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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.

Network199.2.64.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
199.2.64.0
Broadcast address
199.2.79.255
First usable
199.2.64.1
Last usable
199.2.79.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Public public
Old class
C (default /24)
As numbers
Hex C7024000 · Integer 3338813440 to 3338817535
Reverse DNS zones
64.2.199.in-addr.arpa
65.2.199.in-addr.arpa
66.2.199.in-addr.arpa
67.2.199.in-addr.arpa
68.2.199.in-addr.arpa
69.2.199.in-addr.arpa
70.2.199.in-addr.arpa
71.2.199.in-addr.arpa
72.2.199.in-addr.arpa
73.2.199.in-addr.arpa
74.2.199.in-addr.arpa
75.2.199.in-addr.arpa
76.2.199.in-addr.arpa
77.2.199.in-addr.arpa
78.2.199.in-addr.arpa
79.2.199.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000111.00000010.01000000.00000000199.2.64.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network11000111.00000010.01000000.00000000199.2.64.0
Broadcast11000111.00000010.01001111.11111111199.2.79.255
Split into smaller subnets/32
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

199.2.64.0/20 makes 4,096 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1199.2.64.0/32199.2.64.0 to 199.2.64.0—1
2199.2.64.1/32199.2.64.1 to 199.2.64.1—1
3199.2.64.2/32199.2.64.2 to 199.2.64.2—1
4199.2.64.3/32199.2.64.3 to 199.2.64.3—1
5199.2.64.4/32199.2.64.4 to 199.2.64.4—1
6199.2.64.5/32199.2.64.5 to 199.2.64.5—1
7199.2.64.6/32199.2.64.6 to 199.2.64.6—1
8199.2.64.7/32199.2.64.7 to 199.2.64.7—1
9199.2.64.8/32199.2.64.8 to 199.2.64.8—1
10199.2.64.9/32199.2.64.9 to 199.2.64.9—1
11199.2.64.10/32199.2.64.10 to 199.2.64.10—1
12199.2.64.11/32199.2.64.11 to 199.2.64.11—1
13199.2.64.12/32199.2.64.12 to 199.2.64.12—1
14199.2.64.13/32199.2.64.13 to 199.2.64.13—1
15199.2.64.14/32199.2.64.14 to 199.2.64.14—1
16199.2.64.15/32199.2.64.15 to 199.2.64.15—1
17199.2.64.16/32199.2.64.16 to 199.2.64.16—1
18199.2.64.17/32199.2.64.17 to 199.2.64.17—1
19199.2.64.18/32199.2.64.18 to 199.2.64.18—1
20199.2.64.19/32199.2.64.19 to 199.2.64.19—1
21199.2.64.20/32199.2.64.20 to 199.2.64.20—1
22199.2.64.21/32199.2.64.21 to 199.2.64.21—1
23199.2.64.22/32199.2.64.22 to 199.2.64.22—1
24199.2.64.23/32199.2.64.23 to 199.2.64.23—1
25199.2.64.24/32199.2.64.24 to 199.2.64.24—1
26199.2.64.25/32199.2.64.25 to 199.2.64.25—1
27199.2.64.26/32199.2.64.26 to 199.2.64.26—1
28199.2.64.27/32199.2.64.27 to 199.2.64.27—1
29199.2.64.28/32199.2.64.28 to 199.2.64.28—1
30199.2.64.29/32199.2.64.29 to 199.2.64.29—1
31199.2.64.30/32199.2.64.30 to 199.2.64.30—1
32199.2.64.31/32199.2.64.31 to 199.2.64.31—1
33199.2.64.32/32199.2.64.32 to 199.2.64.32—1
34199.2.64.33/32199.2.64.33 to 199.2.64.33—1
