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.

Network174.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
174.0.0.0
Broadcast address
174.255.255.255
First usable
174.0.0.1
Last usable
174.255.255.254
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 AE000000 · Integer 2919235584 to 2936012799
Reverse DNS zone
174.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101110..00000000.00000000.00000000174.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10101110..00000000.00000000.00000000174.0.0.0
Broadcast10101110..11111111.11111111.11111111174.255.255.255
Split into smaller subnets/18
/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)

174.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1174.0.0.0/18174.0.0.1 to 174.0.63.254174.0.63.25516,382
2174.0.64.0/18174.0.64.1 to 174.0.127.254174.0.127.25516,382
3174.0.128.0/18174.0.128.1 to 174.0.191.254174.0.191.25516,382
4174.0.192.0/18174.0.192.1 to 174.0.255.254174.0.255.25516,382
5174.1.0.0/18174.1.0.1 to 174.1.63.254174.1.63.25516,382
6174.1.64.0/18174.1.64.1 to 174.1.127.254174.1.127.25516,382
7174.1.128.0/18174.1.128.1 to 174.1.191.254174.1.191.25516,382
8174.1.192.0/18174.1.192.1 to 174.1.255.254174.1.255.25516,382
9174.2.0.0/18174.2.0.1 to 174.2.63.254174.2.63.25516,382
10174.2.64.0/18174.2.64.1 to 174.2.127.254174.2.127.25516,382
11174.2.128.0/18174.2.128.1 to 174.2.191.254174.2.191.25516,382
12174.2.192.0/18174.2.192.1 to 174.2.255.254174.2.255.25516,382
13174.3.0.0/18174.3.0.1 to 174.3.63.254174.3.63.25516,382
14174.3.64.0/18174.3.64.1 to 174.3.127.254174.3.127.25516,382
15174.3.128.0/18174.3.128.1 to 174.3.191.254174.3.191.25516,382
16174.3.192.0/18174.3.192.1 to 174.3.255.254174.3.255.25516,382
17174.4.0.0/18174.4.0.1 to 174.4.63.254174.4.63.25516,382
18174.4.64.0/18174.4.64.1 to 174.4.127.254174.4.127.25516,382
19174.4.128.0/18174.4.128.1 to 174.4.191.254174.4.191.25516,382
20174.4.192.0/18174.4.192.1 to 174.4.255.254174.4.255.25516,382
21174.5.0.0/18174.5.0.1 to 174.5.63.254174.5.63.25516,382
22174.5.64.0/18174.5.64.1 to 174.5.127.254174.5.127.25516,382
23174.5.128.0/18174.5.128.1 to 174.5.191.254174.5.191.25516,382
24174.5.192.0/18174.5.192.1 to 174.5.255.254174.5.255.25516,382
25174.6.0.0/18174.6.0.1 to 174.6.63.254174.6.63.25516,382
26174.6.64.0/18174.6.64.1 to 174.6.127.254174.6.127.25516,382
27174.6.128.0/18174.6.128.1 to 174.6.191.254174.6.191.25516,382
28174.6.192.0/18174.6.192.1 to 174.6.255.254174.6.255.25516,382
29174.7.0.0/18174.7.0.1 to 174.7.63.254174.7.63.25516,382
30174.7.64.0/18174.7.64.1 to 174.7.127.254174.7.127.25516,382
31174.7.128.0/18174.7.128.1 to 174.7.191.254174.7.191.25516,382
32174.7.192.0/18174.7.192.1 to 174.7.255.254174.7.255.25516,382
33174.8.0.0/18174.8.0.1 to 174.8.63.254174.8.63.25516,382
34174.8.64.0/18174.8.64.1 to 174.8.127.254174.8.127.25516,382
35174.8.128.0/18174.8.128.1 to 174.8.191.254174.8.191.25516,382
36174.8.192.0/18174.8.192.1 to 174.8.255.254174.8.255.25516,382
