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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.

Network110.3.0.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
110.3.0.0
Broadcast address
110.3.15.255
First usable
110.3.0.1
Last usable
110.3.15.254
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
A (default /8)
As numbers
Hex 6E030000 · Integer 1845690368 to 1845694463
Reverse DNS zones
0.3.110.in-addr.arpa
1.3.110.in-addr.arpa
2.3.110.in-addr.arpa
3.3.110.in-addr.arpa
4.3.110.in-addr.arpa
5.3.110.in-addr.arpa
6.3.110.in-addr.arpa
7.3.110.in-addr.arpa
8.3.110.in-addr.arpa
9.3.110.in-addr.arpa
10.3.110.in-addr.arpa
11.3.110.in-addr.arpa
12.3.110.in-addr.arpa
13.3.110.in-addr.arpa
14.3.110.in-addr.arpa
15.3.110.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
Address01101110.00000011.00000000.00000000110.3.0.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network01101110.00000011.00000000.00000000110.3.0.0
Broadcast01101110.00000011.00001111.11111111110.3.15.255
Split into smaller subnets/31
/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)

110.3.0.0/20 makes 2,048 subnets of /31; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1110.3.0.0/31110.3.0.0 to 110.3.0.1—2
2110.3.0.2/31110.3.0.2 to 110.3.0.3—2
3110.3.0.4/31110.3.0.4 to 110.3.0.5—2
4110.3.0.6/31110.3.0.6 to 110.3.0.7—2
5110.3.0.8/31110.3.0.8 to 110.3.0.9—2
6110.3.0.10/31110.3.0.10 to 110.3.0.11—2
7110.3.0.12/31110.3.0.12 to 110.3.0.13—2
8110.3.0.14/31110.3.0.14 to 110.3.0.15—2
9110.3.0.16/31110.3.0.16 to 110.3.0.17—2
10110.3.0.18/31110.3.0.18 to 110.3.0.19—2
11110.3.0.20/31110.3.0.20 to 110.3.0.21—2
12110.3.0.22/31110.3.0.22 to 110.3.0.23—2
13110.3.0.24/31110.3.0.24 to 110.3.0.25—2
14110.3.0.26/31110.3.0.26 to 110.3.0.27—2
15110.3.0.28/31110.3.0.28 to 110.3.0.29—2
16110.3.0.30/31110.3.0.30 to 110.3.0.31—2
17110.3.0.32/31110.3.0.32 to 110.3.0.33—2
18110.3.0.34/31110.3.0.34 to 110.3.0.35—2
19110.3.0.36/31110.3.0.36 to 110.3.0.37—2
20110.3.0.38/31110.3.0.38 to 110.3.0.39—2
21110.3.0.40/31110.3.0.40 to 110.3.0.41—2
22110.3.0.42/31110.3.0.42 to 110.3.0.43—2
23110.3.0.44/31110.3.0.44 to 110.3.0.45—2
24110.3.0.46/31110.3.0.46 to 110.3.0.47—2
25110.3.0.48/31110.3.0.48 to 110.3.0.49—2
26110.3.0.50/31110.3.0.50 to 110.3.0.51—2
27110.3.0.52/31110.3.0.52 to 110.3.0.53—2
28110.3.0.54/31110.3.0.54 to 110.3.0.55—2
29110.3.0.56/31110.3.0.56 to 110.3.0.57—2
30110.3.0.58/31110.3.0.58 to 110.3.0.59—2
31110.3.0.60/31110.3.0.60 to 110.3.0.61—2
32110.3.0.62/31110.3.0.62 to 110.3.0.63—2
