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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.

Network227.232.2.0/24
Usable hosts254
Subnet mask255.255.255.0
Addresses256
Network address
227.232.2.0
Broadcast address
227.232.2.255
First usable
227.232.2.1
Last usable
227.232.2.254
Usable hosts
254 (256 less the network and broadcast addresses)
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255 (Cisco ACLs, OSPF)
Prefix length
/24
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E3E80200 · Integer 3823632896 to 3823633151
Reverse DNS zone
2.232.227.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100011.11101000.00000010..00000000227.232.2.0
Subnet mask11111111.11111111.11111111..00000000255.255.255.0
Network11100011.11101000.00000010..00000000227.232.2.0
Broadcast11100011.11101000.00000010..11111111227.232.2.255
Split into smaller subnets/32
/25 (2)/26 (4)/27 (8)/28 (16)/29 (32)/30 (64)/31 (128)/32 (256)

227.232.2.0/24 makes 256 subnets of /32.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1227.232.2.0/32227.232.2.0 to 227.232.2.0—1
2227.232.2.1/32227.232.2.1 to 227.232.2.1—1
3227.232.2.2/32227.232.2.2 to 227.232.2.2—1
4227.232.2.3/32227.232.2.3 to 227.232.2.3—1
5227.232.2.4/32227.232.2.4 to 227.232.2.4—1
6227.232.2.5/32227.232.2.5 to 227.232.2.5—1
7227.232.2.6/32227.232.2.6 to 227.232.2.6—1
8227.232.2.7/32227.232.2.7 to 227.232.2.7—1
9227.232.2.8/32227.232.2.8 to 227.232.2.8—1
10227.232.2.9/32227.232.2.9 to 227.232.2.9—1
11227.232.2.10/32227.232.2.10 to 227.232.2.10—1
12227.232.2.11/32227.232.2.11 to 227.232.2.11—1
13227.232.2.12/32227.232.2.12 to 227.232.2.12—1
14227.232.2.13/32227.232.2.13 to 227.232.2.13—1
15227.232.2.14/32227.232.2.14 to 227.232.2.14—1
16227.232.2.15/32227.232.2.15 to 227.232.2.15—1
17227.232.2.16/32227.232.2.16 to 227.232.2.16—1
18227.232.2.17/32227.232.2.17 to 227.232.2.17—1
19227.232.2.18/32227.232.2.18 to 227.232.2.18—1
20227.232.2.19/32227.232.2.19 to 227.232.2.19—1
21227.232.2.20/32227.232.2.20 to 227.232.2.20—1
22227.232.2.21/32227.232.2.21 to 227.232.2.21—1
23227.232.2.22/32227.232.2.22 to 227.232.2.22—1
24227.232.2.23/32227.232.2.23 to 227.232.2.23—1
25227.232.2.24/32227.232.2.24 to 227.232.2.24—1
26227.232.2.25/32227.232.2.25 to 227.232.2.25—1
27227.232.2.26/32227.232.2.26 to 227.232.2.26—1
28227.232.2.27/32227.232.2.27 to 227.232.2.27—1
29227.232.2.28/32227.232.2.28 to 227.232.2.28—1
30227.232.2.29/32227.232.2.29 to 227.232.2.29—1
31227.232.2.30/32227.232.2.30 to 227.232.2.30—1
32227.232.2.31/32227.232.2.31 to 227.232.2.31—1
33227.232.2.32/32227.232.2.32 to 227.232.2.32—1
34227.232.2.33/32227.232.2.33 to 227.232.2.33—1
35227.232.2.34/32227.232.2.34 to 227.232.2.34—1
36227.232.2.35/32227.232.2.35 to 227.232.2.35—1
37227.232.2.36/32227.232.2.36 to 227.232.2.36—1
