to 23.2.4.251—1
25323.2.4.252/3223.2.4.252 to 23.2.4.252—1
25423.2.4.253/3223.2.4.253 to 23.2.4.253—1
25523.2.4.254/3223.2.4.254 to 23.2.4.254—1
25623.2.4.255/3223.2.4.255 to 23.2.4.255—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.