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.

Network147.4.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
147.4.0.0
Broadcast address
147.7.255.255
First usable
147.4.0.1
Last usable
147.7.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
B (default /16)
As numbers
Hex 93040000 · Integer 2466512896 to 2466775039
Reverse DNS zones
4.147.in-addr.arpa
5.147.in-addr.arpa
6.147.in-addr.arpa
7.147.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010011.00000100.00000000.00000000147.4.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network10010011.00000100.00000000.00000000147.4.0.0
Broadcast10010011.00000111.11111111.11111111147.7.255.255
Split into smaller subnets/26
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

147.4.0.0/14 makes 4,096 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1147.4.0.0/26147.4.0.1 to 147.4.0.62147.4.0.6362
2147.4.0.64/26147.4.0.65 to 147.4.0.126147.4.0.12762
3147.4.0.128/26147.4.0.129 to 147.4.0.190147.4.0.19162
4147.4.0.192/26147.4.0.193 to 147.4.0.254147.4.0.25562
5147.4.1.0/26147.4.1.1 to 147.4.1.62147.4.1.6362
6147.4.1.64/26147.4.1.65 to 147.4.1.126147.4.1.12762
7147.4.1.128/26147.4.1.129 to 147.4.1.190147.4.1.19162
8147.4.1.192/26147.4.1.193 to 147.4.1.254147.4.1.25562
9147.4.2.0/26147.4.2.1 to 147.4.2.62147.4.2.6362
10147.4.2.64/26147.4.2.65 to 147.4.2.126147.4.2.12762
11147.4.2.128/26147.4.2.129 to 147.4.2.190147.4.2.19162
12147.4.2.192/26147.4.2.193 to 147.4.2.254147.4.2.25562
13147.4.3.0/26147.4.3.1 to 147.4.3.62147.4.3.6362
14147.4.3.64/26147.4.3.65 to 147.4.3.126147.4.3.12762
15147.4.3.128/26147.4.3.129 to 147.4.3.190147.4.3.19162
16147.4.3.192/26147.4.3.193 to 147.4.3.254147.4.3.25562
17147.4.4.0/26147.4.4.1 to 147.4.4.62147.4.4.6362
18147.4.4.64/26147.4.4.65 to 147.4.4.126147.4.4.12762
19147.4.4.128/26147.4.4.129 to 147.4.4.190147.4.4.19162
20147.4.4.192/26147.4.4.193 to 147.4.4.254147.4.4.25562
21147.4.5.0/26147.4.5.1 to 147.4.5.62147.4.5.6362
22147.4.5.64/26147.4.5.65 to 147.4.5.126147.4.5.12762
23147.4.5.128/26147.4.5.129 to 147.4.5.190147.4.5.19162
24147.4.5.192/26147.4.5.193 to 147.4.5.254147.4.5.25562
25147.4.6.0/26147.4.6.1 to 147.4.6.62147.4.6.6362
26147.4.6.64/26147.4.6.65 to 147.4.6.126147.4.6.12762
27147.4.6.128/26147.4.6.129 to 147.4.6.190147.4.6.19162
28147.4.6.192/26147.4.6.193 to 147.4.6.254147.4.6.25562
29147.4.7.0/26147.4.7.1 to 147.4.7.62147.4.7.6362
30147.4.7.64/26147.4.7.65 to 147.4.7.126147.4.7.12762
31147.4.7.128/26147.4.7.129 to 147.4.7.190147.4.7.19162
32147.4.7.192/26147.4.7.193 to 147.4.7.254147.4.7.25562
33147.4.8.0/26147.4.8.1 to 147.4.8.62147.4.8.6362
