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.

Network110.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
110.0.0.0
Broadcast address
110.127.255.255
First usable
110.0.0.1
Last usable
110.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 6E000000 · Integer 1845493760 to 1853882367
Reverse DNS zones
0.110.in-addr.arpa
1.110.in-addr.arpa
2.110.in-addr.arpa
3.110.in-addr.arpa
4.110.in-addr.arpa
5.110.in-addr.arpa
6.110.in-addr.arpa
7.110.in-addr.arpa
8.110.in-addr.arpa
9.110.in-addr.arpa
10.110.in-addr.arpa
11.110.in-addr.arpa
12.110.in-addr.arpa
13.110.in-addr.arpa
14.110.in-addr.arpa
15.110.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101110.00000000.00000000.00000000110.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01101110.00000000.00000000.00000000110.0.0.0
Broadcast01101110.01111111.11111111.11111111110.127.255.255
Split into smaller subnets/18
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

110.0.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1110.0.0.0/18110.0.0.1 to 110.0.63.254110.0.63.25516,382
2110.0.64.0/18110.0.64.1 to 110.0.127.254110.0.127.25516,382
3110.0.128.0/18110.0.128.1 to 110.0.191.254110.0.191.25516,382
4110.0.192.0/18110.0.192.1 to 110.0.255.254110.0.255.25516,382
5110.1.0.0/18110.1.0.1 to 110.1.63.254110.1.63.25516,382
6110.1.64.0/18110.1.64.1 to 110.1.127.254110.1.127.25516,382
7110.1.128.0/18110.1.128.1 to 110.1.191.254110.1.191.25516,382
8110.1.192.0/18110.1.192.1 to 110.1.255.254110.1.255.25516,382
9110.2.0.0/18110.2.0.1 to 110.2.63.254110.2.63.25516,382
10110.2.64.0/18110.2.64.1 to 110.2.127.254110.2.127.25516,382
11110.2.128.0/18110.2.128.1 to 110.2.191.254110.2.191.25516,382
12110.2.192.0/18110.2.192.1 to 110.2.255.254110.2.255.25516,382
13110.3.0.0/18110.3.0.1 to 110.3.63.254110.3.63.25516,382
14110.3.64.0/18110.3.64.1 to 110.3.127.254110.3.127.25516,382
15110.3.128.0/18110.3.128.1 to 110.3.191.254110.3.191.25516,382
16110.3.192.0/18110.3.192.1 to 110.3.255.254110.3.255.25516,382
17110.4.0.0/18110.4.0.1 to 110.4.63.254110.4.63.25516,382
18110.4.64.0/18110.4.64.1 to 110.4.127.254110.4.127.25516,382
19110.4.128.0/18110.4.128.1 to 110.4.191.254110.4.191.25516,382
20110.4.192.0/18110.4.192.1 to 110.4.255.254110.4.255.25516,382
21110.5.0.0/18110.5.0.1 to 110.5.63.254110.5.63.25516,382
22110.5.64.0/18110.5.64.1 to 110.5.127.254110.5.127.25516,382
23110.5.128.0/18110.5.128.1 to 110.5.191.254110.5.191.25516,382
24110.5.192.0/18110.5.192.1 to 110.5.255.254110.5.255.25516,382
25110.6.0.0/18110.6.0.1 to 110.6.63.254110.6.63.25516,382
26110.6.64.0/18110.6.64.1 to 110.6.127.254110.6.127.25516,382
27110.6.128.0/18110.6.128.1 to 110.6.191.254110.6.191.25516,382
28110.6.192.0/18110.6.192.1 to 110.6.255.254110.6.255.25516,382
29110.7.0.0/18110.7.0.1 to 110.7.63.254110.7.63.25516,382
30110.7.64.0/18110.7.64.1 to 110.7.127.254110.7.127.25516,382
31110.7.128.0/18110.7.128.1 to 110.7.191.254110.7.191.25516,382
32110.7.192.0/18110.7.192.1 to 110.7.255.254110.7.255.25516,382
