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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.

Network43.3.76.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
43.3.76.0
Broadcast address
43.3.79.255
First usable
43.3.76.1
Last usable
43.3.79.254
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 2B034C00 · Integer 721636352 to 721637375
Reverse DNS zones
76.3.43.in-addr.arpa
77.3.43.in-addr.arpa
78.3.43.in-addr.arpa
79.3.43.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
Address00101011.00000011.01001100.0000000043.3.76.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00101011.00000011.01001100.0000000043.3.76.0
Broadcast00101011.00000011.01001111.1111111143.3.79.255
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)

43.3.76.0/22 makes 1,024 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
143.3.76.0/3243.3.76.0 to 43.3.76.0—1
243.3.76.1/3243.3.76.1 to 43.3.76.1—1
343.3.76.2/3243.3.76.2 to 43.3.76.2—1
443.3.76.3/3243.3.76.3 to 43.3.76.3—1
543.3.76.4/3243.3.76.4 to 43.3.76.4—1
643.3.76.5/3243.3.76.5 to 43.3.76.5—1
743.3.76.6/3243.3.76.6 to 43.3.76.6—1
843.3.76.7/3243.3.76.7 to 43.3.76.7—1
943.3.76.8/3243.3.76.8 to 43.3.76.8—1
1043.3.76.9/3243.3.76.9 to 43.3.76.9—1
1143.3.76.10/3243.3.76.10 to 43.3.76.10—1
1243.3.76.11/3243.3.76.11 to 43.3.76.11—1
1343.3.76.12/3243.3.76.12 to 43.3.76.12—1
1443.3.76.13/3243.3.76.13 to 43.3.76.13—1
1543.3.76.14/3243.3.76.14 to 43.3.76.14—1
1643.3.76.15/3243.3.76.15 to 43.3.76.15—1
1743.3.76.16/3243.3.76.16 to 43.3.76.16—1
1843.3.76.17/3243.3.76.17 to 43.3.76.17—1
1943.3.76.18/3243.3.76.18 to 43.3.76.18—1
2043.3.76.19/3243.3.76.19 to 43.3.76.19—1
2143.3.76.20/3243.3.76.20 to 43.3.76.20—1
2243.3.76.21/3243.3.76.21 to 43.3.76.21—1
2343.3.76.22/3243.3.76.22 to 43.3.76.22—1
2443.3.76.23/3243.3.76.23 to 43.3.76.23—1
2543.3.76.24/3243.3.76.24 to 43.3.76.24—1
2643.3.76.25/3243.3.76.25 to 43.3.76.25—1
2743.3.76.26/3243.3.76.26 to 43.3.76.26—1
2843.3.76.27/3243.3.76.27 to 43.3.76.27—1
2943.3.76.28/3243.3.76.28 to 43.3.76.28—1
3043.3.76.29/3243.3.76.29 to 43.3.76.29—1
3143.3.76.30/3243.3.76.30 to 43.3.76.30—1
3243.3.76.31/3243.3.76.31 to 43.3.76.31—1
3343.3.76.32/3243.3.76.32 to 43.3.76.32—1
3443.3.76.33/3243.3.76.33 to 43.3.76.33—1
3543.3.76.34/3243.3.76.34 to 43.3.76.34—1
3643.3.76.35/3243.3.76.35 to 43.3.76.35—1
3743.3.76.36/3243.3.76.36 to 43.3.76.36—1
3843.3.76.37/3243.3.76.37 to 43.3.76.37—1
3943.3.76.38/3243.3.76.38 to 43.3.76.38—1