37174.9.0.0/18174.9.0.1 to 174.9.63.254174.9.63.25516,382
38174.9.64.0/18174.9.64.1 to 174.9.127.254174.9.127.25516,382
39174.9.128.0/18174.9.128.1 to 174.9.191.254174.9.191.25516,382
40174.9.192.0/18174.9.192.1 to 174.9.255.254174.9.255.25516,382
41174.10.0.0/18174.10.0.1 to 174.10.63.254174.10.63.25516,382
42174.10.64.0/18174.10.64.1 to 174.10.127.254174.10.127.25516,382
43174.10.128.0/18174.10.128.1 to 174.10.191.254174.10.191.25516,382
44174.10.192.0/18174.10.192.1 to 174.10.255.254174.10.255.25516,382
45174.11.0.0/18174.11.0.1 to 174.11.63.254174.11.63.25516,382
46174.11.64.0/18174.11.64.1 to 174.11.127.254174.11.127.25516,382
47174.11.128.0/18174.11.128.1 to 174.11.191.254174.11.191.25516,382
48174.11.192.0/18174.11.192.1 to 174.11.255.254174.11.255.25516,382
49174.12.0.0/18174.12.0.1 to 174.12.63.254174.12.63.25516,382
50174.12.64.0/18174.12.64.1 to 174.12.127.254174.12.127.25516,382
51174.12.128.0/18174.12.128.1 to 174.12.191.254174.12.191.25516,382
52174.12.192.0/18174.12.192.1 to 174.12.255.254174.12.255.25516,382
53174.13.0.0/18174.13.0.1 to 174.13.63.254174.13.63.25516,382
54174.13.64.0/18174.13.64.1 to 174.13.127.254174.13.127.25516,382
55174.13.128.0/18174.13.128.1 to 174.13.191.254174.13.191.25516,382
56174.13.192.0/18174.13.192.1 to 174.13.255.254174.13.255.25516,382
57174.14.0.0/18174.14.0.1 to 174.14.63.254174.14.63.25516,382
58174.14.64.0/18174.14.64.1 to 174.14.127.254174.14.127.25516,382
59174.14.128.0/18174.14.128.1 to 174.14.191.254174.14.191.25516,382
60174.14.192.0/18174.14.192.1 to 174.14.255.254174.14.255.25516,382
61174.15.0.0/18174.15.0.1 to 174.15.63.254174.15.63.25516,382
62174.15.64.0/18174.15.64.1 to 174.15.127.254174.15.127.25516,382
63174.15.128.0/18174.15.128.1 to 174.15.191.254174.15.191.25516,382
64174.15.192.0/18174.15.192.1 to 174.15.255.254174.15.255.25516,382
65174.16.0.0/18174.16.0.1 to 174.16.63.254174.16.63.25516,382
66174.16.64.0/18174.16.64.1 to 174.16.127.254174.16.127.25516,382
67174.16.128.0/18174.16.128.1 to 174.16.191.254174.16.191.25516,382
68174.16.192.0/18174.16.192.1 to 174.16.255.254174.16.255.25516,382
69174.17.0.0/18174.17.0.1 to 174.17.63.254174.17.63.25516,382
70174.17.64.0/18174.17.64.1 to 174.17.127.254174.17.127.25516,382
71174.17.128.0/18174.17.128.1 to 174.17.191.254174.17.191.25516,382
72174.17.192.0/18174.17.192.1 to 174.17.255.254174.17.255.25516,382
73174.18.0.0/18174.18.0.1 to 174.18.63.254174.18.63.25516,382
74174.18.64.0/18174.18.64.1 to 174.18.127.254174.18.127.25516,382
75174.18.128.0/18174.18.128.1 to 174.18.191.254174.18.191.25516,382
76174.18.192.0/18174.18.192.1 to 174.18.255.254174.18.255.25516,382
77174.19.0.0/18174.19.0.1 to 174.19.63.254174.19.63.25516,382
78174.19.64.0/18174.19.64.1 to 174.19.127.254174.19.127.25516,382
79174.19.128.0/18174.19.128.1 to 174.19.191.254174.19.191.25516,382
80174.19.192.0/18174.19.192.1 to 174.19.255.254174.19.255.25516,382
81174.20.0.0/18174.20.0.1 to 174.20.63.254174.20.63.25516,382