33110.8.0.0/18110.8.0.1 to 110.8.63.254110.8.63.25516,382
34110.8.64.0/18110.8.64.1 to 110.8.127.254110.8.127.25516,382
35110.8.128.0/18110.8.128.1 to 110.8.191.254110.8.191.25516,382
36110.8.192.0/18110.8.192.1 to 110.8.255.254110.8.255.25516,382
37110.9.0.0/18110.9.0.1 to 110.9.63.254110.9.63.25516,382
38110.9.64.0/18110.9.64.1 to 110.9.127.254110.9.127.25516,382
39110.9.128.0/18110.9.128.1 to 110.9.191.254110.9.191.25516,382
40110.9.192.0/18110.9.192.1 to 110.9.255.254110.9.255.25516,382
41110.10.0.0/18110.10.0.1 to 110.10.63.254110.10.63.25516,382
42110.10.64.0/18110.10.64.1 to 110.10.127.254110.10.127.25516,382
43110.10.128.0/18110.10.128.1 to 110.10.191.254110.10.191.25516,382
44110.10.192.0/18110.10.192.1 to 110.10.255.254110.10.255.25516,382
45110.11.0.0/18110.11.0.1 to 110.11.63.254110.11.63.25516,382
46110.11.64.0/18110.11.64.1 to 110.11.127.254110.11.127.25516,382
47110.11.128.0/18110.11.128.1 to 110.11.191.254110.11.191.25516,382
48110.11.192.0/18110.11.192.1 to 110.11.255.254110.11.255.25516,382
49110.12.0.0/18110.12.0.1 to 110.12.63.254110.12.63.25516,382
50110.12.64.0/18110.12.64.1 to 110.12.127.254110.12.127.25516,382
51110.12.128.0/18110.12.128.1 to 110.12.191.254110.12.191.25516,382
52110.12.192.0/18110.12.192.1 to 110.12.255.254110.12.255.25516,382
53110.13.0.0/18110.13.0.1 to 110.13.63.254110.13.63.25516,382
54110.13.64.0/18110.13.64.1 to 110.13.127.254110.13.127.25516,382
55110.13.128.0/18110.13.128.1 to 110.13.191.254110.13.191.25516,382
56110.13.192.0/18110.13.192.1 to 110.13.255.254110.13.255.25516,382
57110.14.0.0/18110.14.0.1 to 110.14.63.254110.14.63.25516,382
58110.14.64.0/18110.14.64.1 to 110.14.127.254110.14.127.25516,382
59110.14.128.0/18110.14.128.1 to 110.14.191.254110.14.191.25516,382
60110.14.192.0/18110.14.192.1 to 110.14.255.254110.14.255.25516,382
61110.15.0.0/18110.15.0.1 to 110.15.63.254110.15.63.25516,382
62110.15.64.0/18110.15.64.1 to 110.15.127.254110.15.127.25516,382
63110.15.128.0/18110.15.128.1 to 110.15.191.254110.15.191.25516,382
64110.15.192.0/18110.15.192.1 to 110.15.255.254110.15.255.25516,382
65110.16.0.0/18110.16.0.1 to 110.16.63.254110.16.63.25516,382
66110.16.64.0/18110.16.64.1 to 110.16.127.254110.16.127.25516,382
67110.16.128.0/18110.16.128.1 to 110.16.191.254110.16.191.25516,382
68110.16.192.0/18110.16.192.1 to 110.16.255.254110.16.255.25516,382
69110.17.0.0/18110.17.0.1 to 110.17.63.254110.17.63.25516,382
70110.17.64.0/18110.17.64.1 to 110.17.127.254110.17.127.25516,382
71110.17.128.0/18110.17.128.1 to 110.17.191.254110.17.191.25516,382
72110.17.192.0/18110.17.192.1 to 110.17.255.254110.17.255.25516,382
73110.18.0.0/18110.18.0.1 to 110.18.63.254110.18.63.25516,382
74110.18.64.0/18110.18.64.1 to 110.18.127.254110.18.127.25516,382
75110.18.128.0/18110.18.128.1 to 110.18.191.254110.18.191.25516,382
76110.18.192.0/18110.18.192.1 to 110.18.255.254110.18.255.25516,382
77110.19.0.0/18110.19.0.1 to 110.19.63.254110.19.63.25516,382
78110.19.64.0/18110.19.64.1 to 110.19.127.254110.19.127.25516,382
