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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.

Network247.41.46.0/23
Usable hosts510
Subnet mask255.255.254.0
Addresses512
Network address
247.41.46.0
Broadcast address
247.41.47.255
First usable
247.41.46.1
Last usable
247.41.47.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F7292E00 · Integer 4146671104 to 4146671615
Reverse DNS zones
46.41.247.in-addr.arpa
47.41.247.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
Address11110111.00101001.00101110.00000000247.41.46.0
Subnet mask11111111.11111111.11111110.00000000255.255.254.0
Network11110111.00101001.00101110.00000000247.41.46.0
Broadcast11110111.00101001.00101111.11111111247.41.47.255
Split into smaller subnets/32
/24 (2)/25 (4)/26 (8)/27 (16)/28 (32)/29 (64)/30 (128)/31 (256)/32 (512)

247.41.46.0/23 makes 512 subnets of /32; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1247.41.46.0/32247.41.46.0 to 247.41.46.0—1
2247.41.46.1/32247.41.46.1 to 247.41.46.1—1
3247.41.46.2/32247.41.46.2 to 247.41.46.2—1
4247.41.46.3/32247.41.46.3 to 247.41.46.3—1
5247.41.46.4/32247.41.46.4 to 247.41.46.4—1
6247.41.46.5/32247.41.46.5 to 247.41.46.5—1
7247.41.46.6/32247.41.46.6 to 247.41.46.6—1
8247.41.46.7/32247.41.46.7 to 247.41.46.7—1
9247.41.46.8/32247.41.46.8 to 247.41.46.8—1
10247.41.46.9/32247.41.46.9 to 247.41.46.9—1
11247.41.46.10/32247.41.46.10 to 247.41.46.10—1
12247.41.46.11/32247.41.46.11 to 247.41.46.11—1
13247.41.46.12/32247.41.46.12 to 247.41.46.12—1
14247.41.46.13/32247.41.46.13 to 247.41.46.13—1
15247.41.46.14/32247.41.46.14 to 247.41.46.14—1
16247.41.46.15/32247.41.46.15 to 247.41.46.15—1
17247.41.46.16/32247.41.46.16 to 247.41.46.16—1
18247.41.46.17/32247.41.46.17 to 247.41.46.17—1
19247.41.46.18/32247.41.46.18 to 247.41.46.18—1
20247.41.46.19/32247.41.46.19 to 247.41.46.19—1
21247.41.46.20/32247.41.46.20 to 247.41.46.20—1
22247.41.46.21/32247.41.46.21 to 247.41.46.21—1
23247.41.46.22/32247.41.46.22 to 247.41.46.22—1
24247.41.46.23/32247.41.46.23 to 247.41.46.23—1
25247.41.46.24/32247.41.46.24 to 247.41.46.24—1
26247.41.46.25/32247.41.46.25 to 247.41.46.25—1
27247.41.46.26/32247.41.46.26 to 247.41.46.26—1
28247.41.46.27/32247.41.46.27 to 247.41.46.27—1
29247.41.46.28/32247.41.46.28 to 247.41.46.28—1
30247.41.46.29/32247.41.46.29 to 247.41.46.29—1
31247.41.46.30/32247.41.46.30 to 247.41.46.30—1
32247.41.46.31/32247.41.46.31 to 247.41.46.31—1
33247.41.46.32/32247.41.46.32 to 247.41.46.32—1
34247.41.46.33/32247.41.46.33 to 247.41.46.33—1
35247.41.46.34/32247.41.46.34 to 247.41.46.34—1
36247.41.46.35/32247.41.46.35 to 247.41.46.35—1
37247.41.46.36/32247.41.46.36 to 247.41.46.36—1
38247.41.46.37/32247.41.46.37 to 247.41.46.37—1
39247.41.46.38/32247.41.46.38 to 247.41.46.38—1
