Speed and call quality testMy IP addressIP subnet calculatorDNS reportWhoIs lookupRemote support

Internet and network

Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

Computers and devices

Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

Make and print

Clean textStrip hidden characters, smart quotes and odd spaces from pasted text.QR code makerMake a QR code for a link, contact or message. Nothing leaves your browser.Wi-Fi QR posterPrint an A4 poster that lets guests join your Wi-Fi by scanning.

Surftec support

Remote supportLet a Surftec engineer connect to your computer to help you.All workingA full-screen confirmation that everything is up and running.

Surftec

Surftec websiteServices, news and how to contact Surftec
Cloud Tools
Guest
GuestNot signed in

Surftec customers will be recognised automatically when they use these tools from their office network.

Customer sign-in is coming soon.

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.

Network232.167.78.0/24
Usable hosts254
Subnet mask255.255.255.0
Addresses256
Network address
232.167.78.0
Broadcast address
232.167.78.255
First usable
232.167.78.1
Last usable
232.167.78.254
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 E8A74E00 · Integer 3903278592 to 3903278847
Reverse DNS zone
78.167.232.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101000.10100111.01001110..00000000232.167.78.0
Subnet mask11111111.11111111.11111111..00000000255.255.255.0
Network11101000.10100111.01001110..00000000232.167.78.0
Broadcast11101000.10100111.01001110..11111111232.167.78.255
Split into smaller subnets/32
/25 (2)/26 (4)/27 (8)/28 (16)/29 (32)/30 (64)/31 (128)/32 (256)

