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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.

Network29.167.78.0/23
Usable hosts510
Subnet mask255.255.254.0
Addresses512
Network address
29.167.78.0
Broadcast address
29.167.79.255
First usable
29.167.78.1
Last usable
29.167.79.254
Usable hosts
510 (512 less the network and broadcast addresses)
Subnet mask
255.255.254.0
Wildcard mask
0.0.1.255 (Cisco ACLs, OSPF)
Prefix length
/23
Type
Public public
Old class
A (default /8)
As numbers
Hex 1DA74E00 · Integer 497503744 to 497504255
Reverse DNS zones
78.167.29.in-addr.arpa
79.167.29.in-addr.arpa
/23 is not on a 8-bit boundary, so it takes 2 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011101.10100111.01001110.0000000029.167.78.0
Subnet mask11111111.11111111.11111110.00000000255.255.254.0
Network00011101.10100111.01001110.0000000029.167.78.0
Broadcast00011101.10100111.01001111.1111111129.167.79.255
Split into smaller subnets/32
/24 (2)/25 (4)/26 (8)/27 (16)/28 (32)/29 (64)/30 (128)/31 (256)/32 (512)

29.167.78.0/23 makes 512 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
129.167.78.0/3229.167.78.0 to 29.167.78.0—1
229.167.78.1/3229.167.78.1 to 29.167.78.1—1
329.167.78.2/3229.167.78.2 to 29.167.78.2—1
429.167.78.3/3229.167.78.3 to 29.167.78.3—1
529.167.78.4/3229.167.78.4 to 29.167.78.4—1
629.167.78.5/3229.167.78.5 to 29.167.78.5—1
729.167.78.6/3229.167.78.6 to 29.167.78.6—1
829.167.78.7/3229.167.78.7 to 29.167.78.7—1
929.167.78.8/3229.167.78.8 to 29.167.78.8—1
1029.167.78.9/3229.167.78.9 to 29.167.78.9—1
1129.167.78.10/3229.167.78.10 to 29.167.78.10—1
1229.167.78.11/3229.167.78.11 to 29.167.78.11—1
1329.167.78.12/3229.167.78.12 to 29.167.78.12—1
1429.167.78.13/3229.167.78.13 to 29.167.78.13—1
1529.167.78.14/3229.167.78.14 to 29.167.78.14—1
1629.167.78.15/3229.167.78.15 to 29.167.78.15—1
1729.167.78.16/3229.167.78.16 to 29.167.78.16—1
1829.167.78.17/3229.167.78.17 to 29.167.78.17—1
1929.167.78.18/3229.167.78.18 to 29.167.78.18—1
2029.167.78.19/3229.167.78.19 to 29.167.78.19—1
2129.167.78.20/3229.167.78.20 to 29.167.78.20—1
2229.167.78.21/3229.167.78.21 to 29.167.78.21—1
2329.167.78.22/3229.167.78.22 to 29.167.78.22—1
2429.167.78.23/3229.167.78.23 to 29.167.78.23—1
2529.167.78.24/3229.167.78.24 to 29.167.78.24—1
2629.167.78.25/3229.167.78.25 to 29.167.78.25—1
2729.167.78.26/3229.167.78.26 to 29.167.78.26—1
2829.167.78.27/3229.167.78.27 to 29.167.78.27—1
2929.167.78.28/3229.167.78.28 to 29.167.78.28—1
3029.167.78.29/3229.167.78.29 to 29.167.78.29—1
3129.167.78.30/3229.167.78.30 to 29.167.78.30—1
3229.167.78.31/3229.167.78.31 to 29.167.78.31—1
3329.167.78.32/3229.167.78.32 to 29.167.78.32—1
3429.167.78.33/3229.167.78.33 to 29.167.78.33—1
3529.167.78.34/3229.167.78.34 to 29.167.78.34—1
3629.167.78.35/3229.167.78.35 to 29.167.78.35—1