40247.41.46.39/32247.41.46.39 to 247.41.46.39—1
41247.41.46.40/32247.41.46.40 to 247.41.46.40—1
42247.41.46.41/32247.41.46.41 to 247.41.46.41—1
43247.41.46.42/32247.41.46.42 to 247.41.46.42—1
44247.41.46.43/32247.41.46.43 to 247.41.46.43—1
45247.41.46.44/32247.41.46.44 to 247.41.46.44—1
46247.41.46.45/32247.41.46.45 to 247.41.46.45—1
47247.41.46.46/32247.41.46.46 to 247.41.46.46—1
48247.41.46.47/32247.41.46.47 to 247.41.46.47—1
49247.41.46.48/32247.41.46.48 to 247.41.46.48—1
50247.41.46.49/32247.41.46.49 to 247.41.46.49—1
51247.41.46.50/32247.41.46.50 to 247.41.46.50—1
52247.41.46.51/32247.41.46.51 to 247.41.46.51—1
53247.41.46.52/32247.41.46.52 to 247.41.46.52—1
54247.41.46.53/32247.41.46.53 to 247.41.46.53—1
55247.41.46.54/32247.41.46.54 to 247.41.46.54—1
56247.41.46.55/32247.41.46.55 to 247.41.46.55—1
57247.41.46.56/32247.41.46.56 to 247.41.46.56—1
58247.41.46.57/32247.41.46.57 to 247.41.46.57—1
59247.41.46.58/32247.41.46.58 to 247.41.46.58—1
60247.41.46.59/32247.41.46.59 to 247.41.46.59—1
61247.41.46.60/32247.41.46.60 to 247.41.46.60—1
62247.41.46.61/32247.41.46.61 to 247.41.46.61—1
63247.41.46.62/32247.41.46.62 to 247.41.46.62—1
64247.41.46.63/32247.41.46.63 to 247.41.46.63—1
65247.41.46.64/32247.41.46.64 to 247.41.46.64—1
66247.41.46.65/32247.41.46.65 to 247.41.46.65—1
67247.41.46.66/32247.41.46.66 to 247.41.46.66—1
68247.41.46.67/32247.41.46.67 to 247.41.46.67—1
69247.41.46.68/32247.41.46.68 to 247.41.46.68—1
70247.41.46.69/32247.41.46.69 to 247.41.46.69—1
71247.41.46.70/32247.41.46.70 to 247.41.46.70—1
72247.41.46.71/32247.41.46.71 to 247.41.46.71—1
73247.41.46.72/32247.41.46.72 to 247.41.46.72—1
74247.41.46.73/32247.41.46.73 to 247.41.46.73—1
75247.41.46.74/32247.41.46.74 to 247.41.46.74—1
76247.41.46.75/32247.41.46.75 to 247.41.46.75—1
77247.41.46.76/32247.41.46.76 to 247.41.46.76—1
78247.41.46.77/32247.41.46.77 to 247.41.46.77—1
79247.41.46.78/32247.41.46.78 to 247.41.46.78—1
80247.41.46.79/32247.41.46.79 to 247.41.46.79—1
81247.41.46.80/32247.41.46.80 to 247.41.46.80—1
82247.41.46.81/32247.41.46.81 to 247.41.46.81—1
83247.41.46.82/32247.41.46.82 to 247.41.46.82—1
84247.41.46.83/32247.41.46.83 to 247.41.46.83—1
85247.41.46.84/32247.41.46.84 to 247.41.46.84—1
86247.41.46.85/32247.41.46.85 to 247.41.46.85—1
87247.41.46.86/32247.41.46.86 to 247.41.46.86—1
88247.41.46.87/32247.41.46.87 to 247.41.46.87—1
89247.41.46.88/32247.41.46.88 to 247.41.46.88—1
90247.41.46.89/32247.41.46.89 to 247.41.46.89—1
91247.41.46.90/32247.41.46.90 to 247.41.46.90—1
92247.41.46.91/32247.41.46.91 to 247.41.46.91—1
93247.41.46.92/32247.41.46.92 to 247.41.46.92—1
94247.41.46.93/32247.41.46.93 to 247.41.46.93—1
95247.41.46.94/32247.41.46.94 to 247.41.46.94—1
96247.41.46.95/32247.41.46.95 to 247.41.46.95—1
97247.41.46.96/32247.41.46.96 to 247.41.46.96—1
