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.

Network169.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
169.0.0.0
Broadcast address
169.255.255.255
First usable
169.0.0.1
Last usable
169.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex A9000000 · Integer 2835349504 to 2852126719
Reverse DNS zone
169.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101001..00000000.00000000.00000000169.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10101001..00000000.00000000.00000000169.0.0.0
Broadcast10101001..11111111.11111111.11111111169.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

169.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1169.0.0.0/19169.0.0.1 to 169.0.31.254169.0.31.2558,190
2169.0.32.0/19169.0.32.1 to 169.0.63.254169.0.63.2558,190
3169.0.64.0/19169.0.64.1 to 169.0.95.254169.0.95.2558,190
4169.0.96.0/19169.0.96.1 to 169.0.127.254169.0.127.2558,190
5169.0.128.0/19169.0.128.1 to 169.0.159.254169.0.159.2558,190
6169.0.160.0/19169.0.160.1 to 169.0.191.254169.0.191.2558,190
7169.0.192.0/19169.0.192.1 to 169.0.223.254169.0.223.2558,190
8169.0.224.0/19169.0.224.1 to 169.0.255.254169.0.255.2558,190
9169.1.0.0/19169.1.0.1 to 169.1.31.254169.1.31.2558,190
10169.1.32.0/19169.1.32.1 to 169.1.63.254169.1.63.2558,190
11169.1.64.0/19169.1.64.1 to 169.1.95.254169.1.95.2558,190
12169.1.96.0/19169.1.96.1 to 169.1.127.254169.1.127.2558,190
13169.1.128.0/19169.1.128.1 to 169.1.159.254169.1.159.2558,190
14169.1.160.0/19169.1.160.1 to 169.1.191.254169.1.191.2558,190
15169.1.192.0/19169.1.192.1 to 169.1.223.254169.1.223.2558,190
16169.1.224.0/19169.1.224.1 to 169.1.255.254169.1.255.2558,190
17169.2.0.0/19169.2.0.1 to 169.2.31.254169.2.31.2558,190
18169.2.32.0/19169.2.32.1 to 169.2.63.254169.2.63.2558,190
19169.2.64.0/19169.2.64.1 to 169.2.95.254169.2.95.2558,190
20169.2.96.0/19169.2.96.1 to 169.2.127.254169.2.127.2558,190
21169.2.128.0/19169.2.128.1 to 169.2.159.254169.2.159.2558,190
22169.2.160.0/19169.2.160.1 to 169.2.191.254169.2.191.2558,190
23169.2.192.0/19169.2.192.1 to 169.2.223.254169.2.223.2558,190
24169.2.224.0/19169.2.224.1 to 169.2.255.254169.2.255.2558,190
25169.3.0.0/19169.3.0.1 to 169.3.31.254169.3.31.2558,190
26169.3.32.0/19169.3.32.1 to 169.3.63.254169.3.63.2558,190
27169.3.64.0/19169.3.64.1 to 169.3.95.254169.3.95.2558,190
28169.3.96.0/19169.3.96.1 to 169.3.127.254169.3.127.2558,190
29169.3.128.0/19169.3.128.1 to 169.3.159.254169.3.159.2558,190
30169.3.160.0/19169.3.160.1 to 169.3.191.254169.3.191.2558,190
31169.3.192.0/19169.3.192.1 to 169.3.223.254169.3.223.2558,190
32169.3.224.0/19169.3.224.1 to 169.3.255.254169.3.255.2558,190
33169.4.0.0/19169.4.0.1 to 169.4.31.254169.4.31.2558,190
34169.4.32.0/19169.4.32.1 to 169.4.63.254169.4.63.2558,190
35169.4.64.0/19169.4.64.1 to 169.4.95.254169.4.95.2558,190
36169.4.96.0/19169.4.96.1 to 169.4.127.254169.4.127.2558,190