232.167.78.0/24 makes 256 subnets of /32.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1232.167.78.0/32232.167.78.0 to 232.167.78.0—1
2232.167.78.1/32232.167.78.1 to 232.167.78.1—1
3232.167.78.2/32232.167.78.2 to 232.167.78.2—1
4232.167.78.3/32232.167.78.3 to 232.167.78.3—1
5232.167.78.4/32232.167.78.4 to 232.167.78.4—1
6232.167.78.5/32232.167.78.5 to 232.167.78.5—1
7232.167.78.6/32232.167.78.6 to 232.167.78.6—1
8232.167.78.7/32232.167.78.7 to 232.167.78.7—1
9232.167.78.8/32232.167.78.8 to 232.167.78.8—1
10232.167.78.9/32232.167.78.9 to 232.167.78.9—1
11232.167.78.10/32232.167.78.10 to 232.167.78.10—1
12232.167.78.11/32232.167.78.11 to 232.167.78.11—1
13232.167.78.12/32232.167.78.12 to 232.167.78.12—1
14232.167.78.13/32232.167.78.13 to 232.167.78.13—1
15232.167.78.14/32232.167.78.14 to 232.167.78.14—1
16232.167.78.15/32232.167.78.15 to 232.167.78.15—1
17232.167.78.16/32232.167.78.16 to 232.167.78.16—1
18232.167.78.17/32232.167.78.17 to 232.167.78.17—1
19232.167.78.18/32232.167.78.18 to 232.167.78.18—1
20232.167.78.19/32232.167.78.19 to 232.167.78.19—1
21232.167.78.20/32232.167.78.20 to 232.167.78.20—1
22232.167.78.21/32232.167.78.21 to 232.167.78.21—1
23232.167.78.22/32232.167.78.22 to 232.167.78.22—1
24232.167.78.23/32232.167.78.23 to 232.167.78.23—1
25232.167.78.24/32232.167.78.24 to 232.167.78.24—1
26232.167.78.25/32232.167.78.25 to 232.167.78.25—1
27232.167.78.26/32232.167.78.26 to 232.167.78.26—1
28232.167.78.27/32232.167.78.27 to 232.167.78.27—1
29232.167.78.28/32232.167.78.28 to 232.167.78.28—1
30232.167.78.29/32232.167.78.29 to 232.167.78.29—1
31232.167.78.30/32232.167.78.30 to 232.167.78.30—1
32232.167.78.31/32232.167.78.31 to 232.167.78.31—1
33232.167.78.32/32232.167.78.32 to 232.167.78.32—1
34232.167.78.33/32232.167.78.33 to 232.167.78.33—1
35232.167.78.34/32232.167.78.34 to 232.167.78.34—1
36232.167.78.35/32232.167.78.35 to 232.167.78.35—1
37232.167.78.36/32232.167.78.36 to 232.167.78.36—1
38232.167.78.37/32232.167.78.37 to 232.167.78.37—1
39232.167.78.38/32232.167.78.38 to 232.167.78.38—1
40232.167.78.39/32232.167.78.39 to 232.167.78.39—1
41232.167.78.40/32232.167.78.40 to 232.167.78.40—1
42232.167.78.41/32232.167.78.41 to 232.167.78.41—1
43232.167.78.42/32232.167.78.42 to 232.167.78.42—1
44232.167.78.43/32232.167.78.43 to 232.167.78.43—1
45232.167.78.44/32232.167.78.44 to 232.167.78.44—1
46232.167.78.45/32232.167.78.45 to 232.167.78.45—1
47232.167.78.46/32232.167.78.46 to 232.167.78.46—1
48232.167.78.47/32232.167.78.47 to 232.167.78.47—1
49232.167.78.48/32232.167.78.48 to 232.167.78.48—1
50232.167.78.49/32232.167.78.49 to 232.167.78.49—1
51232.167.78.50/32232.167.78.50 to 232.167.78.50—1
52232.167.78.51/32232.167.78.51 to 232.167.78.51—1
53232.167.78.52/32232.167.78.52 to 232.167.78.52—1
54232.167.78.53/32232.167.78.53 to 232.167.78.53—1
55232.167.78.54/32232.167.78.54 to 232.167.78.54—1
56232.167.78.55/32232.167.78.55 to 232.167.78.55—1
57232.167.78.56/32232.167.78.56 to 232.167.78.56—1
58232.167.78.57/32232.167.78.57 to 232.167.78.57—1
59232.167.78.58/32232.167.78.58 to 232.167.78.58—1
60232.167.78.59/32232.167.78.59 to 232.167.78.59—1
61232.167.78.60/32232.167.78.60 to 232.167.78.60—1
62232.167.78.61/32232.167.78.61 to 232.167.78.61—1
63232.167.78.62/32232.167.78.62 to 232.167.78.62—1
64232.167.78.63/32232.167.78.63 to 232.167.78.63—1
65232.167.78.64/32232.167.78.64 to 232.167.78.64—1
66232.167.78.65/32232.167.78.65 to 232.167.78.65—1
67232.167.78.66/32232.167.78.66 to 232.167.78.66—1
