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.

Network228.167.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
228.167.0.0
Broadcast address
228.167.255.255
First usable
228.167.0.1
Last usable
228.167.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E4A70000 · Integer 3836149760 to 3836215295
Reverse DNS zone
167.228.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100100.10100111..00000000.00000000228.167.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11100100.10100111..00000000.00000000228.167.0.0
Broadcast11100100.10100111..11111111.11111111228.167.255.255
Split into smaller subnets/27
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

228.167.0.0/16 makes 2,048 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1228.167.0.0/27228.167.0.1 to 228.167.0.30228.167.0.3130
2228.167.0.32/27228.167.0.33 to 228.167.0.62228.167.0.6330
3228.167.0.64/27228.167.0.65 to 228.167.0.94228.167.0.9530
4228.167.0.96/27228.167.0.97 to 228.167.0.126228.167.0.12730
5228.167.0.128/27228.167.0.129 to 228.167.0.158228.167.0.15930
6228.167.0.160/27228.167.0.161 to 228.167.0.190228.167.0.19130
7228.167.0.192/27228.167.0.193 to 228.167.0.222228.167.0.22330
8228.167.0.224/27228.167.0.225 to 228.167.0.254228.167.0.25530
9228.167.1.0/27228.167.1.1 to 228.167.1.30228.167.1.3130
10228.167.1.32/27228.167.1.33 to 228.167.1.62228.167.1.6330
11228.167.1.64/27228.167.1.65 to 228.167.1.94228.167.1.9530
12228.167.1.96/27228.167.1.97 to 228.167.1.126228.167.1.12730
13228.167.1.128/27228.167.1.129 to 228.167.1.158228.167.1.15930
14228.167.1.160/27228.167.1.161 to 228.167.1.190228.167.1.19130
15228.167.1.192/27228.167.1.193 to 228.167.1.222228.167.1.22330
16228.167.1.224/27228.167.1.225 to 228.167.1.254228.167.1.25530
17228.167.2.0/27228.167.2.1 to 228.167.2.30228.167.2.3130
18228.167.2.32/27228.167.2.33 to 228.167.2.62228.167.2.6330
19228.167.2.64/27228.167.2.65 to 228.167.2.94228.167.2.9530
20228.167.2.96/27228.167.2.97 to 228.167.2.126228.167.2.12730
21228.167.2.128/27228.167.2.129 to 228.167.2.158228.167.2.15930
22228.167.2.160/27228.167.2.161 to 228.167.2.190228.167.2.19130
23228.167.2.192/27228.167.2.193 to 228.167.2.222228.167.2.22330
24228.167.2.224/27228.167.2.225 to 228.167.2.254228.167.2.25530
25228.167.3.0/27228.167.3.1 to 228.167.3.30228.167.3.3130
26228.167.3.32/27228.167.3.33 to 228.167.3.62228.167.3.6330
27228.167.3.64/27228.167.3.65 to 228.167.3.94228.167.3.9530
28228.167.3.96/27228.167.3.97 to 228.167.3.126228.167.3.12730
29228.167.3.128/27228.167.3.129 to 228.167.3.158228.167.3.15930
30228.167.3.160/27228.167.3.161 to 228.167.3.190228.167.3.19130
31228.167.3.192/27228.167.3.193 to 228.167.3.222228.167.3.22330
32228.167.3.224/27228.167.3.225 to 228.167.3.254228.167.3.25530
33228.167.4.0/27228.167.4.1 to 228.167.4.30228.167.4.3130
34228.167.4.32/27228.167.4.33 to 228.167.4.62228.167.4.6330
35228.167.4.64/27228.167.4.65 to 228.167.4.94228.167.4.9530