38227.232.2.37/32227.232.2.37 to 227.232.2.37—1
39227.232.2.38/32227.232.2.38 to 227.232.2.38—1
40227.232.2.39/32227.232.2.39 to 227.232.2.39—1
41227.232.2.40/32227.232.2.40 to 227.232.2.40—1
42227.232.2.41/32227.232.2.41 to 227.232.2.41—1
43227.232.2.42/32227.232.2.42 to 227.232.2.42—1
44227.232.2.43/32227.232.2.43 to 227.232.2.43—1
45227.232.2.44/32227.232.2.44 to 227.232.2.44—1
46227.232.2.45/32227.232.2.45 to 227.232.2.45—1
47227.232.2.46/32227.232.2.46 to 227.232.2.46—1
48227.232.2.47/32227.232.2.47 to 227.232.2.47—1
49227.232.2.48/32227.232.2.48 to 227.232.2.48—1
50227.232.2.49/32227.232.2.49 to 227.232.2.49—1
51227.232.2.50/32227.232.2.50 to 227.232.2.50—1
52227.232.2.51/32227.232.2.51 to 227.232.2.51—1
53227.232.2.52/32227.232.2.52 to 227.232.2.52—1
54227.232.2.53/32227.232.2.53 to 227.232.2.53—1
55227.232.2.54/32227.232.2.54 to 227.232.2.54—1
56227.232.2.55/32227.232.2.55 to 227.232.2.55—1
57227.232.2.56/32227.232.2.56 to 227.232.2.56—1
58227.232.2.57/32227.232.2.57 to 227.232.2.57—1
59227.232.2.58/32227.232.2.58 to 227.232.2.58—1
60227.232.2.59/32227.232.2.59 to 227.232.2.59—1
61227.232.2.60/32227.232.2.60 to 227.232.2.60—1
62227.232.2.61/32227.232.2.61 to 227.232.2.61—1
63227.232.2.62/32227.232.2.62 to 227.232.2.62—1
64227.232.2.63/32227.232.2.63 to 227.232.2.63—1
65227.232.2.64/32227.232.2.64 to 227.232.2.64—1
66227.232.2.65/32227.232.2.65 to 227.232.2.65—1
67227.232.2.66/32227.232.2.66 to 227.232.2.66—1
68227.232.2.67/32227.232.2.67 to 227.232.2.67—1
69227.232.2.68/32227.232.2.68 to 227.232.2.68—1
70227.232.2.69/32227.232.2.69 to 227.232.2.69—1
71227.232.2.70/32227.232.2.70 to 227.232.2.70—1
72227.232.2.71/32227.232.2.71 to 227.232.2.71—1
73227.232.2.72/32227.232.2.72 to 227.232.2.72—1
74227.232.2.73/32227.232.2.73 to 227.232.2.73—1
75227.232.2.74/32227.232.2.74 to 227.232.2.74—1
76227.232.2.75/32227.232.2.75 to 227.232.2.75—1
77227.232.2.76/32227.232.2.76 to 227.232.2.76—1
78227.232.2.77/32227.232.2.77 to 227.232.2.77—1
79227.232.2.78/32227.232.2.78 to 227.232.2.78—1
80227.232.2.79/32227.232.2.79 to 227.232.2.79—1
81227.232.2.80/32227.232.2.80 to 227.232.2.80—1
82227.232.2.81/32227.232.2.81 to 227.232.2.81—1
83227.232.2.82/32227.232.2.82 to 227.232.2.82—1
84227.232.2.83/32227.232.2.83 to 227.232.2.83—1
85227.232.2.84/32227.232.2.84 to 227.232.2.84—1
86227.232.2.85/32227.232.2.85 to 227.232.2.85—1
87227.232.2.86/32227.232.2.86 to 227.232.2.86—1
88227.232.2.87/32227.232.2.87 to 227.232.2.87—1
89227.232.2.88/32227.232.2.88 to 227.232.2.88—1
90227.232.2.89/32227.232.2.89 to 227.232.2.89—1
91227.232.2.90/32227.232.2.90 to 227.232.2.90—1
92227.232.2.91/32227.232.2.91 to 227.232.2.91—1
93227.232.2.92/32227.232.2.92 to 227.232.2.92—1
94227.232.2.93/32227.232.2.93 to 227.232.2.93—1
95227.232.2.94/32227.232.2.94 to 227.232.2.94—1
96227.232.2.95/32227.232.2.95 to 227.232.2.95—1
