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.

Network148.136.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
148.136.0.0
Broadcast address
148.139.255.255
First usable
148.136.0.1
Last usable
148.139.255.254
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 94880000 · Integer 2491940864 to 2492203007
Reverse DNS zones
136.148.in-addr.arpa
137.148.in-addr.arpa
138.148.in-addr.arpa
139.148.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
Address10010100.10001000.00000000.00000000148.136.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network10010100.10001000.00000000.00000000148.136.0.0
Broadcast10010100.10001011.11111111.11111111148.139.255.255
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)

148.136.0.0/14 makes 256 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1148.136.0.0/22148.136.0.1 to 148.136.3.254148.136.3.2551,022
2148.136.4.0/22148.136.4.1 to 148.136.7.254148.136.7.2551,022
3148.136.8.0/22148.136.8.1 to 148.136.11.254148.136.11.2551,022
4148.136.12.0/22148.136.12.1 to 148.136.15.254148.136.15.2551,022
5148.136.16.0/22148.136.16.1 to 148.136.19.254148.136.19.2551,022
6148.136.20.0/22148.136.20.1 to 148.136.23.254148.136.23.2551,022
7148.136.24.0/22148.136.24.1 to 148.136.27.254148.136.27.2551,022
8148.136.28.0/22148.136.28.1 to 148.136.31.254148.136.31.2551,022
9148.136.32.0/22148.136.32.1 to 148.136.35.254148.136.35.2551,022
10148.136.36.0/22148.136.36.1 to 148.136.39.254148.136.39.2551,022
11148.136.40.0/22148.136.40.1 to 148.136.43.254148.136.43.2551,022
12148.136.44.0/22148.136.44.1 to 148.136.47.254148.136.47.2551,022
13148.136.48.0/22148.136.48.1 to 148.136.51.254148.136.51.2551,022
14148.136.52.0/22148.136.52.1 to 148.136.55.254148.136.55.2551,022
15148.136.56.0/22148.136.56.1 to 148.136.59.254148.136.59.2551,022
16148.136.60.0/22148.136.60.1 to 148.136.63.254148.136.63.2551,022
17148.136.64.0/22148.136.64.1 to 148.136.67.254148.136.67.2551,022
18148.136.68.0/22148.136.68.1 to 148.136.71.254148.136.71.2551,022
19148.136.72.0/22148.136.72.1 to 148.136.75.254148.136.75.2551,022
20148.136.76.0/22148.136.76.1 to 148.136.79.254148.136.79.2551,022
21148.136.80.0/22148.136.80.1 to 148.136.83.254148.136.83.2551,022
22148.136.84.0/22148.136.84.1 to 148.136.87.254148.136.87.2551,022
23148.136.88.0/22148.136.88.1 to 148.136.91.254148.136.91.2551,022
24148.136.92.0/22148.136.92.1 to 148.136.95.254148.136.95.2551,022
25148.136.96.0/22148.136.96.1 to 148.136.99.254148.136.99.2551,022
26148.136.100.0/22148.136.100.1 to 148.136.103.254148.136.103.2551,022
27148.136.104.0/22148.136.104.1 to 148.136.107.254148.136.107.2551,022
28148.136.108.0/22148.136.108.1 to 148.136.111.254148.136.111.2551,022
29148.136.112.0/22148.136.112.1 to 148.136.115.254148.136.115.2551,022
30148.136.116.0/22148.136.116.1 to 148.136.119.254148.136.119.2551,022
31148.136.120.0/22148.136.120.1 to 148.136.123.254148.136.123.2551,022
32148.136.124.0/22148.136.124.1 to 148.136.127.254148.136.127.2551,022
33148.136.128.0/22148.136.128.1 to 148.136.131.254148.136.131.2551,022
34148.136.132.0/22148.136.132.1 to 148.136.135.254148.136.135.2551,022