36228.167.4.96/27228.167.4.97 to 228.167.4.126228.167.4.12730
37228.167.4.128/27228.167.4.129 to 228.167.4.158228.167.4.15930
38228.167.4.160/27228.167.4.161 to 228.167.4.190228.167.4.19130
39228.167.4.192/27228.167.4.193 to 228.167.4.222228.167.4.22330
40228.167.4.224/27228.167.4.225 to 228.167.4.254228.167.4.25530
41228.167.5.0/27228.167.5.1 to 228.167.5.30228.167.5.3130
42228.167.5.32/27228.167.5.33 to 228.167.5.62228.167.5.6330
43228.167.5.64/27228.167.5.65 to 228.167.5.94228.167.5.9530
44228.167.5.96/27228.167.5.97 to 228.167.5.126228.167.5.12730
45228.167.5.128/27228.167.5.129 to 228.167.5.158228.167.5.15930
46228.167.5.160/27228.167.5.161 to 228.167.5.190228.167.5.19130
47228.167.5.192/27228.167.5.193 to 228.167.5.222228.167.5.22330
48228.167.5.224/27228.167.5.225 to 228.167.5.254228.167.5.25530
49228.167.6.0/27228.167.6.1 to 228.167.6.30228.167.6.3130
50228.167.6.32/27228.167.6.33 to 228.167.6.62228.167.6.6330
51228.167.6.64/27228.167.6.65 to 228.167.6.94228.167.6.9530
52228.167.6.96/27228.167.6.97 to 228.167.6.126228.167.6.12730
53228.167.6.128/27228.167.6.129 to 228.167.6.158228.167.6.15930
54228.167.6.160/27228.167.6.161 to 228.167.6.190228.167.6.19130
55228.167.6.192/27228.167.6.193 to 228.167.6.222228.167.6.22330
56228.167.6.224/27228.167.6.225 to 228.167.6.254228.167.6.25530
57228.167.7.0/27228.167.7.1 to 228.167.7.30228.167.7.3130
58228.167.7.32/27228.167.7.33 to 228.167.7.62228.167.7.6330
59228.167.7.64/27228.167.7.65 to 228.167.7.94228.167.7.9530
60228.167.7.96/27228.167.7.97 to 228.167.7.126228.167.7.12730
61228.167.7.128/27228.167.7.129 to 228.167.7.158228.167.7.15930
62228.167.7.160/27228.167.7.161 to 228.167.7.190228.167.7.19130
63228.167.7.192/27228.167.7.193 to 228.167.7.222228.167.7.22330
64228.167.7.224/27228.167.7.225 to 228.167.7.254228.167.7.25530
65228.167.8.0/27228.167.8.1 to 228.167.8.30228.167.8.3130
66228.167.8.32/27228.167.8.33 to 228.167.8.62228.167.8.6330
67228.167.8.64/27228.167.8.65 to 228.167.8.94228.167.8.9530
68228.167.8.96/27228.167.8.97 to 228.167.8.126228.167.8.12730
69228.167.8.128/27228.167.8.129 to 228.167.8.158228.167.8.15930
70228.167.8.160/27228.167.8.161 to 228.167.8.190228.167.8.19130
71228.167.8.192/27228.167.8.193 to 228.167.8.222228.167.8.22330
72228.167.8.224/27228.167.8.225 to 228.167.8.254228.167.8.25530
73228.167.9.0/27228.167.9.1 to 228.167.9.30228.167.9.3130
74228.167.9.32/27228.167.9.33 to 228.167.9.62228.167.9.6330
75228.167.9.64/27228.167.9.65 to 228.167.9.94228.167.9.9530
76228.167.9.96/27228.167.9.97 to 228.167.9.126228.167.9.12730
77228.167.9.128/27228.167.9.129 to 228.167.9.158228.167.9.15930
78228.167.9.160/27228.167.9.161 to 228.167.9.190228.167.9.19130
79228.167.9.192/27228.167.9.193 to 228.167.9.222228.167.9.22330
80228.167.9.224/27228.167.9.225 to 228.167.9.254228.167.9.25530
81228.167.10.0/27228.167.10.1 to 228.167.10.30228.167.10.3130
82228.167.10.32/27228.167.10.33 to 228.167.10.62228.167.10.6330