4043.3.76.39/3243.3.76.39 to 43.3.76.39—1
4143.3.76.40/3243.3.76.40 to 43.3.76.40—1
4243.3.76.41/3243.3.76.41 to 43.3.76.41—1
4343.3.76.42/3243.3.76.42 to 43.3.76.42—1
4443.3.76.43/3243.3.76.43 to 43.3.76.43—1
4543.3.76.44/3243.3.76.44 to 43.3.76.44—1
4643.3.76.45/3243.3.76.45 to 43.3.76.45—1
4743.3.76.46/3243.3.76.46 to 43.3.76.46—1
4843.3.76.47/3243.3.76.47 to 43.3.76.47—1
4943.3.76.48/3243.3.76.48 to 43.3.76.48—1
5043.3.76.49/3243.3.76.49 to 43.3.76.49—1
5143.3.76.50/3243.3.76.50 to 43.3.76.50—1
5243.3.76.51/3243.3.76.51 to 43.3.76.51—1
5343.3.76.52/3243.3.76.52 to 43.3.76.52—1
5443.3.76.53/3243.3.76.53 to 43.3.76.53—1
5543.3.76.54/3243.3.76.54 to 43.3.76.54—1
5643.3.76.55/3243.3.76.55 to 43.3.76.55—1
5743.3.76.56/3243.3.76.56 to 43.3.76.56—1
5843.3.76.57/3243.3.76.57 to 43.3.76.57—1
5943.3.76.58/3243.3.76.58 to 43.3.76.58—1
6043.3.76.59/3243.3.76.59 to 43.3.76.59—1
6143.3.76.60/3243.3.76.60 to 43.3.76.60—1
6243.3.76.61/3243.3.76.61 to 43.3.76.61—1
6343.3.76.62/3243.3.76.62 to 43.3.76.62—1
6443.3.76.63/3243.3.76.63 to 43.3.76.63—1
6543.3.76.64/3243.3.76.64 to 43.3.76.64—1
6643.3.76.65/3243.3.76.65 to 43.3.76.65—1
6743.3.76.66/3243.3.76.66 to 43.3.76.66—1
6843.3.76.67/3243.3.76.67 to 43.3.76.67—1
6943.3.76.68/3243.3.76.68 to 43.3.76.68—1
7043.3.76.69/3243.3.76.69 to 43.3.76.69—1
7143.3.76.70/3243.3.76.70 to 43.3.76.70—1
7243.3.76.71/3243.3.76.71 to 43.3.76.71—1
7343.3.76.72/3243.3.76.72 to 43.3.76.72—1
7443.3.76.73/3243.3.76.73 to 43.3.76.73—1
7543.3.76.74/3243.3.76.74 to 43.3.76.74—1
7643.3.76.75/3243.3.76.75 to 43.3.76.75—1
7743.3.76.76/3243.3.76.76 to 43.3.76.76—1
7843.3.76.77/3243.3.76.77 to 43.3.76.77—1
7943.3.76.78/3243.3.76.78 to 43.3.76.78—1
8043.3.76.79/3243.3.76.79 to 43.3.76.79—1
8143.3.76.80/3243.3.76.80 to 43.3.76.80—1
8243.3.76.81/3243.3.76.81 to 43.3.76.81—1
8343.3.76.82/3243.3.76.82 to 43.3.76.82—1
8443.3.76.83/3243.3.76.83 to 43.3.76.83—1
8543.3.76.84/3243.3.76.84 to 43.3.76.84—1
8643.3.76.85/3243.3.76.85 to 43.3.76.85—1
8743.3.76.86/3243.3.76.86 to 43.3.76.86—1
8843.3.76.87/3243.3.76.87 to 43.3.76.87—1
8943.3.76.88/3243.3.76.88 to 43.3.76.88—1
9043.3.76.89/3243.3.76.89 to 43.3.76.89—1
9143.3.76.90/3243.3.76.90 to 43.3.76.90—1
9243.3.76.91/3243.3.76.91 to 43.3.76.91—1
9343.3.76.92/3243.3.76.92 to 43.3.76.92—1
9443.3.76.93/3243.3.76.93 to 43.3.76.93—1
9543.3.76.94/3243.3.76.94 to 43.3.76.94—1
9643.3.76.95/3243.3.76.95 to 43.3.76.95—1
9743.3.76.96/3243.3.76.96 to 43.3.76.96—1