33110.3.0.64/31110.3.0.64 to 110.3.0.65—2
34110.3.0.66/31110.3.0.66 to 110.3.0.67—2
35110.3.0.68/31110.3.0.68 to 110.3.0.69—2
36110.3.0.70/31110.3.0.70 to 110.3.0.71—2
37110.3.0.72/31110.3.0.72 to 110.3.0.73—2
38110.3.0.74/31110.3.0.74 to 110.3.0.75—2
39110.3.0.76/31110.3.0.76 to 110.3.0.77—2
40110.3.0.78/31110.3.0.78 to 110.3.0.79—2
41110.3.0.80/31110.3.0.80 to 110.3.0.81—2
42110.3.0.82/31110.3.0.82 to 110.3.0.83—2
43110.3.0.84/31110.3.0.84 to 110.3.0.85—2
44110.3.0.86/31110.3.0.86 to 110.3.0.87—2
45110.3.0.88/31110.3.0.88 to 110.3.0.89—2
46110.3.0.90/31110.3.0.90 to 110.3.0.91—2
47110.3.0.92/31110.3.0.92 to 110.3.0.93—2
48110.3.0.94/31110.3.0.94 to 110.3.0.95—2
49110.3.0.96/31110.3.0.96 to 110.3.0.97—2
50110.3.0.98/31110.3.0.98 to 110.3.0.99—2
51110.3.0.100/31110.3.0.100 to 110.3.0.101—2
52110.3.0.102/31110.3.0.102 to 110.3.0.103—2
53110.3.0.104/31110.3.0.104 to 110.3.0.105—2
54110.3.0.106/31110.3.0.106 to 110.3.0.107—2
55110.3.0.108/31110.3.0.108 to 110.3.0.109—2
56110.3.0.110/31110.3.0.110 to 110.3.0.111—2
57110.3.0.112/31110.3.0.112 to 110.3.0.113—2
58110.3.0.114/31110.3.0.114 to 110.3.0.115—2
59110.3.0.116/31110.3.0.116 to 110.3.0.117—2
60110.3.0.118/31110.3.0.118 to 110.3.0.119—2
61110.3.0.120/31110.3.0.120 to 110.3.0.121—2
62110.3.0.122/31110.3.0.122 to 110.3.0.123—2
63110.3.0.124/31110.3.0.124 to 110.3.0.125—2
64110.3.0.126/31110.3.0.126 to 110.3.0.127—2
65110.3.0.128/31110.3.0.128 to 110.3.0.129—2
66110.3.0.130/31110.3.0.130 to 110.3.0.131—2
67110.3.0.132/31110.3.0.132 to 110.3.0.133—2
68110.3.0.134/31110.3.0.134 to 110.3.0.135—2
69110.3.0.136/31110.3.0.136 to 110.3.0.137—2
70110.3.0.138/31110.3.0.138 to 110.3.0.139—2
71110.3.0.140/31110.3.0.140 to 110.3.0.141—2
72110.3.0.142/31110.3.0.142 to 110.3.0.143—2
73110.3.0.144/31110.3.0.144 to 110.3.0.145—2
74110.3.0.146/31110.3.0.146 to 110.3.0.147—2
75110.3.0.148/31110.3.0.148 to 110.3.0.149—2
76110.3.0.150/31110.3.0.150 to 110.3.0.151—2
77110.3.0.152/31110.3.0.152 to 110.3.0.153—2
78110.3.0.154/31110.3.0.154 to 110.3.0.155—2
79110.3.0.156/31110.3.0.156 to 110.3.0.157—2
80110.3.0.158/31110.3.0.158 to 110.3.0.159—2
81110.3.0.160/31110.3.0.160 to 110.3.0.161—2
82110.3.0.162/31110.3.0.162 to 110.3.0.163—2
83110.3.0.164/31110.3.0.164 to 110.3.0.165—2
84110.3.0.166/31110.3.0.166 to 110.3.0.167—2
85110.3.0.168/31110.3.0.168 to 110.3.0.169—2
86110.3.0.170/31110.3.0.170 to 110.3.0.171—2
87110.3.0.172/31110.3.0.172 to 110.3.0.173—2
88110.3.0.174/31110.3.0.174 to 110.3.0.175—2
89110.3.0.176/31110.3.0.176 to 110.3.0.177—2