83228.167.10.64/27228.167.10.65 to 228.167.10.94228.167.10.9530
84228.167.10.96/27228.167.10.97 to 228.167.10.126228.167.10.12730
85228.167.10.128/27228.167.10.129 to 228.167.10.158228.167.10.15930
86228.167.10.160/27228.167.10.161 to 228.167.10.190228.167.10.19130
87228.167.10.192/27228.167.10.193 to 228.167.10.222228.167.10.22330
88228.167.10.224/27228.167.10.225 to 228.167.10.254228.167.10.25530
89228.167.11.0/27228.167.11.1 to 228.167.11.30228.167.11.3130
90228.167.11.32/27228.167.11.33 to 228.167.11.62228.167.11.6330
91228.167.11.64/27228.167.11.65 to 228.167.11.94228.167.11.9530
92228.167.11.96/27228.167.11.97 to 228.167.11.126228.167.11.12730
93228.167.11.128/27228.167.11.129 to 228.167.11.158228.167.11.15930
94228.167.11.160/27228.167.11.161 to 228.167.11.190228.167.11.19130
95228.167.11.192/27228.167.11.193 to 228.167.11.222228.167.11.22330
96228.167.11.224/27228.167.11.225 to 228.167.11.254228.167.11.25530
97228.167.12.0/27228.167.12.1 to 228.167.12.30228.167.12.3130
98228.167.12.32/27228.167.12.33 to 228.167.12.62228.167.12.6330
99228.167.12.64/27228.167.12.65 to 228.167.12.94228.167.12.9530
100228.167.12.96/27228.167.12.97 to 228.167.12.126228.167.12.12730
101228.167.12.128/27228.167.12.129 to 228.167.12.158228.167.12.15930
102228.167.12.160/27228.167.12.161 to 228.167.12.190228.167.12.19130
103228.167.12.192/27228.167.12.193 to 228.167.12.222228.167.12.22330
104228.167.12.224/27228.167.12.225 to 228.167.12.254228.167.12.25530
105228.167.13.0/27228.167.13.1 to 228.167.13.30228.167.13.3130
106228.167.13.32/27228.167.13.33 to 228.167.13.62228.167.13.6330
107228.167.13.64/27228.167.13.65 to 228.167.13.94228.167.13.9530
108228.167.13.96/27228.167.13.97 to 228.167.13.126228.167.13.12730
109228.167.13.128/27228.167.13.129 to 228.167.13.158228.167.13.15930
110228.167.13.160/27228.167.13.161 to 228.167.13.190228.167.13.19130
111228.167.13.192/27228.167.13.193 to 228.167.13.222228.167.13.22330
112228.167.13.224/27228.167.13.225 to 228.167.13.254228.167.13.25530
113228.167.14.0/27228.167.14.1 to 228.167.14.30228.167.14.3130
114228.167.14.32/27228.167.14.33 to 228.167.14.62228.167.14.6330
115228.167.14.64/27228.167.14.65 to 228.167.14.94228.167.14.9530
116228.167.14.96/27228.167.14.97 to 228.167.14.126228.167.14.12730
117228.167.14.128/27228.167.14.129 to 228.167.14.158228.167.14.15930
118228.167.14.160/27228.167.14.161 to 228.167.14.190228.167.14.19130
119228.167.14.192/27228.167.14.193 to 228.167.14.222228.167.14.22330
120228.167.14.224/27228.167.14.225 to 228.167.14.254228.167.14.25530
121228.167.15.0/27228.167.15.1 to 228.167.15.30228.167.15.3130
122228.167.15.32/27228.167.15.33 to 228.167.15.62228.167.15.6330
123228.167.15.64/27228.167.15.65 to 228.167.15.94228.167.15.9530
124228.167.15.96/27228.167.15.97 to 228.167.15.126228.167.15.12730
125228.167.15.128/27228.167.15.129 to 228.167.15.158228.167.15.15930
126228.167.15.160/27228.167.15.161 to 228.167.15.190228.167.15.19130