98247.41.46.97/32247.41.46.97 to 247.41.46.97—1
99247.41.46.98/32247.41.46.98 to 247.41.46.98—1
100247.41.46.99/32247.41.46.99 to 247.41.46.99—1
101247.41.46.100/32247.41.46.100 to 247.41.46.100—1
102247.41.46.101/32247.41.46.101 to 247.41.46.101—1
103247.41.46.102/32247.41.46.102 to 247.41.46.102—1
104247.41.46.103/32247.41.46.103 to 247.41.46.103—1
105247.41.46.104/32247.41.46.104 to 247.41.46.104—1
106247.41.46.105/32247.41.46.105 to 247.41.46.105—1
107247.41.46.106/32247.41.46.106 to 247.41.46.106—1
108247.41.46.107/32247.41.46.107 to 247.41.46.107—1
109247.41.46.108/32247.41.46.108 to 247.41.46.108—1
110247.41.46.109/32247.41.46.109 to 247.41.46.109—1
111247.41.46.110/32247.41.46.110 to 247.41.46.110—1
112247.41.46.111/32247.41.46.111 to 247.41.46.111—1
113247.41.46.112/32247.41.46.112 to 247.41.46.112—1
114247.41.46.113/32247.41.46.113 to 247.41.46.113—1
115247.41.46.114/32247.41.46.114 to 247.41.46.114—1
116247.41.46.115/32247.41.46.115 to 247.41.46.115—1
117247.41.46.116/32247.41.46.116 to 247.41.46.116—1
118247.41.46.117/32247.41.46.117 to 247.41.46.117—1
119247.41.46.118/32247.41.46.118 to 247.41.46.118—1
120247.41.46.119/32247.41.46.119 to 247.41.46.119—1
121247.41.46.120/32247.41.46.120 to 247.41.46.120—1
122247.41.46.121/32247.41.46.121 to 247.41.46.121—1
123247.41.46.122/32247.41.46.122 to 247.41.46.122—1
124247.41.46.123/32247.41.46.123 to 247.41.46.123—1
125247.41.46.124/32247.41.46.124 to 247.41.46.124—1
126247.41.46.125/32247.41.46.125 to 247.41.46.125—1
127247.41.46.126/32247.41.46.126 to 247.41.46.126—1
128247.41.46.127/32247.41.46.127 to 247.41.46.127—1
129247.41.46.128/32247.41.46.128 to 247.41.46.128—1
130247.41.46.129/32247.41.46.129 to 247.41.46.129—1
131247.41.46.130/32247.41.46.130 to 247.41.46.130—1
132247.41.46.131/32247.41.46.131 to 247.41.46.131—1
133247.41.46.132/32247.41.46.132 to 247.41.46.132—1
134247.41.46.133/32247.41.46.133 to 247.41.46.133—1
135247.41.46.134/32247.41.46.134 to 247.41.46.134—1
136247.41.46.135/32247.41.46.135 to 247.41.46.135—1
137247.41.46.136/32247.41.46.136 to 247.41.46.136—1
138247.41.46.137/32247.41.46.137 to 247.41.46.137—1
139247.41.46.138/32247.41.46.138 to 247.41.46.138—1
140247.41.46.139/32247.41.46.139 to 247.41.46.139—1
141247.41.46.140/32247.41.46.140 to 247.41.46.140—1
142247.41.46.141/32247.41.46.141 to 247.41.46.141—1
143247.41.46.142/32247.41.46.142 to 247.41.46.142—1
144247.41.46.143/32247.41.46.143 to 247.41.46.143—1
145247.41.46.144/32247.41.46.144 to 247.41.46.144—1
146247.41.46.145/32247.41.46.145 to 247.41.46.145—1
147247.41.46.146/32247.41.46.146 to 247.41.46.146—1
148247.41.46.147/32247.41.46.147 to 247.41.46.147—1
149247.41.46.148/32247.41.46.148 to 247.41.46.148—1
150247.41.46.149/32247.41.46.149 to 247.41.46.149—1
151247.41.46.150/32247.41.46.150 to 247.41.46.150—1