82174.20.64.0/18174.20.64.1 to 174.20.127.254174.20.127.25516,382
83174.20.128.0/18174.20.128.1 to 174.20.191.254174.20.191.25516,382
84174.20.192.0/18174.20.192.1 to 174.20.255.254174.20.255.25516,382
85174.21.0.0/18174.21.0.1 to 174.21.63.254174.21.63.25516,382
86174.21.64.0/18174.21.64.1 to 174.21.127.254174.21.127.25516,382
87174.21.128.0/18174.21.128.1 to 174.21.191.254174.21.191.25516,382
88174.21.192.0/18174.21.192.1 to 174.21.255.254174.21.255.25516,382
89174.22.0.0/18174.22.0.1 to 174.22.63.254174.22.63.25516,382
90174.22.64.0/18174.22.64.1 to 174.22.127.254174.22.127.25516,382
91174.22.128.0/18174.22.128.1 to 174.22.191.254174.22.191.25516,382
92174.22.192.0/18174.22.192.1 to 174.22.255.254174.22.255.25516,382
93174.23.0.0/18174.23.0.1 to 174.23.63.254174.23.63.25516,382
94174.23.64.0/18174.23.64.1 to 174.23.127.254174.23.127.25516,382
95174.23.128.0/18174.23.128.1 to 174.23.191.254174.23.191.25516,382
96174.23.192.0/18174.23.192.1 to 174.23.255.254174.23.255.25516,382
97174.24.0.0/18174.24.0.1 to 174.24.63.254174.24.63.25516,382
98174.24.64.0/18174.24.64.1 to 174.24.127.254174.24.127.25516,382
99174.24.128.0/18174.24.128.1 to 174.24.191.254174.24.191.25516,382
100174.24.192.0/18174.24.192.1 to 174.24.255.254174.24.255.25516,382
101174.25.0.0/18174.25.0.1 to 174.25.63.254174.25.63.25516,382
102174.25.64.0/18174.25.64.1 to 174.25.127.254174.25.127.25516,382
103174.25.128.0/18174.25.128.1 to 174.25.191.254174.25.191.25516,382
104174.25.192.0/18174.25.192.1 to 174.25.255.254174.25.255.25516,382
105174.26.0.0/18174.26.0.1 to 174.26.63.254174.26.63.25516,382
106174.26.64.0/18174.26.64.1 to 174.26.127.254174.26.127.25516,382
107174.26.128.0/18174.26.128.1 to 174.26.191.254174.26.191.25516,382
108174.26.192.0/18174.26.192.1 to 174.26.255.254174.26.255.25516,382
109174.27.0.0/18174.27.0.1 to 174.27.63.254174.27.63.25516,382
110174.27.64.0/18174.27.64.1 to 174.27.127.254174.27.127.25516,382
111174.27.128.0/18174.27.128.1 to 174.27.191.254174.27.191.25516,382
112174.27.192.0/18174.27.192.1 to 174.27.255.254174.27.255.25516,382
113174.28.0.0/18174.28.0.1 to 174.28.63.254174.28.63.25516,382
114174.28.64.0/18174.28.64.1 to 174.28.127.254174.28.127.25516,382
115174.28.128.0/18174.28.128.1 to 174.28.191.254174.28.191.25516,382
116174.28.192.0/18174.28.192.1 to 174.28.255.254174.28.255.25516,382
117174.29.0.0/18174.29.0.1 to 174.29.63.254174.29.63.25516,382
118174.29.64.0/18174.29.64.1 to 174.29.127.254174.29.127.25516,382
119174.29.128.0/18174.29.128.1 to 174.29.191.254174.29.191.25516,382
120174.29.192.0/18174.29.192.1 to 174.29.255.254174.29.255.25516,382
121174.30.0.0/18174.30.0.1 to 174.30.63.254174.30.63.25516,382
122174.30.64.0/18174.30.64.1 to 174.30.127.254174.30.127.25516,382
123174.30.128.0/18174.30.128.1 to 174.30.191.254174.30.191.25516,382
124174.30.192.0/18174.30.192.1 to 174.30.255.254174.30.255.25516,382
125174.31.0.0/18174.31.0.1 to 174.31.63.254174.31.63.25516,382
