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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.

Network51.2.232.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
51.2.232.0
Broadcast address
51.2.235.255
First usable
51.2.232.1
Last usable
51.2.235.254
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 3302E800 · Integer 855828480 to 855829503
Reverse DNS zones
232.2.51.in-addr.arpa
233.2.51.in-addr.arpa
234.2.51.in-addr.arpa
235.2.51.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
Address00110011.00000010.11101000.0000000051.2.232.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00110011.00000010.11101000.0000000051.2.232.0
Broadcast00110011.00000010.11101011.1111111151.2.235.255
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)

51.2.232.0/22 makes 1,024 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
151.2.232.0/3251.2.232.0 to 51.2.232.0—1
251.2.232.1/3251.2.232.1 to 51.2.232.1—1
351.2.232.2/3251.2.232.2 to 51.2.232.2—1
451.2.232.3/3251.2.232.3 to 51.2.232.3—1
551.2.232.4/3251.2.232.4 to 51.2.232.4—1
651.2.232.5/3251.2.232.5 to 51.2.232.5—1
751.2.232.6/3251.2.232.6 to 51.2.232.6—1
851.2.232.7/3251.2.232.7 to 51.2.232.7—1
951.2.232.8/3251.2.232.8 to 51.2.232.8—1
1051.2.232.9/3251.2.232.9 to 51.2.232.9—1
1151.2.232.10/3251.2.232.10 to 51.2.232.10—1
1251.2.232.11/3251.2.232.11 to 51.2.232.11—1
1351.2.232.12/3251.2.232.12 to 51.2.232.12—1
1451.2.232.13/3251.2.232.13 to 51.2.232.13—1
1551.2.232.14/3251.2.232.14 to 51.2.232.14—1
1651.2.232.15/3251.2.232.15 to 51.2.232.15—1
1751.2.232.16/3251.2.232.16 to 51.2.232.16—1
1851.2.232.17/3251.2.232.17 to 51.2.232.17—1
1951.2.232.18/3251.2.232.18 to 51.2.232.18—1
2051.2.232.19/3251.2.232.19 to 51.2.232.19—1
2151.2.232.20/3251.2.232.20 to 51.2.232.20—1
2251.2.232.21/3251.2.232.21 to 51.2.232.21—1
2351.2.232.22/3251.2.232.22 to 51.2.232.22—1
2451.2.232.23/3251.2.232.23 to 51.2.232.23—1
2551.2.232.24/3251.2.232.24 to 51.2.232.24—1
2651.2.232.25/3251.2.232.25 to 51.2.232.25—1
2751.2.232.26/3251.2.232.26 to 51.2.232.26—1
2851.2.232.27/3251.2.232.27 to 51.2.232.27—1
2951.2.232.28/3251.2.232.28 to 51.2.232.28—1
3051.2.232.29/3251.2.232.29 to 51.2.232.29—1
3151.2.232.30/3251.2.232.30 to 51.2.232.30—1
3251.2.232.31/3251.2.232.31 to 51.2.232.31—1
3351.2.232.32/3251.2.232.32 to 51.2.232.32—1
3451.2.232.33/3251.2.232.33 to 51.2.232.33—1
3551.2.232.34/3251.2.232.34 to 51.2.232.34—1
3651.2.232.35/3251.2.232.35 to 51.2.232.35—1
3751.2.232.36/3251.2.232.36 to 51.2.232.36—1
3851.2.232.37/3251.2.232.37 to 51.2.232.37—1
3951.2.232.38/3251.2.232.38 to 51.2.232.38—1
4051.2.232.39/3251.2.232.39 to 51.2.232.39—1