79110.19.128.0/18110.19.128.1 to 110.19.191.254110.19.191.25516,382
80110.19.192.0/18110.19.192.1 to 110.19.255.254110.19.255.25516,382
81110.20.0.0/18110.20.0.1 to 110.20.63.254110.20.63.25516,382
82110.20.64.0/18110.20.64.1 to 110.20.127.254110.20.127.25516,382
83110.20.128.0/18110.20.128.1 to 110.20.191.254110.20.191.25516,382
84110.20.192.0/18110.20.192.1 to 110.20.255.254110.20.255.25516,382
85110.21.0.0/18110.21.0.1 to 110.21.63.254110.21.63.25516,382
86110.21.64.0/18110.21.64.1 to 110.21.127.254110.21.127.25516,382
87110.21.128.0/18110.21.128.1 to 110.21.191.254110.21.191.25516,382
88110.21.192.0/18110.21.192.1 to 110.21.255.254110.21.255.25516,382
89110.22.0.0/18110.22.0.1 to 110.22.63.254110.22.63.25516,382
90110.22.64.0/18110.22.64.1 to 110.22.127.254110.22.127.25516,382
91110.22.128.0/18110.22.128.1 to 110.22.191.254110.22.191.25516,382
92110.22.192.0/18110.22.192.1 to 110.22.255.254110.22.255.25516,382
93110.23.0.0/18110.23.0.1 to 110.23.63.254110.23.63.25516,382
94110.23.64.0/18110.23.64.1 to 110.23.127.254110.23.127.25516,382
95110.23.128.0/18110.23.128.1 to 110.23.191.254110.23.191.25516,382
96110.23.192.0/18110.23.192.1 to 110.23.255.254110.23.255.25516,382
97110.24.0.0/18110.24.0.1 to 110.24.63.254110.24.63.25516,382
98110.24.64.0/18110.24.64.1 to 110.24.127.254110.24.127.25516,382
99110.24.128.0/18110.24.128.1 to 110.24.191.254110.24.191.25516,382
100110.24.192.0/18110.24.192.1 to 110.24.255.254110.24.255.25516,382
101110.25.0.0/18110.25.0.1 to 110.25.63.254110.25.63.25516,382
102110.25.64.0/18110.25.64.1 to 110.25.127.254110.25.127.25516,382
103110.25.128.0/18110.25.128.1 to 110.25.191.254110.25.191.25516,382
104110.25.192.0/18110.25.192.1 to 110.25.255.254110.25.255.25516,382
105110.26.0.0/18110.26.0.1 to 110.26.63.254110.26.63.25516,382
106110.26.64.0/18110.26.64.1 to 110.26.127.254110.26.127.25516,382
107110.26.128.0/18110.26.128.1 to 110.26.191.254110.26.191.25516,382
108110.26.192.0/18110.26.192.1 to 110.26.255.254110.26.255.25516,382
109110.27.0.0/18110.27.0.1 to 110.27.63.254110.27.63.25516,382
110110.27.64.0/18110.27.64.1 to 110.27.127.254110.27.127.25516,382
111110.27.128.0/18110.27.128.1 to 110.27.191.254110.27.191.25516,382
112110.27.192.0/18110.27.192.1 to 110.27.255.254110.27.255.25516,382
113110.28.0.0/18110.28.0.1 to 110.28.63.254110.28.63.25516,382
114110.28.64.0/18110.28.64.1 to 110.28.127.254110.28.127.25516,382
115110.28.128.0/18110.28.128.1 to 110.28.191.254110.28.191.25516,382
116110.28.192.0/18110.28.192.1 to 110.28.255.254110.28.255.25516,382
117110.29.0.0/18110.29.0.1 to 110.29.63.254110.29.63.25516,382
118110.29.64.0/18110.29.64.1 to 110.29.127.254110.29.127.25516,382
119110.29.128.0/18110.29.128.1 to 110.29.191.254110.29.191.25516,382
120110.29.192.0/18110.29.192.1 to 110.29.255.254110.29.255.25516,382
121110.30.0.0/18110.30.0.1 to 110.30.63.254110.30.63.25516,382
122110.30.64.0/18110.30.64.1 to 110.30.127.254110.30.127.25516,382
123110.30.128.0/18110.30.128.1 to 110.30.191.254110.30.191.25516,382