126174.31.64.0/18174.31.64.1 to 174.31.127.254174.31.127.25516,382
127174.31.128.0/18174.31.128.1 to 174.31.191.254174.31.191.25516,382
128174.31.192.0/18174.31.192.1 to 174.31.255.254174.31.255.25516,382
129174.32.0.0/18174.32.0.1 to 174.32.63.254174.32.63.25516,382
130174.32.64.0/18174.32.64.1 to 174.32.127.254174.32.127.25516,382
131174.32.128.0/18174.32.128.1 to 174.32.191.254174.32.191.25516,382
132174.32.192.0/18174.32.192.1 to 174.32.255.254174.32.255.25516,382
133174.33.0.0/18174.33.0.1 to 174.33.63.254174.33.63.25516,382
134174.33.64.0/18174.33.64.1 to 174.33.127.254174.33.127.25516,382
135174.33.128.0/18174.33.128.1 to 174.33.191.254174.33.191.25516,382
136174.33.192.0/18174.33.192.1 to 174.33.255.254174.33.255.25516,382
137174.34.0.0/18174.34.0.1 to 174.34.63.254174.34.63.25516,382
138174.34.64.0/18174.34.64.1 to 174.34.127.254174.34.127.25516,382
139174.34.128.0/18174.34.128.1 to 174.34.191.254174.34.191.25516,382
140174.34.192.0/18174.34.192.1 to 174.34.255.254174.34.255.25516,382
141174.35.0.0/18174.35.0.1 to 174.35.63.254174.35.63.25516,382
142174.35.64.0/18174.35.64.1 to 174.35.127.254174.35.127.25516,382
143174.35.128.0/18174.35.128.1 to 174.35.191.254174.35.191.25516,382
144174.35.192.0/18174.35.192.1 to 174.35.255.254174.35.255.25516,382
145174.36.0.0/18174.36.0.1 to 174.36.63.254174.36.63.25516,382
146174.36.64.0/18174.36.64.1 to 174.36.127.254174.36.127.25516,382
147174.36.128.0/18174.36.128.1 to 174.36.191.254174.36.191.25516,382
148174.36.192.0/18174.36.192.1 to 174.36.255.254174.36.255.25516,382
149174.37.0.0/18174.37.0.1 to 174.37.63.254174.37.63.25516,382
150174.37.64.0/18174.37.64.1 to 174.37.127.254174.37.127.25516,382
151174.37.128.0/18174.37.128.1 to 174.37.191.254174.37.191.25516,382
152174.37.192.0/18174.37.192.1 to 174.37.255.254174.37.255.25516,382
153174.38.0.0/18174.38.0.1 to 174.38.63.254174.38.63.25516,382
154174.38.64.0/18174.38.64.1 to 174.38.127.254174.38.127.25516,382
155174.38.128.0/18174.38.128.1 to 174.38.191.254174.38.191.25516,382
156174.38.192.0/18174.38.192.1 to 174.38.255.254174.38.255.25516,382
157174.39.0.0/18174.39.0.1 to 174.39.63.254174.39.63.25516,382
158174.39.64.0/18174.39.64.1 to 174.39.127.254174.39.127.25516,382
159174.39.128.0/18174.39.128.1 to 174.39.191.254174.39.191.25516,382
160174.39.192.0/18174.39.192.1 to 174.39.255.254174.39.255.25516,382
161174.40.0.0/18174.40.0.1 to 174.40.63.254174.40.63.25516,382
162174.40.64.0/18174.40.64.1 to 174.40.127.254174.40.127.25516,382
163174.40.128.0/18174.40.128.1 to 174.40.191.254174.40.191.25516,382
164174.40.192.0/18174.40.192.1 to 174.40.255.254174.40.255.25516,382
165174.41.0.0/18174.41.0.1 to 174.41.63.254174.41.63.25516,382
166174.41.64.0/18174.41.64.1 to 174.41.127.254174.41.127.25516,382
167174.41.128.0/18174.41.128.1 to 174.41.191.254174.41.191.25516,382
168174.41.192.0/18174.41.192.1 to 174.41.255.254174.41.255.25516,382
169174.42.0.0/18174.42.0.1 to 174.42.63.254174.42.63.25516,382