127228.167.15.192/27228.167.15.193 to 228.167.15.222228.167.15.22330
128228.167.15.224/27228.167.15.225 to 228.167.15.254228.167.15.25530
129228.167.16.0/27228.167.16.1 to 228.167.16.30228.167.16.3130
130228.167.16.32/27228.167.16.33 to 228.167.16.62228.167.16.6330
131228.167.16.64/27228.167.16.65 to 228.167.16.94228.167.16.9530
132228.167.16.96/27228.167.16.97 to 228.167.16.126228.167.16.12730
133228.167.16.128/27228.167.16.129 to 228.167.16.158228.167.16.15930
134228.167.16.160/27228.167.16.161 to 228.167.16.190228.167.16.19130
135228.167.16.192/27228.167.16.193 to 228.167.16.222228.167.16.22330
136228.167.16.224/27228.167.16.225 to 228.167.16.254228.167.16.25530
137228.167.17.0/27228.167.17.1 to 228.167.17.30228.167.17.3130
138228.167.17.32/27228.167.17.33 to 228.167.17.62228.167.17.6330
139228.167.17.64/27228.167.17.65 to 228.167.17.94228.167.17.9530
140228.167.17.96/27228.167.17.97 to 228.167.17.126228.167.17.12730
141228.167.17.128/27228.167.17.129 to 228.167.17.158228.167.17.15930
142228.167.17.160/27228.167.17.161 to 228.167.17.190228.167.17.19130
143228.167.17.192/27228.167.17.193 to 228.167.17.222228.167.17.22330
144228.167.17.224/27228.167.17.225 to 228.167.17.254228.167.17.25530
145228.167.18.0/27228.167.18.1 to 228.167.18.30228.167.18.3130
146228.167.18.32/27228.167.18.33 to 228.167.18.62228.167.18.6330
147228.167.18.64/27228.167.18.65 to 228.167.18.94228.167.18.9530
148228.167.18.96/27228.167.18.97 to 228.167.18.126228.167.18.12730
149228.167.18.128/27228.167.18.129 to 228.167.18.158228.167.18.15930
150228.167.18.160/27228.167.18.161 to 228.167.18.190228.167.18.19130
151228.167.18.192/27228.167.18.193 to 228.167.18.222228.167.18.22330
152228.167.18.224/27228.167.18.225 to 228.167.18.254228.167.18.25530
153228.167.19.0/27228.167.19.1 to 228.167.19.30228.167.19.3130
154228.167.19.32/27228.167.19.33 to 228.167.19.62228.167.19.6330
155228.167.19.64/27228.167.19.65 to 228.167.19.94228.167.19.9530
156228.167.19.96/27228.167.19.97 to 228.167.19.126228.167.19.12730
157228.167.19.128/27228.167.19.129 to 228.167.19.158228.167.19.15930
158228.167.19.160/27228.167.19.161 to 228.167.19.190228.167.19.19130
159228.167.19.192/27228.167.19.193 to 228.167.19.222228.167.19.22330
160228.167.19.224/27228.167.19.225 to 228.167.19.254228.167.19.25530
161228.167.20.0/27228.167.20.1 to 228.167.20.30228.167.20.3130
162228.167.20.32/27228.167.20.33 to 228.167.20.62228.167.20.6330
163228.167.20.64/27228.167.20.65 to 228.167.20.94228.167.20.9530
164228.167.20.96/27228.167.20.97 to 228.167.20.126228.167.20.12730
165228.167.20.128/27228.167.20.129 to 228.167.20.158228.167.20.15930
166228.167.20.160/27228.167.20.161 to 228.167.20.190228.167.20.19130
167228.167.20.192/27228.167.20.193 to 228.167.20.222228.167.20.22330
168228.167.20.224/27228.167.20.225 to 228.167.20.254228.167.20.25530
169228.167.21.0/27228.167.21.1 to 228.167.21.30228.167.21.3130
170228.167.21.32/27228.167.21.33 to 228.167.21.62228.167.21.6330