35148.136.136.0/22148.136.136.1 to 148.136.139.254148.136.139.2551,022
36148.136.140.0/22148.136.140.1 to 148.136.143.254148.136.143.2551,022
37148.136.144.0/22148.136.144.1 to 148.136.147.254148.136.147.2551,022
38148.136.148.0/22148.136.148.1 to 148.136.151.254148.136.151.2551,022
39148.136.152.0/22148.136.152.1 to 148.136.155.254148.136.155.2551,022
40148.136.156.0/22148.136.156.1 to 148.136.159.254148.136.159.2551,022
41148.136.160.0/22148.136.160.1 to 148.136.163.254148.136.163.2551,022
42148.136.164.0/22148.136.164.1 to 148.136.167.254148.136.167.2551,022
43148.136.168.0/22148.136.168.1 to 148.136.171.254148.136.171.2551,022
44148.136.172.0/22148.136.172.1 to 148.136.175.254148.136.175.2551,022
45148.136.176.0/22148.136.176.1 to 148.136.179.254148.136.179.2551,022
46148.136.180.0/22148.136.180.1 to 148.136.183.254148.136.183.2551,022
47148.136.184.0/22148.136.184.1 to 148.136.187.254148.136.187.2551,022
48148.136.188.0/22148.136.188.1 to 148.136.191.254148.136.191.2551,022
49148.136.192.0/22148.136.192.1 to 148.136.195.254148.136.195.2551,022
50148.136.196.0/22148.136.196.1 to 148.136.199.254148.136.199.2551,022
51148.136.200.0/22148.136.200.1 to 148.136.203.254148.136.203.2551,022
52148.136.204.0/22148.136.204.1 to 148.136.207.254148.136.207.2551,022
53148.136.208.0/22148.136.208.1 to 148.136.211.254148.136.211.2551,022
54148.136.212.0/22148.136.212.1 to 148.136.215.254148.136.215.2551,022
55148.136.216.0/22148.136.216.1 to 148.136.219.254148.136.219.2551,022
56148.136.220.0/22148.136.220.1 to 148.136.223.254148.136.223.2551,022
57148.136.224.0/22148.136.224.1 to 148.136.227.254148.136.227.2551,022
58148.136.228.0/22148.136.228.1 to 148.136.231.254148.136.231.2551,022
59148.136.232.0/22148.136.232.1 to 148.136.235.254148.136.235.2551,022
60148.136.236.0/22148.136.236.1 to 148.136.239.254148.136.239.2551,022
61148.136.240.0/22148.136.240.1 to 148.136.243.254148.136.243.2551,022
62148.136.244.0/22148.136.244.1 to 148.136.247.254148.136.247.2551,022
63148.136.248.0/22148.136.248.1 to 148.136.251.254148.136.251.2551,022
64148.136.252.0/22148.136.252.1 to 148.136.255.254148.136.255.2551,022
65148.137.0.0/22148.137.0.1 to 148.137.3.254148.137.3.2551,022
66148.137.4.0/22148.137.4.1 to 148.137.7.254148.137.7.2551,022
67148.137.8.0/22148.137.8.1 to 148.137.11.254148.137.11.2551,022
68148.137.12.0/22148.137.12.1 to 148.137.15.254148.137.15.2551,022
69148.137.16.0/22148.137.16.1 to 148.137.19.254148.137.19.2551,022
70148.137.20.0/22148.137.20.1 to 148.137.23.254148.137.23.2551,022
71148.137.24.0/22148.137.24.1 to 148.137.27.254148.137.27.2551,022
72148.137.28.0/22148.137.28.1 to 148.137.31.254148.137.31.2551,022
73148.137.32.0/22148.137.32.1 to 148.137.35.254148.137.35.2551,022
74148.137.36.0/22148.137.36.1 to 148.137.39.254148.137.39.2551,022
75148.137.40.0/22148.137.40.1 to 148.137.43.254148.137.43.2551,022
76148.137.44.0/22148.137.44.1 to 148.137.47.254148.137.47.2551,022
77148.137.48.0/22148.137.48.1 to 148.137.51.254148.137.51.2551,022
78148.137.52.0/22148.137.52.1 to 148.137.55.254148.137.55.2551,022
79148.137.56.0/22148.137.56.1 to 148.137.59.254148.137.59.2551,022