9843.3.76.97/3243.3.76.97 to 43.3.76.97—1
9943.3.76.98/3243.3.76.98 to 43.3.76.98—1
10043.3.76.99/3243.3.76.99 to 43.3.76.99—1
10143.3.76.100/3243.3.76.100 to 43.3.76.100—1
10243.3.76.101/3243.3.76.101 to 43.3.76.101—1
10343.3.76.102/3243.3.76.102 to 43.3.76.102—1
10443.3.76.103/3243.3.76.103 to 43.3.76.103—1
10543.3.76.104/3243.3.76.104 to 43.3.76.104—1
10643.3.76.105/3243.3.76.105 to 43.3.76.105—1
10743.3.76.106/3243.3.76.106 to 43.3.76.106—1
10843.3.76.107/3243.3.76.107 to 43.3.76.107—1
10943.3.76.108/3243.3.76.108 to 43.3.76.108—1
11043.3.76.109/3243.3.76.109 to 43.3.76.109—1
11143.3.76.110/3243.3.76.110 to 43.3.76.110—1
11243.3.76.111/3243.3.76.111 to 43.3.76.111—1
11343.3.76.112/3243.3.76.112 to 43.3.76.112—1
11443.3.76.113/3243.3.76.113 to 43.3.76.113—1
11543.3.76.114/3243.3.76.114 to 43.3.76.114—1
11643.3.76.115/3243.3.76.115 to 43.3.76.115—1
11743.3.76.116/3243.3.76.116 to 43.3.76.116—1
11843.3.76.117/3243.3.76.117 to 43.3.76.117—1
11943.3.76.118/3243.3.76.118 to 43.3.76.118—1
12043.3.76.119/3243.3.76.119 to 43.3.76.119—1
12143.3.76.120/3243.3.76.120 to 43.3.76.120—1
12243.3.76.121/3243.3.76.121 to 43.3.76.121—1
12343.3.76.122/3243.3.76.122 to 43.3.76.122—1
12443.3.76.123/3243.3.76.123 to 43.3.76.123—1
12543.3.76.124/3243.3.76.124 to 43.3.76.124—1
12643.3.76.125/3243.3.76.125 to 43.3.76.125—1
12743.3.76.126/3243.3.76.126 to 43.3.76.126—1
12843.3.76.127/3243.3.76.127 to 43.3.76.127—1
12943.3.76.128/3243.3.76.128 to 43.3.76.128—1
13043.3.76.129/3243.3.76.129 to 43.3.76.129—1
13143.3.76.130/3243.3.76.130 to 43.3.76.130—1
13243.3.76.131/3243.3.76.131 to 43.3.76.131—1
13343.3.76.132/3243.3.76.132 to 43.3.76.132—1
13443.3.76.133/3243.3.76.133 to 43.3.76.133—1
13543.3.76.134/3243.3.76.134 to 43.3.76.134—1
13643.3.76.135/3243.3.76.135 to 43.3.76.135—1
13743.3.76.136/3243.3.76.136 to 43.3.76.136—1
13843.3.76.137/3243.3.76.137 to 43.3.76.137—1
13943.3.76.138/3243.3.76.138 to 43.3.76.138—1
14043.3.76.139/3243.3.76.139 to 43.3.76.139—1
14143.3.76.140/3243.3.76.140 to 43.3.76.140—1
14243.3.76.141/3243.3.76.141 to 43.3.76.141—1
14343.3.76.142/3243.3.76.142 to 43.3.76.142—1
14443.3.76.143/3243.3.76.143 to 43.3.76.143—1
14543.3.76.144/3243.3.76.144 to 43.3.76.144—1
14643.3.76.145/3243.3.76.145 to 43.3.76.145—1
14743.3.76.146/3243.3.76.146 to 43.3.76.146—1
14843.3.76.147/3243.3.76.147 to 43.3.76.147—1
14943.3.76.148/3243.3.76.148 to 43.3.76.148—1
15043.3.76.149/3243.3.76.149 to 43.3.76.149—1
15143.3.76.150/3243.3.76.150 to 43.3.76.150—1