34147.4.8.64/26147.4.8.65 to 147.4.8.126147.4.8.12762
35147.4.8.128/26147.4.8.129 to 147.4.8.190147.4.8.19162
36147.4.8.192/26147.4.8.193 to 147.4.8.254147.4.8.25562
37147.4.9.0/26147.4.9.1 to 147.4.9.62147.4.9.6362
38147.4.9.64/26147.4.9.65 to 147.4.9.126147.4.9.12762
39147.4.9.128/26147.4.9.129 to 147.4.9.190147.4.9.19162
40147.4.9.192/26147.4.9.193 to 147.4.9.254147.4.9.25562
41147.4.10.0/26147.4.10.1 to 147.4.10.62147.4.10.6362
42147.4.10.64/26147.4.10.65 to 147.4.10.126147.4.10.12762
43147.4.10.128/26147.4.10.129 to 147.4.10.190147.4.10.19162
44147.4.10.192/26147.4.10.193 to 147.4.10.254147.4.10.25562
45147.4.11.0/26147.4.11.1 to 147.4.11.62147.4.11.6362
46147.4.11.64/26147.4.11.65 to 147.4.11.126147.4.11.12762
47147.4.11.128/26147.4.11.129 to 147.4.11.190147.4.11.19162
48147.4.11.192/26147.4.11.193 to 147.4.11.254147.4.11.25562
49147.4.12.0/26147.4.12.1 to 147.4.12.62147.4.12.6362
50147.4.12.64/26147.4.12.65 to 147.4.12.126147.4.12.12762
51147.4.12.128/26147.4.12.129 to 147.4.12.190147.4.12.19162
52147.4.12.192/26147.4.12.193 to 147.4.12.254147.4.12.25562
53147.4.13.0/26147.4.13.1 to 147.4.13.62147.4.13.6362
54147.4.13.64/26147.4.13.65 to 147.4.13.126147.4.13.12762
55147.4.13.128/26147.4.13.129 to 147.4.13.190147.4.13.19162
56147.4.13.192/26147.4.13.193 to 147.4.13.254147.4.13.25562
57147.4.14.0/26147.4.14.1 to 147.4.14.62147.4.14.6362
58147.4.14.64/26147.4.14.65 to 147.4.14.126147.4.14.12762
59147.4.14.128/26147.4.14.129 to 147.4.14.190147.4.14.19162
60147.4.14.192/26147.4.14.193 to 147.4.14.254147.4.14.25562
61147.4.15.0/26147.4.15.1 to 147.4.15.62147.4.15.6362
62147.4.15.64/26147.4.15.65 to 147.4.15.126147.4.15.12762
63147.4.15.128/26147.4.15.129 to 147.4.15.190147.4.15.19162
64147.4.15.192/26147.4.15.193 to 147.4.15.254147.4.15.25562
65147.4.16.0/26147.4.16.1 to 147.4.16.62147.4.16.6362
66147.4.16.64/26147.4.16.65 to 147.4.16.126147.4.16.12762
67147.4.16.128/26147.4.16.129 to 147.4.16.190147.4.16.19162
68147.4.16.192/26147.4.16.193 to 147.4.16.254147.4.16.25562
69147.4.17.0/26147.4.17.1 to 147.4.17.62147.4.17.6362
70147.4.17.64/26147.4.17.65 to 147.4.17.126147.4.17.12762
71147.4.17.128/26147.4.17.129 to 147.4.17.190147.4.17.19162
72147.4.17.192/26147.4.17.193 to 147.4.17.254147.4.17.25562
73147.4.18.0/26147.4.18.1 to 147.4.18.62147.4.18.6362
74147.4.18.64/26147.4.18.65 to 147.4.18.126147.4.18.12762
75147.4.18.128/26147.4.18.129 to 147.4.18.190147.4.18.19162
76147.4.18.192/26147.4.18.193 to 147.4.18.254147.4.18.25562
77147.4.19.0/26147.4.19.1 to 147.4.19.62147.4.19.6362
78147.4.19.64/26147.4.19.65 to 147.4.19.126147.4.19.12762
79147.4.19.128/26147.4.19.129 to 147.4.19.190147.4.19.19162
