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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.

Network238.131.76.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
238.131.76.0
Broadcast address
238.131.79.255
First usable
238.131.76.1
Last usable
238.131.79.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EE834C00 · Integer 4001582080 to 4001583103
Reverse DNS zones
76.131.238.in-addr.arpa
77.131.238.in-addr.arpa
78.131.238.in-addr.arpa
79.131.238.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
Address11101110.10000011.01001100.00000000238.131.76.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network11101110.10000011.01001100.00000000238.131.76.0
Broadcast11101110.10000011.01001111.11111111238.131.79.255
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)

238.131.76.0/22 makes 1,024 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1238.131.76.0/32238.131.76.0 to 238.131.76.0—1
2238.131.76.1/32238.131.76.1 to 238.131.76.1—1
3238.131.76.2/32238.131.76.2 to 238.131.76.2—1
4238.131.76.3/32238.131.76.3 to 238.131.76.3—1
5238.131.76.4/32238.131.76.4 to 238.131.76.4—1
6238.131.76.5/32238.131.76.5 to 238.131.76.5—1
7238.131.76.6/32238.131.76.6 to 238.131.76.6—1
8238.131.76.7/32238.131.76.7 to 238.131.76.7—1
9238.131.76.8/32238.131.76.8 to 238.131.76.8—1
10238.131.76.9/32238.131.76.9 to 238.131.76.9—1
11238.131.76.10/32238.131.76.10 to 238.131.76.10—1
12238.131.76.11/32238.131.76.11 to 238.131.76.11—1
13238.131.76.12/32238.131.76.12 to 238.131.76.12—1
14238.131.76.13/32238.131.76.13 to 238.131.76.13—1
15238.131.76.14/32238.131.76.14 to 238.131.76.14—1
16238.131.76.15/32238.131.76.15 to 238.131.76.15—1
17238.131.76.16/32238.131.76.16 to 238.131.76.16—1
18238.131.76.17/32238.131.76.17 to 238.131.76.17—1
19238.131.76.18/32238.131.76.18 to 238.131.76.18—1
20238.131.76.19/32238.131.76.19 to 238.131.76.19—1
21238.131.76.20/32238.131.76.20 to 238.131.76.20—1
22238.131.76.21/32238.131.76.21 to 238.131.76.21—1
23238.131.76.22/32238.131.76.22 to 238.131.76.22—1
24238.131.76.23/32238.131.76.23 to 238.131.76.23—1
25238.131.76.24/32238.131.76.24 to 238.131.76.24—1
26238.131.76.25/32238.131.76.25 to 238.131.76.25—1
27238.131.76.26/32238.131.76.26 to 238.131.76.26—1
28238.131.76.27/32238.131.76.27 to 238.131.76.27—1
29238.131.76.28/32238.131.76.28 to 238.131.76.28—1
30238.131.76.29/32238.131.76.29 to 238.131.76.29—1
31238.131.76.30/32238.131.76.30 to 238.131.76.30—1
32238.131.76.31/32238.131.76.31 to 238.131.76.31—1
33238.131.76.32/32238.131.76.32 to 238.131.76.32—1
34238.131.76.33/32238.131.76.33 to 238.131.76.33—1
35238.131.76.34/32238.131.76.34 to 238.131.76.34—1
36238.131.76.35/32238.131.76.35 to 238.131.76.35—1
37238.131.76.36/32238.131.76.36 to 238.131.76.36—1
38238.131.76.37/32238.131.76.37 to 238.131.76.37—1
39238.131.76.38/32238.131.76.38 to 238.131.76.38—1
40238.131.76.39/32238.131.76.39 to 238.131.76.39—1
41238.131.76.40/32238.131.76.40 to 238.131.76.40—1