37169.4.128.0/19169.4.128.1 to 169.4.159.254169.4.159.2558,190
38169.4.160.0/19169.4.160.1 to 169.4.191.254169.4.191.2558,190
39169.4.192.0/19169.4.192.1 to 169.4.223.254169.4.223.2558,190
40169.4.224.0/19169.4.224.1 to 169.4.255.254169.4.255.2558,190
41169.5.0.0/19169.5.0.1 to 169.5.31.254169.5.31.2558,190
42169.5.32.0/19169.5.32.1 to 169.5.63.254169.5.63.2558,190
43169.5.64.0/19169.5.64.1 to 169.5.95.254169.5.95.2558,190
44169.5.96.0/19169.5.96.1 to 169.5.127.254169.5.127.2558,190
45169.5.128.0/19169.5.128.1 to 169.5.159.254169.5.159.2558,190
46169.5.160.0/19169.5.160.1 to 169.5.191.254169.5.191.2558,190
47169.5.192.0/19169.5.192.1 to 169.5.223.254169.5.223.2558,190
48169.5.224.0/19169.5.224.1 to 169.5.255.254169.5.255.2558,190
49169.6.0.0/19169.6.0.1 to 169.6.31.254169.6.31.2558,190
50169.6.32.0/19169.6.32.1 to 169.6.63.254169.6.63.2558,190
51169.6.64.0/19169.6.64.1 to 169.6.95.254169.6.95.2558,190
52169.6.96.0/19169.6.96.1 to 169.6.127.254169.6.127.2558,190
53169.6.128.0/19169.6.128.1 to 169.6.159.254169.6.159.2558,190
54169.6.160.0/19169.6.160.1 to 169.6.191.254169.6.191.2558,190
55169.6.192.0/19169.6.192.1 to 169.6.223.254169.6.223.2558,190
56169.6.224.0/19169.6.224.1 to 169.6.255.254169.6.255.2558,190
57169.7.0.0/19169.7.0.1 to 169.7.31.254169.7.31.2558,190
58169.7.32.0/19169.7.32.1 to 169.7.63.254169.7.63.2558,190
59169.7.64.0/19169.7.64.1 to 169.7.95.254169.7.95.2558,190
60169.7.96.0/19169.7.96.1 to 169.7.127.254169.7.127.2558,190
61169.7.128.0/19169.7.128.1 to 169.7.159.254169.7.159.2558,190
62169.7.160.0/19169.7.160.1 to 169.7.191.254169.7.191.2558,190
63169.7.192.0/19169.7.192.1 to 169.7.223.254169.7.223.2558,190
64169.7.224.0/19169.7.224.1 to 169.7.255.254169.7.255.2558,190
65169.8.0.0/19169.8.0.1 to 169.8.31.254169.8.31.2558,190
66169.8.32.0/19169.8.32.1 to 169.8.63.254169.8.63.2558,190
67169.8.64.0/19169.8.64.1 to 169.8.95.254169.8.95.2558,190
68169.8.96.0/19169.8.96.1 to 169.8.127.254169.8.127.2558,190
69169.8.128.0/19169.8.128.1 to 169.8.159.254169.8.159.2558,190
70169.8.160.0/19169.8.160.1 to 169.8.191.254169.8.191.2558,190
71169.8.192.0/19169.8.192.1 to 169.8.223.254169.8.223.2558,190
72169.8.224.0/19169.8.224.1 to 169.8.255.254169.8.255.2558,190
73169.9.0.0/19169.9.0.1 to 169.9.31.254169.9.31.2558,190
74169.9.32.0/19169.9.32.1 to 169.9.63.254169.9.63.2558,190
75169.9.64.0/19169.9.64.1 to 169.9.95.254169.9.95.2558,190
76169.9.96.0/19169.9.96.1 to 169.9.127.254169.9.127.2558,190
77169.9.128.0/19169.9.128.1 to 169.9.159.254169.9.159.2558,190
78169.9.160.0/19169.9.160.1 to 169.9.191.254169.9.191.2558,190
79169.9.192.0/19169.9.192.1 to 169.9.223.254169.9.223.2558,190
80169.9.224.0/19169.9.224.1 to 169.9.255.254169.9.255.2558,190
81169.10.0.0/19169.10.0.1 to 169.10.31.254169.10.31.2558,190
82169.10.32.0/19169.10.32.1 to 169.10.63.254169.10.63.2558,190
83169.10.64.0/19169.10.64.1 to 169.10.95.254169.10.95.2558,190