80147.4.19.192/26147.4.19.193 to 147.4.19.254147.4.19.25562
81147.4.20.0/26147.4.20.1 to 147.4.20.62147.4.20.6362
82147.4.20.64/26147.4.20.65 to 147.4.20.126147.4.20.12762
83147.4.20.128/26147.4.20.129 to 147.4.20.190147.4.20.19162
84147.4.20.192/26147.4.20.193 to 147.4.20.254147.4.20.25562
85147.4.21.0/26147.4.21.1 to 147.4.21.62147.4.21.6362
86147.4.21.64/26147.4.21.65 to 147.4.21.126147.4.21.12762
87147.4.21.128/26147.4.21.129 to 147.4.21.190147.4.21.19162
88147.4.21.192/26147.4.21.193 to 147.4.21.254147.4.21.25562
89147.4.22.0/26147.4.22.1 to 147.4.22.62147.4.22.6362
90147.4.22.64/26147.4.22.65 to 147.4.22.126147.4.22.12762
91147.4.22.128/26147.4.22.129 to 147.4.22.190147.4.22.19162
92147.4.22.192/26147.4.22.193 to 147.4.22.254147.4.22.25562
93147.4.23.0/26147.4.23.1 to 147.4.23.62147.4.23.6362
94147.4.23.64/26147.4.23.65 to 147.4.23.126147.4.23.12762
95147.4.23.128/26147.4.23.129 to 147.4.23.190147.4.23.19162
96147.4.23.192/26147.4.23.193 to 147.4.23.254147.4.23.25562
97147.4.24.0/26147.4.24.1 to 147.4.24.62147.4.24.6362
98147.4.24.64/26147.4.24.65 to 147.4.24.126147.4.24.12762
99147.4.24.128/26147.4.24.129 to 147.4.24.190147.4.24.19162
100147.4.24.192/26147.4.24.193 to 147.4.24.254147.4.24.25562
101147.4.25.0/26147.4.25.1 to 147.4.25.62147.4.25.6362
102147.4.25.64/26147.4.25.65 to 147.4.25.126147.4.25.12762
103147.4.25.128/26147.4.25.129 to 147.4.25.190147.4.25.19162
104147.4.25.192/26147.4.25.193 to 147.4.25.254147.4.25.25562
105147.4.26.0/26147.4.26.1 to 147.4.26.62147.4.26.6362
106147.4.26.64/26147.4.26.65 to 147.4.26.126147.4.26.12762
107147.4.26.128/26147.4.26.129 to 147.4.26.190147.4.26.19162
108147.4.26.192/26147.4.26.193 to 147.4.26.254147.4.26.25562
109147.4.27.0/26147.4.27.1 to 147.4.27.62147.4.27.6362
110147.4.27.64/26147.4.27.65 to 147.4.27.126147.4.27.12762
111147.4.27.128/26147.4.27.129 to 147.4.27.190147.4.27.19162
112147.4.27.192/26147.4.27.193 to 147.4.27.254147.4.27.25562
113147.4.28.0/26147.4.28.1 to 147.4.28.62147.4.28.6362
114147.4.28.64/26147.4.28.65 to 147.4.28.126147.4.28.12762
115147.4.28.128/26147.4.28.129 to 147.4.28.190147.4.28.19162
116147.4.28.192/26147.4.28.193 to 147.4.28.254147.4.28.25562
117147.4.29.0/26147.4.29.1 to 147.4.29.62147.4.29.6362
118147.4.29.64/26147.4.29.65 to 147.4.29.126147.4.29.12762
119147.4.29.128/26147.4.29.129 to 147.4.29.190147.4.29.19162
120147.4.29.192/26147.4.29.193 to 147.4.29.254147.4.29.25562
121147.4.30.0/26147.4.30.1 to 147.4.30.62147.4.30.6362
122147.4.30.64/26147.4.30.65 to 147.4.30.126147.4.30.12762
123147.4.30.128/26147.4.30.129 to 147.4.30.190147.4.30.19162
124147.4.30.192/26147.4.30.193 to 147.4.30.254147.4.30.25562