42238.131.76.41/32238.131.76.41 to 238.131.76.41—1
43238.131.76.42/32238.131.76.42 to 238.131.76.42—1
44238.131.76.43/32238.131.76.43 to 238.131.76.43—1
45238.131.76.44/32238.131.76.44 to 238.131.76.44—1
46238.131.76.45/32238.131.76.45 to 238.131.76.45—1
47238.131.76.46/32238.131.76.46 to 238.131.76.46—1
48238.131.76.47/32238.131.76.47 to 238.131.76.47—1
49238.131.76.48/32238.131.76.48 to 238.131.76.48—1
50238.131.76.49/32238.131.76.49 to 238.131.76.49—1
51238.131.76.50/32238.131.76.50 to 238.131.76.50—1
52238.131.76.51/32238.131.76.51 to 238.131.76.51—1
53238.131.76.52/32238.131.76.52 to 238.131.76.52—1
54238.131.76.53/32238.131.76.53 to 238.131.76.53—1
55238.131.76.54/32238.131.76.54 to 238.131.76.54—1
56238.131.76.55/32238.131.76.55 to 238.131.76.55—1
57238.131.76.56/32238.131.76.56 to 238.131.76.56—1
58238.131.76.57/32238.131.76.57 to 238.131.76.57—1
59238.131.76.58/32238.131.76.58 to 238.131.76.58—1
60238.131.76.59/32238.131.76.59 to 238.131.76.59—1
61238.131.76.60/32238.131.76.60 to 238.131.76.60—1
62238.131.76.61/32238.131.76.61 to 238.131.76.61—1
63238.131.76.62/32238.131.76.62 to 238.131.76.62—1
64238.131.76.63/32238.131.76.63 to 238.131.76.63—1
65238.131.76.64/32238.131.76.64 to 238.131.76.64—1
66238.131.76.65/32238.131.76.65 to 238.131.76.65—1
67238.131.76.66/32238.131.76.66 to 238.131.76.66—1
68238.131.76.67/32238.131.76.67 to 238.131.76.67—1
69238.131.76.68/32238.131.76.68 to 238.131.76.68—1
70238.131.76.69/32238.131.76.69 to 238.131.76.69—1
71238.131.76.70/32238.131.76.70 to 238.131.76.70—1
72238.131.76.71/32238.131.76.71 to 238.131.76.71—1
73238.131.76.72/32238.131.76.72 to 238.131.76.72—1
74238.131.76.73/32238.131.76.73 to 238.131.76.73—1
75238.131.76.74/32238.131.76.74 to 238.131.76.74—1
76238.131.76.75/32238.131.76.75 to 238.131.76.75—1
77238.131.76.76/32238.131.76.76 to 238.131.76.76—1
78238.131.76.77/32238.131.76.77 to 238.131.76.77—1
79238.131.76.78/32238.131.76.78 to 238.131.76.78—1
80238.131.76.79/32238.131.76.79 to 238.131.76.79—1
81238.131.76.80/32238.131.76.80 to 238.131.76.80—1
82238.131.76.81/32238.131.76.81 to 238.131.76.81—1
83238.131.76.82/32238.131.76.82 to 238.131.76.82—1
84238.131.76.83/32238.131.76.83 to 238.131.76.83—1
85238.131.76.84/32238.131.76.84 to 238.131.76.84—1
86238.131.76.85/32238.131.76.85 to 238.131.76.85—1
87238.131.76.86/32238.131.76.86 to 238.131.76.86—1
88238.131.76.87/32238.131.76.87 to 238.131.76.87—1
89238.131.76.88/32238.131.76.88 to 238.131.76.88—1
90238.131.76.89/32238.131.76.89 to 238.131.76.89—1
91238.131.76.90/32238.131.76.90 to 238.131.76.90—1
92238.131.76.91/32238.131.76.91 to 238.131.76.91—1
93238.131.76.92/32238.131.76.92 to 238.131.76.92—1
94238.131.76.93/32238.131.76.93 to 238.131.76.93—1
95238.131.76.94/32238.131.76.94 to 238.131.76.94—1
96238.131.76.95/32238.131.76.95 to 238.131.76.95—1
97238.131.76.96/32238.131.76.96 to 238.131.76.96—1
98238.131.76.97/32238.131.76.97 to 238.131.76.97—1