124110.30.192.0/18110.30.192.1 to 110.30.255.254110.30.255.25516,382
125110.31.0.0/18110.31.0.1 to 110.31.63.254110.31.63.25516,382
126110.31.64.0/18110.31.64.1 to 110.31.127.254110.31.127.25516,382
127110.31.128.0/18110.31.128.1 to 110.31.191.254110.31.191.25516,382
128110.31.192.0/18110.31.192.1 to 110.31.255.254110.31.255.25516,382
129110.32.0.0/18110.32.0.1 to 110.32.63.254110.32.63.25516,382
130110.32.64.0/18110.32.64.1 to 110.32.127.254110.32.127.25516,382
131110.32.128.0/18110.32.128.1 to 110.32.191.254110.32.191.25516,382
132110.32.192.0/18110.32.192.1 to 110.32.255.254110.32.255.25516,382
133110.33.0.0/18110.33.0.1 to 110.33.63.254110.33.63.25516,382
134110.33.64.0/18110.33.64.1 to 110.33.127.254110.33.127.25516,382
135110.33.128.0/18110.33.128.1 to 110.33.191.254110.33.191.25516,382
136110.33.192.0/18110.33.192.1 to 110.33.255.254110.33.255.25516,382
137110.34.0.0/18110.34.0.1 to 110.34.63.254110.34.63.25516,382
138110.34.64.0/18110.34.64.1 to 110.34.127.254110.34.127.25516,382
139110.34.128.0/18110.34.128.1 to 110.34.191.254110.34.191.25516,382
140110.34.192.0/18110.34.192.1 to 110.34.255.254110.34.255.25516,382
141110.35.0.0/18110.35.0.1 to 110.35.63.254110.35.63.25516,382
142110.35.64.0/18110.35.64.1 to 110.35.127.254110.35.127.25516,382
143110.35.128.0/18110.35.128.1 to 110.35.191.254110.35.191.25516,382
144110.35.192.0/18110.35.192.1 to 110.35.255.254110.35.255.25516,382
145110.36.0.0/18110.36.0.1 to 110.36.63.254110.36.63.25516,382
146110.36.64.0/18110.36.64.1 to 110.36.127.254110.36.127.25516,382
147110.36.128.0/18110.36.128.1 to 110.36.191.254110.36.191.25516,382
148110.36.192.0/18110.36.192.1 to 110.36.255.254110.36.255.25516,382
149110.37.0.0/18110.37.0.1 to 110.37.63.254110.37.63.25516,382
150110.37.64.0/18110.37.64.1 to 110.37.127.254110.37.127.25516,382
151110.37.128.0/18110.37.128.1 to 110.37.191.254110.37.191.25516,382
152110.37.192.0/18110.37.192.1 to 110.37.255.254110.37.255.25516,382
153110.38.0.0/18110.38.0.1 to 110.38.63.254110.38.63.25516,382
154110.38.64.0/18110.38.64.1 to 110.38.127.254110.38.127.25516,382
155110.38.128.0/18110.38.128.1 to 110.38.191.254110.38.191.25516,382
156110.38.192.0/18110.38.192.1 to 110.38.255.254110.38.255.25516,382
157110.39.0.0/18110.39.0.1 to 110.39.63.254110.39.63.25516,382
158110.39.64.0/18110.39.64.1 to 110.39.127.254110.39.127.25516,382
159110.39.128.0/18110.39.128.1 to 110.39.191.254110.39.191.25516,382
160110.39.192.0/18110.39.192.1 to 110.39.255.254110.39.255.25516,382
161110.40.0.0/18110.40.0.1 to 110.40.63.254110.40.63.25516,382
162110.40.64.0/18110.40.64.1 to 110.40.127.254110.40.127.25516,382
163110.40.128.0/18110.40.128.1 to 110.40.191.254110.40.191.25516,382
164110.40.192.0/18110.40.192.1 to 110.40.255.254110.40.255.25516,382
165110.41.0.0/18110.41.0.1 to 110.41.63.254110.41.63.25516,382
166110.41.64.0/18110.41.64.1 to 110.41.127.254110.41.127.25516,382
167110.41.128.0/18110.41.128.1 to 110.41.191.254110.41.191.25516,382
168110.41.192.0/18110.41.192.1 to 110.41.255.254110.41.255.25516,382