84169.10.96.0/19169.10.96.1 to 169.10.127.254169.10.127.2558,190
85169.10.128.0/19169.10.128.1 to 169.10.159.254169.10.159.2558,190
86169.10.160.0/19169.10.160.1 to 169.10.191.254169.10.191.2558,190
87169.10.192.0/19169.10.192.1 to 169.10.223.254169.10.223.2558,190
88169.10.224.0/19169.10.224.1 to 169.10.255.254169.10.255.2558,190
89169.11.0.0/19169.11.0.1 to 169.11.31.254169.11.31.2558,190
90169.11.32.0/19169.11.32.1 to 169.11.63.254169.11.63.2558,190
91169.11.64.0/19169.11.64.1 to 169.11.95.254169.11.95.2558,190
92169.11.96.0/19169.11.96.1 to 169.11.127.254169.11.127.2558,190
93169.11.128.0/19169.11.128.1 to 169.11.159.254169.11.159.2558,190
94169.11.160.0/19169.11.160.1 to 169.11.191.254169.11.191.2558,190
95169.11.192.0/19169.11.192.1 to 169.11.223.254169.11.223.2558,190
96169.11.224.0/19169.11.224.1 to 169.11.255.254169.11.255.2558,190
97169.12.0.0/19169.12.0.1 to 169.12.31.254169.12.31.2558,190
98169.12.32.0/19169.12.32.1 to 169.12.63.254169.12.63.2558,190
99169.12.64.0/19169.12.64.1 to 169.12.95.254169.12.95.2558,190
100169.12.96.0/19169.12.96.1 to 169.12.127.254169.12.127.2558,190
101169.12.128.0/19169.12.128.1 to 169.12.159.254169.12.159.2558,190
102169.12.160.0/19169.12.160.1 to 169.12.191.254169.12.191.2558,190
103169.12.192.0/19169.12.192.1 to 169.12.223.254169.12.223.2558,190
104169.12.224.0/19169.12.224.1 to 169.12.255.254169.12.255.2558,190
105169.13.0.0/19169.13.0.1 to 169.13.31.254169.13.31.2558,190
106169.13.32.0/19169.13.32.1 to 169.13.63.254169.13.63.2558,190
107169.13.64.0/19169.13.64.1 to 169.13.95.254169.13.95.2558,190
108169.13.96.0/19169.13.96.1 to 169.13.127.254169.13.127.2558,190
109169.13.128.0/19169.13.128.1 to 169.13.159.254169.13.159.2558,190
110169.13.160.0/19169.13.160.1 to 169.13.191.254169.13.191.2558,190
111169.13.192.0/19169.13.192.1 to 169.13.223.254169.13.223.2558,190
112169.13.224.0/19169.13.224.1 to 169.13.255.254169.13.255.2558,190
113169.14.0.0/19169.14.0.1 to 169.14.31.254169.14.31.2558,190
114169.14.32.0/19169.14.32.1 to 169.14.63.254169.14.63.2558,190
115169.14.64.0/19169.14.64.1 to 169.14.95.254169.14.95.2558,190
116169.14.96.0/19169.14.96.1 to 169.14.127.254169.14.127.2558,190
117169.14.128.0/19169.14.128.1 to 169.14.159.254169.14.159.2558,190
118169.14.160.0/19169.14.160.1 to 169.14.191.254169.14.191.2558,190
119169.14.192.0/19169.14.192.1 to 169.14.223.254169.14.223.2558,190
120169.14.224.0/19169.14.224.1 to 169.14.255.254169.14.255.2558,190
121169.15.0.0/19169.15.0.1 to 169.15.31.254169.15.31.2558,190
122169.15.32.0/19169.15.32.1 to 169.15.63.254169.15.63.2558,190
123169.15.64.0/19169.15.64.1 to 169.15.95.254169.15.95.2558,190
124169.15.96.0/19169.15.96.1 to 169.15.127.254169.15.127.2558,190
125169.15.128.0/19169.15.128.1 to 169.15.159.254169.15.159.2558,190
126169.15.160.0/19169.15.160.1 to 169.15.191.254169.15.191.2558,190
127169.15.192.0/19169.15.192.1 to 169.15.223.254169.15.223.2558,190