4151.2.232.40/3251.2.232.40 to 51.2.232.40—1
4251.2.232.41/3251.2.232.41 to 51.2.232.41—1
4351.2.232.42/3251.2.232.42 to 51.2.232.42—1
4451.2.232.43/3251.2.232.43 to 51.2.232.43—1
4551.2.232.44/3251.2.232.44 to 51.2.232.44—1
4651.2.232.45/3251.2.232.45 to 51.2.232.45—1
4751.2.232.46/3251.2.232.46 to 51.2.232.46—1
4851.2.232.47/3251.2.232.47 to 51.2.232.47—1
4951.2.232.48/3251.2.232.48 to 51.2.232.48—1
5051.2.232.49/3251.2.232.49 to 51.2.232.49—1
5151.2.232.50/3251.2.232.50 to 51.2.232.50—1
5251.2.232.51/3251.2.232.51 to 51.2.232.51—1
5351.2.232.52/3251.2.232.52 to 51.2.232.52—1
5451.2.232.53/3251.2.232.53 to 51.2.232.53—1
5551.2.232.54/3251.2.232.54 to 51.2.232.54—1
5651.2.232.55/3251.2.232.55 to 51.2.232.55—1
5751.2.232.56/3251.2.232.56 to 51.2.232.56—1
5851.2.232.57/3251.2.232.57 to 51.2.232.57—1
5951.2.232.58/3251.2.232.58 to 51.2.232.58—1
6051.2.232.59/3251.2.232.59 to 51.2.232.59—1
6151.2.232.60/3251.2.232.60 to 51.2.232.60—1
6251.2.232.61/3251.2.232.61 to 51.2.232.61—1
6351.2.232.62/3251.2.232.62 to 51.2.232.62—1
6451.2.232.63/3251.2.232.63 to 51.2.232.63—1
6551.2.232.64/3251.2.232.64 to 51.2.232.64—1
6651.2.232.65/3251.2.232.65 to 51.2.232.65—1
6751.2.232.66/3251.2.232.66 to 51.2.232.66—1
6851.2.232.67/3251.2.232.67 to 51.2.232.67—1
6951.2.232.68/3251.2.232.68 to 51.2.232.68—1
7051.2.232.69/3251.2.232.69 to 51.2.232.69—1
7151.2.232.70/3251.2.232.70 to 51.2.232.70—1
7251.2.232.71/3251.2.232.71 to 51.2.232.71—1
7351.2.232.72/3251.2.232.72 to 51.2.232.72—1
7451.2.232.73/3251.2.232.73 to 51.2.232.73—1
7551.2.232.74/3251.2.232.74 to 51.2.232.74—1
7651.2.232.75/3251.2.232.75 to 51.2.232.75—1
7751.2.232.76/3251.2.232.76 to 51.2.232.76—1
7851.2.232.77/3251.2.232.77 to 51.2.232.77—1
7951.2.232.78/3251.2.232.78 to 51.2.232.78—1
8051.2.232.79/3251.2.232.79 to 51.2.232.79—1
8151.2.232.80/3251.2.232.80 to 51.2.232.80—1
8251.2.232.81/3251.2.232.81 to 51.2.232.81—1
8351.2.232.82/3251.2.232.82 to 51.2.232.82—1
8451.2.232.83/3251.2.232.83 to 51.2.232.83—1
8551.2.232.84/3251.2.232.84 to 51.2.232.84—1
8651.2.232.85/3251.2.232.85 to 51.2.232.85—1
8751.2.232.86/3251.2.232.86 to 51.2.232.86—1
8851.2.232.87/3251.2.232.87 to 51.2.232.87—1
8951.2.232.88/3251.2.232.88 to 51.2.232.88—1
9051.2.232.89/3251.2.232.89 to 51.2.232.89—1
9151.2.232.90/3251.2.232.90 to 51.2.232.90—1
9251.2.232.91/3251.2.232.91 to 51.2.232.91—1
9351.2.232.92/3251.2.232.92 to 51.2.232.92—1
9451.2.232.93/3251.2.232.93 to 51.2.232.93—1
9551.2.232.94/3251.2.232.94 to 51.2.232.94—1
9651.2.232.95/3251.2.232.95 to 51.2.232.95—1
9751.2.232.96/3251.2.232.96 to 51.2.232.96—1
9851.2.232.97/3251.2.232.97 to 51.2.232.97—1
