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.

Network145.232.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
145.232.0.0
Broadcast address
145.235.255.255
First usable
145.232.0.1
Last usable
145.235.255.254
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 91E80000 · Integer 2447900672 to 2448162815
Reverse DNS zones
232.145.in-addr.arpa
233.145.in-addr.arpa
234.145.in-addr.arpa
235.145.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
Address10010001.11101000.00000000.00000000145.232.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network10010001.11101000.00000000.00000000145.232.0.0
Broadcast10010001.11101011.11111111.11111111145.235.255.255
Split into smaller subnets/22
/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)

145.232.0.0/14 makes 256 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1145.232.0.0/22145.232.0.1 to 145.232.3.254145.232.3.2551,022
2145.232.4.0/22145.232.4.1 to 145.232.7.254145.232.7.2551,022
3145.232.8.0/22145.232.8.1 to 145.232.11.254145.232.11.2551,022
4145.232.12.0/22145.232.12.1 to 145.232.15.254145.232.15.2551,022
5145.232.16.0/22145.232.16.1 to 145.232.19.254145.232.19.2551,022
6145.232.20.0/22145.232.20.1 to 145.232.23.254145.232.23.2551,022
7145.232.24.0/22145.232.24.1 to 145.232.27.254145.232.27.2551,022
8145.232.28.0/22145.232.28.1 to 145.232.31.254145.232.31.2551,022
9145.232.32.0/22145.232.32.1 to 145.232.35.254145.232.35.2551,022
10145.232.36.0/22145.232.36.1 to 145.232.39.254145.232.39.2551,022
11145.232.40.0/22145.232.40.1 to 145.232.43.254145.232.43.2551,022
12145.232.44.0/22145.232.44.1 to 145.232.47.254145.232.47.2551,022
13145.232.48.0/22145.232.48.1 to 145.232.51.254145.232.51.2551,022
14145.232.52.0/22145.232.52.1 to 145.232.55.254145.232.55.2551,022
15145.232.56.0/22145.232.56.1 to 145.232.59.254145.232.59.2551,022
16145.232.60.0/22145.232.60.1 to 145.232.63.254145.232.63.2551,022
17145.232.64.0/22145.232.64.1 to 145.232.67.254145.232.67.2551,022
18145.232.68.0/22145.232.68.1 to 145.232.71.254145.232.71.2551,022
19145.232.72.0/22145.232.72.1 to 145.232.75.254145.232.75.2551,022
20145.232.76.0/22145.232.76.1 to 145.232.79.254145.232.79.2551,022
21145.232.80.0/22145.232.80.1 to 145.232.83.254145.232.83.2551,022
22145.232.84.0/22145.232.84.1 to 145.232.87.254145.232.87.2551,022
23145.232.88.0/22145.232.88.1 to 145.232.91.254145.232.91.2551,022
24145.232.92.0/22145.232.92.1 to 145.232.95.254145.232.95.2551,022
25145.232.96.0/22145.232.96.1 to 145.232.99.254145.232.99.2551,022
26145.232.100.0/22145.232.100.1 to 145.232.103.254145.232.103.2551,022
27145.232.104.0/22145.232.104.1 to 145.232.107.254145.232.107.2551,022
28145.232.108.0/22145.232.108.1 to 145.232.111.254145.232.111.2551,022
29145.232.112.0/22145.232.112.1 to 145.232.115.254145.232.115.2551,022
30145.232.116.0/22145.232.116.1 to 145.232.119.254145.232.119.2551,022
31145.232.120.0/22145.232.120.1 to 145.232.123.254145.232.123.2551,022
32145.232.124.0/22145.232.124.1 to 145.232.127.254145.232.127.2551,022
33145.232.128.0/22145.232.128.1 to 145.232.131.254145.232.131.2551,022
34145.232.132.0/22145.232.132.1 to 145.232.135.254145.232.135.2551,022