125147.4.31.0/26147.4.31.1 to 147.4.31.62147.4.31.6362
126147.4.31.64/26147.4.31.65 to 147.4.31.126147.4.31.12762
127147.4.31.128/26147.4.31.129 to 147.4.31.190147.4.31.19162
128147.4.31.192/26147.4.31.193 to 147.4.31.254147.4.31.25562
129147.4.32.0/26147.4.32.1 to 147.4.32.62147.4.32.6362
130147.4.32.64/26147.4.32.65 to 147.4.32.126147.4.32.12762
131147.4.32.128/26147.4.32.129 to 147.4.32.190147.4.32.19162
132147.4.32.192/26147.4.32.193 to 147.4.32.254147.4.32.25562
133147.4.33.0/26147.4.33.1 to 147.4.33.62147.4.33.6362
134147.4.33.64/26147.4.33.65 to 147.4.33.126147.4.33.12762
135147.4.33.128/26147.4.33.129 to 147.4.33.190147.4.33.19162
136147.4.33.192/26147.4.33.193 to 147.4.33.254147.4.33.25562
137147.4.34.0/26147.4.34.1 to 147.4.34.62147.4.34.6362
138147.4.34.64/26147.4.34.65 to 147.4.34.126147.4.34.12762
139147.4.34.128/26147.4.34.129 to 147.4.34.190147.4.34.19162
140147.4.34.192/26147.4.34.193 to 147.4.34.254147.4.34.25562
141147.4.35.0/26147.4.35.1 to 147.4.35.62147.4.35.6362
142147.4.35.64/26147.4.35.65 to 147.4.35.126147.4.35.12762
143147.4.35.128/26147.4.35.129 to 147.4.35.190147.4.35.19162
144147.4.35.192/26147.4.35.193 to 147.4.35.254147.4.35.25562
145147.4.36.0/26147.4.36.1 to 147.4.36.62147.4.36.6362
146147.4.36.64/26147.4.36.65 to 147.4.36.126147.4.36.12762
147147.4.36.128/26147.4.36.129 to 147.4.36.190147.4.36.19162
148147.4.36.192/26147.4.36.193 to 147.4.36.254147.4.36.25562
149147.4.37.0/26147.4.37.1 to 147.4.37.62147.4.37.6362
150147.4.37.64/26147.4.37.65 to 147.4.37.126147.4.37.12762
151147.4.37.128/26147.4.37.129 to 147.4.37.190147.4.37.19162
152147.4.37.192/26147.4.37.193 to 147.4.37.254147.4.37.25562
153147.4.38.0/26147.4.38.1 to 147.4.38.62147.4.38.6362
154147.4.38.64/26147.4.38.65 to 147.4.38.126147.4.38.12762
155147.4.38.128/26147.4.38.129 to 147.4.38.190147.4.38.19162
156147.4.38.192/26147.4.38.193 to 147.4.38.254147.4.38.25562
157147.4.39.0/26147.4.39.1 to 147.4.39.62147.4.39.6362
158147.4.39.64/26147.4.39.65 to 147.4.39.126147.4.39.12762
159147.4.39.128/26147.4.39.129 to 147.4.39.190147.4.39.19162
160147.4.39.192/26147.4.39.193 to 147.4.39.254147.4.39.25562
161147.4.40.0/26147.4.40.1 to 147.4.40.62147.4.40.6362
162147.4.40.64/26147.4.40.65 to 147.4.40.126147.4.40.12762
163147.4.40.128/26147.4.40.129 to 147.4.40.190147.4.40.19162
164147.4.40.192/26147.4.40.193 to 147.4.40.254147.4.40.25562
165147.4.41.0/26147.4.41.1 to 147.4.41.62147.4.41.6362
166147.4.41.64/26147.4.41.65 to 147.4.41.126147.4.41.12762
167147.4.41.128/26147.4.41.129 to 147.4.41.190147.4.41.19162
168147.4.41.192/26147.4.41.193 to 147.4.41.254147.4.41.25562