90110.3.0.178/31110.3.0.178 to 110.3.0.179—2
91110.3.0.180/31110.3.0.180 to 110.3.0.181—2
92110.3.0.182/31110.3.0.182 to 110.3.0.183—2
93110.3.0.184/31110.3.0.184 to 110.3.0.185—2
94110.3.0.186/31110.3.0.186 to 110.3.0.187—2
95110.3.0.188/31110.3.0.188 to 110.3.0.189—2
96110.3.0.190/31110.3.0.190 to 110.3.0.191—2
97110.3.0.192/31110.3.0.192 to 110.3.0.193—2
98110.3.0.194/31110.3.0.194 to 110.3.0.195—2
99110.3.0.196/31110.3.0.196 to 110.3.0.197—2
100110.3.0.198/31110.3.0.198 to 110.3.0.199—2
101110.3.0.200/31110.3.0.200 to 110.3.0.201—2
102110.3.0.202/31110.3.0.202 to 110.3.0.203—2
103110.3.0.204/31110.3.0.204 to 110.3.0.205—2
104110.3.0.206/31110.3.0.206 to 110.3.0.207—2
105110.3.0.208/31110.3.0.208 to 110.3.0.209—2
106110.3.0.210/31110.3.0.210 to 110.3.0.211—2
107110.3.0.212/31110.3.0.212 to 110.3.0.213—2
108110.3.0.214/31110.3.0.214 to 110.3.0.215—2
109110.3.0.216/31110.3.0.216 to 110.3.0.217—2
110110.3.0.218/31110.3.0.218 to 110.3.0.219—2
111110.3.0.220/31110.3.0.220 to 110.3.0.221—2
112110.3.0.222/31110.3.0.222 to 110.3.0.223—2
113110.3.0.224/31110.3.0.224 to 110.3.0.225—2
114110.3.0.226/31110.3.0.226 to 110.3.0.227—2
115110.3.0.228/31110.3.0.228 to 110.3.0.229—2
116110.3.0.230/31110.3.0.230 to 110.3.0.231—2
117110.3.0.232/31110.3.0.232 to 110.3.0.233—2
118110.3.0.234/31110.3.0.234 to 110.3.0.235—2
119110.3.0.236/31110.3.0.236 to 110.3.0.237—2
120110.3.0.238/31110.3.0.238 to 110.3.0.239—2
121110.3.0.240/31110.3.0.240 to 110.3.0.241—2
122110.3.0.242/31110.3.0.242 to 110.3.0.243—2
123110.3.0.244/31110.3.0.244 to 110.3.0.245—2
124110.3.0.246/31110.3.0.246 to 110.3.0.247—2
125110.3.0.248/31110.3.0.248 to 110.3.0.249—2
126110.3.0.250/31110.3.0.250 to 110.3.0.251—2
127110.3.0.252/31110.3.0.252 to 110.3.0.253—2
128110.3.0.254/31110.3.0.254 to 110.3.0.255—2
129110.3.1.0/31110.3.1.0 to 110.3.1.1—2
130110.3.1.2/31110.3.1.2 to 110.3.1.3—2
131110.3.1.4/31110.3.1.4 to 110.3.1.5—2
132110.3.1.6/31110.3.1.6 to 110.3.1.7—2
133110.3.1.8/31110.3.1.8 to 110.3.1.9—2
134110.3.1.10/31110.3.1.10 to 110.3.1.11—2
135110.3.1.12/31110.3.1.12 to 110.3.1.13—2
136110.3.1.14/31110.3.1.14 to 110.3.1.15—2
137110.3.1.16/31110.3.1.16 to 110.3.1.17—2
138110.3.1.18/31110.3.1.18 to 110.3.1.19—2
139110.3.1.20/31110.3.1.20 to 110.3.1.21—2
140110.3.1.22/31110.3.1.22 to 110.3.1.23—2
141110.3.1.24/31110.3.1.24 to 110.3.1.25—2
142110.3.1.26/31110.3.1.26 to 110.3.1.27—2
143110.3.1.28/31110.3.1.28 to 110.3.1.29—2
144110.3.1.30/31110.3.1.30 to 110.3.1.31—2
145110.3.1.32/31110.3.1.32 to 110.3.1.33—2
146110.3.1.34/31110.3.1.34 to 110.3.1.35—2