97227.232.2.96/32227.232.2.96 to 227.232.2.96—1
98227.232.2.97/32227.232.2.97 to 227.232.2.97—1
99227.232.2.98/32227.232.2.98 to 227.232.2.98—1
100227.232.2.99/32227.232.2.99 to 227.232.2.99—1
101227.232.2.100/32227.232.2.100 to 227.232.2.100—1
102227.232.2.101/32227.232.2.101 to 227.232.2.101—1
103227.232.2.102/32227.232.2.102 to 227.232.2.102—1
104227.232.2.103/32227.232.2.103 to 227.232.2.103—1
105227.232.2.104/32227.232.2.104 to 227.232.2.104—1
106227.232.2.105/32227.232.2.105 to 227.232.2.105—1
107227.232.2.106/32227.232.2.106 to 227.232.2.106—1
108227.232.2.107/32227.232.2.107 to 227.232.2.107—1
109227.232.2.108/32227.232.2.108 to 227.232.2.108—1
110227.232.2.109/32227.232.2.109 to 227.232.2.109—1
111227.232.2.110/32227.232.2.110 to 227.232.2.110—1
112227.232.2.111/32227.232.2.111 to 227.232.2.111—1
113227.232.2.112/32227.232.2.112 to 227.232.2.112—1
114227.232.2.113/32227.232.2.113 to 227.232.2.113—1
115227.232.2.114/32227.232.2.114 to 227.232.2.114—1
116227.232.2.115/32227.232.2.115 to 227.232.2.115—1
117227.232.2.116/32227.232.2.116 to 227.232.2.116—1
118227.232.2.117/32227.232.2.117 to 227.232.2.117—1
119227.232.2.118/32227.232.2.118 to 227.232.2.118—1
120227.232.2.119/32227.232.2.119 to 227.232.2.119—1
121227.232.2.120/32227.232.2.120 to 227.232.2.120—1
122227.232.2.121/32227.232.2.121 to 227.232.2.121—1
123227.232.2.122/32227.232.2.122 to 227.232.2.122—1
124227.232.2.123/32227.232.2.123 to 227.232.2.123—1
125227.232.2.124/32227.232.2.124 to 227.232.2.124—1
126227.232.2.125/32227.232.2.125 to 227.232.2.125—1
127227.232.2.126/32227.232.2.126 to 227.232.2.126—1
128227.232.2.127/32227.232.2.127 to 227.232.2.127—1
129227.232.2.128/32227.232.2.128 to 227.232.2.128—1
130227.232.2.129/32227.232.2.129 to 227.232.2.129—1
131227.232.2.130/32227.232.2.130 to 227.232.2.130—1
132227.232.2.131/32227.232.2.131 to 227.232.2.131—1
133227.232.2.132/32227.232.2.132 to 227.232.2.132—1
134227.232.2.133/32227.232.2.133 to 227.232.2.133—1
135227.232.2.134/32227.232.2.134 to 227.232.2.134—1
136227.232.2.135/32227.232.2.135 to 227.232.2.135—1
137227.232.2.136/32227.232.2.136 to 227.232.2.136—1
138227.232.2.137/32227.232.2.137 to 227.232.2.137—1
139227.232.2.138/32227.232.2.138 to 227.232.2.138—1
140227.232.2.139/32227.232.2.139 to 227.232.2.139—1
141227.232.2.140/32227.232.2.140 to 227.232.2.140—1
142227.232.2.141/32227.232.2.141 to 227.232.2.141—1
143227.232.2.142/32227.232.2.142 to 227.232.2.142—1
144227.232.2.143/32227.232.2.143 to 227.232.2.143—1
145227.232.2.144/32227.232.2.144 to 227.232.2.144—1
146227.232.2.145/32227.232.2.145 to 227.232.2.145—1
147227.232.2.146/32227.232.2.146 to 227.232.2.146—1
148227.232.2.147/32227.232.2.147 to 227.232.2.147—1
149227.232.2.148/32227.232.2.148 to 227.232.2.148—1
150227.232.2.149/32227.232.2.149 to 227.232.2.149—1
