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.

Network254.160.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
254.160.0.0
Broadcast address
254.191.255.255
First usable
254.160.0.1
Last usable
254.191.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FEA00000 · Integer 4271898624 to 4273995775
Reverse DNS zones
160.254.in-addr.arpa
161.254.in-addr.arpa
162.254.in-addr.arpa
163.254.in-addr.arpa
164.254.in-addr.arpa
165.254.in-addr.arpa
166.254.in-addr.arpa
167.254.in-addr.arpa
168.254.in-addr.arpa
169.254.in-addr.arpa
170.254.in-addr.arpa
171.254.in-addr.arpa
172.254.in-addr.arpa
173.254.in-addr.arpa
174.254.in-addr.arpa
175.254.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111110.10100000.00000000.00000000254.160.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11111110.10100000.00000000.00000000254.160.0.0
Broadcast11111110.10111111.11111111.11111111254.191.255.255
Split into smaller subnets/22
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

254.160.0.0/11 makes 2,048 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.160.0.0/22254.160.0.1 to 254.160.3.254254.160.3.2551,022
2254.160.4.0/22254.160.4.1 to 254.160.7.254254.160.7.2551,022
3254.160.8.0/22254.160.8.1 to 254.160.11.254254.160.11.2551,022
4254.160.12.0/22254.160.12.1 to 254.160.15.254254.160.15.2551,022
5254.160.16.0/22254.160.16.1 to 254.160.19.254254.160.19.2551,022
6254.160.20.0/22254.160.20.1 to 254.160.23.254254.160.23.2551,022
7254.160.24.0/22254.160.24.1 to 254.160.27.254254.160.27.2551,022
8254.160.28.0/22254.160.28.1 to 254.160.31.254254.160.31.2551,022
9254.160.32.0/22254.160.32.1 to 254.160.35.254254.160.35.2551,022
10254.160.36.0/22254.160.36.1 to 254.160.39.254254.160.39.2551,022
11254.160.40.0/22254.160.40.1 to 254.160.43.254254.160.43.2551,022
12254.160.44.0/22254.160.44.1 to 254.160.47.254254.160.47.2551,022
13254.160.48.0/22254.160.48.1 to 254.160.51.254254.160.51.2551,022
14254.160.52.0/22254.160.52.1 to 254.160.55.254254.160.55.2551,022
15254.160.56.0/22254.160.56.1 to 254.160.59.254254.160.59.2551,022
16254.160.60.0/22254.160.60.1 to 254.160.63.254254.160.63.2551,022
17254.160.64.0/22254.160.64.1 to 254.160.67.254254.160.67.2551,022
18254.160.68.0/22254.160.68.1 to 254.160.71.254254.160.71.2551,022
19254.160.72.0/22254.160.72.1 to 254.160.75.254254.160.75.2551,022
20254.160.76.0/22254.160.76.1 to 254.160.79.254254.160.79.2551,022
21254.160.80.0/22254.160.80.1 to 254.160.83.254254.160.83.2551,022
22254.160.84.0/22254.160.84.1 to 254.160.87.254254.160.87.2551,022
23254.160.88.0/22254.160.88.1 to 254.160.91.254254.160.91.2551,022
24254.160.92.0/22254.160.92.1 to 254.160.95.254254.160.95.2551,022
25254.160.96.0/22254.160.96.1 to 254.160.99.254254.160.99.2551,022
26254.160.100.0/22254.160.100.1 to 254.160.103.254254.160.103.2551,022
27254.160.104.0/22254.160.104.1 to 254.160.107.254254.160.107.2551,022
28254.160.108.0/22254.160.108.1 to 254.160.111.254254.160.111.2551,022
29254.160.112.0/22254.160.112.1 to 254.160.115.254254.160.115.2551,022
30254.160.116.0/22254.160.116.1 to 254.160.119.254254.160.119.2551,022
31254.160.120.0/22254.160.120.1 to 254.160.123.254254.160.123.2551,022