35199.2.64.34/32199.2.64.34 to 199.2.64.34—1
36199.2.64.35/32199.2.64.35 to 199.2.64.35—1
37199.2.64.36/32199.2.64.36 to 199.2.64.36—1
38199.2.64.37/32199.2.64.37 to 199.2.64.37—1
39199.2.64.38/32199.2.64.38 to 199.2.64.38—1
40199.2.64.39/32199.2.64.39 to 199.2.64.39—1
41199.2.64.40/32199.2.64.40 to 199.2.64.40—1
42199.2.64.41/32199.2.64.41 to 199.2.64.41—1
43199.2.64.42/32199.2.64.42 to 199.2.64.42—1
44199.2.64.43/32199.2.64.43 to 199.2.64.43—1
45199.2.64.44/32199.2.64.44 to 199.2.64.44—1
46199.2.64.45/32199.2.64.45 to 199.2.64.45—1
47199.2.64.46/32199.2.64.46 to 199.2.64.46—1
48199.2.64.47/32199.2.64.47 to 199.2.64.47—1
49199.2.64.48/32199.2.64.48 to 199.2.64.48—1
50199.2.64.49/32199.2.64.49 to 199.2.64.49—1
51199.2.64.50/32199.2.64.50 to 199.2.64.50—1
52199.2.64.51/32199.2.64.51 to 199.2.64.51—1
53199.2.64.52/32199.2.64.52 to 199.2.64.52—1
54199.2.64.53/32199.2.64.53 to 199.2.64.53—1
55199.2.64.54/32199.2.64.54 to 199.2.64.54—1
56199.2.64.55/32199.2.64.55 to 199.2.64.55—1
57199.2.64.56/32199.2.64.56 to 199.2.64.56—1
58199.2.64.57/32199.2.64.57 to 199.2.64.57—1
59199.2.64.58/32199.2.64.58 to 199.2.64.58—1
60199.2.64.59/32199.2.64.59 to 199.2.64.59—1
61199.2.64.60/32199.2.64.60 to 199.2.64.60—1
62199.2.64.61/32199.2.64.61 to 199.2.64.61—1
63199.2.64.62/32199.2.64.62 to 199.2.64.62—1
64199.2.64.63/32199.2.64.63 to 199.2.64.63—1
65199.2.64.64/32199.2.64.64 to 199.2.64.64—1
66199.2.64.65/32199.2.64.65 to 199.2.64.65—1
67199.2.64.66/32199.2.64.66 to 199.2.64.66—1
68199.2.64.67/32199.2.64.67 to 199.2.64.67—1
69199.2.64.68/32199.2.64.68 to 199.2.64.68—1
70199.2.64.69/32199.2.64.69 to 199.2.64.69—1
71199.2.64.70/32199.2.64.70 to 199.2.64.70—1
72199.2.64.71/32199.2.64.71 to 199.2.64.71—1
73199.2.64.72/32199.2.64.72 to 199.2.64.72—1
74199.2.64.73/32199.2.64.73 to 199.2.64.73—1
75199.2.64.74/32199.2.64.74 to 199.2.64.74—1
76199.2.64.75/32199.2.64.75 to 199.2.64.75—1
77199.2.64.76/32199.2.64.76 to 199.2.64.76—1
78199.2.64.77/32199.2.64.77 to 199.2.64.77—1
79199.2.64.78/32199.2.64.78 to 199.2.64.78—1
80199.2.64.79/32199.2.64.79 to 199.2.64.79—1
81199.2.64.80/32199.2.64.80 to 199.2.64.80—1
82199.2.64.81/32199.2.64.81 to 199.2.64.81—1
83199.2.64.82/32199.2.64.82 to 199.2.64.82—1
84199.2.64.83/32199.2.64.83 to 199.2.64.83—1
85199.2.64.84/32199.2.64.84 to 199.2.64.84—1
86199.2.64.85/32199.2.64.85 to 199.2.64.85—1
87199.2.64.86/32199.2.64.86 to 199.2.64.86—1
88199.2.64.87/32199.2.64.87 to 199.2.64.87—1
89199.2.64.88/32199.2.64.88 to 199.2.64.88—1
90199.2.64.89/32199.2.64.89 to 199.2.64.89—1
91199.2.64.90/32199.2.64.90 to 199.2.64.90—1
92199.2.64.91/32199.2.64.91 to 199.2.64.91—1
93199.2.64.92/32199.2.64.92 to 199.2.64.92—1