35145.232.136.0/22145.232.136.1 to 145.232.139.254145.232.139.2551,022
36145.232.140.0/22145.232.140.1 to 145.232.143.254145.232.143.2551,022
37145.232.144.0/22145.232.144.1 to 145.232.147.254145.232.147.2551,022
38145.232.148.0/22145.232.148.1 to 145.232.151.254145.232.151.2551,022
39145.232.152.0/22145.232.152.1 to 145.232.155.254145.232.155.2551,022
40145.232.156.0/22145.232.156.1 to 145.232.159.254145.232.159.2551,022
41145.232.160.0/22145.232.160.1 to 145.232.163.254145.232.163.2551,022
42145.232.164.0/22145.232.164.1 to 145.232.167.254145.232.167.2551,022
43145.232.168.0/22145.232.168.1 to 145.232.171.254145.232.171.2551,022
44145.232.172.0/22145.232.172.1 to 145.232.175.254145.232.175.2551,022
45145.232.176.0/22145.232.176.1 to 145.232.179.254145.232.179.2551,022
46145.232.180.0/22145.232.180.1 to 145.232.183.254145.232.183.2551,022
47145.232.184.0/22145.232.184.1 to 145.232.187.254145.232.187.2551,022
48145.232.188.0/22145.232.188.1 to 145.232.191.254145.232.191.2551,022
49145.232.192.0/22145.232.192.1 to 145.232.195.254145.232.195.2551,022
50145.232.196.0/22145.232.196.1 to 145.232.199.254145.232.199.2551,022
51145.232.200.0/22145.232.200.1 to 145.232.203.254145.232.203.2551,022
52145.232.204.0/22145.232.204.1 to 145.232.207.254145.232.207.2551,022
53145.232.208.0/22145.232.208.1 to 145.232.211.254145.232.211.2551,022
54145.232.212.0/22145.232.212.1 to 145.232.215.254145.232.215.2551,022
55145.232.216.0/22145.232.216.1 to 145.232.219.254145.232.219.2551,022
56145.232.220.0/22145.232.220.1 to 145.232.223.254145.232.223.2551,022
57145.232.224.0/22145.232.224.1 to 145.232.227.254145.232.227.2551,022
58145.232.228.0/22145.232.228.1 to 145.232.231.254145.232.231.2551,022
59145.232.232.0/22145.232.232.1 to 145.232.235.254145.232.235.2551,022
60145.232.236.0/22145.232.236.1 to 145.232.239.254145.232.239.2551,022
61145.232.240.0/22145.232.240.1 to 145.232.243.254145.232.243.2551,022
62145.232.244.0/22145.232.244.1 to 145.232.247.254145.232.247.2551,022
63145.232.248.0/22145.232.248.1 to 145.232.251.254145.232.251.2551,022
64145.232.252.0/22145.232.252.1 to 145.232.255.254145.232.255.2551,022
65145.233.0.0/22145.233.0.1 to 145.233.3.254145.233.3.2551,022
66145.233.4.0/22145.233.4.1 to 145.233.7.254145.233.7.2551,022
67145.233.8.0/22145.233.8.1 to 145.233.11.254145.233.11.2551,022
68145.233.12.0/22145.233.12.1 to 145.233.15.254145.233.15.2551,022
69145.233.16.0/22145.233.16.1 to 145.233.19.254145.233.19.2551,022
70145.233.20.0/22145.233.20.1 to 145.233.23.254145.233.23.2551,022
71145.233.24.0/22145.233.24.1 to 145.233.27.254145.233.27.2551,022
72145.233.28.0/22145.233.28.1 to 145.233.31.254145.233.31.2551,022
73145.233.32.0/22145.233.32.1 to 145.233.35.254145.233.35.2551,022
74145.233.36.0/22145.233.36.1 to 145.233.39.254145.233.39.2551,022
75145.233.40.0/22145.233.40.1 to 145.233.43.254145.233.43.2551,022
76145.233.44.0/22145.233.44.1 to 145.233.47.254145.233.47.2551,022
77145.233.48.0/22145.233.48.1 to 145.233.51.254145.233.51.2551,022
78145.233.52.0/22145.233.52.1 to 145.233.55.254145.233.55.2551,022
79145.233.56.0/22145.233.56.1 to 145.233.59.254145.233.59.2551,022