80148.137.60.0/22148.137.60.1 to 148.137.63.254148.137.63.2551,022
81148.137.64.0/22148.137.64.1 to 148.137.67.254148.137.67.2551,022
82148.137.68.0/22148.137.68.1 to 148.137.71.254148.137.71.2551,022
83148.137.72.0/22148.137.72.1 to 148.137.75.254148.137.75.2551,022
84148.137.76.0/22148.137.76.1 to 148.137.79.254148.137.79.2551,022
85148.137.80.0/22148.137.80.1 to 148.137.83.254148.137.83.2551,022
86148.137.84.0/22148.137.84.1 to 148.137.87.254148.137.87.2551,022
87148.137.88.0/22148.137.88.1 to 148.137.91.254148.137.91.2551,022
88148.137.92.0/22148.137.92.1 to 148.137.95.254148.137.95.2551,022
89148.137.96.0/22148.137.96.1 to 148.137.99.254148.137.99.2551,022
90148.137.100.0/22148.137.100.1 to 148.137.103.254148.137.103.2551,022
91148.137.104.0/22148.137.104.1 to 148.137.107.254148.137.107.2551,022
92148.137.108.0/22148.137.108.1 to 148.137.111.254148.137.111.2551,022
93148.137.112.0/22148.137.112.1 to 148.137.115.254148.137.115.2551,022
94148.137.116.0/22148.137.116.1 to 148.137.119.254148.137.119.2551,022
95148.137.120.0/22148.137.120.1 to 148.137.123.254148.137.123.2551,022
96148.137.124.0/22148.137.124.1 to 148.137.127.254148.137.127.2551,022
97148.137.128.0/22148.137.128.1 to 148.137.131.254148.137.131.2551,022
98148.137.132.0/22148.137.132.1 to 148.137.135.254148.137.135.2551,022
99148.137.136.0/22148.137.136.1 to 148.137.139.254148.137.139.2551,022
100148.137.140.0/22148.137.140.1 to 148.137.143.254148.137.143.2551,022
101148.137.144.0/22148.137.144.1 to 148.137.147.254148.137.147.2551,022
102148.137.148.0/22148.137.148.1 to 148.137.151.254148.137.151.2551,022
103148.137.152.0/22148.137.152.1 to 148.137.155.254148.137.155.2551,022
104148.137.156.0/22148.137.156.1 to 148.137.159.254148.137.159.2551,022
105148.137.160.0/22148.137.160.1 to 148.137.163.254148.137.163.2551,022
106148.137.164.0/22148.137.164.1 to 148.137.167.254148.137.167.2551,022
107148.137.168.0/22148.137.168.1 to 148.137.171.254148.137.171.2551,022
108148.137.172.0/22148.137.172.1 to 148.137.175.254148.137.175.2551,022
109148.137.176.0/22148.137.176.1 to 148.137.179.254148.137.179.2551,022
110148.137.180.0/22148.137.180.1 to 148.137.183.254148.137.183.2551,022
111148.137.184.0/22148.137.184.1 to 148.137.187.254148.137.187.2551,022
112148.137.188.0/22148.137.188.1 to 148.137.191.254148.137.191.2551,022
113148.137.192.0/22148.137.192.1 to 148.137.195.254148.137.195.2551,022
114148.137.196.0/22148.137.196.1 to 148.137.199.254148.137.199.2551,022
115148.137.200.0/22148.137.200.1 to 148.137.203.254148.137.203.2551,022
116148.137.204.0/22148.137.204.1 to 148.137.207.254148.137.207.2551,022
117148.137.208.0/22148.137.208.1 to 148.137.211.254148.137.211.2551,022
118148.137.212.0/22148.137.212.1 to 148.137.215.254148.137.215.2551,022
119148.137.216.0/22148.137.216.1 to 148.137.219.254148.137.219.2551,022
120148.137.220.0/22148.137.220.1 to 148.137.223.254148.137.223.2551,022
121148.137.224.0/22148.137.224.1 to 148.137.227.254148.137.227.2551,022
122148.137.228.0/22148.137.228.1 to 148.137.231.254148.137.231.2551,022
123148.137.232.0/22148.137.232.1 to 148.137.235.254148.137.235.2551,022
