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.

Network149.48.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
149.48.0.0
Broadcast address
149.49.255.255
First usable
149.48.0.1
Last usable
149.49.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex 95300000 · Integer 2502950912 to 2503081983
Reverse DNS zones
48.149.in-addr.arpa
49.149.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010101.00110000.00000000.00000000149.48.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10010101.00110000.00000000.00000000149.48.0.0
Broadcast10010101.00110001.11111111.11111111149.49.255.255
Split into smaller subnets/27
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

149.48.0.0/15 makes 4,096 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1149.48.0.0/27149.48.0.1 to 149.48.0.30149.48.0.3130
2149.48.0.32/27149.48.0.33 to 149.48.0.62149.48.0.6330
3149.48.0.64/27149.48.0.65 to 149.48.0.94149.48.0.9530
4149.48.0.96/27149.48.0.97 to 149.48.0.126149.48.0.12730
5149.48.0.128/27149.48.0.129 to 149.48.0.158149.48.0.15930
6149.48.0.160/27149.48.0.161 to 149.48.0.190149.48.0.19130
7149.48.0.192/27149.48.0.193 to 149.48.0.222149.48.0.22330
8149.48.0.224/27149.48.0.225 to 149.48.0.254149.48.0.25530
9149.48.1.0/27149.48.1.1 to 149.48.1.30149.48.1.3130
10149.48.1.32/27149.48.1.33 to 149.48.1.62149.48.1.6330
11149.48.1.64/27149.48.1.65 to 149.48.1.94149.48.1.9530
12149.48.1.96/27149.48.1.97 to 149.48.1.126149.48.1.12730
13149.48.1.128/27149.48.1.129 to 149.48.1.158149.48.1.15930
14149.48.1.160/27149.48.1.161 to 149.48.1.190149.48.1.19130
15149.48.1.192/27149.48.1.193 to 149.48.1.222149.48.1.22330
16149.48.1.224/27149.48.1.225 to 149.48.1.254149.48.1.25530
17149.48.2.0/27149.48.2.1 to 149.48.2.30149.48.2.3130
18149.48.2.32/27149.48.2.33 to 149.48.2.62149.48.2.6330
19149.48.2.64/27149.48.2.65 to 149.48.2.94149.48.2.9530
20149.48.2.96/27149.48.2.97 to 149.48.2.126149.48.2.12730
21149.48.2.128/27149.48.2.129 to 149.48.2.158149.48.2.15930
22149.48.2.160/27149.48.2.161 to 149.48.2.190149.48.2.19130
23149.48.2.192/27149.48.2.193 to 149.48.2.222149.48.2.22330
24149.48.2.224/27149.48.2.225 to 149.48.2.254149.48.2.25530
25149.48.3.0/27149.48.3.1 to 149.48.3.30149.48.3.3130
26149.48.3.32/27149.48.3.33 to 149.48.3.62149.48.3.6330
27149.48.3.64/27149.48.3.65 to 149.48.3.94149.48.3.9530
28149.48.3.96/27149.48.3.97 to 149.48.3.126149.48.3.12730
29149.48.3.128/27149.48.3.129 to 149.48.3.158149.48.3.15930
30149.48.3.160/27149.48.3.161 to 149.48.3.190149.48.3.19130
31149.48.3.192/27149.48.3.193 to 149.48.3.222149.48.3.22330
32149.48.3.224/27149.48.3.225 to 149.48.3.254149.48.3.25530
33149.48.4.0/27149.48.4.1 to 149.48.4.30149.48.4.3130
34149.48.4.32/27149.48.4.33 to 149.48.4.62149.48.4.6330
35149.48.4.64/27149.48.4.65 to 149.48.4.94149.48.4.9530
36149.48.4.96/27149.48.4.97 to 149.48.4.126149.48.4.12730
37149.48.4.128/27149.48.4.129 to 149.48.4.158149.48.4.15930
38149.48.4.160/27149.48.4.161 to 149.48.4.190149.48.4.19130
39149.48.4.192/27149.48.4.193 to 149.48.4.222149.48.4.22330
40149.48.4.224/27149.48.4.225 to 149.48.4.254149.48.4.25530
41149.48.5.0/27149.48.5.1 to 149.48.5.30149.48.5.3130
42149.48.5.32/27149.48.5.33 to 149.48.5.62149.48.5.6330
43149.48.5.64/27149.48.5.65 to 149.48.5.94149.48.5.9530
44149.48.5.96/27149.48.5.97 to 149.48.5.126149.48.5.12730
45149.48.5.128/27149.48.5.129 to 149.48.5.158149.48.5.15930
46149.48.5.160/27149.48.5.161 to 149.48.5.190149.48.5.19130
47149.48.5.192/27149.48.5.193 to 149.48.5.222149.48.5.22330
48149.48.5.224/27149.48.5.225 to 149.48.5.254149.48.5.25530
49149.48.6.0/27149.48.6.1 to 149.48.6.30149.48.6.3130
50149.48.6.32/27149.48.6.33 to 149.48.6.62149.48.6.6330
51149.48.6.64/27149.48.6.65 to 149.48.6.94149.48.6.9530