80145.233.60.0/22145.233.60.1 to 145.233.63.254145.233.63.2551,022
81145.233.64.0/22145.233.64.1 to 145.233.67.254145.233.67.2551,022
82145.233.68.0/22145.233.68.1 to 145.233.71.254145.233.71.2551,022
83145.233.72.0/22145.233.72.1 to 145.233.75.254145.233.75.2551,022
84145.233.76.0/22145.233.76.1 to 145.233.79.254145.233.79.2551,022
85145.233.80.0/22145.233.80.1 to 145.233.83.254145.233.83.2551,022
86145.233.84.0/22145.233.84.1 to 145.233.87.254145.233.87.2551,022
87145.233.88.0/22145.233.88.1 to 145.233.91.254145.233.91.2551,022
88145.233.92.0/22145.233.92.1 to 145.233.95.254145.233.95.2551,022
89145.233.96.0/22145.233.96.1 to 145.233.99.254145.233.99.2551,022
90145.233.100.0/22145.233.100.1 to 145.233.103.254145.233.103.2551,022
91145.233.104.0/22145.233.104.1 to 145.233.107.254145.233.107.2551,022
92145.233.108.0/22145.233.108.1 to 145.233.111.254145.233.111.2551,022
93145.233.112.0/22145.233.112.1 to 145.233.115.254145.233.115.2551,022
94145.233.116.0/22145.233.116.1 to 145.233.119.254145.233.119.2551,022
95145.233.120.0/22145.233.120.1 to 145.233.123.254145.233.123.2551,022
96145.233.124.0/22145.233.124.1 to 145.233.127.254145.233.127.2551,022
97145.233.128.0/22145.233.128.1 to 145.233.131.254145.233.131.2551,022
98145.233.132.0/22145.233.132.1 to 145.233.135.254145.233.135.2551,022
99145.233.136.0/22145.233.136.1 to 145.233.139.254145.233.139.2551,022
100145.233.140.0/22145.233.140.1 to 145.233.143.254145.233.143.2551,022
101145.233.144.0/22145.233.144.1 to 145.233.147.254145.233.147.2551,022
102145.233.148.0/22145.233.148.1 to 145.233.151.254145.233.151.2551,022
103145.233.152.0/22145.233.152.1 to 145.233.155.254145.233.155.2551,022
104145.233.156.0/22145.233.156.1 to 145.233.159.254145.233.159.2551,022
105145.233.160.0/22145.233.160.1 to 145.233.163.254145.233.163.2551,022
106145.233.164.0/22145.233.164.1 to 145.233.167.254145.233.167.2551,022
107145.233.168.0/22145.233.168.1 to 145.233.171.254145.233.171.2551,022
108145.233.172.0/22145.233.172.1 to 145.233.175.254145.233.175.2551,022
109145.233.176.0/22145.233.176.1 to 145.233.179.254145.233.179.2551,022
110145.233.180.0/22145.233.180.1 to 145.233.183.254145.233.183.2551,022
111145.233.184.0/22145.233.184.1 to 145.233.187.254145.233.187.2551,022
112145.233.188.0/22145.233.188.1 to 145.233.191.254145.233.191.2551,022
113145.233.192.0/22145.233.192.1 to 145.233.195.254145.233.195.2551,022
114145.233.196.0/22145.233.196.1 to 145.233.199.254145.233.199.2551,022
115145.233.200.0/22145.233.200.1 to 145.233.203.254145.233.203.2551,022
116145.233.204.0/22145.233.204.1 to 145.233.207.254145.233.207.2551,022
117145.233.208.0/22145.233.208.1 to 145.233.211.254145.233.211.2551,022
118145.233.212.0/22145.233.212.1 to 145.233.215.254145.233.215.2551,022
119145.233.216.0/22145.233.216.1 to 145.233.219.254145.233.219.2551,022
120145.233.220.0/22145.233.220.1 to 145.233.223.254145.233.223.2551,022
121145.233.224.0/22145.233.224.1 to 145.233.227.254145.233.227.2551,022
122145.233.228.0/22145.233.228.1 to 145.233.231.254145.233.231.2551,022
123145.233.232.0/22145.233.232.1 to 145.233.235.254145.233.235.2551,022