99238.131.76.98/32238.131.76.98 to 238.131.76.98—1
100238.131.76.99/32238.131.76.99 to 238.131.76.99—1
101238.131.76.100/32238.131.76.100 to 238.131.76.100—1
102238.131.76.101/32238.131.76.101 to 238.131.76.101—1
103238.131.76.102/32238.131.76.102 to 238.131.76.102—1
104238.131.76.103/32238.131.76.103 to 238.131.76.103—1
105238.131.76.104/32238.131.76.104 to 238.131.76.104—1
106238.131.76.105/32238.131.76.105 to 238.131.76.105—1
107238.131.76.106/32238.131.76.106 to 238.131.76.106—1
108238.131.76.107/32238.131.76.107 to 238.131.76.107—1
109238.131.76.108/32238.131.76.108 to 238.131.76.108—1
110238.131.76.109/32238.131.76.109 to 238.131.76.109—1
111238.131.76.110/32238.131.76.110 to 238.131.76.110—1
112238.131.76.111/32238.131.76.111 to 238.131.76.111—1
113238.131.76.112/32238.131.76.112 to 238.131.76.112—1
114238.131.76.113/32238.131.76.113 to 238.131.76.113—1
115238.131.76.114/32238.131.76.114 to 238.131.76.114—1
116238.131.76.115/32238.131.76.115 to 238.131.76.115—1
117238.131.76.116/32238.131.76.116 to 238.131.76.116—1
118238.131.76.117/32238.131.76.117 to 238.131.76.117—1
119238.131.76.118/32238.131.76.118 to 238.131.76.118—1
120238.131.76.119/32238.131.76.119 to 238.131.76.119—1
121238.131.76.120/32238.131.76.120 to 238.131.76.120—1
122238.131.76.121/32238.131.76.121 to 238.131.76.121—1
123238.131.76.122/32238.131.76.122 to 238.131.76.122—1
124238.131.76.123/32238.131.76.123 to 238.131.76.123—1
125238.131.76.124/32238.131.76.124 to 238.131.76.124—1
126238.131.76.125/32238.131.76.125 to 238.131.76.125—1
127238.131.76.126/32238.131.76.126 to 238.131.76.126—1
128238.131.76.127/32238.131.76.127 to 238.131.76.127—1
129238.131.76.128/32238.131.76.128 to 238.131.76.128—1
130238.131.76.129/32238.131.76.129 to 238.131.76.129—1
131238.131.76.130/32238.131.76.130 to 238.131.76.130—1
132238.131.76.131/32238.131.76.131 to 238.131.76.131—1
133238.131.76.132/32238.131.76.132 to 238.131.76.132—1
134238.131.76.133/32238.131.76.133 to 238.131.76.133—1
135238.131.76.134/32238.131.76.134 to 238.131.76.134—1
136238.131.76.135/32238.131.76.135 to 238.131.76.135—1
137238.131.76.136/32238.131.76.136 to 238.131.76.136—1
138238.131.76.137/32238.131.76.137 to 238.131.76.137—1
139238.131.76.138/32238.131.76.138 to 238.131.76.138—1
140238.131.76.139/32238.131.76.139 to 238.131.76.139—1
141238.131.76.140/32238.131.76.140 to 238.131.76.140—1
142238.131.76.141/32238.131.76.141 to 238.131.76.141—1
143238.131.76.142/32238.131.76.142 to 238.131.76.142—1
144238.131.76.143/32238.131.76.143 to 238.131.76.143—1
145238.131.76.144/32238.131.76.144 to 238.131.76.144—1
146238.131.76.145/32238.131.76.145 to 238.131.76.145—1
147238.131.76.146/32238.131.76.146 to 238.131.76.146—1
148238.131.76.147/32238.131.76.147 to 238.131.76.147—1
149238.131.76.148/32238.131.76.148 to 238.131.76.148—1
150238.131.76.149/32238.131.76.149 to 238.131.76.149—1
151238.131.76.150/32238.131.76.150 to 238.131.76.150—1