32254.160.124.0/22254.160.124.1 to 254.160.127.254254.160.127.2551,022
33254.160.128.0/22254.160.128.1 to 254.160.131.254254.160.131.2551,022
34254.160.132.0/22254.160.132.1 to 254.160.135.254254.160.135.2551,022
35254.160.136.0/22254.160.136.1 to 254.160.139.254254.160.139.2551,022
36254.160.140.0/22254.160.140.1 to 254.160.143.254254.160.143.2551,022
37254.160.144.0/22254.160.144.1 to 254.160.147.254254.160.147.2551,022
38254.160.148.0/22254.160.148.1 to 254.160.151.254254.160.151.2551,022
39254.160.152.0/22254.160.152.1 to 254.160.155.254254.160.155.2551,022
40254.160.156.0/22254.160.156.1 to 254.160.159.254254.160.159.2551,022
41254.160.160.0/22254.160.160.1 to 254.160.163.254254.160.163.2551,022
42254.160.164.0/22254.160.164.1 to 254.160.167.254254.160.167.2551,022
43254.160.168.0/22254.160.168.1 to 254.160.171.254254.160.171.2551,022
44254.160.172.0/22254.160.172.1 to 254.160.175.254254.160.175.2551,022
45254.160.176.0/22254.160.176.1 to 254.160.179.254254.160.179.2551,022
46254.160.180.0/22254.160.180.1 to 254.160.183.254254.160.183.2551,022
47254.160.184.0/22254.160.184.1 to 254.160.187.254254.160.187.2551,022
48254.160.188.0/22254.160.188.1 to 254.160.191.254254.160.191.2551,022
49254.160.192.0/22254.160.192.1 to 254.160.195.254254.160.195.2551,022
50254.160.196.0/22254.160.196.1 to 254.160.199.254254.160.199.2551,022
51254.160.200.0/22254.160.200.1 to 254.160.203.254254.160.203.2551,022
52254.160.204.0/22254.160.204.1 to 254.160.207.254254.160.207.2551,022
53254.160.208.0/22254.160.208.1 to 254.160.211.254254.160.211.2551,022
54254.160.212.0/22254.160.212.1 to 254.160.215.254254.160.215.2551,022
55254.160.216.0/22254.160.216.1 to 254.160.219.254254.160.219.2551,022
56254.160.220.0/22254.160.220.1 to 254.160.223.254254.160.223.2551,022
57254.160.224.0/22254.160.224.1 to 254.160.227.254254.160.227.2551,022
58254.160.228.0/22254.160.228.1 to 254.160.231.254254.160.231.2551,022
59254.160.232.0/22254.160.232.1 to 254.160.235.254254.160.235.2551,022
60254.160.236.0/22254.160.236.1 to 254.160.239.254254.160.239.2551,022
61254.160.240.0/22254.160.240.1 to 254.160.243.254254.160.243.2551,022
62254.160.244.0/22254.160.244.1 to 254.160.247.254254.160.247.2551,022
63254.160.248.0/22254.160.248.1 to 254.160.251.254254.160.251.2551,022
64254.160.252.0/22254.160.252.1 to 254.160.255.254254.160.255.2551,022
65254.161.0.0/22254.161.0.1 to 254.161.3.254254.161.3.2551,022
66254.161.4.0/22254.161.4.1 to 254.161.7.254254.161.7.2551,022
67254.161.8.0/22254.161.8.1 to 254.161.11.254254.161.11.2551,022
68254.161.12.0/22254.161.12.1 to 254.161.15.254254.161.15.2551,022
69254.161.16.0/22254.161.16.1 to 254.161.19.254254.161.19.2551,022
70254.161.20.0/22254.161.20.1 to 254.161.23.254254.161.23.2551,022
71254.161.24.0/22254.161.24.1 to 254.161.27.254254.161.27.2551,022
72254.161.28.0/22254.161.28.1 to 254.161.31.254254.161.31.2551,022
73254.161.32.0/22254.161.32.1 to 254.161.35.254254.161.35.2551,022
74254.161.36.0/22254.161.36.1 to 254.161.39.254254.161.39.2551,022
75254.161.40.0/22254.161.40.1 to 254.161.43.254254.161.43.2551,022
76254.161.44.0/22254.161.44.1 to 254.161.47.254254.161.47.2551,022
77254.161.48.0/22254.161.48.1 to 254.161.51.254254.161.51.2551,022