15243.3.76.151/3243.3.76.151 to 43.3.76.151—1
15343.3.76.152/3243.3.76.152 to 43.3.76.152—1
15443.3.76.153/3243.3.76.153 to 43.3.76.153—1
15543.3.76.154/3243.3.76.154 to 43.3.76.154—1
15643.3.76.155/3243.3.76.155 to 43.3.76.155—1
15743.3.76.156/3243.3.76.156 to 43.3.76.156—1
15843.3.76.157/3243.3.76.157 to 43.3.76.157—1
15943.3.76.158/3243.3.76.158 to 43.3.76.158—1
16043.3.76.159/3243.3.76.159 to 43.3.76.159—1
16143.3.76.160/3243.3.76.160 to 43.3.76.160—1
16243.3.76.161/3243.3.76.161 to 43.3.76.161—1
16343.3.76.162/3243.3.76.162 to 43.3.76.162—1
16443.3.76.163/3243.3.76.163 to 43.3.76.163—1
16543.3.76.164/3243.3.76.164 to 43.3.76.164—1
16643.3.76.165/3243.3.76.165 to 43.3.76.165—1
16743.3.76.166/3243.3.76.166 to 43.3.76.166—1
16843.3.76.167/3243.3.76.167 to 43.3.76.167—1
16943.3.76.168/3243.3.76.168 to 43.3.76.168—1
17043.3.76.169/3243.3.76.169 to 43.3.76.169—1
17143.3.76.170/3243.3.76.170 to 43.3.76.170—1
17243.3.76.171/3243.3.76.171 to 43.3.76.171—1
17343.3.76.172/3243.3.76.172 to 43.3.76.172—1
17443.3.76.173/3243.3.76.173 to 43.3.76.173—1
17543.3.76.174/3243.3.76.174 to 43.3.76.174—1
17643.3.76.175/3243.3.76.175 to 43.3.76.175—1
17743.3.76.176/3243.3.76.176 to 43.3.76.176—1
17843.3.76.177/3243.3.76.177 to 43.3.76.177—1
17943.3.76.178/3243.3.76.178 to 43.3.76.178—1
18043.3.76.179/3243.3.76.179 to 43.3.76.179—1
18143.3.76.180/3243.3.76.180 to 43.3.76.180—1
18243.3.76.181/3243.3.76.181 to 43.3.76.181—1
18343.3.76.182/3243.3.76.182 to 43.3.76.182—1
18443.3.76.183/3243.3.76.183 to 43.3.76.183—1
18543.3.76.184/3243.3.76.184 to 43.3.76.184—1
18643.3.76.185/3243.3.76.185 to 43.3.76.185—1
18743.3.76.186/3243.3.76.186 to 43.3.76.186—1
18843.3.76.187/3243.3.76.187 to 43.3.76.187—1
18943.3.76.188/3243.3.76.188 to 43.3.76.188—1
19043.3.76.189/3243.3.76.189 to 43.3.76.189—1
19143.3.76.190/3243.3.76.190 to 43.3.76.190—1
19243.3.76.191/3243.3.76.191 to 43.3.76.191—1
19343.3.76.192/3243.3.76.192 to 43.3.76.192—1
19443.3.76.193/3243.3.76.193 to 43.3.76.193—1
19543.3.76.194/3243.3.76.194 to 43.3.76.194—1
19643.3.76.195/3243.3.76.195 to 43.3.76.195—1
19743.3.76.196/3243.3.76.196 to 43.3.76.196—1
19843.3.76.197/3243.3.76.197 to 43.3.76.197—1
19943.3.76.198/3243.3.76.198 to 43.3.76.198—1
20043.3.76.199/3243.3.76.199 to 43.3.76.199—1
20143.3.76.200/3243.3.76.200 to 43.3.76.200—1
20243.3.76.201/3243.3.76.201 to 43.3.76.201—1
20343.3.76.202/3243.3.76.202 to 43.3.76.202—1
20443.3.76.203/3243.3.76.203 to 43.3.76.203—1