3729.167.78.36/3229.167.78.36 to 29.167.78.36—1
3829.167.78.37/3229.167.78.37 to 29.167.78.37—1
3929.167.78.38/3229.167.78.38 to 29.167.78.38—1
4029.167.78.39/3229.167.78.39 to 29.167.78.39—1
4129.167.78.40/3229.167.78.40 to 29.167.78.40—1
4229.167.78.41/3229.167.78.41 to 29.167.78.41—1
4329.167.78.42/3229.167.78.42 to 29.167.78.42—1
4429.167.78.43/3229.167.78.43 to 29.167.78.43—1
4529.167.78.44/3229.167.78.44 to 29.167.78.44—1
4629.167.78.45/3229.167.78.45 to 29.167.78.45—1
4729.167.78.46/3229.167.78.46 to 29.167.78.46—1
4829.167.78.47/3229.167.78.47 to 29.167.78.47—1
4929.167.78.48/3229.167.78.48 to 29.167.78.48—1
5029.167.78.49/3229.167.78.49 to 29.167.78.49—1
5129.167.78.50/3229.167.78.50 to 29.167.78.50—1
5229.167.78.51/3229.167.78.51 to 29.167.78.51—1
5329.167.78.52/3229.167.78.52 to 29.167.78.52—1
5429.167.78.53/3229.167.78.53 to 29.167.78.53—1
5529.167.78.54/3229.167.78.54 to 29.167.78.54—1
5629.167.78.55/3229.167.78.55 to 29.167.78.55—1
5729.167.78.56/3229.167.78.56 to 29.167.78.56—1
5829.167.78.57/3229.167.78.57 to 29.167.78.57—1
5929.167.78.58/3229.167.78.58 to 29.167.78.58—1
6029.167.78.59/3229.167.78.59 to 29.167.78.59—1
6129.167.78.60/3229.167.78.60 to 29.167.78.60—1
6229.167.78.61/3229.167.78.61 to 29.167.78.61—1
6329.167.78.62/3229.167.78.62 to 29.167.78.62—1
6429.167.78.63/3229.167.78.63 to 29.167.78.63—1
6529.167.78.64/3229.167.78.64 to 29.167.78.64—1
6629.167.78.65/3229.167.78.65 to 29.167.78.65—1
6729.167.78.66/3229.167.78.66 to 29.167.78.66—1
6829.167.78.67/3229.167.78.67 to 29.167.78.67—1
6929.167.78.68/3229.167.78.68 to 29.167.78.68—1
7029.167.78.69/3229.167.78.69 to 29.167.78.69—1
7129.167.78.70/3229.167.78.70 to 29.167.78.70—1
7229.167.78.71/3229.167.78.71 to 29.167.78.71—1
7329.167.78.72/3229.167.78.72 to 29.167.78.72—1
7429.167.78.73/3229.167.78.73 to 29.167.78.73—1
7529.167.78.74/3229.167.78.74 to 29.167.78.74—1
7629.167.78.75/3229.167.78.75 to 29.167.78.75—1
7729.167.78.76/3229.167.78.76 to 29.167.78.76—1
7829.167.78.77/3229.167.78.77 to 29.167.78.77—1
7929.167.78.78/3229.167.78.78 to 29.167.78.78—1
8029.167.78.79/3229.167.78.79 to 29.167.78.79—1
8129.167.78.80/3229.167.78.80 to 29.167.78.80—1
8229.167.78.81/3229.167.78.81 to 29.167.78.81—1
8329.167.78.82/3229.167.78.82 to 29.167.78.82—1
8429.167.78.83/3229.167.78.83 to 29.167.78.83—1
8529.167.78.84/3229.167.78.84 to 29.167.78.84—1
8629.167.78.85/3229.167.78.85 to 29.167.78.85—1
8729.167.78.86/3229.167.78.86 to 29.167.78.86—1
8829.167.78.87/3229.167.78.87 to 29.167.78.87—1
8929.167.78.88/3229.167.78.88 to 29.167.78.88—1
9029.167.78.89/3229.167.78.89 to 29.167.78.89—1
9129.167.78.90/3229.167.78.90 to 29.167.78.90—1
9229.167.78.91/3229.167.78.91 to 29.167.78.91—1
9329.167.78.92/3229.167.78.92 to 29.167.78.92—1
9429.167.78.93/3229.167.78.93 to 29.167.78.93—1
9529.167.78.94/3229.167.78.94 to 29.167.78.94—1