124145.233.236.0/22145.233.236.1 to 145.233.239.254145.233.239.2551,022
125145.233.240.0/22145.233.240.1 to 145.233.243.254145.233.243.2551,022
126145.233.244.0/22145.233.244.1 to 145.233.247.254145.233.247.2551,022
127145.233.248.0/22145.233.248.1 to 145.233.251.254145.233.251.2551,022
128145.233.252.0/22145.233.252.1 to 145.233.255.254145.233.255.2551,022
129145.234.0.0/22145.234.0.1 to 145.234.3.254145.234.3.2551,022
130145.234.4.0/22145.234.4.1 to 145.234.7.254145.234.7.2551,022
131145.234.8.0/22145.234.8.1 to 145.234.11.254145.234.11.2551,022
132145.234.12.0/22145.234.12.1 to 145.234.15.254145.234.15.2551,022
133145.234.16.0/22145.234.16.1 to 145.234.19.254145.234.19.2551,022
134145.234.20.0/22145.234.20.1 to 145.234.23.254145.234.23.2551,022
135145.234.24.0/22145.234.24.1 to 145.234.27.254145.234.27.2551,022
136145.234.28.0/22145.234.28.1 to 145.234.31.254145.234.31.2551,022
137145.234.32.0/22145.234.32.1 to 145.234.35.254145.234.35.2551,022
138145.234.36.0/22145.234.36.1 to 145.234.39.254145.234.39.2551,022
139145.234.40.0/22145.234.40.1 to 145.234.43.254145.234.43.2551,022
140145.234.44.0/22145.234.44.1 to 145.234.47.254145.234.47.2551,022
141145.234.48.0/22145.234.48.1 to 145.234.51.254145.234.51.2551,022
142145.234.52.0/22145.234.52.1 to 145.234.55.254145.234.55.2551,022
143145.234.56.0/22145.234.56.1 to 145.234.59.254145.234.59.2551,022
144145.234.60.0/22145.234.60.1 to 145.234.63.254145.234.63.2551,022
145145.234.64.0/22145.234.64.1 to 145.234.67.254145.234.67.2551,022
146145.234.68.0/22145.234.68.1 to 145.234.71.254145.234.71.2551,022
147145.234.72.0/22145.234.72.1 to 145.234.75.254145.234.75.2551,022
148145.234.76.0/22145.234.76.1 to 145.234.79.254145.234.79.2551,022
149145.234.80.0/22145.234.80.1 to 145.234.83.254145.234.83.2551,022
150145.234.84.0/22145.234.84.1 to 145.234.87.254145.234.87.2551,022
151145.234.88.0/22145.234.88.1 to 145.234.91.254145.234.91.2551,022
152145.234.92.0/22145.234.92.1 to 145.234.95.254145.234.95.2551,022
153145.234.96.0/22145.234.96.1 to 145.234.99.254145.234.99.2551,022
154145.234.100.0/22145.234.100.1 to 145.234.103.254145.234.103.2551,022
155145.234.104.0/22145.234.104.1 to 145.234.107.254145.234.107.2551,022
156145.234.108.0/22145.234.108.1 to 145.234.111.254145.234.111.2551,022
157145.234.112.0/22145.234.112.1 to 145.234.115.254145.234.115.2551,022
158145.234.116.0/22145.234.116.1 to 145.234.119.254145.234.119.2551,022
159145.234.120.0/22145.234.120.1 to 145.234.123.254145.234.123.2551,022
160145.234.124.0/22145.234.124.1 to 145.234.127.254145.234.127.2551,022
161145.234.128.0/22145.234.128.1 to 145.234.131.254145.234.131.2551,022
162145.234.132.0/22145.234.132.1 to 145.234.135.254145.234.135.2551,022
163145.234.136.0/22145.234.136.1 to 145.234.139.254145.234.139.2551,022
164145.234.140.0/22145.234.140.1 to 145.234.143.254145.234.143.2551,022
165145.234.144.0/22145.234.144.1 to 145.234.147.254145.234.147.2551,022
166145.234.148.0/22145.234.148.1 to 145.234.151.254145.234.151.2551,022
167145.234.152.0/22145.234.152.1 to 145.234.155.254145.234.155.2551,022
168145.234.156.0/22145.234.156.1 to 145.234.159.254145.234.159.2551,022