171228.167.21.64/27228.167.21.65 to 228.167.21.94228.167.21.9530
172228.167.21.96/27228.167.21.97 to 228.167.21.126228.167.21.12730
173228.167.21.128/27228.167.21.129 to 228.167.21.158228.167.21.15930
174228.167.21.160/27228.167.21.161 to 228.167.21.190228.167.21.19130
175228.167.21.192/27228.167.21.193 to 228.167.21.222228.167.21.22330
176228.167.21.224/27228.167.21.225 to 228.167.21.254228.167.21.25530
177228.167.22.0/27228.167.22.1 to 228.167.22.30228.167.22.3130
178228.167.22.32/27228.167.22.33 to 228.167.22.62228.167.22.6330
179228.167.22.64/27228.167.22.65 to 228.167.22.94228.167.22.9530
180228.167.22.96/27228.167.22.97 to 228.167.22.126228.167.22.12730
181228.167.22.128/27228.167.22.129 to 228.167.22.158228.167.22.15930
182228.167.22.160/27228.167.22.161 to 228.167.22.190228.167.22.19130
183228.167.22.192/27228.167.22.193 to 228.167.22.222228.167.22.22330
184228.167.22.224/27228.167.22.225 to 228.167.22.254228.167.22.25530
185228.167.23.0/27228.167.23.1 to 228.167.23.30228.167.23.3130
186228.167.23.32/27228.167.23.33 to 228.167.23.62228.167.23.6330
187228.167.23.64/27228.167.23.65 to 228.167.23.94228.167.23.9530
188228.167.23.96/27228.167.23.97 to 228.167.23.126228.167.23.12730
189228.167.23.128/27228.167.23.129 to 228.167.23.158228.167.23.15930
190228.167.23.160/27228.167.23.161 to 228.167.23.190228.167.23.19130
191228.167.23.192/27228.167.23.193 to 228.167.23.222228.167.23.22330
192228.167.23.224/27228.167.23.225 to 228.167.23.254228.167.23.25530
193228.167.24.0/27228.167.24.1 to 228.167.24.30228.167.24.3130
194228.167.24.32/27228.167.24.33 to 228.167.24.62228.167.24.6330
195228.167.24.64/27228.167.24.65 to 228.167.24.94228.167.24.9530
196228.167.24.96/27228.167.24.97 to 228.167.24.126228.167.24.12730
197228.167.24.128/27228.167.24.129 to 228.167.24.158228.167.24.15930
198228.167.24.160/27228.167.24.161 to 228.167.24.190228.167.24.19130
199228.167.24.192/27228.167.24.193 to 228.167.24.222228.167.24.22330
200228.167.24.224/27228.167.24.225 to 228.167.24.254228.167.24.25530
201228.167.25.0/27228.167.25.1 to 228.167.25.30228.167.25.3130
202228.167.25.32/27228.167.25.33 to 228.167.25.62228.167.25.6330
203228.167.25.64/27228.167.25.65 to 228.167.25.94228.167.25.9530
204228.167.25.96/27228.167.25.97 to 228.167.25.126228.167.25.12730
205228.167.25.128/27228.167.25.129 to 228.167.25.158228.167.25.15930
206228.167.25.160/27228.167.25.161 to 228.167.25.190228.167.25.19130
207228.167.25.192/27228.167.25.193 to 228.167.25.222228.167.25.22330
208228.167.25.224/27228.167.25.225 to 228.167.25.254228.167.25.25530
209228.167.26.0/27228.167.26.1 to 228.167.26.30228.167.26.3130
210228.167.26.32/27228.167.26.33 to 228.167.26.62228.167.26.6330
211228.167.26.64/27228.167.26.65 to 228.167.26.94228.167.26.9530
212228.167.26.96/27228.167.26.97 to 228.167.26.126228.167.26.12730
213228.167.26.128/27228.167.26.129 to 228.167.26.158228.167.26.15930