68232.167.78.67/32232.167.78.67 to 232.167.78.67—1
69232.167.78.68/32232.167.78.68 to 232.167.78.68—1
70232.167.78.69/32232.167.78.69 to 232.167.78.69—1
71232.167.78.70/32232.167.78.70 to 232.167.78.70—1
72232.167.78.71/32232.167.78.71 to 232.167.78.71—1
73232.167.78.72/32232.167.78.72 to 232.167.78.72—1
74232.167.78.73/32232.167.78.73 to 232.167.78.73—1
75232.167.78.74/32232.167.78.74 to 232.167.78.74—1
76232.167.78.75/32232.167.78.75 to 232.167.78.75—1
77232.167.78.76/32232.167.78.76 to 232.167.78.76—1
78232.167.78.77/32232.167.78.77 to 232.167.78.77—1
79232.167.78.78/32232.167.78.78 to 232.167.78.78—1
80232.167.78.79/32232.167.78.79 to 232.167.78.79—1
81232.167.78.80/32232.167.78.80 to 232.167.78.80—1
82232.167.78.81/32232.167.78.81 to 232.167.78.81—1
83232.167.78.82/32232.167.78.82 to 232.167.78.82—1
84232.167.78.83/32232.167.78.83 to 232.167.78.83—1
85232.167.78.84/32232.167.78.84 to 232.167.78.84—1
86232.167.78.85/32232.167.78.85 to 232.167.78.85—1
87232.167.78.86/32232.167.78.86 to 232.167.78.86—1
88232.167.78.87/32232.167.78.87 to 232.167.78.87—1
89232.167.78.88/32232.167.78.88 to 232.167.78.88—1
90232.167.78.89/32232.167.78.89 to 232.167.78.89—1
91232.167.78.90/32232.167.78.90 to 232.167.78.90—1
92232.167.78.91/32232.167.78.91 to 232.167.78.91—1
93232.167.78.92/32232.167.78.92 to 232.167.78.92—1
94232.167.78.93/32232.167.78.93 to 232.167.78.93—1
95232.167.78.94/32232.167.78.94 to 232.167.78.94—1
96232.167.78.95/32232.167.78.95 to 232.167.78.95—1
97232.167.78.96/32232.167.78.96 to 232.167.78.96—1
98232.167.78.97/32232.167.78.97 to 232.167.78.97—1
99232.167.78.98/32232.167.78.98 to 232.167.78.98—1
100232.167.78.99/32232.167.78.99 to 232.167.78.99—1
101232.167.78.100/32232.167.78.100 to 232.167.78.100—1
102232.167.78.101/32232.167.78.101 to 232.167.78.101—1
103232.167.78.102/32232.167.78.102 to 232.167.78.102—1
104232.167.78.103/32232.167.78.103 to 232.167.78.103—1
105232.167.78.104/32232.167.78.104 to 232.167.78.104—1
106232.167.78.105/32232.167.78.105 to 232.167.78.105—1
107232.167.78.106/32232.167.78.106 to 232.167.78.106—1
108232.167.78.107/32232.167.78.107 to 232.167.78.107—1
109232.167.78.108/32232.167.78.108 to 232.167.78.108—1
110232.167.78.109/32232.167.78.109 to 232.167.78.109—1
111232.167.78.110/32232.167.78.110 to 232.167.78.110—1
112232.167.78.111/32232.167.78.111 to 232.167.78.111—1
113232.167.78.112/32232.167.78.112 to 232.167.78.112—1
114232.167.78.113/32232.167.78.113 to 232.167.78.113—1
115232.167.78.114/32232.167.78.114 to 232.167.78.114—1
116232.167.78.115/32232.167.78.115 to 232.167.78.115—1
117232.167.78.116/32232.167.78.116 to 232.167.78.116—1
118232.167.78.117/32232.167.78.117 to 232.167.78.117—1
119232.167.78.118/32232.167.78.118 to 232.167.78.118—1
120232.167.78.119/32232.167.78.119 to 232.167.78.119—1
121232.167.78.120/32232.167.78.120 to 232.167.78.120—1
122232.167.78.121/32232.167.78.121 to 232.167.78.121—1
123232.167.78.122/32232.167.78.122 to 232.167.78.122—1
124232.167.78.123/32232.167.78.123 to 232.167.78.123—1
125232.167.78.124/32232.167.78.124 to 232.167.78.124—1
126232.167.78.125/32232.167.78.125 to 232.167.78.125—1
127232.167.78.126/32232.167.78.126 to 232.167.78.126—1
128232.167.78.127/32232.167.78.127 to 232.167.78.127—1
129232.167.78.128/32232.167.78.128 to 232.167.78.128—1
130232.167.78.129/32232.167.78.129 to 232.167.78.129—1
131232.167.78.130/32232.167.78.130 to 232.167.78.130—1
132232.167.78.131/32232.167.78.131 to 232.167.78.131—1