169145.234.160.0/22145.234.160.1 to 145.234.163.254145.234.163.2551,022
170145.234.164.0/22145.234.164.1 to 145.234.167.254145.234.167.2551,022
171145.234.168.0/22145.234.168.1 to 145.234.171.254145.234.171.2551,022
172145.234.172.0/22145.234.172.1 to 145.234.175.254145.234.175.2551,022
173145.234.176.0/22145.234.176.1 to 145.234.179.254145.234.179.2551,022
174145.234.180.0/22145.234.180.1 to 145.234.183.254145.234.183.2551,022
175145.234.184.0/22145.234.184.1 to 145.234.187.254145.234.187.2551,022
176145.234.188.0/22145.234.188.1 to 145.234.191.254145.234.191.2551,022
177145.234.192.0/22145.234.192.1 to 145.234.195.254145.234.195.2551,022
178145.234.196.0/22145.234.196.1 to 145.234.199.254145.234.199.2551,022
179145.234.200.0/22145.234.200.1 to 145.234.203.254145.234.203.2551,022
180145.234.204.0/22145.234.204.1 to 145.234.207.254145.234.207.2551,022
181145.234.208.0/22145.234.208.1 to 145.234.211.254145.234.211.2551,022
182145.234.212.0/22145.234.212.1 to 145.234.215.254145.234.215.2551,022
183145.234.216.0/22145.234.216.1 to 145.234.219.254145.234.219.2551,022
184145.234.220.0/22145.234.220.1 to 145.234.223.254145.234.223.2551,022
185145.234.224.0/22145.234.224.1 to 145.234.227.254145.234.227.2551,022
186145.234.228.0/22145.234.228.1 to 145.234.231.254145.234.231.2551,022
187145.234.232.0/22145.234.232.1 to 145.234.235.254145.234.235.2551,022
188145.234.236.0/22145.234.236.1 to 145.234.239.254145.234.239.2551,022
189145.234.240.0/22145.234.240.1 to 145.234.243.254145.234.243.2551,022
190145.234.244.0/22145.234.244.1 to 145.234.247.254145.234.247.2551,022
191145.234.248.0/22145.234.248.1 to 145.234.251.254145.234.251.2551,022
192145.234.252.0/22145.234.252.1 to 145.234.255.254145.234.255.2551,022
193145.235.0.0/22145.235.0.1 to 145.235.3.254145.235.3.2551,022
194145.235.4.0/22145.235.4.1 to 145.235.7.254145.235.7.2551,022
195145.235.8.0/22145.235.8.1 to 145.235.11.254145.235.11.2551,022
196145.235.12.0/22145.235.12.1 to 145.235.15.254145.235.15.2551,022
197145.235.16.0/22145.235.16.1 to 145.235.19.254145.235.19.2551,022
198145.235.20.0/22145.235.20.1 to 145.235.23.254145.235.23.2551,022
199145.235.24.0/22145.235.24.1 to 145.235.27.254145.235.27.2551,022
200145.235.28.0/22145.235.28.1 to 145.235.31.254145.235.31.2551,022
201145.235.32.0/22145.235.32.1 to 145.235.35.254145.235.35.2551,022
202145.235.36.0/22145.235.36.1 to 145.235.39.254145.235.39.2551,022
203145.235.40.0/22145.235.40.1 to 145.235.43.254145.235.43.2551,022
204145.235.44.0/22145.235.44.1 to 145.235.47.254145.235.47.2551,022
205145.235.48.0/22145.235.48.1 to 145.235.51.254145.235.51.2551,022
206145.235.52.0/22145.235.52.1 to 145.235.55.254145.235.55.2551,022
207145.235.56.0/22145.235.56.1 to 145.235.59.254145.235.59.2551,022
208145.235.60.0/22145.235.60.1 to 145.235.63.254145.235.63.2551,022
209145.235.64.0/22145.235.64.1 to 145.235.67.254145.235.67.2551,022
210145.235.68.0/22145.235.68.1 to 145.235.71.254145.235.71.2551,022
211145.235.72.0/22145.235.72.1 to 145.235.75.254145.235.75.2551,022
212145.235.76.0/22145.235.76.1 to 145.235.79.254145.235.79.2551,022
213145.235.80.0/22145.235.80.1 to 145.235.83.254145.235.83.2551,022