124148.137.236.0/22148.137.236.1 to 148.137.239.254148.137.239.2551,022
125148.137.240.0/22148.137.240.1 to 148.137.243.254148.137.243.2551,022
126148.137.244.0/22148.137.244.1 to 148.137.247.254148.137.247.2551,022
127148.137.248.0/22148.137.248.1 to 148.137.251.254148.137.251.2551,022
128148.137.252.0/22148.137.252.1 to 148.137.255.254148.137.255.2551,022
129148.138.0.0/22148.138.0.1 to 148.138.3.254148.138.3.2551,022
130148.138.4.0/22148.138.4.1 to 148.138.7.254148.138.7.2551,022
131148.138.8.0/22148.138.8.1 to 148.138.11.254148.138.11.2551,022
132148.138.12.0/22148.138.12.1 to 148.138.15.254148.138.15.2551,022
133148.138.16.0/22148.138.16.1 to 148.138.19.254148.138.19.2551,022
134148.138.20.0/22148.138.20.1 to 148.138.23.254148.138.23.2551,022
135148.138.24.0/22148.138.24.1 to 148.138.27.254148.138.27.2551,022
136148.138.28.0/22148.138.28.1 to 148.138.31.254148.138.31.2551,022
137148.138.32.0/22148.138.32.1 to 148.138.35.254148.138.35.2551,022
138148.138.36.0/22148.138.36.1 to 148.138.39.254148.138.39.2551,022
139148.138.40.0/22148.138.40.1 to 148.138.43.254148.138.43.2551,022
140148.138.44.0/22148.138.44.1 to 148.138.47.254148.138.47.2551,022
141148.138.48.0/22148.138.48.1 to 148.138.51.254148.138.51.2551,022
142148.138.52.0/22148.138.52.1 to 148.138.55.254148.138.55.2551,022
143148.138.56.0/22148.138.56.1 to 148.138.59.254148.138.59.2551,022
144148.138.60.0/22148.138.60.1 to 148.138.63.254148.138.63.2551,022
145148.138.64.0/22148.138.64.1 to 148.138.67.254148.138.67.2551,022
146148.138.68.0/22148.138.68.1 to 148.138.71.254148.138.71.2551,022
147148.138.72.0/22148.138.72.1 to 148.138.75.254148.138.75.2551,022
148148.138.76.0/22148.138.76.1 to 148.138.79.254148.138.79.2551,022
149148.138.80.0/22148.138.80.1 to 148.138.83.254148.138.83.2551,022
150148.138.84.0/22148.138.84.1 to 148.138.87.254148.138.87.2551,022
151148.138.88.0/22148.138.88.1 to 148.138.91.254148.138.91.2551,022
152148.138.92.0/22148.138.92.1 to 148.138.95.254148.138.95.2551,022
153148.138.96.0/22148.138.96.1 to 148.138.99.254148.138.99.2551,022
154148.138.100.0/22148.138.100.1 to 148.138.103.254148.138.103.2551,022
155148.138.104.0/22148.138.104.1 to 148.138.107.254148.138.107.2551,022
156148.138.108.0/22148.138.108.1 to 148.138.111.254148.138.111.2551,022
157148.138.112.0/22148.138.112.1 to 148.138.115.254148.138.115.2551,022
158148.138.116.0/22148.138.116.1 to 148.138.119.254148.138.119.2551,022
159148.138.120.0/22148.138.120.1 to 148.138.123.254148.138.123.2551,022
160148.138.124.0/22148.138.124.1 to 148.138.127.254148.138.127.2551,022
161148.138.128.0/22148.138.128.1 to 148.138.131.254148.138.131.2551,022
162148.138.132.0/22148.138.132.1 to 148.138.135.254148.138.135.2551,022
163148.138.136.0/22148.138.136.1 to 148.138.139.254148.138.139.2551,022
164148.138.140.0/22148.138.140.1 to 148.138.143.254148.138.143.2551,022
165148.138.144.0/22148.138.144.1 to 148.138.147.254148.138.147.2551,022
166148.138.148.0/22148.138.148.1 to 148.138.151.254148.138.151.2551,022
167148.138.152.0/22148.138.152.1 to 148.138.155.254148.138.155.2551,022
168148.138.156.0/22148.138.156.1 to 148.138.159.254148.138.159.2551,022