152238.131.76.151/32238.131.76.151 to 238.131.76.151—1
153238.131.76.152/32238.131.76.152 to 238.131.76.152—1
154238.131.76.153/32238.131.76.153 to 238.131.76.153—1
155238.131.76.154/32238.131.76.154 to 238.131.76.154—1
156238.131.76.155/32238.131.76.155 to 238.131.76.155—1
157238.131.76.156/32238.131.76.156 to 238.131.76.156—1
158238.131.76.157/32238.131.76.157 to 238.131.76.157—1
159238.131.76.158/32238.131.76.158 to 238.131.76.158—1
160238.131.76.159/32238.131.76.159 to 238.131.76.159—1
161238.131.76.160/32238.131.76.160 to 238.131.76.160—1
162238.131.76.161/32238.131.76.161 to 238.131.76.161—1
163238.131.76.162/32238.131.76.162 to 238.131.76.162—1
164238.131.76.163/32238.131.76.163 to 238.131.76.163—1
165238.131.76.164/32238.131.76.164 to 238.131.76.164—1
166238.131.76.165/32238.131.76.165 to 238.131.76.165—1
167238.131.76.166/32238.131.76.166 to 238.131.76.166—1
168238.131.76.167/32238.131.76.167 to 238.131.76.167—1
169238.131.76.168/32238.131.76.168 to 238.131.76.168—1
170238.131.76.169/32238.131.76.169 to 238.131.76.169—1
171238.131.76.170/32238.131.76.170 to 238.131.76.170—1
172238.131.76.171/32238.131.76.171 to 238.131.76.171—1
173238.131.76.172/32238.131.76.172 to 238.131.76.172—1
174238.131.76.173/32238.131.76.173 to 238.131.76.173—1
175238.131.76.174/32238.131.76.174 to 238.131.76.174—1
176238.131.76.175/32238.131.76.175 to 238.131.76.175—1
177238.131.76.176/32238.131.76.176 to 238.131.76.176—1
178238.131.76.177/32238.131.76.177 to 238.131.76.177—1
179238.131.76.178/32238.131.76.178 to 238.131.76.178—1
180238.131.76.179/32238.131.76.179 to 238.131.76.179—1
181238.131.76.180/32238.131.76.180 to 238.131.76.180—1
182238.131.76.181/32238.131.76.181 to 238.131.76.181—1
183238.131.76.182/32238.131.76.182 to 238.131.76.182—1
184238.131.76.183/32238.131.76.183 to 238.131.76.183—1
185238.131.76.184/32238.131.76.184 to 238.131.76.184—1
186238.131.76.185/32238.131.76.185 to 238.131.76.185—1
187238.131.76.186/32238.131.76.186 to 238.131.76.186—1
188238.131.76.187/32238.131.76.187 to 238.131.76.187—1
189238.131.76.188/32238.131.76.188 to 238.131.76.188—1
190238.131.76.189/32238.131.76.189 to 238.131.76.189—1
191238.131.76.190/32238.131.76.190 to 238.131.76.190—1
192238.131.76.191/32238.131.76.191 to 238.131.76.191—1
193238.131.76.192/32238.131.76.192 to 238.131.76.192—1
194238.131.76.193/32238.131.76.193 to 238.131.76.193—1
195238.131.76.194/32238.131.76.194 to 238.131.76.194—1
196238.131.76.195/32238.131.76.195 to 238.131.76.195—1
197238.131.76.196/32238.131.76.196 to 238.131.76.196—1
198238.131.76.197/32238.131.76.197 to 238.131.76.197—1
199238.131.76.198/32238.131.76.198 to 238.131.76.198—1
200238.131.76.199/32238.131.76.199 to 238.131.76.199—1
201238.131.76.200/32238.131.76.200 to 238.131.76.200—1
202238.131.76.201/32238.131.76.201 to 238.131.76.201—1
203238.131.76.202/32238.131.76.202 to 238.131.76.202—1
204238.131.76.203/32238.131.76.203 to 238.131.76.203—1