9629.167.78.95/3229.167.78.95 to 29.167.78.95—1
9729.167.78.96/3229.167.78.96 to 29.167.78.96—1
9829.167.78.97/3229.167.78.97 to 29.167.78.97—1
9929.167.78.98/3229.167.78.98 to 29.167.78.98—1
10029.167.78.99/3229.167.78.99 to 29.167.78.99—1
10129.167.78.100/3229.167.78.100 to 29.167.78.100—1
10229.167.78.101/3229.167.78.101 to 29.167.78.101—1
10329.167.78.102/3229.167.78.102 to 29.167.78.102—1
10429.167.78.103/3229.167.78.103 to 29.167.78.103—1
10529.167.78.104/3229.167.78.104 to 29.167.78.104—1
10629.167.78.105/3229.167.78.105 to 29.167.78.105—1
10729.167.78.106/3229.167.78.106 to 29.167.78.106—1
10829.167.78.107/3229.167.78.107 to 29.167.78.107—1
10929.167.78.108/3229.167.78.108 to 29.167.78.108—1
11029.167.78.109/3229.167.78.109 to 29.167.78.109—1
11129.167.78.110/3229.167.78.110 to 29.167.78.110—1
11229.167.78.111/3229.167.78.111 to 29.167.78.111—1
11329.167.78.112/3229.167.78.112 to 29.167.78.112—1
11429.167.78.113/3229.167.78.113 to 29.167.78.113—1
11529.167.78.114/3229.167.78.114 to 29.167.78.114—1
11629.167.78.115/3229.167.78.115 to 29.167.78.115—1
11729.167.78.116/3229.167.78.116 to 29.167.78.116—1
11829.167.78.117/3229.167.78.117 to 29.167.78.117—1
11929.167.78.118/3229.167.78.118 to 29.167.78.118—1
12029.167.78.119/3229.167.78.119 to 29.167.78.119—1
12129.167.78.120/3229.167.78.120 to 29.167.78.120—1
12229.167.78.121/3229.167.78.121 to 29.167.78.121—1
12329.167.78.122/3229.167.78.122 to 29.167.78.122—1
12429.167.78.123/3229.167.78.123 to 29.167.78.123—1
12529.167.78.124/3229.167.78.124 to 29.167.78.124—1
12629.167.78.125/3229.167.78.125 to 29.167.78.125—1
12729.167.78.126/3229.167.78.126 to 29.167.78.126—1
12829.167.78.127/3229.167.78.127 to 29.167.78.127—1
12929.167.78.128/3229.167.78.128 to 29.167.78.128—1
13029.167.78.129/3229.167.78.129 to 29.167.78.129—1
13129.167.78.130/3229.167.78.130 to 29.167.78.130—1
13229.167.78.131/3229.167.78.131 to 29.167.78.131—1
13329.167.78.132/3229.167.78.132 to 29.167.78.132—1
13429.167.78.133/3229.167.78.133 to 29.167.78.133—1
13529.167.78.134/3229.167.78.134 to 29.167.78.134—1
13629.167.78.135/3229.167.78.135 to 29.167.78.135—1
13729.167.78.136/3229.167.78.136 to 29.167.78.136—1
13829.167.78.137/3229.167.78.137 to 29.167.78.137—1
13929.167.78.138/3229.167.78.138 to 29.167.78.138—1
14029.167.78.139/3229.167.78.139 to 29.167.78.139—1
14129.167.78.140/3229.167.78.140 to 29.167.78.140—1
14229.167.78.141/3229.167.78.141 to 29.167.78.141—1
14329.167.78.142/3229.167.78.142 to 29.167.78.142—1
14429.167.78.143/3229.167.78.143 to 29.167.78.143—1
14529.167.78.144/3229.167.78.144 to 29.167.78.144—1
14629.167.78.145/3229.167.78.145 to 29.167.78.145—1
14729.167.78.146/3229.167.78.146 to 29.167.78.146—1
14829.167.78.147/3229.167.78.147 to 29.167.78.147—1
14929.167.78.148/3229.167.78.148 to 29.167.78.148—1