147110.3.1.36/31110.3.1.36 to 110.3.1.37—2
148110.3.1.38/31110.3.1.38 to 110.3.1.39—2
149110.3.1.40/31110.3.1.40 to 110.3.1.41—2
150110.3.1.42/31110.3.1.42 to 110.3.1.43—2
151110.3.1.44/31110.3.1.44 to 110.3.1.45—2
152110.3.1.46/31110.3.1.46 to 110.3.1.47—2
153110.3.1.48/31110.3.1.48 to 110.3.1.49—2
154110.3.1.50/31110.3.1.50 to 110.3.1.51—2
155110.3.1.52/31110.3.1.52 to 110.3.1.53—2
156110.3.1.54/31110.3.1.54 to 110.3.1.55—2
157110.3.1.56/31110.3.1.56 to 110.3.1.57—2
158110.3.1.58/31110.3.1.58 to 110.3.1.59—2
159110.3.1.60/31110.3.1.60 to 110.3.1.61—2
160110.3.1.62/31110.3.1.62 to 110.3.1.63—2
161110.3.1.64/31110.3.1.64 to 110.3.1.65—2
162110.3.1.66/31110.3.1.66 to 110.3.1.67—2
163110.3.1.68/31110.3.1.68 to 110.3.1.69—2
164110.3.1.70/31110.3.1.70 to 110.3.1.71—2
165110.3.1.72/31110.3.1.72 to 110.3.1.73—2
166110.3.1.74/31110.3.1.74 to 110.3.1.75—2
167110.3.1.76/31110.3.1.76 to 110.3.1.77—2
168110.3.1.78/31110.3.1.78 to 110.3.1.79—2
169110.3.1.80/31110.3.1.80 to 110.3.1.81—2
170110.3.1.82/31110.3.1.82 to 110.3.1.83—2
171110.3.1.84/31110.3.1.84 to 110.3.1.85—2
172110.3.1.86/31110.3.1.86 to 110.3.1.87—2
173110.3.1.88/31110.3.1.88 to 110.3.1.89—2
174110.3.1.90/31110.3.1.90 to 110.3.1.91—2
175110.3.1.92/31110.3.1.92 to 110.3.1.93—2
176110.3.1.94/31110.3.1.94 to 110.3.1.95—2
177110.3.1.96/31110.3.1.96 to 110.3.1.97—2
178110.3.1.98/31110.3.1.98 to 110.3.1.99—2
179110.3.1.100/31110.3.1.100 to 110.3.1.101—2
180110.3.1.102/31110.3.1.102 to 110.3.1.103—2
181110.3.1.104/31110.3.1.104 to 110.3.1.105—2
182110.3.1.106/31110.3.1.106 to 110.3.1.107—2
183110.3.1.108/31110.3.1.108 to 110.3.1.109—2
184110.3.1.110/31110.3.1.110 to 110.3.1.111—2
185110.3.1.112/31110.3.1.112 to 110.3.1.113—2
186110.3.1.114/31110.3.1.114 to 110.3.1.115—2
187110.3.1.116/31110.3.1.116 to 110.3.1.117—2
188110.3.1.118/31110.3.1.118 to 110.3.1.119—2
189110.3.1.120/31110.3.1.120 to 110.3.1.121—2
190110.3.1.122/31110.3.1.122 to 110.3.1.123—2
191110.3.1.124/31110.3.1.124 to 110.3.1.125—2
192110.3.1.126/31110.3.1.126 to 110.3.1.127—2
193110.3.1.128/31110.3.1.128 to 110.3.1.129—2
194110.3.1.130/31110.3.1.130 to 110.3.1.131—2
195110.3.1.132/31110.3.1.132 to 110.3.1.133—2
196110.3.1.134/31110.3.1.134 to 110.3.1.135—2
197110.3.1.136/31110.3.1.136 to 110.3.1.137—2
198110.3.1.138/31110.3.1.138 to 110.3.1.139—2
199110.3.1.140/31110.3.1.140 to 110.3.1.141—2
200110.3.1.142/31110.3.1.142 to 110.3.1.143—2
201110.3.1.144/31110.3.1.144 to 110.3.1.145—2
202110.3.1.146/31110.3.1.146 to 110.3.1.147—2