128169.15.224.0/19169.15.224.1 to 169.15.255.254169.15.255.2558,190
129169.16.0.0/19169.16.0.1 to 169.16.31.254169.16.31.2558,190
130169.16.32.0/19169.16.32.1 to 169.16.63.254169.16.63.2558,190
131169.16.64.0/19169.16.64.1 to 169.16.95.254169.16.95.2558,190
132169.16.96.0/19169.16.96.1 to 169.16.127.254169.16.127.2558,190
133169.16.128.0/19169.16.128.1 to 169.16.159.254169.16.159.2558,190
134169.16.160.0/19169.16.160.1 to 169.16.191.254169.16.191.2558,190
135169.16.192.0/19169.16.192.1 to 169.16.223.254169.16.223.2558,190
136169.16.224.0/19169.16.224.1 to 169.16.255.254169.16.255.2558,190
137169.17.0.0/19169.17.0.1 to 169.17.31.254169.17.31.2558,190
138169.17.32.0/19169.17.32.1 to 169.17.63.254169.17.63.2558,190
139169.17.64.0/19169.17.64.1 to 169.17.95.254169.17.95.2558,190
140169.17.96.0/19169.17.96.1 to 169.17.127.254169.17.127.2558,190
141169.17.128.0/19169.17.128.1 to 169.17.159.254169.17.159.2558,190
142169.17.160.0/19169.17.160.1 to 169.17.191.254169.17.191.2558,190
143169.17.192.0/19169.17.192.1 to 169.17.223.254169.17.223.2558,190
144169.17.224.0/19169.17.224.1 to 169.17.255.254169.17.255.2558,190
145169.18.0.0/19169.18.0.1 to 169.18.31.254169.18.31.2558,190
146169.18.32.0/19169.18.32.1 to 169.18.63.254169.18.63.2558,190
147169.18.64.0/19169.18.64.1 to 169.18.95.254169.18.95.2558,190
148169.18.96.0/19169.18.96.1 to 169.18.127.254169.18.127.2558,190
149169.18.128.0/19169.18.128.1 to 169.18.159.254169.18.159.2558,190
150169.18.160.0/19169.18.160.1 to 169.18.191.254169.18.191.2558,190
151169.18.192.0/19169.18.192.1 to 169.18.223.254169.18.223.2558,190
152169.18.224.0/19169.18.224.1 to 169.18.255.254169.18.255.2558,190
153169.19.0.0/19169.19.0.1 to 169.19.31.254169.19.31.2558,190
154169.19.32.0/19169.19.32.1 to 169.19.63.254169.19.63.2558,190
155169.19.64.0/19169.19.64.1 to 169.19.95.254169.19.95.2558,190
156169.19.96.0/19169.19.96.1 to 169.19.127.254169.19.127.2558,190
157169.19.128.0/19169.19.128.1 to 169.19.159.254169.19.159.2558,190
158169.19.160.0/19169.19.160.1 to 169.19.191.254169.19.191.2558,190
159169.19.192.0/19169.19.192.1 to 169.19.223.254169.19.223.2558,190
160169.19.224.0/19169.19.224.1 to 169.19.255.254169.19.255.2558,190
161169.20.0.0/19169.20.0.1 to 169.20.31.254169.20.31.2558,190
162169.20.32.0/19169.20.32.1 to 169.20.63.254169.20.63.2558,190
163169.20.64.0/19169.20.64.1 to 169.20.95.254169.20.95.2558,190
164169.20.96.0/19169.20.96.1 to 169.20.127.254169.20.127.2558,190
165169.20.128.0/19169.20.128.1 to 169.20.159.254169.20.159.2558,190
166169.20.160.0/19169.20.160.1 to 169.20.191.254169.20.191.2558,190
167169.20.192.0/19169.20.192.1 to 169.20.223.254169.20.223.2558,190
168169.20.224.0/19169.20.224.1 to 169.20.255.254169.20.255.2558,190
169169.21.0.0/19169.21.0.1 to 169.21.31.254169.21.31.2558,190
170169.21.32.0/19169.21.32.1 to 169.21.63.254169.21.63.2558,190