94199.2.64.93/32199.2.64.93 to 199.2.64.93—1
95199.2.64.94/32199.2.64.94 to 199.2.64.94—1
96199.2.64.95/32199.2.64.95 to 199.2.64.95—1
97199.2.64.96/32199.2.64.96 to 199.2.64.96—1
98199.2.64.97/32199.2.64.97 to 199.2.64.97—1
99199.2.64.98/32199.2.64.98 to 199.2.64.98—1
100199.2.64.99/32199.2.64.99 to 199.2.64.99—1
101199.2.64.100/32199.2.64.100 to 199.2.64.100—1
102199.2.64.101/32199.2.64.101 to 199.2.64.101—1
103199.2.64.102/32199.2.64.102 to 199.2.64.102—1
104199.2.64.103/32199.2.64.103 to 199.2.64.103—1
105199.2.64.104/32199.2.64.104 to 199.2.64.104—1
106199.2.64.105/32199.2.64.105 to 199.2.64.105—1
107199.2.64.106/32199.2.64.106 to 199.2.64.106—1
108199.2.64.107/32199.2.64.107 to 199.2.64.107—1
109199.2.64.108/32199.2.64.108 to 199.2.64.108—1
110199.2.64.109/32199.2.64.109 to 199.2.64.109—1
111199.2.64.110/32199.2.64.110 to 199.2.64.110—1
112199.2.64.111/32199.2.64.111 to 199.2.64.111—1
113199.2.64.112/32199.2.64.112 to 199.2.64.112—1
114199.2.64.113/32199.2.64.113 to 199.2.64.113—1
115199.2.64.114/32199.2.64.114 to 199.2.64.114—1
116199.2.64.115/32199.2.64.115 to 199.2.64.115—1
117199.2.64.116/32199.2.64.116 to 199.2.64.116—1
118199.2.64.117/32199.2.64.117 to 199.2.64.117—1
119199.2.64.118/32199.2.64.118 to 199.2.64.118—1
120199.2.64.119/32199.2.64.119 to 199.2.64.119—1
121199.2.64.120/32199.2.64.120 to 199.2.64.120—1
122199.2.64.121/32199.2.64.121 to 199.2.64.121—1
123199.2.64.122/32199.2.64.122 to 199.2.64.122—1
124199.2.64.123/32199.2.64.123 to 199.2.64.123—1
125199.2.64.124/32199.2.64.124 to 199.2.64.124—1
126199.2.64.125/32199.2.64.125 to 199.2.64.125—1
127199.2.64.126/32199.2.64.126 to 199.2.64.126—1
128199.2.64.127/32199.2.64.127 to 199.2.64.127—1
129199.2.64.128/32199.2.64.128 to 199.2.64.128—1
130199.2.64.129/32199.2.64.129 to 199.2.64.129—1
131199.2.64.130/32199.2.64.130 to 199.2.64.130—1
132199.2.64.131/32199.2.64.131 to 199.2.64.131—1
133199.2.64.132/32199.2.64.132 to 199.2.64.132—1
134199.2.64.133/32199.2.64.133 to 199.2.64.133—1
135199.2.64.134/32199.2.64.134 to 199.2.64.134—1
136199.2.64.135/32199.2.64.135 to 199.2.64.135—1
137199.2.64.136/32199.2.64.136 to 199.2.64.136—1
138199.2.64.137/32199.2.64.137 to 199.2.64.137—1
139199.2.64.138/32199.2.64.138 to 199.2.64.138—1
140199.2.64.139/32199.2.64.139 to 199.2.64.139—1
141199.2.64.140/32199.2.64.140 to 199.2.64.140—1
142199.2.64.141/32199.2.64.141 to 199.2.64.141—1
143199.2.64.142/32199.2.64.142 to 199.2.64.142—1
144199.2.64.143/32199.2.64.143 to 199.2.64.143—1
145199.2.64.144/32199.2.64.144 to 199.2.64.144—1
146199.2.64.145/32199.2.64.145 to 199.2.64.145—1
147199.2.64.146/32199.2.64.146 to 199.2.64.146—1
148199.2.64.147/32199.2.64.147 to 199.2.64.147—1