169147.4.42.0/26147.4.42.1 to 147.4.42.62147.4.42.6362
170147.4.42.64/26147.4.42.65 to 147.4.42.126147.4.42.12762
171147.4.42.128/26147.4.42.129 to 147.4.42.190147.4.42.19162
172147.4.42.192/26147.4.42.193 to 147.4.42.254147.4.42.25562
173147.4.43.0/26147.4.43.1 to 147.4.43.62147.4.43.6362
174147.4.43.64/26147.4.43.65 to 147.4.43.126147.4.43.12762
175147.4.43.128/26147.4.43.129 to 147.4.43.190147.4.43.19162
176147.4.43.192/26147.4.43.193 to 147.4.43.254147.4.43.25562
177147.4.44.0/26147.4.44.1 to 147.4.44.62147.4.44.6362
178147.4.44.64/26147.4.44.65 to 147.4.44.126147.4.44.12762
179147.4.44.128/26147.4.44.129 to 147.4.44.190147.4.44.19162
180147.4.44.192/26147.4.44.193 to 147.4.44.254147.4.44.25562
181147.4.45.0/26147.4.45.1 to 147.4.45.62147.4.45.6362
182147.4.45.64/26147.4.45.65 to 147.4.45.126147.4.45.12762
183147.4.45.128/26147.4.45.129 to 147.4.45.190147.4.45.19162
184147.4.45.192/26147.4.45.193 to 147.4.45.254147.4.45.25562
185147.4.46.0/26147.4.46.1 to 147.4.46.62147.4.46.6362
186147.4.46.64/26147.4.46.65 to 147.4.46.126147.4.46.12762
187147.4.46.128/26147.4.46.129 to 147.4.46.190147.4.46.19162
188147.4.46.192/26147.4.46.193 to 147.4.46.254147.4.46.25562
189147.4.47.0/26147.4.47.1 to 147.4.47.62147.4.47.6362
190147.4.47.64/26147.4.47.65 to 147.4.47.126147.4.47.12762
191147.4.47.128/26147.4.47.129 to 147.4.47.190147.4.47.19162
192147.4.47.192/26147.4.47.193 to 147.4.47.254147.4.47.25562
193147.4.48.0/26147.4.48.1 to 147.4.48.62147.4.48.6362
194147.4.48.64/26147.4.48.65 to 147.4.48.126147.4.48.12762
195147.4.48.128/26147.4.48.129 to 147.4.48.190147.4.48.19162
196147.4.48.192/26147.4.48.193 to 147.4.48.254147.4.48.25562
197147.4.49.0/26147.4.49.1 to 147.4.49.62147.4.49.6362
198147.4.49.64/26147.4.49.65 to 147.4.49.126147.4.49.12762
199147.4.49.128/26147.4.49.129 to 147.4.49.190147.4.49.19162
200147.4.49.192/26147.4.49.193 to 147.4.49.254147.4.49.25562
201147.4.50.0/26147.4.50.1 to 147.4.50.62147.4.50.6362
202147.4.50.64/26147.4.50.65 to 147.4.50.126147.4.50.12762
203147.4.50.128/26147.4.50.129 to 147.4.50.190147.4.50.19162
204147.4.50.192/26147.4.50.193 to 147.4.50.254147.4.50.25562
205147.4.51.0/26147.4.51.1 to 147.4.51.62147.4.51.6362
206147.4.51.64/26147.4.51.65 to 147.4.51.126147.4.51.12762
207147.4.51.128/26147.4.51.129 to 147.4.51.190147.4.51.19162
208147.4.51.192/26147.4.51.193 to 147.4.51.254147.4.51.25562
209147.4.52.0/26147.4.52.1 to 147.4.52.62147.4.52.6362
210147.4.52.64/26147.4.52.65 to 147.4.52.126147.4.52.12762
211147.4.52.128/26147.4.52.129 to 147.4.52.190147.4.52.19162
212147.4.52.192/26147.4.52.193 to 147.4.52.254147.4.52.25562
213147.4.53.0/26147.4.53.1 to 147.4.53.62147.4.53.6362