214145.235.84.0/22145.235.84.1 to 145.235.87.254145.235.87.2551,022
215145.235.88.0/22145.235.88.1 to 145.235.91.254145.235.91.2551,022
216145.235.92.0/22145.235.92.1 to 145.235.95.254145.235.95.2551,022
217145.235.96.0/22145.235.96.1 to 145.235.99.254145.235.99.2551,022
218145.235.100.0/22145.235.100.1 to 145.235.103.254145.235.103.2551,022
219145.235.104.0/22145.235.104.1 to 145.235.107.254145.235.107.2551,022
220145.235.108.0/22145.235.108.1 to 145.235.111.254145.235.111.2551,022
221145.235.112.0/22145.235.112.1 to 145.235.115.254145.235.115.2551,022
222145.235.116.0/22145.235.116.1 to 145.235.119.254145.235.119.2551,022
223145.235.120.0/22145.235.120.1 to 145.235.123.254145.235.123.2551,022
224145.235.124.0/22145.235.124.1 to 145.235.127.254145.235.127.2551,022
225145.235.128.0/22145.235.128.1 to 145.235.131.254145.235.131.2551,022
226145.235.132.0/22145.235.132.1 to 145.235.135.254145.235.135.2551,022
227145.235.136.0/22145.235.136.1 to 145.235.139.254145.235.139.2551,022
228145.235.140.0/22145.235.140.1 to 145.235.143.254145.235.143.2551,022
229145.235.144.0/22145.235.144.1 to 145.235.147.254145.235.147.2551,022
230145.235.148.0/22145.235.148.1 to 145.235.151.254145.235.151.2551,022
231145.235.152.0/22145.235.152.1 to 145.235.155.254145.235.155.2551,022
232145.235.156.0/22145.235.156.1 to 145.235.159.254145.235.159.2551,022
233145.235.160.0/22145.235.160.1 to 145.235.163.254145.235.163.2551,022
234145.235.164.0/22145.235.164.1 to 145.235.167.254145.235.167.2551,022
235145.235.168.0/22145.235.168.1 to 145.235.171.254145.235.171.2551,022
236145.235.172.0/22145.235.172.1 to 145.235.175.254145.235.175.2551,022
237145.235.176.0/22145.235.176.1 to 145.235.179.254145.235.179.2551,022
238145.235.180.0/22145.235.180.1 to 145.235.183.254145.235.183.2551,022
239145.235.184.0/22145.235.184.1 to 145.235.187.254145.235.187.2551,022
240145.235.188.0/22145.235.188.1 to 145.235.191.254145.235.191.2551,022
241145.235.192.0/22145.235.192.1 to 145.235.195.254145.235.195.2551,022
242145.235.196.0/22145.235.196.1 to 145.235.199.254145.235.199.2551,022
243145.235.200.0/22145.235.200.1 to 145.235.203.254145.235.203.2551,022
244145.235.204.0/22145.235.204.1 to 145.235.207.254145.235.207.2551,022
245145.235.208.0/22145.235.208.1 to 145.235.211.254145.235.211.2551,022
246145.235.212.0/22145.235.212.1 to 145.235.215.254145.235.215.2551,022
247145.235.216.0/22145.235.216.1 to 145.235.219.254145.235.219.2551,022
248145.235.220.0/22145.235.220.1 to 145.235.223.254145.235.223.2551,022
249145.235.224.0/22145.235.224.1 to 145.235.227.254145.235.227.2551,022
250145.235.228.0/22145.235.228.1 to 145.235.231.254145.235.231.2551,022
251145.235.232.0/22145.235.232.1 to 145.235.235.254145.235.235.2551,022
252145.235.236.0/22145.235.236.1 to 145.235.239.254145.235.239.2551,022
253145.235.240.0/22145.235.240.1 to 145.235.243.254145.235.243.2551,022
254145.235.244.0/22145.235.244.1 to 145.235.247.254145.235.247.2551,022
255145.235.248.0/22145.235.248.1 to 145.235.251.254145.235.251.2551,022
256145.235.252.0/22145.235.252.1 to 145.235.255.254145.235.255.2551,022

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.