20543.3.76.204/3243.3.76.204 to 43.3.76.204—1
20643.3.76.205/3243.3.76.205 to 43.3.76.205—1
20743.3.76.206/3243.3.76.206 to 43.3.76.206—1
20843.3.76.207/3243.3.76.207 to 43.3.76.207—1
20943.3.76.208/3243.3.76.208 to 43.3.76.208—1
21043.3.76.209/3243.3.76.209 to 43.3.76.209—1
21143.3.76.210/3243.3.76.210 to 43.3.76.210—1
21243.3.76.211/3243.3.76.211 to 43.3.76.211—1
21343.3.76.212/3243.3.76.212 to 43.3.76.212—1
21443.3.76.213/3243.3.76.213 to 43.3.76.213—1
21543.3.76.214/3243.3.76.214 to 43.3.76.214—1
21643.3.76.215/3243.3.76.215 to 43.3.76.215—1
21743.3.76.216/3243.3.76.216 to 43.3.76.216—1
21843.3.76.217/3243.3.76.217 to 43.3.76.217—1
21943.3.76.218/3243.3.76.218 to 43.3.76.218—1
22043.3.76.219/3243.3.76.219 to 43.3.76.219—1
22143.3.76.220/3243.3.76.220 to 43.3.76.220—1
22243.3.76.221/3243.3.76.221 to 43.3.76.221—1
22343.3.76.222/3243.3.76.222 to 43.3.76.222—1
22443.3.76.223/3243.3.76.223 to 43.3.76.223—1
22543.3.76.224/3243.3.76.224 to 43.3.76.224—1
22643.3.76.225/3243.3.76.225 to 43.3.76.225—1
22743.3.76.226/3243.3.76.226 to 43.3.76.226—1
22843.3.76.227/3243.3.76.227 to 43.3.76.227—1
22943.3.76.228/3243.3.76.228 to 43.3.76.228—1
23043.3.76.229/3243.3.76.229 to 43.3.76.229—1
23143.3.76.230/3243.3.76.230 to 43.3.76.230—1
23243.3.76.231/3243.3.76.231 to 43.3.76.231—1
23343.3.76.232/3243.3.76.232 to 43.3.76.232—1
23443.3.76.233/3243.3.76.233 to 43.3.76.233—1
23543.3.76.234/3243.3.76.234 to 43.3.76.234—1
23643.3.76.235/3243.3.76.235 to 43.3.76.235—1
23743.3.76.236/3243.3.76.236 to 43.3.76.236—1
23843.3.76.237/3243.3.76.237 to 43.3.76.237—1
23943.3.76.238/3243.3.76.238 to 43.3.76.238—1
24043.3.76.239/3243.3.76.239 to 43.3.76.239—1
24143.3.76.240/3243.3.76.240 to 43.3.76.240—1
24243.3.76.241/3243.3.76.241 to 43.3.76.241—1
24343.3.76.242/3243.3.76.242 to 43.3.76.242—1
24443.3.76.243/3243.3.76.243 to 43.3.76.243—1
24543.3.76.244/3243.3.76.244 to 43.3.76.244—1
24643.3.76.245/3243.3.76.245 to 43.3.76.245—1
24743.3.76.246/3243.3.76.246 to 43.3.76.246—1
24843.3.76.247/3243.3.76.247 to 43.3.76.247—1
24943.3.76.248/3243.3.76.248 to 43.3.76.248—1
25043.3.76.249/3243.3.76.249 to 43.3.76.249—1
25143.3.76.250/3243.3.76.250 to 43.3.76.250—1
25243.3.76.251/3243.3.76.251 to 43.3.76.251—1
25343.3.76.252/3243.3.76.252 to 43.3.76.252—1
25443.3.76.253/3243.3.76.253 to 43.3.76.253—1
25543.3.76.254/3243.3.76.254 to 43.3.76.254—1
25643.3.76.255/3243.3.76.255 to 43.3.76.255—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.