9951.2.232.98/3251.2.232.98 to 51.2.232.98—1
10051.2.232.99/3251.2.232.99 to 51.2.232.99—1
10151.2.232.100/3251.2.232.100 to 51.2.232.100—1
10251.2.232.101/3251.2.232.101 to 51.2.232.101—1
10351.2.232.102/3251.2.232.102 to 51.2.232.102—1
10451.2.232.103/3251.2.232.103 to 51.2.232.103—1
10551.2.232.104/3251.2.232.104 to 51.2.232.104—1
10651.2.232.105/3251.2.232.105 to 51.2.232.105—1
10751.2.232.106/3251.2.232.106 to 51.2.232.106—1
10851.2.232.107/3251.2.232.107 to 51.2.232.107—1
10951.2.232.108/3251.2.232.108 to 51.2.232.108—1
11051.2.232.109/3251.2.232.109 to 51.2.232.109—1
11151.2.232.110/3251.2.232.110 to 51.2.232.110—1
11251.2.232.111/3251.2.232.111 to 51.2.232.111—1
11351.2.232.112/3251.2.232.112 to 51.2.232.112—1
11451.2.232.113/3251.2.232.113 to 51.2.232.113—1
11551.2.232.114/3251.2.232.114 to 51.2.232.114—1
11651.2.232.115/3251.2.232.115 to 51.2.232.115—1
11751.2.232.116/3251.2.232.116 to 51.2.232.116—1
11851.2.232.117/3251.2.232.117 to 51.2.232.117—1
11951.2.232.118/3251.2.232.118 to 51.2.232.118—1
12051.2.232.119/3251.2.232.119 to 51.2.232.119—1
12151.2.232.120/3251.2.232.120 to 51.2.232.120—1
12251.2.232.121/3251.2.232.121 to 51.2.232.121—1
12351.2.232.122/3251.2.232.122 to 51.2.232.122—1
12451.2.232.123/3251.2.232.123 to 51.2.232.123—1
12551.2.232.124/3251.2.232.124 to 51.2.232.124—1
12651.2.232.125/3251.2.232.125 to 51.2.232.125—1
12751.2.232.126/3251.2.232.126 to 51.2.232.126—1
12851.2.232.127/3251.2.232.127 to 51.2.232.127—1
12951.2.232.128/3251.2.232.128 to 51.2.232.128—1
13051.2.232.129/3251.2.232.129 to 51.2.232.129—1
13151.2.232.130/3251.2.232.130 to 51.2.232.130—1
13251.2.232.131/3251.2.232.131 to 51.2.232.131—1
13351.2.232.132/3251.2.232.132 to 51.2.232.132—1
13451.2.232.133/3251.2.232.133 to 51.2.232.133—1
13551.2.232.134/3251.2.232.134 to 51.2.232.134—1
13651.2.232.135/3251.2.232.135 to 51.2.232.135—1
13751.2.232.136/3251.2.232.136 to 51.2.232.136—1
13851.2.232.137/3251.2.232.137 to 51.2.232.137—1
13951.2.232.138/3251.2.232.138 to 51.2.232.138—1
14051.2.232.139/3251.2.232.139 to 51.2.232.139—1
14151.2.232.140/3251.2.232.140 to 51.2.232.140—1
14251.2.232.141/3251.2.232.141 to 51.2.232.141—1
14351.2.232.142/3251.2.232.142 to 51.2.232.142—1
14451.2.232.143/3251.2.232.143 to 51.2.232.143—1
14551.2.232.144/3251.2.232.144 to 51.2.232.144—1
14651.2.232.145/3251.2.232.145 to 51.2.232.145—1
14751.2.232.146/3251.2.232.146 to 51.2.232.146—1
14851.2.232.147/3251.2.232.147 to 51.2.232.147—1
14951.2.232.148/3251.2.232.148 to 51.2.232.148—1
15051.2.232.149/3251.2.232.149 to 51.2.232.149—1
15151.2.232.150/3251.2.232.150 to 51.2.232.150—1