205238.131.76.204/32238.131.76.204 to 238.131.76.204—1
206238.131.76.205/32238.131.76.205 to 238.131.76.205—1
207238.131.76.206/32238.131.76.206 to 238.131.76.206—1
208238.131.76.207/32238.131.76.207 to 238.131.76.207—1
209238.131.76.208/32238.131.76.208 to 238.131.76.208—1
210238.131.76.209/32238.131.76.209 to 238.131.76.209—1
211238.131.76.210/32238.131.76.210 to 238.131.76.210—1
212238.131.76.211/32238.131.76.211 to 238.131.76.211—1
213238.131.76.212/32238.131.76.212 to 238.131.76.212—1
214238.131.76.213/32238.131.76.213 to 238.131.76.213—1
215238.131.76.214/32238.131.76.214 to 238.131.76.214—1
216238.131.76.215/32238.131.76.215 to 238.131.76.215—1
217238.131.76.216/32238.131.76.216 to 238.131.76.216—1
218238.131.76.217/32238.131.76.217 to 238.131.76.217—1
219238.131.76.218/32238.131.76.218 to 238.131.76.218—1
220238.131.76.219/32238.131.76.219 to 238.131.76.219—1
221238.131.76.220/32238.131.76.220 to 238.131.76.220—1
222238.131.76.221/32238.131.76.221 to 238.131.76.221—1
223238.131.76.222/32238.131.76.222 to 238.131.76.222—1
224238.131.76.223/32238.131.76.223 to 238.131.76.223—1
225238.131.76.224/32238.131.76.224 to 238.131.76.224—1
226238.131.76.225/32238.131.76.225 to 238.131.76.225—1
227238.131.76.226/32238.131.76.226 to 238.131.76.226—1
228238.131.76.227/32238.131.76.227 to 238.131.76.227—1
229238.131.76.228/32238.131.76.228 to 238.131.76.228—1
230238.131.76.229/32238.131.76.229 to 238.131.76.229—1
231238.131.76.230/32238.131.76.230 to 238.131.76.230—1
232238.131.76.231/32238.131.76.231 to 238.131.76.231—1
233238.131.76.232/32238.131.76.232 to 238.131.76.232—1
234238.131.76.233/32238.131.76.233 to 238.131.76.233—1
235238.131.76.234/32238.131.76.234 to 238.131.76.234—1
236238.131.76.235/32238.131.76.235 to 238.131.76.235—1
237238.131.76.236/32238.131.76.236 to 238.131.76.236—1
238238.131.76.237/32238.131.76.237 to 238.131.76.237—1
239238.131.76.238/32238.131.76.238 to 238.131.76.238—1
240238.131.76.239/32238.131.76.239 to 238.131.76.239—1
241238.131.76.240/32238.131.76.240 to 238.131.76.240—1
242238.131.76.241/32238.131.76.241 to 238.131.76.241—1
243238.131.76.242/32238.131.76.242 to 238.131.76.242—1
244238.131.76.243/32238.131.76.243 to 238.131.76.243—1
245238.131.76.244/32238.131.76.244 to 238.131.76.244—1
246238.131.76.245/32238.131.76.245 to 238.131.76.245—1
247238.131.76.246/32238.131.76.246 to 238.131.76.246—1
248238.131.76.247/32238.131.76.247 to 238.131.76.247—1
249238.131.76.248/32238.131.76.248 to 238.131.76.248—1
250238.131.76.249/32238.131.76.249 to 238.131.76.249—1
251238.131.76.250/32238.131.76.250 to 238.131.76.250—1
252238.131.76.251/32238.131.76.251 to 238.131.76.251—1
253238.131.76.252/32238.131.76.252 to 238.131.76.252—1
254238.131.76.253/32238.131.76.253 to 238.131.76.253—1
255238.131.76.254/32238.131.76.254 to 238.131.76.254—1
256238.131.76.255/32238.131.76.255 to 238.131.76.255—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.