169148.138.160.0/22148.138.160.1 to 148.138.163.254148.138.163.2551,022
170148.138.164.0/22148.138.164.1 to 148.138.167.254148.138.167.2551,022
171148.138.168.0/22148.138.168.1 to 148.138.171.254148.138.171.2551,022
172148.138.172.0/22148.138.172.1 to 148.138.175.254148.138.175.2551,022
173148.138.176.0/22148.138.176.1 to 148.138.179.254148.138.179.2551,022
174148.138.180.0/22148.138.180.1 to 148.138.183.254148.138.183.2551,022
175148.138.184.0/22148.138.184.1 to 148.138.187.254148.138.187.2551,022
176148.138.188.0/22148.138.188.1 to 148.138.191.254148.138.191.2551,022
177148.138.192.0/22148.138.192.1 to 148.138.195.254148.138.195.2551,022
178148.138.196.0/22148.138.196.1 to 148.138.199.254148.138.199.2551,022
179148.138.200.0/22148.138.200.1 to 148.138.203.254148.138.203.2551,022
180148.138.204.0/22148.138.204.1 to 148.138.207.254148.138.207.2551,022
181148.138.208.0/22148.138.208.1 to 148.138.211.254148.138.211.2551,022
182148.138.212.0/22148.138.212.1 to 148.138.215.254148.138.215.2551,022
183148.138.216.0/22148.138.216.1 to 148.138.219.254148.138.219.2551,022
184148.138.220.0/22148.138.220.1 to 148.138.223.254148.138.223.2551,022
185148.138.224.0/22148.138.224.1 to 148.138.227.254148.138.227.2551,022
186148.138.228.0/22148.138.228.1 to 148.138.231.254148.138.231.2551,022
187148.138.232.0/22148.138.232.1 to 148.138.235.254148.138.235.2551,022
188148.138.236.0/22148.138.236.1 to 148.138.239.254148.138.239.2551,022
189148.138.240.0/22148.138.240.1 to 148.138.243.254148.138.243.2551,022
190148.138.244.0/22148.138.244.1 to 148.138.247.254148.138.247.2551,022
191148.138.248.0/22148.138.248.1 to 148.138.251.254148.138.251.2551,022
192148.138.252.0/22148.138.252.1 to 148.138.255.254148.138.255.2551,022
193148.139.0.0/22148.139.0.1 to 148.139.3.254148.139.3.2551,022
194148.139.4.0/22148.139.4.1 to 148.139.7.254148.139.7.2551,022
195148.139.8.0/22148.139.8.1 to 148.139.11.254148.139.11.2551,022
196148.139.12.0/22148.139.12.1 to 148.139.15.254148.139.15.2551,022
197148.139.16.0/22148.139.16.1 to 148.139.19.254148.139.19.2551,022
198148.139.20.0/22148.139.20.1 to 148.139.23.254148.139.23.2551,022
199148.139.24.0/22148.139.24.1 to 148.139.27.254148.139.27.2551,022
200148.139.28.0/22148.139.28.1 to 148.139.31.254148.139.31.2551,022
201148.139.32.0/22148.139.32.1 to 148.139.35.254148.139.35.2551,022
202148.139.36.0/22148.139.36.1 to 148.139.39.254148.139.39.2551,022
203148.139.40.0/22148.139.40.1 to 148.139.43.254148.139.43.2551,022
204148.139.44.0/22148.139.44.1 to 148.139.47.254148.139.47.2551,022
205148.139.48.0/22148.139.48.1 to 148.139.51.254148.139.51.2551,022
206148.139.52.0/22148.139.52.1 to 148.139.55.254148.139.55.2551,022
207148.139.56.0/22148.139.56.1 to 148.139.59.254148.139.59.2551,022
208148.139.60.0/22148.139.60.1 to 148.139.63.254148.139.63.2551,022
209148.139.64.0/22148.139.64.1 to 148.139.67.254148.139.67.2551,022
210148.139.68.0/22148.139.68.1 to 148.139.71.254148.139.71.2551,022
211148.139.72.0/22148.139.72.1 to 148.139.75.254148.139.75.2551,022
212148.139.76.0/22148.139.76.1 to 148.139.79.254148.139.79.2551,022
213148.139.80.0/22148.139.80.1 to 148.139.83.254148.139.83.2551,022