15251.2.232.151/3251.2.232.151 to 51.2.232.151—1
15351.2.232.152/3251.2.232.152 to 51.2.232.152—1
15451.2.232.153/3251.2.232.153 to 51.2.232.153—1
15551.2.232.154/3251.2.232.154 to 51.2.232.154—1
15651.2.232.155/3251.2.232.155 to 51.2.232.155—1
15751.2.232.156/3251.2.232.156 to 51.2.232.156—1
15851.2.232.157/3251.2.232.157 to 51.2.232.157—1
15951.2.232.158/3251.2.232.158 to 51.2.232.158—1
16051.2.232.159/3251.2.232.159 to 51.2.232.159—1
16151.2.232.160/3251.2.232.160 to 51.2.232.160—1
16251.2.232.161/3251.2.232.161 to 51.2.232.161—1
16351.2.232.162/3251.2.232.162 to 51.2.232.162—1
16451.2.232.163/3251.2.232.163 to 51.2.232.163—1
16551.2.232.164/3251.2.232.164 to 51.2.232.164—1
16651.2.232.165/3251.2.232.165 to 51.2.232.165—1
16751.2.232.166/3251.2.232.166 to 51.2.232.166—1
16851.2.232.167/3251.2.232.167 to 51.2.232.167—1
16951.2.232.168/3251.2.232.168 to 51.2.232.168—1
17051.2.232.169/3251.2.232.169 to 51.2.232.169—1
17151.2.232.170/3251.2.232.170 to 51.2.232.170—1
17251.2.232.171/3251.2.232.171 to 51.2.232.171—1
17351.2.232.172/3251.2.232.172 to 51.2.232.172—1
17451.2.232.173/3251.2.232.173 to 51.2.232.173—1
17551.2.232.174/3251.2.232.174 to 51.2.232.174—1
17651.2.232.175/3251.2.232.175 to 51.2.232.175—1
17751.2.232.176/3251.2.232.176 to 51.2.232.176—1
17851.2.232.177/3251.2.232.177 to 51.2.232.177—1
17951.2.232.178/3251.2.232.178 to 51.2.232.178—1
18051.2.232.179/3251.2.232.179 to 51.2.232.179—1
18151.2.232.180/3251.2.232.180 to 51.2.232.180—1
18251.2.232.181/3251.2.232.181 to 51.2.232.181—1
18351.2.232.182/3251.2.232.182 to 51.2.232.182—1
18451.2.232.183/3251.2.232.183 to 51.2.232.183—1
18551.2.232.184/3251.2.232.184 to 51.2.232.184—1
18651.2.232.185/3251.2.232.185 to 51.2.232.185—1
18751.2.232.186/3251.2.232.186 to 51.2.232.186—1
18851.2.232.187/3251.2.232.187 to 51.2.232.187—1
18951.2.232.188/3251.2.232.188 to 51.2.232.188—1
19051.2.232.189/3251.2.232.189 to 51.2.232.189—1
19151.2.232.190/3251.2.232.190 to 51.2.232.190—1
19251.2.232.191/3251.2.232.191 to 51.2.232.191—1
19351.2.232.192/3251.2.232.192 to 51.2.232.192—1
19451.2.232.193/3251.2.232.193 to 51.2.232.193—1
19551.2.232.194/3251.2.232.194 to 51.2.232.194—1
19651.2.232.195/3251.2.232.195 to 51.2.232.195—1
19751.2.232.196/3251.2.232.196 to 51.2.232.196—1
19851.2.232.197/3251.2.232.197 to 51.2.232.197—1
19951.2.232.198/3251.2.232.198 to 51.2.232.198—1
20051.2.232.199/3251.2.232.199 to 51.2.232.199—1
20151.2.232.200/3251.2.232.200 to 51.2.232.200—1
20251.2.232.201/3251.2.232.201 to 51.2.232.201—1
20351.2.232.202/3251.2.232.202 to 51.2.232.202—1
20451.2.232.203/3251.2.232.203 to 51.2.232.203—1