170174.42.64.0/18174.42.64.1 to 174.42.127.254174.42.127.25516,382
171174.42.128.0/18174.42.128.1 to 174.42.191.254174.42.191.25516,382
172174.42.192.0/18174.42.192.1 to 174.42.255.254174.42.255.25516,382
173174.43.0.0/18174.43.0.1 to 174.43.63.254174.43.63.25516,382
174174.43.64.0/18174.43.64.1 to 174.43.127.254174.43.127.25516,382
175174.43.128.0/18174.43.128.1 to 174.43.191.254174.43.191.25516,382
176174.43.192.0/18174.43.192.1 to 174.43.255.254174.43.255.25516,382
177174.44.0.0/18174.44.0.1 to 174.44.63.254174.44.63.25516,382
178174.44.64.0/18174.44.64.1 to 174.44.127.254174.44.127.25516,382
179174.44.128.0/18174.44.128.1 to 174.44.191.254174.44.191.25516,382
180174.44.192.0/18174.44.192.1 to 174.44.255.254174.44.255.25516,382
181174.45.0.0/18174.45.0.1 to 174.45.63.254174.45.63.25516,382
182174.45.64.0/18174.45.64.1 to 174.45.127.254174.45.127.25516,382
183174.45.128.0/18174.45.128.1 to 174.45.191.254174.45.191.25516,382
184174.45.192.0/18174.45.192.1 to 174.45.255.254174.45.255.25516,382
185174.46.0.0/18174.46.0.1 to 174.46.63.254174.46.63.25516,382
186174.46.64.0/18174.46.64.1 to 174.46.127.254174.46.127.25516,382
187174.46.128.0/18174.46.128.1 to 174.46.191.254174.46.191.25516,382
188174.46.192.0/18174.46.192.1 to 174.46.255.254174.46.255.25516,382
189174.47.0.0/18174.47.0.1 to 174.47.63.254174.47.63.25516,382
190174.47.64.0/18174.47.64.1 to 174.47.127.254174.47.127.25516,382
191174.47.128.0/18174.47.128.1 to 174.47.191.254174.47.191.25516,382
192174.47.192.0/18174.47.192.1 to 174.47.255.254174.47.255.25516,382
193174.48.0.0/18174.48.0.1 to 174.48.63.254174.48.63.25516,382
194174.48.64.0/18174.48.64.1 to 174.48.127.254174.48.127.25516,382
195174.48.128.0/18174.48.128.1 to 174.48.191.254174.48.191.25516,382
196174.48.192.0/18174.48.192.1 to 174.48.255.254174.48.255.25516,382
197174.49.0.0/18174.49.0.1 to 174.49.63.254174.49.63.25516,382
198174.49.64.0/18174.49.64.1 to 174.49.127.254174.49.127.25516,382
199174.49.128.0/18174.49.128.1 to 174.49.191.254174.49.191.25516,382
200174.49.192.0/18174.49.192.1 to 174.49.255.254174.49.255.25516,382
201174.50.0.0/18174.50.0.1 to 174.50.63.254174.50.63.25516,382
202174.50.64.0/18174.50.64.1 to 174.50.127.254174.50.127.25516,382
203174.50.128.0/18174.50.128.1 to 174.50.191.254174.50.191.25516,382
204174.50.192.0/18174.50.192.1 to 174.50.255.254174.50.255.25516,382
205174.51.0.0/18174.51.0.1 to 174.51.63.254174.51.63.25516,382
206174.51.64.0/18174.51.64.1 to 174.51.127.254174.51.127.25516,382
207174.51.128.0/18174.51.128.1 to 174.51.191.254174.51.191.25516,382
208174.51.192.0/18174.51.192.1 to 174.51.255.254174.51.255.25516,382
209174.52.0.0/18174.52.0.1 to 174.52.63.254174.52.63.25516,382
210174.52.64.0/18174.52.64.1 to 174.52.127.254174.52.127.25516,382
211174.52.128.0/18174.52.128.1 to 174.52.191.254174.52.191.25516,382
212174.52.192.0/18174.52.192.1 to 174.52.255.254174.52.255.25516,382
213174.53.0.0/18174.53.0.1 to 174.53.63.254174.53.63.25516,382