171169.21.64.0/19169.21.64.1 to 169.21.95.254169.21.95.2558,190
172169.21.96.0/19169.21.96.1 to 169.21.127.254169.21.127.2558,190
173169.21.128.0/19169.21.128.1 to 169.21.159.254169.21.159.2558,190
174169.21.160.0/19169.21.160.1 to 169.21.191.254169.21.191.2558,190
175169.21.192.0/19169.21.192.1 to 169.21.223.254169.21.223.2558,190
176169.21.224.0/19169.21.224.1 to 169.21.255.254169.21.255.2558,190
177169.22.0.0/19169.22.0.1 to 169.22.31.254169.22.31.2558,190
178169.22.32.0/19169.22.32.1 to 169.22.63.254169.22.63.2558,190
179169.22.64.0/19169.22.64.1 to 169.22.95.254169.22.95.2558,190
180169.22.96.0/19169.22.96.1 to 169.22.127.254169.22.127.2558,190
181169.22.128.0/19169.22.128.1 to 169.22.159.254169.22.159.2558,190
182169.22.160.0/19169.22.160.1 to 169.22.191.254169.22.191.2558,190
183169.22.192.0/19169.22.192.1 to 169.22.223.254169.22.223.2558,190
184169.22.224.0/19169.22.224.1 to 169.22.255.254169.22.255.2558,190
185169.23.0.0/19169.23.0.1 to 169.23.31.254169.23.31.2558,190
186169.23.32.0/19169.23.32.1 to 169.23.63.254169.23.63.2558,190
187169.23.64.0/19169.23.64.1 to 169.23.95.254169.23.95.2558,190
188169.23.96.0/19169.23.96.1 to 169.23.127.254169.23.127.2558,190
189169.23.128.0/19169.23.128.1 to 169.23.159.254169.23.159.2558,190
190169.23.160.0/19169.23.160.1 to 169.23.191.254169.23.191.2558,190
191169.23.192.0/19169.23.192.1 to 169.23.223.254169.23.223.2558,190
192169.23.224.0/19169.23.224.1 to 169.23.255.254169.23.255.2558,190
193169.24.0.0/19169.24.0.1 to 169.24.31.254169.24.31.2558,190
194169.24.32.0/19169.24.32.1 to 169.24.63.254169.24.63.2558,190
195169.24.64.0/19169.24.64.1 to 169.24.95.254169.24.95.2558,190
196169.24.96.0/19169.24.96.1 to 169.24.127.254169.24.127.2558,190
197169.24.128.0/19169.24.128.1 to 169.24.159.254169.24.159.2558,190
198169.24.160.0/19169.24.160.1 to 169.24.191.254169.24.191.2558,190
199169.24.192.0/19169.24.192.1 to 169.24.223.254169.24.223.2558,190
200169.24.224.0/19169.24.224.1 to 169.24.255.254169.24.255.2558,190
201169.25.0.0/19169.25.0.1 to 169.25.31.254169.25.31.2558,190
202169.25.32.0/19169.25.32.1 to 169.25.63.254169.25.63.2558,190
203169.25.64.0/19169.25.64.1 to 169.25.95.254169.25.95.2558,190
204169.25.96.0/19169.25.96.1 to 169.25.127.254169.25.127.2558,190
205169.25.128.0/19169.25.128.1 to 169.25.159.254169.25.159.2558,190
206169.25.160.0/19169.25.160.1 to 169.25.191.254169.25.191.2558,190
207169.25.192.0/19169.25.192.1 to 169.25.223.254169.25.223.2558,190
208169.25.224.0/19169.25.224.1 to 169.25.255.254169.25.255.2558,190
209169.26.0.0/19169.26.0.1 to 169.26.31.254169.26.31.2558,190
210169.26.32.0/19169.26.32.1 to 169.26.63.254169.26.63.2558,190
211169.26.64.0/19169.26.64.1 to 169.26.95.254169.26.95.2558,190
212169.26.96.0/19169.26.96.1 to 169.26.127.254169.26.127.2558,190
213169.26.128.0/19169.26.128.1 to 169.26.159.254169.26.159.2558,190