78254.161.52.0/22254.161.52.1 to 254.161.55.254254.161.55.2551,022
79254.161.56.0/22254.161.56.1 to 254.161.59.254254.161.59.2551,022
80254.161.60.0/22254.161.60.1 to 254.161.63.254254.161.63.2551,022
81254.161.64.0/22254.161.64.1 to 254.161.67.254254.161.67.2551,022
82254.161.68.0/22254.161.68.1 to 254.161.71.254254.161.71.2551,022
83254.161.72.0/22254.161.72.1 to 254.161.75.254254.161.75.2551,022
84254.161.76.0/22254.161.76.1 to 254.161.79.254254.161.79.2551,022
85254.161.80.0/22254.161.80.1 to 254.161.83.254254.161.83.2551,022
86254.161.84.0/22254.161.84.1 to 254.161.87.254254.161.87.2551,022
87254.161.88.0/22254.161.88.1 to 254.161.91.254254.161.91.2551,022
88254.161.92.0/22254.161.92.1 to 254.161.95.254254.161.95.2551,022
89254.161.96.0/22254.161.96.1 to 254.161.99.254254.161.99.2551,022
90254.161.100.0/22254.161.100.1 to 254.161.103.254254.161.103.2551,022
91254.161.104.0/22254.161.104.1 to 254.161.107.254254.161.107.2551,022
92254.161.108.0/22254.161.108.1 to 254.161.111.254254.161.111.2551,022
93254.161.112.0/22254.161.112.1 to 254.161.115.254254.161.115.2551,022
94254.161.116.0/22254.161.116.1 to 254.161.119.254254.161.119.2551,022
95254.161.120.0/22254.161.120.1 to 254.161.123.254254.161.123.2551,022
96254.161.124.0/22254.161.124.1 to 254.161.127.254254.161.127.2551,022
97254.161.128.0/22254.161.128.1 to 254.161.131.254254.161.131.2551,022
98254.161.132.0/22254.161.132.1 to 254.161.135.254254.161.135.2551,022
99254.161.136.0/22254.161.136.1 to 254.161.139.254254.161.139.2551,022
100254.161.140.0/22254.161.140.1 to 254.161.143.254254.161.143.2551,022
101254.161.144.0/22254.161.144.1 to 254.161.147.254254.161.147.2551,022
102254.161.148.0/22254.161.148.1 to 254.161.151.254254.161.151.2551,022
103254.161.152.0/22254.161.152.1 to 254.161.155.254254.161.155.2551,022
104254.161.156.0/22254.161.156.1 to 254.161.159.254254.161.159.2551,022
105254.161.160.0/22254.161.160.1 to 254.161.163.254254.161.163.2551,022
106254.161.164.0/22254.161.164.1 to 254.161.167.254254.161.167.2551,022
107254.161.168.0/22254.161.168.1 to 254.161.171.254254.161.171.2551,022
108254.161.172.0/22254.161.172.1 to 254.161.175.254254.161.175.2551,022
109254.161.176.0/22254.161.176.1 to 254.161.179.254254.161.179.2551,022
110254.161.180.0/22254.161.180.1 to 254.161.183.254254.161.183.2551,022
111254.161.184.0/22254.161.184.1 to 254.161.187.254254.161.187.2551,022
112254.161.188.0/22254.161.188.1 to 254.161.191.254254.161.191.2551,022
113254.161.192.0/22254.161.192.1 to 254.161.195.254254.161.195.2551,022
114254.161.196.0/22254.161.196.1 to 254.161.199.254254.161.199.2551,022
115254.161.200.0/22254.161.200.1 to 254.161.203.254254.161.203.2551,022
116254.161.204.0/22254.161.204.1 to 254.161.207.254254.161.207.2551,022
117254.161.208.0/22254.161.208.1 to 254.161.211.254254.161.211.2551,022
118254.161.212.0/22254.161.212.1 to 254.161.215.254254.161.215.2551,022
119254.161.216.0/22254.161.216.1 to 254.161.219.254254.161.219.2551,022
120254.161.220.0/22254.161.220.1 to 254.161.223.254254.161.223.2551,022
121254.161.224.0/22254.161.224.1 to 254.161.227.254254.161.227.2551,022
122254.161.228.0/22254.161.228.1 to 254.161.231.254254.161.231.2551,022