151227.232.2.150/32227.232.2.150 to 227.232.2.150—1
152227.232.2.151/32227.232.2.151 to 227.232.2.151—1
153227.232.2.152/32227.232.2.152 to 227.232.2.152—1
154227.232.2.153/32227.232.2.153 to 227.232.2.153—1
155227.232.2.154/32227.232.2.154 to 227.232.2.154—1
156227.232.2.155/32227.232.2.155 to 227.232.2.155—1
157227.232.2.156/32227.232.2.156 to 227.232.2.156—1
158227.232.2.157/32227.232.2.157 to 227.232.2.157—1
159227.232.2.158/32227.232.2.158 to 227.232.2.158—1
160227.232.2.159/32227.232.2.159 to 227.232.2.159—1
161227.232.2.160/32227.232.2.160 to 227.232.2.160—1
162227.232.2.161/32227.232.2.161 to 227.232.2.161—1
163227.232.2.162/32227.232.2.162 to 227.232.2.162—1
164227.232.2.163/32227.232.2.163 to 227.232.2.163—1
165227.232.2.164/32227.232.2.164 to 227.232.2.164—1
166227.232.2.165/32227.232.2.165 to 227.232.2.165—1
167227.232.2.166/32227.232.2.166 to 227.232.2.166—1
168227.232.2.167/32227.232.2.167 to 227.232.2.167—1
169227.232.2.168/32227.232.2.168 to 227.232.2.168—1
170227.232.2.169/32227.232.2.169 to 227.232.2.169—1
171227.232.2.170/32227.232.2.170 to 227.232.2.170—1
172227.232.2.171/32227.232.2.171 to 227.232.2.171—1
173227.232.2.172/32227.232.2.172 to 227.232.2.172—1
174227.232.2.173/32227.232.2.173 to 227.232.2.173—1
175227.232.2.174/32227.232.2.174 to 227.232.2.174—1
176227.232.2.175/32227.232.2.175 to 227.232.2.175—1
177227.232.2.176/32227.232.2.176 to 227.232.2.176—1
178227.232.2.177/32227.232.2.177 to 227.232.2.177—1
179227.232.2.178/32227.232.2.178 to 227.232.2.178—1
180227.232.2.179/32227.232.2.179 to 227.232.2.179—1
181227.232.2.180/32227.232.2.180 to 227.232.2.180—1
182227.232.2.181/32227.232.2.181 to 227.232.2.181—1
183227.232.2.182/32227.232.2.182 to 227.232.2.182—1
184227.232.2.183/32227.232.2.183 to 227.232.2.183—1
185227.232.2.184/32227.232.2.184 to 227.232.2.184—1
186227.232.2.185/32227.232.2.185 to 227.232.2.185—1
187227.232.2.186/32227.232.2.186 to 227.232.2.186—1
188227.232.2.187/32227.232.2.187 to 227.232.2.187—1
189227.232.2.188/32227.232.2.188 to 227.232.2.188—1
190227.232.2.189/32227.232.2.189 to 227.232.2.189—1
191227.232.2.190/32227.232.2.190 to 227.232.2.190—1
192227.232.2.191/32227.232.2.191 to 227.232.2.191—1
193227.232.2.192/32227.232.2.192 to 227.232.2.192—1
194227.232.2.193/32227.232.2.193 to 227.232.2.193—1
195227.232.2.194/32227.232.2.194 to 227.232.2.194—1
196227.232.2.195/32227.232.2.195 to 227.232.2.195—1
197227.232.2.196/32227.232.2.196 to 227.232.2.196—1
198227.232.2.197/32227.232.2.197 to 227.232.2.197—1
199227.232.2.198/32227.232.2.198 to 227.232.2.198—1
200227.232.2.199/32227.232.2.199 to 227.232.2.199—1
201227.232.2.200/32227.232.2.200 to 227.232.2.200—1
202227.232.2.201/32227.232.2.201 to 227.232.2.201—1
203227.232.2.202/32227.232.2.202 to 227.232.2.202—1