214174.53.64.0/18174.53.64.1 to 174.53.127.254174.53.127.25516,382
215174.53.128.0/18174.53.128.1 to 174.53.191.254174.53.191.25516,382
216174.53.192.0/18174.53.192.1 to 174.53.255.254174.53.255.25516,382
217174.54.0.0/18174.54.0.1 to 174.54.63.254174.54.63.25516,382
218174.54.64.0/18174.54.64.1 to 174.54.127.254174.54.127.25516,382
219174.54.128.0/18174.54.128.1 to 174.54.191.254174.54.191.25516,382
220174.54.192.0/18174.54.192.1 to 174.54.255.254174.54.255.25516,382
221174.55.0.0/18174.55.0.1 to 174.55.63.254174.55.63.25516,382
222174.55.64.0/18174.55.64.1 to 174.55.127.254174.55.127.25516,382
223174.55.128.0/18174.55.128.1 to 174.55.191.254174.55.191.25516,382
224174.55.192.0/18174.55.192.1 to 174.55.255.254174.55.255.25516,382
225174.56.0.0/18174.56.0.1 to 174.56.63.254174.56.63.25516,382
226174.56.64.0/18174.56.64.1 to 174.56.127.254174.56.127.25516,382
227174.56.128.0/18174.56.128.1 to 174.56.191.254174.56.191.25516,382
228174.56.192.0/18174.56.192.1 to 174.56.255.254174.56.255.25516,382
229174.57.0.0/18174.57.0.1 to 174.57.63.254174.57.63.25516,382
230174.57.64.0/18174.57.64.1 to 174.57.127.254174.57.127.25516,382
231174.57.128.0/18174.57.128.1 to 174.57.191.254174.57.191.25516,382
232174.57.192.0/18174.57.192.1 to 174.57.255.254174.57.255.25516,382
233174.58.0.0/18174.58.0.1 to 174.58.63.254174.58.63.25516,382
234174.58.64.0/18174.58.64.1 to 174.58.127.254174.58.127.25516,382
235174.58.128.0/18174.58.128.1 to 174.58.191.254174.58.191.25516,382
236174.58.192.0/18174.58.192.1 to 174.58.255.254174.58.255.25516,382
237174.59.0.0/18174.59.0.1 to 174.59.63.254174.59.63.25516,382
238174.59.64.0/18174.59.64.1 to 174.59.127.254174.59.127.25516,382
239174.59.128.0/18174.59.128.1 to 174.59.191.254174.59.191.25516,382
240174.59.192.0/18174.59.192.1 to 174.59.255.254174.59.255.25516,382
241174.60.0.0/18174.60.0.1 to 174.60.63.254174.60.63.25516,382
242174.60.64.0/18174.60.64.1 to 174.60.127.254174.60.127.25516,382
243174.60.128.0/18174.60.128.1 to 174.60.191.254174.60.191.25516,382
244174.60.192.0/18174.60.192.1 to 174.60.255.254174.60.255.25516,382
245174.61.0.0/18174.61.0.1 to 174.61.63.254174.61.63.25516,382
246174.61.64.0/18174.61.64.1 to 174.61.127.254174.61.127.25516,382
247174.61.128.0/18174.61.128.1 to 174.61.191.254174.61.191.25516,382
248174.61.192.0/18174.61.192.1 to 174.61.255.254174.61.255.25516,382
249174.62.0.0/18174.62.0.1 to 174.62.63.254174.62.63.25516,382
250174.62.64.0/18174.62.64.1 to 174.62.127.254174.62.127.25516,382
251174.62.128.0/18174.62.128.1 to 174.62.191.254174.62.191.25516,382
252174.62.192.0/18174.62.192.1 to 174.62.255.254174.62.255.25516,382
253174.63.0.0/18174.63.0.1 to 174.63.63.254174.63.63.25516,382
254174.63.64.0/18174.63.64.1 to 174.63.127.254174.63.127.25516,382
255174.63.128.0/18174.63.128.1 to 174.63.191.254174.63.191.25516,382
256174.63.192.0/18174.63.192.1 to 174.63.255.254174.63.255.25516,382

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.