214148.139.84.0/22148.139.84.1 to 148.139.87.254148.139.87.2551,022
215148.139.88.0/22148.139.88.1 to 148.139.91.254148.139.91.2551,022
216148.139.92.0/22148.139.92.1 to 148.139.95.254148.139.95.2551,022
217148.139.96.0/22148.139.96.1 to 148.139.99.254148.139.99.2551,022
218148.139.100.0/22148.139.100.1 to 148.139.103.254148.139.103.2551,022
219148.139.104.0/22148.139.104.1 to 148.139.107.254148.139.107.2551,022
220148.139.108.0/22148.139.108.1 to 148.139.111.254148.139.111.2551,022
221148.139.112.0/22148.139.112.1 to 148.139.115.254148.139.115.2551,022
222148.139.116.0/22148.139.116.1 to 148.139.119.254148.139.119.2551,022
223148.139.120.0/22148.139.120.1 to 148.139.123.254148.139.123.2551,022
224148.139.124.0/22148.139.124.1 to 148.139.127.254148.139.127.2551,022
225148.139.128.0/22148.139.128.1 to 148.139.131.254148.139.131.2551,022
226148.139.132.0/22148.139.132.1 to 148.139.135.254148.139.135.2551,022
227148.139.136.0/22148.139.136.1 to 148.139.139.254148.139.139.2551,022
228148.139.140.0/22148.139.140.1 to 148.139.143.254148.139.143.2551,022
229148.139.144.0/22148.139.144.1 to 148.139.147.254148.139.147.2551,022
230148.139.148.0/22148.139.148.1 to 148.139.151.254148.139.151.2551,022
231148.139.152.0/22148.139.152.1 to 148.139.155.254148.139.155.2551,022
232148.139.156.0/22148.139.156.1 to 148.139.159.254148.139.159.2551,022
233148.139.160.0/22148.139.160.1 to 148.139.163.254148.139.163.2551,022
234148.139.164.0/22148.139.164.1 to 148.139.167.254148.139.167.2551,022
235148.139.168.0/22148.139.168.1 to 148.139.171.254148.139.171.2551,022
236148.139.172.0/22148.139.172.1 to 148.139.175.254148.139.175.2551,022
237148.139.176.0/22148.139.176.1 to 148.139.179.254148.139.179.2551,022
238148.139.180.0/22148.139.180.1 to 148.139.183.254148.139.183.2551,022
239148.139.184.0/22148.139.184.1 to 148.139.187.254148.139.187.2551,022
240148.139.188.0/22148.139.188.1 to 148.139.191.254148.139.191.2551,022
241148.139.192.0/22148.139.192.1 to 148.139.195.254148.139.195.2551,022
242148.139.196.0/22148.139.196.1 to 148.139.199.254148.139.199.2551,022
243148.139.200.0/22148.139.200.1 to 148.139.203.254148.139.203.2551,022
244148.139.204.0/22148.139.204.1 to 148.139.207.254148.139.207.2551,022
245148.139.208.0/22148.139.208.1 to 148.139.211.254148.139.211.2551,022
246148.139.212.0/22148.139.212.1 to 148.139.215.254148.139.215.2551,022
247148.139.216.0/22148.139.216.1 to 148.139.219.254148.139.219.2551,022
248148.139.220.0/22148.139.220.1 to 148.139.223.254148.139.223.2551,022
249148.139.224.0/22148.139.224.1 to 148.139.227.254148.139.227.2551,022
250148.139.228.0/22148.139.228.1 to 148.139.231.254148.139.231.2551,022
251148.139.232.0/22148.139.232.1 to 148.139.235.254148.139.235.2551,022
252148.139.236.0/22148.139.236.1 to 148.139.239.254148.139.239.2551,022
253148.139.240.0/22148.139.240.1 to 148.139.243.254148.139.243.2551,022
254148.139.244.0/22148.139.244.1 to 148.139.247.254148.139.247.2551,022
255148.139.248.0/22148.139.248.1 to 148.139.251.254148.139.251.2551,022
256148.139.252.0/22148.139.252.1 to 148.139.255.254148.139.255.2551,022

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.