152247.41.46.151/32247.41.46.151 to 247.41.46.151—1
153247.41.46.152/32247.41.46.152 to 247.41.46.152—1
154247.41.46.153/32247.41.46.153 to 247.41.46.153—1
155247.41.46.154/32247.41.46.154 to 247.41.46.154—1
156247.41.46.155/32247.41.46.155 to 247.41.46.155—1
157247.41.46.156/32247.41.46.156 to 247.41.46.156—1
158247.41.46.157/32247.41.46.157 to 247.41.46.157—1
159247.41.46.158/32247.41.46.158 to 247.41.46.158—1
160247.41.46.159/32247.41.46.159 to 247.41.46.159—1
161247.41.46.160/32247.41.46.160 to 247.41.46.160—1
162247.41.46.161/32247.41.46.161 to 247.41.46.161—1
163247.41.46.162/32247.41.46.162 to 247.41.46.162—1
164247.41.46.163/32247.41.46.163 to 247.41.46.163—1
165247.41.46.164/32247.41.46.164 to 247.41.46.164—1
166247.41.46.165/32247.41.46.165 to 247.41.46.165—1
167247.41.46.166/32247.41.46.166 to 247.41.46.166—1
168247.41.46.167/32247.41.46.167 to 247.41.46.167—1
169247.41.46.168/32247.41.46.168 to 247.41.46.168—1
170247.41.46.169/32247.41.46.169 to 247.41.46.169—1
171247.41.46.170/32247.41.46.170 to 247.41.46.170—1
172247.41.46.171/32247.41.46.171 to 247.41.46.171—1
173247.41.46.172/32247.41.46.172 to 247.41.46.172—1
174247.41.46.173/32247.41.46.173 to 247.41.46.173—1
175247.41.46.174/32247.41.46.174 to 247.41.46.174—1
176247.41.46.175/32247.41.46.175 to 247.41.46.175—1
177247.41.46.176/32247.41.46.176 to 247.41.46.176—1
178247.41.46.177/32247.41.46.177 to 247.41.46.177—1
179247.41.46.178/32247.41.46.178 to 247.41.46.178—1
180247.41.46.179/32247.41.46.179 to 247.41.46.179—1
181247.41.46.180/32247.41.46.180 to 247.41.46.180—1
182247.41.46.181/32247.41.46.181 to 247.41.46.181—1
183247.41.46.182/32247.41.46.182 to 247.41.46.182—1
184247.41.46.183/32247.41.46.183 to 247.41.46.183—1
185247.41.46.184/32247.41.46.184 to 247.41.46.184—1
186247.41.46.185/32247.41.46.185 to 247.41.46.185—1
187247.41.46.186/32247.41.46.186 to 247.41.46.186—1
188247.41.46.187/32247.41.46.187 to 247.41.46.187—1
189247.41.46.188/32247.41.46.188 to 247.41.46.188—1
190247.41.46.189/32247.41.46.189 to 247.41.46.189—1
191247.41.46.190/32247.41.46.190 to 247.41.46.190—1
192247.41.46.191/32247.41.46.191 to 247.41.46.191—1
193247.41.46.192/32247.41.46.192 to 247.41.46.192—1
194247.41.46.193/32247.41.46.193 to 247.41.46.193—1
195247.41.46.194/32247.41.46.194 to 247.41.46.194—1
196247.41.46.195/32247.41.46.195 to 247.41.46.195—1
197247.41.46.196/32247.41.46.196 to 247.41.46.196—1
198247.41.46.197/32247.41.46.197 to 247.41.46.197—1
199247.41.46.198/32247.41.46.198 to 247.41.46.198—1
200247.41.46.199/32247.41.46.199 to 247.41.46.199—1
201247.41.46.200/32247.41.46.200 to 247.41.46.200—1
202247.41.46.201/32247.41.46.201 to 247.41.46.201—1
203247.41.46.202/32247.41.46.202 to 247.41.46.202—1
204247.41.46.203/32247.41.46.203 to 247.41.46.203—1