214169.26.160.0/19169.26.160.1 to 169.26.191.254169.26.191.2558,190
215169.26.192.0/19169.26.192.1 to 169.26.223.254169.26.223.2558,190
216169.26.224.0/19169.26.224.1 to 169.26.255.254169.26.255.2558,190
217169.27.0.0/19169.27.0.1 to 169.27.31.254169.27.31.2558,190
218169.27.32.0/19169.27.32.1 to 169.27.63.254169.27.63.2558,190
219169.27.64.0/19169.27.64.1 to 169.27.95.254169.27.95.2558,190
220169.27.96.0/19169.27.96.1 to 169.27.127.254169.27.127.2558,190
221169.27.128.0/19169.27.128.1 to 169.27.159.254169.27.159.2558,190
222169.27.160.0/19169.27.160.1 to 169.27.191.254169.27.191.2558,190
223169.27.192.0/19169.27.192.1 to 169.27.223.254169.27.223.2558,190
224169.27.224.0/19169.27.224.1 to 169.27.255.254169.27.255.2558,190
225169.28.0.0/19169.28.0.1 to 169.28.31.254169.28.31.2558,190
226169.28.32.0/19169.28.32.1 to 169.28.63.254169.28.63.2558,190
227169.28.64.0/19169.28.64.1 to 169.28.95.254169.28.95.2558,190
228169.28.96.0/19169.28.96.1 to 169.28.127.254169.28.127.2558,190
229169.28.128.0/19169.28.128.1 to 169.28.159.254169.28.159.2558,190
230169.28.160.0/19169.28.160.1 to 169.28.191.254169.28.191.2558,190
231169.28.192.0/19169.28.192.1 to 169.28.223.254169.28.223.2558,190
232169.28.224.0/19169.28.224.1 to 169.28.255.254169.28.255.2558,190
233169.29.0.0/19169.29.0.1 to 169.29.31.254169.29.31.2558,190
234169.29.32.0/19169.29.32.1 to 169.29.63.254169.29.63.2558,190
235169.29.64.0/19169.29.64.1 to 169.29.95.254169.29.95.2558,190
236169.29.96.0/19169.29.96.1 to 169.29.127.254169.29.127.2558,190
237169.29.128.0/19169.29.128.1 to 169.29.159.254169.29.159.2558,190
238169.29.160.0/19169.29.160.1 to 169.29.191.254169.29.191.2558,190
239169.29.192.0/19169.29.192.1 to 169.29.223.254169.29.223.2558,190
240169.29.224.0/19169.29.224.1 to 169.29.255.254169.29.255.2558,190
241169.30.0.0/19169.30.0.1 to 169.30.31.254169.30.31.2558,190
242169.30.32.0/19169.30.32.1 to 169.30.63.254169.30.63.2558,190
243169.30.64.0/19169.30.64.1 to 169.30.95.254169.30.95.2558,190
244169.30.96.0/19169.30.96.1 to 169.30.127.254169.30.127.2558,190
245169.30.128.0/19169.30.128.1 to 169.30.159.254169.30.159.2558,190
246169.30.160.0/19169.30.160.1 to 169.30.191.254169.30.191.2558,190
247169.30.192.0/19169.30.192.1 to 169.30.223.254169.30.223.2558,190
248169.30.224.0/19169.30.224.1 to 169.30.255.254169.30.255.2558,190
249169.31.0.0/19169.31.0.1 to 169.31.31.254169.31.31.2558,190
250169.31.32.0/19169.31.32.1 to 169.31.63.254169.31.63.2558,190
251169.31.64.0/19169.31.64.1 to 169.31.95.254169.31.95.2558,190
252169.31.96.0/19169.31.96.1 to 169.31.127.254169.31.127.2558,190
253169.31.128.0/19169.31.128.1 to 169.31.159.254169.31.159.2558,190
254169.31.160.0/19169.31.160.1 to 169.31.191.254169.31.191.2558,190
255169.31.192.0/19169.31.192.1 to 169.31.223.254169.31.223.2558,190
256169.31.224.0/19169.31.224.1 to 169.31.255.254169.31.255.2558,190

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.