123254.161.232.0/22254.161.232.1 to 254.161.235.254254.161.235.2551,022
124254.161.236.0/22254.161.236.1 to 254.161.239.254254.161.239.2551,022
125254.161.240.0/22254.161.240.1 to 254.161.243.254254.161.243.2551,022
126254.161.244.0/22254.161.244.1 to 254.161.247.254254.161.247.2551,022
127254.161.248.0/22254.161.248.1 to 254.161.251.254254.161.251.2551,022
128254.161.252.0/22254.161.252.1 to 254.161.255.254254.161.255.2551,022
129254.162.0.0/22254.162.0.1 to 254.162.3.254254.162.3.2551,022
130254.162.4.0/22254.162.4.1 to 254.162.7.254254.162.7.2551,022
131254.162.8.0/22254.162.8.1 to 254.162.11.254254.162.11.2551,022
132254.162.12.0/22254.162.12.1 to 254.162.15.254254.162.15.2551,022
133254.162.16.0/22254.162.16.1 to 254.162.19.254254.162.19.2551,022
134254.162.20.0/22254.162.20.1 to 254.162.23.254254.162.23.2551,022
135254.162.24.0/22254.162.24.1 to 254.162.27.254254.162.27.2551,022
136254.162.28.0/22254.162.28.1 to 254.162.31.254254.162.31.2551,022
137254.162.32.0/22254.162.32.1 to 254.162.35.254254.162.35.2551,022
138254.162.36.0/22254.162.36.1 to 254.162.39.254254.162.39.2551,022
139254.162.40.0/22254.162.40.1 to 254.162.43.254254.162.43.2551,022
140254.162.44.0/22254.162.44.1 to 254.162.47.254254.162.47.2551,022
141254.162.48.0/22254.162.48.1 to 254.162.51.254254.162.51.2551,022
142254.162.52.0/22254.162.52.1 to 254.162.55.254254.162.55.2551,022
143254.162.56.0/22254.162.56.1 to 254.162.59.254254.162.59.2551,022
144254.162.60.0/22254.162.60.1 to 254.162.63.254254.162.63.2551,022
145254.162.64.0/22254.162.64.1 to 254.162.67.254254.162.67.2551,022
146254.162.68.0/22254.162.68.1 to 254.162.71.254254.162.71.2551,022
147254.162.72.0/22254.162.72.1 to 254.162.75.254254.162.75.2551,022
148254.162.76.0/22254.162.76.1 to 254.162.79.254254.162.79.2551,022
149254.162.80.0/22254.162.80.1 to 254.162.83.254254.162.83.2551,022
150254.162.84.0/22254.162.84.1 to 254.162.87.254254.162.87.2551,022
151254.162.88.0/22254.162.88.1 to 254.162.91.254254.162.91.2551,022
152254.162.92.0/22254.162.92.1 to 254.162.95.254254.162.95.2551,022
153254.162.96.0/22254.162.96.1 to 254.162.99.254254.162.99.2551,022
154254.162.100.0/22254.162.100.1 to 254.162.103.254254.162.103.2551,022
155254.162.104.0/22254.162.104.1 to 254.162.107.254254.162.107.2551,022
156254.162.108.0/22254.162.108.1 to 254.162.111.254254.162.111.2551,022
157254.162.112.0/22254.162.112.1 to 254.162.115.254254.162.115.2551,022
158254.162.116.0/22254.162.116.1 to 254.162.119.254254.162.119.2551,022
159254.162.120.0/22254.162.120.1 to 254.162.123.254254.162.123.2551,022
160254.162.124.0/22254.162.124.1 to 254.162.127.254254.162.127.2551,022
161254.162.128.0/22254.162.128.1 to 254.162.131.254254.162.131.2551,022
162254.162.132.0/22254.162.132.1 to 254.162.135.254254.162.135.2551,022
163254.162.136.0/22254.162.136.1 to 254.162.139.254254.162.139.2551,022
164254.162.140.0/22254.162.140.1 to 254.162.143.254254.162.143.2551,022
165254.162.144.0/22254.162.144.1 to 254.162.147.254254.162.147.2551,022
166254.162.148.0/22254.162.148.1 to 254.162.151.254254.162.151.2551,022
167254.162.152.0/22254.162.152.1 to 254.162.155.254254.162.155.2551,022