203110.3.1.148/31110.3.1.148 to 110.3.1.149—2
204110.3.1.150/31110.3.1.150 to 110.3.1.151—2
205110.3.1.152/31110.3.1.152 to 110.3.1.153—2
206110.3.1.154/31110.3.1.154 to 110.3.1.155—2
207110.3.1.156/31110.3.1.156 to 110.3.1.157—2
208110.3.1.158/31110.3.1.158 to 110.3.1.159—2
209110.3.1.160/31110.3.1.160 to 110.3.1.161—2
210110.3.1.162/31110.3.1.162 to 110.3.1.163—2
211110.3.1.164/31110.3.1.164 to 110.3.1.165—2
212110.3.1.166/31110.3.1.166 to 110.3.1.167—2
213110.3.1.168/31110.3.1.168 to 110.3.1.169—2
214110.3.1.170/31110.3.1.170 to 110.3.1.171—2
215110.3.1.172/31110.3.1.172 to 110.3.1.173—2
216110.3.1.174/31110.3.1.174 to 110.3.1.175—2
217110.3.1.176/31110.3.1.176 to 110.3.1.177—2
218110.3.1.178/31110.3.1.178 to 110.3.1.179—2
219110.3.1.180/31110.3.1.180 to 110.3.1.181—2
220110.3.1.182/31110.3.1.182 to 110.3.1.183—2
221110.3.1.184/31110.3.1.184 to 110.3.1.185—2
222110.3.1.186/31110.3.1.186 to 110.3.1.187—2
223110.3.1.188/31110.3.1.188 to 110.3.1.189—2
224110.3.1.190/31110.3.1.190 to 110.3.1.191—2
225110.3.1.192/31110.3.1.192 to 110.3.1.193—2
226110.3.1.194/31110.3.1.194 to 110.3.1.195—2
227110.3.1.196/31110.3.1.196 to 110.3.1.197—2
228110.3.1.198/31110.3.1.198 to 110.3.1.199—2
229110.3.1.200/31110.3.1.200 to 110.3.1.201—2
230110.3.1.202/31110.3.1.202 to 110.3.1.203—2
231110.3.1.204/31110.3.1.204 to 110.3.1.205—2
232110.3.1.206/31110.3.1.206 to 110.3.1.207—2
233110.3.1.208/31110.3.1.208 to 110.3.1.209—2
234110.3.1.210/31110.3.1.210 to 110.3.1.211—2
235110.3.1.212/31110.3.1.212 to 110.3.1.213—2
236110.3.1.214/31110.3.1.214 to 110.3.1.215—2
237110.3.1.216/31110.3.1.216 to 110.3.1.217—2
238110.3.1.218/31110.3.1.218 to 110.3.1.219—2
239110.3.1.220/31110.3.1.220 to 110.3.1.221—2
240110.3.1.222/31110.3.1.222 to 110.3.1.223—2
241110.3.1.224/31110.3.1.224 to 110.3.1.225—2
242110.3.1.226/31110.3.1.226 to 110.3.1.227—2
243110.3.1.228/31110.3.1.228 to 110.3.1.229—2
244110.3.1.230/31110.3.1.230 to 110.3.1.231—2
245110.3.1.232/31110.3.1.232 to 110.3.1.233—2
246110.3.1.234/31110.3.1.234 to 110.3.1.235—2
247110.3.1.236/31110.3.1.236 to 110.3.1.237—2
248110.3.1.238/31110.3.1.238 to 110.3.1.239—2
249110.3.1.240/31110.3.1.240 to 110.3.1.241—2
250110.3.1.242/31110.3.1.242 to 110.3.1.243—2
251110.3.1.244/31110.3.1.244 to 110.3.1.245—2
252110.3.1.246/31110.3.1.246 to 110.3.1.247—2
253110.3.1.248/31110.3.1.248 to 110.3.1.249—2
254110.3.1.250/31110.3.1.250 to 110.3.1.251—2
255110.3.1.252/31110.3.1.252 to 110.3.1.253—2
256110.3.1.254/31110.3.1.254 to 110.3.1.255—2

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.