133232.167.78.132/32232.167.78.132 to 232.167.78.132—1
134232.167.78.133/32232.167.78.133 to 232.167.78.133—1
135232.167.78.134/32232.167.78.134 to 232.167.78.134—1
136232.167.78.135/32232.167.78.135 to 232.167.78.135—1
137232.167.78.136/32232.167.78.136 to 232.167.78.136—1
138232.167.78.137/32232.167.78.137 to 232.167.78.137—1
139232.167.78.138/32232.167.78.138 to 232.167.78.138—1
140232.167.78.139/32232.167.78.139 to 232.167.78.139—1
141232.167.78.140/32232.167.78.140 to 232.167.78.140—1
142232.167.78.141/32232.167.78.141 to 232.167.78.141—1
143232.167.78.142/32232.167.78.142 to 232.167.78.142—1
144232.167.78.143/32232.167.78.143 to 232.167.78.143—1
145232.167.78.144/32232.167.78.144 to 232.167.78.144—1
146232.167.78.145/32232.167.78.145 to 232.167.78.145—1
147232.167.78.146/32232.167.78.146 to 232.167.78.146—1
148232.167.78.147/32232.167.78.147 to 232.167.78.147—1
149232.167.78.148/32232.167.78.148 to 232.167.78.148—1
150232.167.78.149/32232.167.78.149 to 232.167.78.149—1
151232.167.78.150/32232.167.78.150 to 232.167.78.150—1
152232.167.78.151/32232.167.78.151 to 232.167.78.151—1
153232.167.78.152/32232.167.78.152 to 232.167.78.152—1
154232.167.78.153/32232.167.78.153 to 232.167.78.153—1
155232.167.78.154/32232.167.78.154 to 232.167.78.154—1
156232.167.78.155/32232.167.78.155 to 232.167.78.155—1
157232.167.78.156/32232.167.78.156 to 232.167.78.156—1
158232.167.78.157/32232.167.78.157 to 232.167.78.157—1
159232.167.78.158/32232.167.78.158 to 232.167.78.158—1
160232.167.78.159/32232.167.78.159 to 232.167.78.159—1
161232.167.78.160/32232.167.78.160 to 232.167.78.160—1
162232.167.78.161/32232.167.78.161 to 232.167.78.161—1
163232.167.78.162/32232.167.78.162 to 232.167.78.162—1
164232.167.78.163/32232.167.78.163 to 232.167.78.163—1
165232.167.78.164/32232.167.78.164 to 232.167.78.164—1
166232.167.78.165/32232.167.78.165 to 232.167.78.165—1
167232.167.78.166/32232.167.78.166 to 232.167.78.166—1
168232.167.78.167/32232.167.78.167 to 232.167.78.167—1
169232.167.78.168/32232.167.78.168 to 232.167.78.168—1
170232.167.78.169/32232.167.78.169 to 232.167.78.169—1
171232.167.78.170/32232.167.78.170 to 232.167.78.170—1
172232.167.78.171/32232.167.78.171 to 232.167.78.171—1
173232.167.78.172/32232.167.78.172 to 232.167.78.172—1
174232.167.78.173/32232.167.78.173 to 232.167.78.173—1
175232.167.78.174/32232.167.78.174 to 232.167.78.174—1
176232.167.78.175/32232.167.78.175 to 232.167.78.175—1
177232.167.78.176/32232.167.78.176 to 232.167.78.176—1
178232.167.78.177/32232.167.78.177 to 232.167.78.177—1
179232.167.78.178/32232.167.78.178 to 232.167.78.178—1
180232.167.78.179/32232.167.78.179 to 232.167.78.179—1
181232.167.78.180/32232.167.78.180 to 232.167.78.180—1
182232.167.78.181/32232.167.78.181 to 232.167.78.181—1
183232.167.78.182/32232.167.78.182 to 232.167.78.182—1
184232.167.78.183/32232.167.78.183 to 232.167.78.183—1
185232.167.78.184/32232.167.78.184 to 232.167.78.184—1
186232.167.78.185/32232.167.78.185 to 232.167.78.185—1
187232.167.78.186/32232.167.78.186 to 232.167.78.186—1
188232.167.78.187/32232.167.78.187 to 232.167.78.187—1
189232.167.78.188/32232.167.78.188 to 232.167.78.188—1
190232.167.78.189/32232.167.78.189 to 232.167.78.189—1
191232.167.78.190/32232.167.78.190 to 232.167.78.190—1
192232.167.78.191/32232.167.78.191 to 232.167.78.191—1
193232.167.78.192/32232.167.78.192 to 232.167.78.192—1
194232.167.78.193/32232.167.78.193 to 232.167.78.193—1