168254.162.156.0/22254.162.156.1 to 254.162.159.254254.162.159.2551,022
169254.162.160.0/22254.162.160.1 to 254.162.163.254254.162.163.2551,022
170254.162.164.0/22254.162.164.1 to 254.162.167.254254.162.167.2551,022
171254.162.168.0/22254.162.168.1 to 254.162.171.254254.162.171.2551,022
172254.162.172.0/22254.162.172.1 to 254.162.175.254254.162.175.2551,022
173254.162.176.0/22254.162.176.1 to 254.162.179.254254.162.179.2551,022
174254.162.180.0/22254.162.180.1 to 254.162.183.254254.162.183.2551,022
175254.162.184.0/22254.162.184.1 to 254.162.187.254254.162.187.2551,022
176254.162.188.0/22254.162.188.1 to 254.162.191.254254.162.191.2551,022
177254.162.192.0/22254.162.192.1 to 254.162.195.254254.162.195.2551,022
178254.162.196.0/22254.162.196.1 to 254.162.199.254254.162.199.2551,022
179254.162.200.0/22254.162.200.1 to 254.162.203.254254.162.203.2551,022
180254.162.204.0/22254.162.204.1 to 254.162.207.254254.162.207.2551,022
181254.162.208.0/22254.162.208.1 to 254.162.211.254254.162.211.2551,022
182254.162.212.0/22254.162.212.1 to 254.162.215.254254.162.215.2551,022
183254.162.216.0/22254.162.216.1 to 254.162.219.254254.162.219.2551,022
184254.162.220.0/22254.162.220.1 to 254.162.223.254254.162.223.2551,022
185254.162.224.0/22254.162.224.1 to 254.162.227.254254.162.227.2551,022
186254.162.228.0/22254.162.228.1 to 254.162.231.254254.162.231.2551,022
187254.162.232.0/22254.162.232.1 to 254.162.235.254254.162.235.2551,022
188254.162.236.0/22254.162.236.1 to 254.162.239.254254.162.239.2551,022
189254.162.240.0/22254.162.240.1 to 254.162.243.254254.162.243.2551,022
190254.162.244.0/22254.162.244.1 to 254.162.247.254254.162.247.2551,022
191254.162.248.0/22254.162.248.1 to 254.162.251.254254.162.251.2551,022
192254.162.252.0/22254.162.252.1 to 254.162.255.254254.162.255.2551,022
193254.163.0.0/22254.163.0.1 to 254.163.3.254254.163.3.2551,022
194254.163.4.0/22254.163.4.1 to 254.163.7.254254.163.7.2551,022
195254.163.8.0/22254.163.8.1 to 254.163.11.254254.163.11.2551,022
196254.163.12.0/22254.163.12.1 to 254.163.15.254254.163.15.2551,022
197254.163.16.0/22254.163.16.1 to 254.163.19.254254.163.19.2551,022
198254.163.20.0/22254.163.20.1 to 254.163.23.254254.163.23.2551,022
199254.163.24.0/22254.163.24.1 to 254.163.27.254254.163.27.2551,022
200254.163.28.0/22254.163.28.1 to 254.163.31.254254.163.31.2551,022
201254.163.32.0/22254.163.32.1 to 254.163.35.254254.163.35.2551,022
202254.163.36.0/22254.163.36.1 to 254.163.39.254254.163.39.2551,022
203254.163.40.0/22254.163.40.1 to 254.163.43.254254.163.43.2551,022
204254.163.44.0/22254.163.44.1 to 254.163.47.254254.163.47.2551,022
205254.163.48.0/22254.163.48.1 to 254.163.51.254254.163.51.2551,022
206254.163.52.0/22254.163.52.1 to 254.163.55.254254.163.55.2551,022
207254.163.56.0/22254.163.56.1 to 254.163.59.254254.163.59.2551,022
208254.163.60.0/22254.163.60.1 to 254.163.63.254254.163.63.2551,022
209254.163.64.0/22254.163.64.1 to 254.163.67.254254.163.67.2551,022
210254.163.68.0/22254.163.68.1 to 254.163.71.254254.163.71.2551,022
211254.163.72.0/22254.163.72.1 to 254.163.75.254254.163.75.2551,022
212254.163.76.0/22254.163.76.1 to 254.163.79.254254.163.79.2551,022
213254.163.80.0/22254.163.80.1 to 254.163.83.254254.163.83.2551,022