15029.167.78.149/3229.167.78.149 to 29.167.78.149—1
15129.167.78.150/3229.167.78.150 to 29.167.78.150—1
15229.167.78.151/3229.167.78.151 to 29.167.78.151—1
15329.167.78.152/3229.167.78.152 to 29.167.78.152—1
15429.167.78.153/3229.167.78.153 to 29.167.78.153—1
15529.167.78.154/3229.167.78.154 to 29.167.78.154—1
15629.167.78.155/3229.167.78.155 to 29.167.78.155—1
15729.167.78.156/3229.167.78.156 to 29.167.78.156—1
15829.167.78.157/3229.167.78.157 to 29.167.78.157—1
15929.167.78.158/3229.167.78.158 to 29.167.78.158—1
16029.167.78.159/3229.167.78.159 to 29.167.78.159—1
16129.167.78.160/3229.167.78.160 to 29.167.78.160—1
16229.167.78.161/3229.167.78.161 to 29.167.78.161—1
16329.167.78.162/3229.167.78.162 to 29.167.78.162—1
16429.167.78.163/3229.167.78.163 to 29.167.78.163—1
16529.167.78.164/3229.167.78.164 to 29.167.78.164—1
16629.167.78.165/3229.167.78.165 to 29.167.78.165—1
16729.167.78.166/3229.167.78.166 to 29.167.78.166—1
16829.167.78.167/3229.167.78.167 to 29.167.78.167—1
16929.167.78.168/3229.167.78.168 to 29.167.78.168—1
17029.167.78.169/3229.167.78.169 to 29.167.78.169—1
17129.167.78.170/3229.167.78.170 to 29.167.78.170—1
17229.167.78.171/3229.167.78.171 to 29.167.78.171—1
17329.167.78.172/3229.167.78.172 to 29.167.78.172—1
17429.167.78.173/3229.167.78.173 to 29.167.78.173—1
17529.167.78.174/3229.167.78.174 to 29.167.78.174—1
17629.167.78.175/3229.167.78.175 to 29.167.78.175—1
17729.167.78.176/3229.167.78.176 to 29.167.78.176—1
17829.167.78.177/3229.167.78.177 to 29.167.78.177—1
17929.167.78.178/3229.167.78.178 to 29.167.78.178—1
18029.167.78.179/3229.167.78.179 to 29.167.78.179—1
18129.167.78.180/3229.167.78.180 to 29.167.78.180—1
18229.167.78.181/3229.167.78.181 to 29.167.78.181—1
18329.167.78.182/3229.167.78.182 to 29.167.78.182—1
18429.167.78.183/3229.167.78.183 to 29.167.78.183—1
18529.167.78.184/3229.167.78.184 to 29.167.78.184—1
18629.167.78.185/3229.167.78.185 to 29.167.78.185—1
18729.167.78.186/3229.167.78.186 to 29.167.78.186—1
18829.167.78.187/3229.167.78.187 to 29.167.78.187—1
18929.167.78.188/3229.167.78.188 to 29.167.78.188—1
19029.167.78.189/3229.167.78.189 to 29.167.78.189—1
19129.167.78.190/3229.167.78.190 to 29.167.78.190—1
19229.167.78.191/3229.167.78.191 to 29.167.78.191—1
19329.167.78.192/3229.167.78.192 to 29.167.78.192—1
19429.167.78.193/3229.167.78.193 to 29.167.78.193—1
19529.167.78.194/3229.167.78.194 to 29.167.78.194—1
19629.167.78.195/3229.167.78.195 to 29.167.78.195—1
19729.167.78.196/3229.167.78.196 to 29.167.78.196—1
19829.167.78.197/3229.167.78.197 to 29.167.78.197—1
19929.167.78.198/3229.167.78.198 to 29.167.78.198—1
20029.167.78.199/3229.167.78.199 to 29.167.78.199—1
20129.167.78.200/3229.167.78.200 to 29.167.78.200—1
20229.167.78.201/3229.167.78.201 to 29.167.78.201—1
20329.167.78.202/3229.167.78.202 to 29.167.78.202—1