204227.232.2.203/32227.232.2.203 to 227.232.2.203—1
205227.232.2.204/32227.232.2.204 to 227.232.2.204—1
206227.232.2.205/32227.232.2.205 to 227.232.2.205—1
207227.232.2.206/32227.232.2.206 to 227.232.2.206—1
208227.232.2.207/32227.232.2.207 to 227.232.2.207—1
209227.232.2.208/32227.232.2.208 to 227.232.2.208—1
210227.232.2.209/32227.232.2.209 to 227.232.2.209—1
211227.232.2.210/32227.232.2.210 to 227.232.2.210—1
212227.232.2.211/32227.232.2.211 to 227.232.2.211—1
213227.232.2.212/32227.232.2.212 to 227.232.2.212—1
214227.232.2.213/32227.232.2.213 to 227.232.2.213—1
215227.232.2.214/32227.232.2.214 to 227.232.2.214—1
216227.232.2.215/32227.232.2.215 to 227.232.2.215—1
217227.232.2.216/32227.232.2.216 to 227.232.2.216—1
218227.232.2.217/32227.232.2.217 to 227.232.2.217—1
219227.232.2.218/32227.232.2.218 to 227.232.2.218—1
220227.232.2.219/32227.232.2.219 to 227.232.2.219—1
221227.232.2.220/32227.232.2.220 to 227.232.2.220—1
222227.232.2.221/32227.232.2.221 to 227.232.2.221—1
223227.232.2.222/32227.232.2.222 to 227.232.2.222—1
224227.232.2.223/32227.232.2.223 to 227.232.2.223—1
225227.232.2.224/32227.232.2.224 to 227.232.2.224—1
226227.232.2.225/32227.232.2.225 to 227.232.2.225—1
227227.232.2.226/32227.232.2.226 to 227.232.2.226—1
228227.232.2.227/32227.232.2.227 to 227.232.2.227—1
229227.232.2.228/32227.232.2.228 to 227.232.2.228—1
230227.232.2.229/32227.232.2.229 to 227.232.2.229—1
231227.232.2.230/32227.232.2.230 to 227.232.2.230—1
232227.232.2.231/32227.232.2.231 to 227.232.2.231—1
233227.232.2.232/32227.232.2.232 to 227.232.2.232—1
234227.232.2.233/32227.232.2.233 to 227.232.2.233—1
235227.232.2.234/32227.232.2.234 to 227.232.2.234—1
236227.232.2.235/32227.232.2.235 to 227.232.2.235—1
237227.232.2.236/32227.232.2.236 to 227.232.2.236—1
238227.232.2.237/32227.232.2.237 to 227.232.2.237—1
239227.232.2.238/32227.232.2.238 to 227.232.2.238—1
240227.232.2.239/32227.232.2.239 to 227.232.2.239—1
241227.232.2.240/32227.232.2.240 to 227.232.2.240—1
242227.232.2.241/32227.232.2.241 to 227.232.2.241—1
243227.232.2.242/32227.232.2.242 to 227.232.2.242—1
244227.232.2.243/32227.232.2.243 to 227.232.2.243—1
245227.232.2.244/32227.232.2.244 to 227.232.2.244—1
246227.232.2.245/32227.232.2.245 to 227.232.2.245—1
247227.232.2.246/32227.232.2.246 to 227.232.2.246—1
248227.232.2.247/32227.232.2.247 to 227.232.2.247—1
249227.232.2.248/32227.232.2.248 to 227.232.2.248—1
250227.232.2.249/32227.232.2.249 to 227.232.2.249—1
251227.232.2.250/32227.232.2.250 to 227.232.2.250—1
252227.232.2.251/32227.232.2.251 to 227.232.2.251—1
253227.232.2.252/32227.232.2.252 to 227.232.2.252—1
254227.232.2.253/32227.232.2.253 to 227.232.2.253—1
255227.232.2.254/32227.232.2.254 to 227.232.2.254—1
256227.232.2.255/32227.232.2.255 to 227.232.2.255—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.