214254.163.84.0/22254.163.84.1 to 254.163.87.254254.163.87.2551,022
215254.163.88.0/22254.163.88.1 to 254.163.91.254254.163.91.2551,022
216254.163.92.0/22254.163.92.1 to 254.163.95.254254.163.95.2551,022
217254.163.96.0/22254.163.96.1 to 254.163.99.254254.163.99.2551,022
218254.163.100.0/22254.163.100.1 to 254.163.103.254254.163.103.2551,022
219254.163.104.0/22254.163.104.1 to 254.163.107.254254.163.107.2551,022
220254.163.108.0/22254.163.108.1 to 254.163.111.254254.163.111.2551,022
221254.163.112.0/22254.163.112.1 to 254.163.115.254254.163.115.2551,022
222254.163.116.0/22254.163.116.1 to 254.163.119.254254.163.119.2551,022
223254.163.120.0/22254.163.120.1 to 254.163.123.254254.163.123.2551,022
224254.163.124.0/22254.163.124.1 to 254.163.127.254254.163.127.2551,022
225254.163.128.0/22254.163.128.1 to 254.163.131.254254.163.131.2551,022
226254.163.132.0/22254.163.132.1 to 254.163.135.254254.163.135.2551,022
227254.163.136.0/22254.163.136.1 to 254.163.139.254254.163.139.2551,022
228254.163.140.0/22254.163.140.1 to 254.163.143.254254.163.143.2551,022
229254.163.144.0/22254.163.144.1 to 254.163.147.254254.163.147.2551,022
230254.163.148.0/22254.163.148.1 to 254.163.151.254254.163.151.2551,022
231254.163.152.0/22254.163.152.1 to 254.163.155.254254.163.155.2551,022
232254.163.156.0/22254.163.156.1 to 254.163.159.254254.163.159.2551,022
233254.163.160.0/22254.163.160.1 to 254.163.163.254254.163.163.2551,022
234254.163.164.0/22254.163.164.1 to 254.163.167.254254.163.167.2551,022
235254.163.168.0/22254.163.168.1 to 254.163.171.254254.163.171.2551,022
236254.163.172.0/22254.163.172.1 to 254.163.175.254254.163.175.2551,022
237254.163.176.0/22254.163.176.1 to 254.163.179.254254.163.179.2551,022
238254.163.180.0/22254.163.180.1 to 254.163.183.254254.163.183.2551,022
239254.163.184.0/22254.163.184.1 to 254.163.187.254254.163.187.2551,022
240254.163.188.0/22254.163.188.1 to 254.163.191.254254.163.191.2551,022
241254.163.192.0/22254.163.192.1 to 254.163.195.254254.163.195.2551,022
242254.163.196.0/22254.163.196.1 to 254.163.199.254254.163.199.2551,022
243254.163.200.0/22254.163.200.1 to 254.163.203.254254.163.203.2551,022
244254.163.204.0/22254.163.204.1 to 254.163.207.254254.163.207.2551,022
245254.163.208.0/22254.163.208.1 to 254.163.211.254254.163.211.2551,022
246254.163.212.0/22254.163.212.1 to 254.163.215.254254.163.215.2551,022
247254.163.216.0/22254.163.216.1 to 254.163.219.254254.163.219.2551,022
248254.163.220.0/22254.163.220.1 to 254.163.223.254254.163.223.2551,022
249254.163.224.0/22254.163.224.1 to 254.163.227.254254.163.227.2551,022
250254.163.228.0/22254.163.228.1 to 254.163.231.254254.163.231.2551,022
251254.163.232.0/22254.163.232.1 to 254.163.235.254254.163.235.2551,022
252254.163.236.0/22254.163.236.1 to 254.163.239.254254.163.239.2551,022
253254.163.240.0/22254.163.240.1 to 254.163.243.254254.163.243.2551,022
254254.163.244.0/22254.163.244.1 to 254.163.247.254254.163.247.2551,022
255254.163.248.0/22254.163.248.1 to 254.163.251.254254.163.251.2551,022
256254.163.252.0/22254.163.252.1 to 254.163.255.254254.163.255.2551,022

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.