214147.4.53.64/26147.4.53.65 to 147.4.53.126147.4.53.12762
215147.4.53.128/26147.4.53.129 to 147.4.53.190147.4.53.19162
216147.4.53.192/26147.4.53.193 to 147.4.53.254147.4.53.25562
217147.4.54.0/26147.4.54.1 to 147.4.54.62147.4.54.6362
218147.4.54.64/26147.4.54.65 to 147.4.54.126147.4.54.12762
219147.4.54.128/26147.4.54.129 to 147.4.54.190147.4.54.19162
220147.4.54.192/26147.4.54.193 to 147.4.54.254147.4.54.25562
221147.4.55.0/26147.4.55.1 to 147.4.55.62147.4.55.6362
222147.4.55.64/26147.4.55.65 to 147.4.55.126147.4.55.12762
223147.4.55.128/26147.4.55.129 to 147.4.55.190147.4.55.19162
224147.4.55.192/26147.4.55.193 to 147.4.55.254147.4.55.25562
225147.4.56.0/26147.4.56.1 to 147.4.56.62147.4.56.6362
226147.4.56.64/26147.4.56.65 to 147.4.56.126147.4.56.12762
227147.4.56.128/26147.4.56.129 to 147.4.56.190147.4.56.19162
228147.4.56.192/26147.4.56.193 to 147.4.56.254147.4.56.25562
229147.4.57.0/26147.4.57.1 to 147.4.57.62147.4.57.6362
230147.4.57.64/26147.4.57.65 to 147.4.57.126147.4.57.12762
231147.4.57.128/26147.4.57.129 to 147.4.57.190147.4.57.19162
232147.4.57.192/26147.4.57.193 to 147.4.57.254147.4.57.25562
233147.4.58.0/26147.4.58.1 to 147.4.58.62147.4.58.6362
234147.4.58.64/26147.4.58.65 to 147.4.58.126147.4.58.12762
235147.4.58.128/26147.4.58.129 to 147.4.58.190147.4.58.19162
236147.4.58.192/26147.4.58.193 to 147.4.58.254147.4.58.25562
237147.4.59.0/26147.4.59.1 to 147.4.59.62147.4.59.6362
238147.4.59.64/26147.4.59.65 to 147.4.59.126147.4.59.12762
239147.4.59.128/26147.4.59.129 to 147.4.59.190147.4.59.19162
240147.4.59.192/26147.4.59.193 to 147.4.59.254147.4.59.25562
241147.4.60.0/26147.4.60.1 to 147.4.60.62147.4.60.6362
242147.4.60.64/26147.4.60.65 to 147.4.60.126147.4.60.12762
243147.4.60.128/26147.4.60.129 to 147.4.60.190147.4.60.19162
244147.4.60.192/26147.4.60.193 to 147.4.60.254147.4.60.25562
245147.4.61.0/26147.4.61.1 to 147.4.61.62147.4.61.6362
246147.4.61.64/26147.4.61.65 to 147.4.61.126147.4.61.12762
247147.4.61.128/26147.4.61.129 to 147.4.61.190147.4.61.19162
248147.4.61.192/26147.4.61.193 to 147.4.61.254147.4.61.25562
249147.4.62.0/26147.4.62.1 to 147.4.62.62147.4.62.6362
250147.4.62.64/26147.4.62.65 to 147.4.62.126147.4.62.12762
251147.4.62.128/26147.4.62.129 to 147.4.62.190147.4.62.19162
252147.4.62.192/26147.4.62.193 to 147.4.62.254147.4.62.25562
253147.4.63.0/26147.4.63.1 to 147.4.63.62147.4.63.6362
254147.4.63.64/26147.4.63.65 to 147.4.63.126147.4.63.12762
255147.4.63.128/26147.4.63.129 to 147.4.63.190147.4.63.19162
256147.4.63.192/26147.4.63.193 to 147.4.63.254147.4.63.25562

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.