214228.167.26.160/27228.167.26.161 to 228.167.26.190228.167.26.19130
215228.167.26.192/27228.167.26.193 to 228.167.26.222228.167.26.22330
216228.167.26.224/27228.167.26.225 to 228.167.26.254228.167.26.25530
217228.167.27.0/27228.167.27.1 to 228.167.27.30228.167.27.3130
218228.167.27.32/27228.167.27.33 to 228.167.27.62228.167.27.6330
219228.167.27.64/27228.167.27.65 to 228.167.27.94228.167.27.9530
220228.167.27.96/27228.167.27.97 to 228.167.27.126228.167.27.12730
221228.167.27.128/27228.167.27.129 to 228.167.27.158228.167.27.15930
222228.167.27.160/27228.167.27.161 to 228.167.27.190228.167.27.19130
223228.167.27.192/27228.167.27.193 to 228.167.27.222228.167.27.22330
224228.167.27.224/27228.167.27.225 to 228.167.27.254228.167.27.25530
225228.167.28.0/27228.167.28.1 to 228.167.28.30228.167.28.3130
226228.167.28.32/27228.167.28.33 to 228.167.28.62228.167.28.6330
227228.167.28.64/27228.167.28.65 to 228.167.28.94228.167.28.9530
228228.167.28.96/27228.167.28.97 to 228.167.28.126228.167.28.12730
229228.167.28.128/27228.167.28.129 to 228.167.28.158228.167.28.15930
230228.167.28.160/27228.167.28.161 to 228.167.28.190228.167.28.19130
231228.167.28.192/27228.167.28.193 to 228.167.28.222228.167.28.22330
232228.167.28.224/27228.167.28.225 to 228.167.28.254228.167.28.25530
233228.167.29.0/27228.167.29.1 to 228.167.29.30228.167.29.3130
234228.167.29.32/27228.167.29.33 to 228.167.29.62228.167.29.6330
235228.167.29.64/27228.167.29.65 to 228.167.29.94228.167.29.9530
236228.167.29.96/27228.167.29.97 to 228.167.29.126228.167.29.12730
237228.167.29.128/27228.167.29.129 to 228.167.29.158228.167.29.15930
238228.167.29.160/27228.167.29.161 to 228.167.29.190228.167.29.19130
239228.167.29.192/27228.167.29.193 to 228.167.29.222228.167.29.22330
240228.167.29.224/27228.167.29.225 to 228.167.29.254228.167.29.25530
241228.167.30.0/27228.167.30.1 to 228.167.30.30228.167.30.3130
242228.167.30.32/27228.167.30.33 to 228.167.30.62228.167.30.6330
243228.167.30.64/27228.167.30.65 to 228.167.30.94228.167.30.9530
244228.167.30.96/27228.167.30.97 to 228.167.30.126228.167.30.12730
245228.167.30.128/27228.167.30.129 to 228.167.30.158228.167.30.15930
246228.167.30.160/27228.167.30.161 to 228.167.30.190228.167.30.19130
247228.167.30.192/27228.167.30.193 to 228.167.30.222228.167.30.22330
248228.167.30.224/27228.167.30.225 to 228.167.30.254228.167.30.25530
249228.167.31.0/27228.167.31.1 to 228.167.31.30228.167.31.3130
250228.167.31.32/27228.167.31.33 to 228.167.31.62228.167.31.6330
251228.167.31.64/27228.167.31.65 to 228.167.31.94228.167.31.9530
252228.167.31.96/27228.167.31.97 to 228.167.31.126228.167.31.12730
253228.167.31.128/27228.167.31.129 to 228.167.31.158228.167.31.15930
254228.167.31.160/27228.167.31.161 to 228.167.31.190228.167.31.19130
255228.167.31.192/27228.167.31.193 to 228.167.31.222228.167.31.22330
256228.167.31.224/27228.167.31.225 to 228.167.31.254228.167.31.25530

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.