20429.167.78.203/3229.167.78.203 to 29.167.78.203—1
20529.167.78.204/3229.167.78.204 to 29.167.78.204—1
20629.167.78.205/3229.167.78.205 to 29.167.78.205—1
20729.167.78.206/3229.167.78.206 to 29.167.78.206—1
20829.167.78.207/3229.167.78.207 to 29.167.78.207—1
20929.167.78.208/3229.167.78.208 to 29.167.78.208—1
21029.167.78.209/3229.167.78.209 to 29.167.78.209—1
21129.167.78.210/3229.167.78.210 to 29.167.78.210—1
21229.167.78.211/3229.167.78.211 to 29.167.78.211—1
21329.167.78.212/3229.167.78.212 to 29.167.78.212—1
21429.167.78.213/3229.167.78.213 to 29.167.78.213—1
21529.167.78.214/3229.167.78.214 to 29.167.78.214—1
21629.167.78.215/3229.167.78.215 to 29.167.78.215—1
21729.167.78.216/3229.167.78.216 to 29.167.78.216—1
21829.167.78.217/3229.167.78.217 to 29.167.78.217—1
21929.167.78.218/3229.167.78.218 to 29.167.78.218—1
22029.167.78.219/3229.167.78.219 to 29.167.78.219—1
22129.167.78.220/3229.167.78.220 to 29.167.78.220—1
22229.167.78.221/3229.167.78.221 to 29.167.78.221—1
22329.167.78.222/3229.167.78.222 to 29.167.78.222—1
22429.167.78.223/3229.167.78.223 to 29.167.78.223—1
22529.167.78.224/3229.167.78.224 to 29.167.78.224—1
22629.167.78.225/3229.167.78.225 to 29.167.78.225—1
22729.167.78.226/3229.167.78.226 to 29.167.78.226—1
22829.167.78.227/3229.167.78.227 to 29.167.78.227—1
22929.167.78.228/3229.167.78.228 to 29.167.78.228—1
23029.167.78.229/3229.167.78.229 to 29.167.78.229—1
23129.167.78.230/3229.167.78.230 to 29.167.78.230—1
23229.167.78.231/3229.167.78.231 to 29.167.78.231—1
23329.167.78.232/3229.167.78.232 to 29.167.78.232—1
23429.167.78.233/3229.167.78.233 to 29.167.78.233—1
23529.167.78.234/3229.167.78.234 to 29.167.78.234—1
23629.167.78.235/3229.167.78.235 to 29.167.78.235—1
23729.167.78.236/3229.167.78.236 to 29.167.78.236—1
23829.167.78.237/3229.167.78.237 to 29.167.78.237—1
23929.167.78.238/3229.167.78.238 to 29.167.78.238—1
24029.167.78.239/3229.167.78.239 to 29.167.78.239—1
24129.167.78.240/3229.167.78.240 to 29.167.78.240—1
24229.167.78.241/3229.167.78.241 to 29.167.78.241—1
24329.167.78.242/3229.167.78.242 to 29.167.78.242—1
24429.167.78.243/3229.167.78.243 to 29.167.78.243—1
24529.167.78.244/3229.167.78.244 to 29.167.78.244—1
24629.167.78.245/3229.167.78.245 to 29.167.78.245—1
24729.167.78.246/3229.167.78.246 to 29.167.78.246—1
24829.167.78.247/3229.167.78.247 to 29.167.78.247—1
24929.167.78.248/3229.167.78.248 to 29.167.78.248—1
25029.167.78.249/3229.167.78.249 to 29.167.78.249—1
25129.167.78.250/3229.167.78.250 to 29.167.78.250—1
25229.167.78.251/3229.167.78.251 to 29.167.78.251—1
25329.167.78.252/3229.167.78.252 to 29.167.78.252—1
25429.167.78.253/3229.167.78.253 to 29.167.78.253—1
25529.167.78.254/3229.167.78.254 to 29.167.78.254—1
25629.167.78.255/3229.167.78.255 to 29.167.78.255—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.