149199.2.64.148/32199.2.64.148 to 199.2.64.148—1
150199.2.64.149/32199.2.64.149 to 199.2.64.149—1
151199.2.64.150/32199.2.64.150 to 199.2.64.150—1
152199.2.64.151/32199.2.64.151 to 199.2.64.151—1
153199.2.64.152/32199.2.64.152 to 199.2.64.152—1
154199.2.64.153/32199.2.64.153 to 199.2.64.153—1
155199.2.64.154/32199.2.64.154 to 199.2.64.154—1
156199.2.64.155/32199.2.64.155 to 199.2.64.155—1
157199.2.64.156/32199.2.64.156 to 199.2.64.156—1
158199.2.64.157/32199.2.64.157 to 199.2.64.157—1
159199.2.64.158/32199.2.64.158 to 199.2.64.158—1
160199.2.64.159/32199.2.64.159 to 199.2.64.159—1
161199.2.64.160/32199.2.64.160 to 199.2.64.160—1
162199.2.64.161/32199.2.64.161 to 199.2.64.161—1
163199.2.64.162/32199.2.64.162 to 199.2.64.162—1
164199.2.64.163/32199.2.64.163 to 199.2.64.163—1
165199.2.64.164/32199.2.64.164 to 199.2.64.164—1
166199.2.64.165/32199.2.64.165 to 199.2.64.165—1
167199.2.64.166/32199.2.64.166 to 199.2.64.166—1
168199.2.64.167/32199.2.64.167 to 199.2.64.167—1
169199.2.64.168/32199.2.64.168 to 199.2.64.168—1
170199.2.64.169/32199.2.64.169 to 199.2.64.169—1
171199.2.64.170/32199.2.64.170 to 199.2.64.170—1
172199.2.64.171/32199.2.64.171 to 199.2.64.171—1
173199.2.64.172/32199.2.64.172 to 199.2.64.172—1
174199.2.64.173/32199.2.64.173 to 199.2.64.173—1
175199.2.64.174/32199.2.64.174 to 199.2.64.174—1
176199.2.64.175/32199.2.64.175 to 199.2.64.175—1
177199.2.64.176/32199.2.64.176 to 199.2.64.176—1
178199.2.64.177/32199.2.64.177 to 199.2.64.177—1
179199.2.64.178/32199.2.64.178 to 199.2.64.178—1
180199.2.64.179/32199.2.64.179 to 199.2.64.179—1
181199.2.64.180/32199.2.64.180 to 199.2.64.180—1
182199.2.64.181/32199.2.64.181 to 199.2.64.181—1
183199.2.64.182/32199.2.64.182 to 199.2.64.182—1
184199.2.64.183/32199.2.64.183 to 199.2.64.183—1
185199.2.64.184/32199.2.64.184 to 199.2.64.184—1
186199.2.64.185/32199.2.64.185 to 199.2.64.185—1
187199.2.64.186/32199.2.64.186 to 199.2.64.186—1
188199.2.64.187/32199.2.64.187 to 199.2.64.187—1
189199.2.64.188/32199.2.64.188 to 199.2.64.188—1
190199.2.64.189/32199.2.64.189 to 199.2.64.189—1
191199.2.64.190/32199.2.64.190 to 199.2.64.190—1
192199.2.64.191/32199.2.64.191 to 199.2.64.191—1
193199.2.64.192/32199.2.64.192 to 199.2.64.192—1
194199.2.64.193/32199.2.64.193 to 199.2.64.193—1
195199.2.64.194/32199.2.64.194 to 199.2.64.194—1
196199.2.64.195/32199.2.64.195 to 199.2.64.195—1
197199.2.64.196/32199.2.64.196 to 199.2.64.196—1
198199.2.64.197/32199.2.64.197 to 199.2.64.197—1
199199.2.64.198/32199.2.64.198 to 199.2.64.198—1
200199.2.64.199/32199.2.64.199 to 199.2.64.199—1
201199.2.64.200/32199.2.64.200 to 199.2.64.200—1
202199.2.64.201/32199.2.64.201 to 199.2.64.201—1
203199.2.64.202/32199.2.64.202 to 199.2.64.202—1