169110.42.0.0/18110.42.0.1 to 110.42.63.254110.42.63.25516,382
170110.42.64.0/18110.42.64.1 to 110.42.127.254110.42.127.25516,382
171110.42.128.0/18110.42.128.1 to 110.42.191.254110.42.191.25516,382
172110.42.192.0/18110.42.192.1 to 110.42.255.254110.42.255.25516,382
173110.43.0.0/18110.43.0.1 to 110.43.63.254110.43.63.25516,382
174110.43.64.0/18110.43.64.1 to 110.43.127.254110.43.127.25516,382
175110.43.128.0/18110.43.128.1 to 110.43.191.254110.43.191.25516,382
176110.43.192.0/18110.43.192.1 to 110.43.255.254110.43.255.25516,382
177110.44.0.0/18110.44.0.1 to 110.44.63.254110.44.63.25516,382
178110.44.64.0/18110.44.64.1 to 110.44.127.254110.44.127.25516,382
179110.44.128.0/18110.44.128.1 to 110.44.191.254110.44.191.25516,382
180110.44.192.0/18110.44.192.1 to 110.44.255.254110.44.255.25516,382
181110.45.0.0/18110.45.0.1 to 110.45.63.254110.45.63.25516,382
182110.45.64.0/18110.45.64.1 to 110.45.127.254110.45.127.25516,382
183110.45.128.0/18110.45.128.1 to 110.45.191.254110.45.191.25516,382
184110.45.192.0/18110.45.192.1 to 110.45.255.254110.45.255.25516,382
185110.46.0.0/18110.46.0.1 to 110.46.63.254110.46.63.25516,382
186110.46.64.0/18110.46.64.1 to 110.46.127.254110.46.127.25516,382
187110.46.128.0/18110.46.128.1 to 110.46.191.254110.46.191.25516,382
188110.46.192.0/18110.46.192.1 to 110.46.255.254110.46.255.25516,382
189110.47.0.0/18110.47.0.1 to 110.47.63.254110.47.63.25516,382
190110.47.64.0/18110.47.64.1 to 110.47.127.254110.47.127.25516,382
191110.47.128.0/18110.47.128.1 to 110.47.191.254110.47.191.25516,382
192110.47.192.0/18110.47.192.1 to 110.47.255.254110.47.255.25516,382
193110.48.0.0/18110.48.0.1 to 110.48.63.254110.48.63.25516,382
194110.48.64.0/18110.48.64.1 to 110.48.127.254110.48.127.25516,382
195110.48.128.0/18110.48.128.1 to 110.48.191.254110.48.191.25516,382
196110.48.192.0/18110.48.192.1 to 110.48.255.254110.48.255.25516,382
197110.49.0.0/18110.49.0.1 to 110.49.63.254110.49.63.25516,382
198110.49.64.0/18110.49.64.1 to 110.49.127.254110.49.127.25516,382
199110.49.128.0/18110.49.128.1 to 110.49.191.254110.49.191.25516,382
200110.49.192.0/18110.49.192.1 to 110.49.255.254110.49.255.25516,382
201110.50.0.0/18110.50.0.1 to 110.50.63.254110.50.63.25516,382
202110.50.64.0/18110.50.64.1 to 110.50.127.254110.50.127.25516,382
203110.50.128.0/18110.50.128.1 to 110.50.191.254110.50.191.25516,382
204110.50.192.0/18110.50.192.1 to 110.50.255.254110.50.255.25516,382
205110.51.0.0/18110.51.0.1 to 110.51.63.254110.51.63.25516,382
206110.51.64.0/18110.51.64.1 to 110.51.127.254110.51.127.25516,382
207110.51.128.0/18110.51.128.1 to 110.51.191.254110.51.191.25516,382
208110.51.192.0/18110.51.192.1 to 110.51.255.254110.51.255.25516,382
209110.52.0.0/18110.52.0.1 to 110.52.63.254110.52.63.25516,382
210110.52.64.0/18110.52.64.1 to 110.52.127.254110.52.127.25516,382
211110.52.128.0/18110.52.128.1 to 110.52.191.254110.52.191.25516,382
212110.52.192.0/18110.52.192.1 to 110.52.255.254110.52.255.25516,382