205247.41.46.204/32247.41.46.204 to 247.41.46.204—1
206247.41.46.205/32247.41.46.205 to 247.41.46.205—1
207247.41.46.206/32247.41.46.206 to 247.41.46.206—1
208247.41.46.207/32247.41.46.207 to 247.41.46.207—1
209247.41.46.208/32247.41.46.208 to 247.41.46.208—1
210247.41.46.209/32247.41.46.209 to 247.41.46.209—1
211247.41.46.210/32247.41.46.210 to 247.41.46.210—1
212247.41.46.211/32247.41.46.211 to 247.41.46.211—1
213247.41.46.212/32247.41.46.212 to 247.41.46.212—1
214247.41.46.213/32247.41.46.213 to 247.41.46.213—1
215247.41.46.214/32247.41.46.214 to 247.41.46.214—1
216247.41.46.215/32247.41.46.215 to 247.41.46.215—1
217247.41.46.216/32247.41.46.216 to 247.41.46.216—1
218247.41.46.217/32247.41.46.217 to 247.41.46.217—1
219247.41.46.218/32247.41.46.218 to 247.41.46.218—1
220247.41.46.219/32247.41.46.219 to 247.41.46.219—1
221247.41.46.220/32247.41.46.220 to 247.41.46.220—1
222247.41.46.221/32247.41.46.221 to 247.41.46.221—1
223247.41.46.222/32247.41.46.222 to 247.41.46.222—1
224247.41.46.223/32247.41.46.223 to 247.41.46.223—1
225247.41.46.224/32247.41.46.224 to 247.41.46.224—1
226247.41.46.225/32247.41.46.225 to 247.41.46.225—1
227247.41.46.226/32247.41.46.226 to 247.41.46.226—1
228247.41.46.227/32247.41.46.227 to 247.41.46.227—1
229247.41.46.228/32247.41.46.228 to 247.41.46.228—1
230247.41.46.229/32247.41.46.229 to 247.41.46.229—1
231247.41.46.230/32247.41.46.230 to 247.41.46.230—1
232247.41.46.231/32247.41.46.231 to 247.41.46.231—1
233247.41.46.232/32247.41.46.232 to 247.41.46.232—1
234247.41.46.233/32247.41.46.233 to 247.41.46.233—1
235247.41.46.234/32247.41.46.234 to 247.41.46.234—1
236247.41.46.235/32247.41.46.235 to 247.41.46.235—1
237247.41.46.236/32247.41.46.236 to 247.41.46.236—1
238247.41.46.237/32247.41.46.237 to 247.41.46.237—1
239247.41.46.238/32247.41.46.238 to 247.41.46.238—1
240247.41.46.239/32247.41.46.239 to 247.41.46.239—1
241247.41.46.240/32247.41.46.240 to 247.41.46.240—1
242247.41.46.241/32247.41.46.241 to 247.41.46.241—1
243247.41.46.242/32247.41.46.242 to 247.41.46.242—1
244247.41.46.243/32247.41.46.243 to 247.41.46.243—1
245247.41.46.244/32247.41.46.244 to 247.41.46.244—1
246247.41.46.245/32247.41.46.245 to 247.41.46.245—1
247247.41.46.246/32247.41.46.246 to 247.41.46.246—1
248247.41.46.247/32247.41.46.247 to 247.41.46.247—1
249247.41.46.248/32247.41.46.248 to 247.41.46.248—1
250247.41.46.249/32247.41.46.249 to 247.41.46.249—1
251247.41.46.250/32247.41.46.250 to 247.41.46.250—1
252247.41.46.251/32247.41.46.251 to 247.41.46.251—1
253247.41.46.252/32247.41.46.252 to 247.41.46.252—1
254247.41.46.253/32247.41.46.253 to 247.41.46.253—1
255247.41.46.254/32247.41.46.254 to 247.41.46.254—1
256247.41.46.255/32247.41.46.255 to 247.41.46.255—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.