204199.2.64.203/32199.2.64.203 to 199.2.64.203—1
205199.2.64.204/32199.2.64.204 to 199.2.64.204—1
206199.2.64.205/32199.2.64.205 to 199.2.64.205—1
207199.2.64.206/32199.2.64.206 to 199.2.64.206—1
208199.2.64.207/32199.2.64.207 to 199.2.64.207—1
209199.2.64.208/32199.2.64.208 to 199.2.64.208—1
210199.2.64.209/32199.2.64.209 to 199.2.64.209—1
211199.2.64.210/32199.2.64.210 to 199.2.64.210—1
212199.2.64.211/32199.2.64.211 to 199.2.64.211—1
213199.2.64.212/32199.2.64.212 to 199.2.64.212—1
214199.2.64.213/32199.2.64.213 to 199.2.64.213—1
215199.2.64.214/32199.2.64.214 to 199.2.64.214—1
216199.2.64.215/32199.2.64.215 to 199.2.64.215—1
217199.2.64.216/32199.2.64.216 to 199.2.64.216—1
218199.2.64.217/32199.2.64.217 to 199.2.64.217—1
219199.2.64.218/32199.2.64.218 to 199.2.64.218—1
220199.2.64.219/32199.2.64.219 to 199.2.64.219—1
221199.2.64.220/32199.2.64.220 to 199.2.64.220—1
222199.2.64.221/32199.2.64.221 to 199.2.64.221—1
223199.2.64.222/32199.2.64.222 to 199.2.64.222—1
224199.2.64.223/32199.2.64.223 to 199.2.64.223—1
225199.2.64.224/32199.2.64.224 to 199.2.64.224—1
226199.2.64.225/32199.2.64.225 to 199.2.64.225—1
227199.2.64.226/32199.2.64.226 to 199.2.64.226—1
228199.2.64.227/32199.2.64.227 to 199.2.64.227—1
229199.2.64.228/32199.2.64.228 to 199.2.64.228—1
230199.2.64.229/32199.2.64.229 to 199.2.64.229—1
231199.2.64.230/32199.2.64.230 to 199.2.64.230—1
232199.2.64.231/32199.2.64.231 to 199.2.64.231—1
233199.2.64.232/32199.2.64.232 to 199.2.64.232—1
234199.2.64.233/32199.2.64.233 to 199.2.64.233—1
235199.2.64.234/32199.2.64.234 to 199.2.64.234—1
236199.2.64.235/32199.2.64.235 to 199.2.64.235—1
237199.2.64.236/32199.2.64.236 to 199.2.64.236—1
238199.2.64.237/32199.2.64.237 to 199.2.64.237—1
239199.2.64.238/32199.2.64.238 to 199.2.64.238—1
240199.2.64.239/32199.2.64.239 to 199.2.64.239—1
241199.2.64.240/32199.2.64.240 to 199.2.64.240—1
242199.2.64.241/32199.2.64.241 to 199.2.64.241—1
243199.2.64.242/32199.2.64.242 to 199.2.64.242—1
244199.2.64.243/32199.2.64.243 to 199.2.64.243—1
245199.2.64.244/32199.2.64.244 to 199.2.64.244—1
246199.2.64.245/32199.2.64.245 to 199.2.64.245—1
247199.2.64.246/32199.2.64.246 to 199.2.64.246—1
248199.2.64.247/32199.2.64.247 to 199.2.64.247—1
249199.2.64.248/32199.2.64.248 to 199.2.64.248—1
250199.2.64.249/32199.2.64.249 to 199.2.64.249—1
251199.2.64.250/32199.2.64.250 to 199.2.64.250—1
252199.2.64.251/32199.2.64.251 to 199.2.64.251—1
253199.2.64.252/32199.2.64.252 to 199.2.64.252—1
254199.2.64.253/32199.2.64.253 to 199.2.64.253—1
255199.2.64.254/32199.2.64.254 to 199.2.64.254—1
256199.2.64.255/32199.2.64.255 to 199.2.64.255—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.