195232.167.78.194/32232.167.78.194 to 232.167.78.194—1
196232.167.78.195/32232.167.78.195 to 232.167.78.195—1
197232.167.78.196/32232.167.78.196 to 232.167.78.196—1
198232.167.78.197/32232.167.78.197 to 232.167.78.197—1
199232.167.78.198/32232.167.78.198 to 232.167.78.198—1
200232.167.78.199/32232.167.78.199 to 232.167.78.199—1
201232.167.78.200/32232.167.78.200 to 232.167.78.200—1
202232.167.78.201/32232.167.78.201 to 232.167.78.201—1
203232.167.78.202/32232.167.78.202 to 232.167.78.202—1
204232.167.78.203/32232.167.78.203 to 232.167.78.203—1
205232.167.78.204/32232.167.78.204 to 232.167.78.204—1
206232.167.78.205/32232.167.78.205 to 232.167.78.205—1
207232.167.78.206/32232.167.78.206 to 232.167.78.206—1
208232.167.78.207/32232.167.78.207 to 232.167.78.207—1
209232.167.78.208/32232.167.78.208 to 232.167.78.208—1
210232.167.78.209/32232.167.78.209 to 232.167.78.209—1
211232.167.78.210/32232.167.78.210 to 232.167.78.210—1
212232.167.78.211/32232.167.78.211 to 232.167.78.211—1
213232.167.78.212/32232.167.78.212 to 232.167.78.212—1
214232.167.78.213/32232.167.78.213 to 232.167.78.213—1
215232.167.78.214/32232.167.78.214 to 232.167.78.214—1
216232.167.78.215/32232.167.78.215 to 232.167.78.215—1
217232.167.78.216/32232.167.78.216 to 232.167.78.216—1
218232.167.78.217/32232.167.78.217 to 232.167.78.217—1
219232.167.78.218/32232.167.78.218 to 232.167.78.218—1
220232.167.78.219/32232.167.78.219 to 232.167.78.219—1
221232.167.78.220/32232.167.78.220 to 232.167.78.220—1
222232.167.78.221/32232.167.78.221 to 232.167.78.221—1
223232.167.78.222/32232.167.78.222 to 232.167.78.222—1
224232.167.78.223/32232.167.78.223 to 232.167.78.223—1
225232.167.78.224/32232.167.78.224 to 232.167.78.224—1
226232.167.78.225/32232.167.78.225 to 232.167.78.225—1
227232.167.78.226/32232.167.78.226 to 232.167.78.226—1
228232.167.78.227/32232.167.78.227 to 232.167.78.227—1
229232.167.78.228/32232.167.78.228 to 232.167.78.228—1
230232.167.78.229/32232.167.78.229 to 232.167.78.229—1
231232.167.78.230/32232.167.78.230 to 232.167.78.230—1
232232.167.78.231/32232.167.78.231 to 232.167.78.231—1
233232.167.78.232/32232.167.78.232 to 232.167.78.232—1
234232.167.78.233/32232.167.78.233 to 232.167.78.233—1
235232.167.78.234/32232.167.78.234 to 232.167.78.234—1
236232.167.78.235/32232.167.78.235 to 232.167.78.235—1
237232.167.78.236/32232.167.78.236 to 232.167.78.236—1
238232.167.78.237/32232.167.78.237 to 232.167.78.237—1
239232.167.78.238/32232.167.78.238 to 232.167.78.238—1
240232.167.78.239/32232.167.78.239 to 232.167.78.239—1
241232.167.78.240/32232.167.78.240 to 232.167.78.240—1
242232.167.78.241/32232.167.78.241 to 232.167.78.241—1
243232.167.78.242/32232.167.78.242 to 232.167.78.242—1
244232.167.78.243/32232.167.78.243 to 232.167.78.243—1
245232.167.78.244/32232.167.78.244 to 232.167.78.244—1
246232.167.78.245/32232.167.78.245 to 232.167.78.245—1
247232.167.78.246/32232.167.78.246 to 232.167.78.246—1
248232.167.78.247/32232.167.78.247 to 232.167.78.247—1
249232.167.78.248/32232.167.78.248 to 232.167.78.248—1
250232.167.78.249/32232.167.78.249 to 232.167.78.249—1
251232.167.78.250/32232.167.78.250 to 232.167.78.250—1
252232.167.78.251/32232.167.78.251 to 232.167.78.251—1
253232.167.78.252/32232.167.78.252 to 232.167.78.252—1
254232.167.78.253/32232.167.78.253 to 232.167.78.253—1
255232.167.78.254/32232.167.78.254 to 232.167.78.254—1
256232.167.78.255/32232.167.78.255 to 232.167.78.255—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.