20551.2.232.204/3251.2.232.204 to 51.2.232.204—1
20651.2.232.205/3251.2.232.205 to 51.2.232.205—1
20751.2.232.206/3251.2.232.206 to 51.2.232.206—1
20851.2.232.207/3251.2.232.207 to 51.2.232.207—1
20951.2.232.208/3251.2.232.208 to 51.2.232.208—1
21051.2.232.209/3251.2.232.209 to 51.2.232.209—1
21151.2.232.210/3251.2.232.210 to 51.2.232.210—1
21251.2.232.211/3251.2.232.211 to 51.2.232.211—1
21351.2.232.212/3251.2.232.212 to 51.2.232.212—1
21451.2.232.213/3251.2.232.213 to 51.2.232.213—1
21551.2.232.214/3251.2.232.214 to 51.2.232.214—1
21651.2.232.215/3251.2.232.215 to 51.2.232.215—1
21751.2.232.216/3251.2.232.216 to 51.2.232.216—1
21851.2.232.217/3251.2.232.217 to 51.2.232.217—1
21951.2.232.218/3251.2.232.218 to 51.2.232.218—1
22051.2.232.219/3251.2.232.219 to 51.2.232.219—1
22151.2.232.220/3251.2.232.220 to 51.2.232.220—1
22251.2.232.221/3251.2.232.221 to 51.2.232.221—1
22351.2.232.222/3251.2.232.222 to 51.2.232.222—1
22451.2.232.223/3251.2.232.223 to 51.2.232.223—1
22551.2.232.224/3251.2.232.224 to 51.2.232.224—1
22651.2.232.225/3251.2.232.225 to 51.2.232.225—1
22751.2.232.226/3251.2.232.226 to 51.2.232.226—1
22851.2.232.227/3251.2.232.227 to 51.2.232.227—1
22951.2.232.228/3251.2.232.228 to 51.2.232.228—1
23051.2.232.229/3251.2.232.229 to 51.2.232.229—1
23151.2.232.230/3251.2.232.230 to 51.2.232.230—1
23251.2.232.231/3251.2.232.231 to 51.2.232.231—1
23351.2.232.232/3251.2.232.232 to 51.2.232.232—1
23451.2.232.233/3251.2.232.233 to 51.2.232.233—1
23551.2.232.234/3251.2.232.234 to 51.2.232.234—1
23651.2.232.235/3251.2.232.235 to 51.2.232.235—1
23751.2.232.236/3251.2.232.236 to 51.2.232.236—1
23851.2.232.237/3251.2.232.237 to 51.2.232.237—1
23951.2.232.238/3251.2.232.238 to 51.2.232.238—1
24051.2.232.239/3251.2.232.239 to 51.2.232.239—1
24151.2.232.240/3251.2.232.240 to 51.2.232.240—1
24251.2.232.241/3251.2.232.241 to 51.2.232.241—1
24351.2.232.242/3251.2.232.242 to 51.2.232.242—1
24451.2.232.243/3251.2.232.243 to 51.2.232.243—1
24551.2.232.244/3251.2.232.244 to 51.2.232.244—1
24651.2.232.245/3251.2.232.245 to 51.2.232.245—1
24751.2.232.246/3251.2.232.246 to 51.2.232.246—1
24851.2.232.247/3251.2.232.247 to 51.2.232.247—1
24951.2.232.248/3251.2.232.248 to 51.2.232.248—1
25051.2.232.249/3251.2.232.249 to 51.2.232.249—1
25151.2.232.250/3251.2.232.250 to 51.2.232.250—1
25251.2.232.251/3251.2.232.251 to 51.2.232.251—1
25351.2.232.252/3251.2.232.252 to 51.2.232.252—1
25451.2.232.253/3251.2.232.253 to 51.2.232.253—1
25551.2.232.254/3251.2.232.254 to 51.2.232.254—1
25651.2.232.255/3251.2.232.255 to 51.2.232.255—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.