213110.53.0.0/18110.53.0.1 to 110.53.63.254110.53.63.25516,382
214110.53.64.0/18110.53.64.1 to 110.53.127.254110.53.127.25516,382
215110.53.128.0/18110.53.128.1 to 110.53.191.254110.53.191.25516,382
216110.53.192.0/18110.53.192.1 to 110.53.255.254110.53.255.25516,382
217110.54.0.0/18110.54.0.1 to 110.54.63.254110.54.63.25516,382
218110.54.64.0/18110.54.64.1 to 110.54.127.254110.54.127.25516,382
219110.54.128.0/18110.54.128.1 to 110.54.191.254110.54.191.25516,382
220110.54.192.0/18110.54.192.1 to 110.54.255.254110.54.255.25516,382
221110.55.0.0/18110.55.0.1 to 110.55.63.254110.55.63.25516,382
222110.55.64.0/18110.55.64.1 to 110.55.127.254110.55.127.25516,382
223110.55.128.0/18110.55.128.1 to 110.55.191.254110.55.191.25516,382
224110.55.192.0/18110.55.192.1 to 110.55.255.254110.55.255.25516,382
225110.56.0.0/18110.56.0.1 to 110.56.63.254110.56.63.25516,382
226110.56.64.0/18110.56.64.1 to 110.56.127.254110.56.127.25516,382
227110.56.128.0/18110.56.128.1 to 110.56.191.254110.56.191.25516,382
228110.56.192.0/18110.56.192.1 to 110.56.255.254110.56.255.25516,382
229110.57.0.0/18110.57.0.1 to 110.57.63.254110.57.63.25516,382
230110.57.64.0/18110.57.64.1 to 110.57.127.254110.57.127.25516,382
231110.57.128.0/18110.57.128.1 to 110.57.191.254110.57.191.25516,382
232110.57.192.0/18110.57.192.1 to 110.57.255.254110.57.255.25516,382
233110.58.0.0/18110.58.0.1 to 110.58.63.254110.58.63.25516,382
234110.58.64.0/18110.58.64.1 to 110.58.127.254110.58.127.25516,382
235110.58.128.0/18110.58.128.1 to 110.58.191.254110.58.191.25516,382
236110.58.192.0/18110.58.192.1 to 110.58.255.254110.58.255.25516,382
237110.59.0.0/18110.59.0.1 to 110.59.63.254110.59.63.25516,382
238110.59.64.0/18110.59.64.1 to 110.59.127.254110.59.127.25516,382
239110.59.128.0/18110.59.128.1 to 110.59.191.254110.59.191.25516,382
240110.59.192.0/18110.59.192.1 to 110.59.255.254110.59.255.25516,382
241110.60.0.0/18110.60.0.1 to 110.60.63.254110.60.63.25516,382
242110.60.64.0/18110.60.64.1 to 110.60.127.254110.60.127.25516,382
243110.60.128.0/18110.60.128.1 to 110.60.191.254110.60.191.25516,382
244110.60.192.0/18110.60.192.1 to 110.60.255.254110.60.255.25516,382
245110.61.0.0/18110.61.0.1 to 110.61.63.254110.61.63.25516,382
246110.61.64.0/18110.61.64.1 to 110.61.127.254110.61.127.25516,382
247110.61.128.0/18110.61.128.1 to 110.61.191.254110.61.191.25516,382
248110.61.192.0/18110.61.192.1 to 110.61.255.254110.61.255.25516,382
249110.62.0.0/18110.62.0.1 to 110.62.63.254110.62.63.25516,382
250110.62.64.0/18110.62.64.1 to 110.62.127.254110.62.127.25516,382
251110.62.128.0/18110.62.128.1 to 110.62.191.254110.62.191.25516,382
252110.62.192.0/18110.62.192.1 to 110.62.255.254110.62.255.25516,382
253110.63.0.0/18110.63.0.1 to 110.63.63.254110.63.63.25516,382
254110.63.64.0/18110.63.64.1 to 110.63.127.254110.63.127.25516,382
255110.63.128.0/18110.63.128.1 to 110.63.191.254110.63.191.25516,382
256110.63.192.0/18110.63.192.1 to 110.63.255.254110.63.255.25516,382

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.