52149.48.6.96/27149.48.6.97 to 149.48.6.126149.48.6.12730
53149.48.6.128/27149.48.6.129 to 149.48.6.158149.48.6.15930
54149.48.6.160/27149.48.6.161 to 149.48.6.190149.48.6.19130
55149.48.6.192/27149.48.6.193 to 149.48.6.222149.48.6.22330
56149.48.6.224/27149.48.6.225 to 149.48.6.254149.48.6.25530
57149.48.7.0/27149.48.7.1 to 149.48.7.30149.48.7.3130
58149.48.7.32/27149.48.7.33 to 149.48.7.62149.48.7.6330
59149.48.7.64/27149.48.7.65 to 149.48.7.94149.48.7.9530
60149.48.7.96/27149.48.7.97 to 149.48.7.126149.48.7.12730
61149.48.7.128/27149.48.7.129 to 149.48.7.158149.48.7.15930
62149.48.7.160/27149.48.7.161 to 149.48.7.190149.48.7.19130
63149.48.7.192/27149.48.7.193 to 149.48.7.222149.48.7.22330
64149.48.7.224/27149.48.7.225 to 149.48.7.254149.48.7.25530
65149.48.8.0/27149.48.8.1 to 149.48.8.30149.48.8.3130
66149.48.8.32/27149.48.8.33 to 149.48.8.62149.48.8.6330
67149.48.8.64/27149.48.8.65 to 149.48.8.94149.48.8.9530
68149.48.8.96/27149.48.8.97 to 149.48.8.126149.48.8.12730
69149.48.8.128/27149.48.8.129 to 149.48.8.158149.48.8.15930
70149.48.8.160/27149.48.8.161 to 149.48.8.190149.48.8.19130
71149.48.8.192/27149.48.8.193 to 149.48.8.222149.48.8.22330
72149.48.8.224/27149.48.8.225 to 149.48.8.254149.48.8.25530
73149.48.9.0/27149.48.9.1 to 149.48.9.30149.48.9.3130
74149.48.9.32/27149.48.9.33 to 149.48.9.62149.48.9.6330
75149.48.9.64/27149.48.9.65 to 149.48.9.94149.48.9.9530
76149.48.9.96/27149.48.9.97 to 149.48.9.126149.48.9.12730
77149.48.9.128/27149.48.9.129 to 149.48.9.158149.48.9.15930
78149.48.9.160/27149.48.9.161 to 149.48.9.190149.48.9.19130
79149.48.9.192/27149.48.9.193 to 149.48.9.222149.48.9.22330
80149.48.9.224/27149.48.9.225 to 149.48.9.254149.48.9.25530
81149.48.10.0/27149.48.10.1 to 149.48.10.30149.48.10.3130
82149.48.10.32/27149.48.10.33 to 149.48.10.62149.48.10.6330
83149.48.10.64/27149.48.10.65 to 149.48.10.94149.48.10.9530
84149.48.10.96/27149.48.10.97 to 149.48.10.126149.48.10.12730
85149.48.10.128/27149.48.10.129 to 149.48.10.158149.48.10.15930
86149.48.10.160/27149.48.10.161 to 149.48.10.190149.48.10.19130
87149.48.10.192/27149.48.10.193 to 149.48.10.222149.48.10.22330
88149.48.10.224/27149.48.10.225 to 149.48.10.254149.48.10.25530
89149.48.11.0/27149.48.11.1 to 149.48.11.30149.48.11.3130
90149.48.11.32/27149.48.11.33 to 149.48.11.62149.48.11.6330
91149.48.11.64/27149.48.11.65 to 149.48.11.94149.48.11.9530
92149.48.11.96/27149.48.11.97 to 149.48.11.126149.48.11.12730
93149.48.11.128/27149.48.11.129 to 149.48.11.158149.48.11.15930
94149.48.11.160/27149.48.11.161 to 149.48.11.190149.48.11.19130
95149.48.11.192/27149.48.11.193 to 149.48.11.222149.48.11.22330
96149.48.11.224/27149.48.11.225 to 149.48.11.254149.48.11.25530
97149.48.12.0/27149.48.12.1 to 149.48.12.30149.48.12.3130
98149.48.12.32/27149.48.12.33 to 149.48.12.62149.48.12.6330
99149.48.12.64/27149.48.12.65 to 149.48.12.94149.48.12.9530
100149.48.12.96/27149.48.12.97 to 149.48.12.126149.48.12.12730
101149.48.12.128/27149.48.12.129 to 149.48.12.158149.48.12.15930
102149.48.12.160/27149.48.12.161 to 149.48.12.190149.48.12.19130
103149.48.12.192/27149.48.12.193 to 149.48.12.222149.48.12.22330
104149.48.12.224/27149.48.12.225 to 149.48.12.254149.48.12.25530
105149.48.13.0/27149.48.13.1 to 149.48.13.30149.48.13.3130
106149.48.13.32/27149.48.13.33 to 149.48.13.62149.48.13.6330
107149.48.13.64/27149.48.13.65 to 149.48.13.94149.48.13.9530
108149.48.13.96/27149.48.13.97 to 149.48.13.126149.48.13.12730
109149.48.13.128/27149.48.13.129 to 149.48.13.158149.48.13.15930
110149.48.13.160/27149.48.13.161 to 149.48.13.190149.48.13.19130
111149.48.13.192/27149.48.13.193 to 149.48.13.222149.48.13.22330
112149.48.13.224/27149.48.13.225 to 149.48.13.254149.48.13.25530
113149.48.14.0/27149.48.14.1 to 149.48.14.30149.48.14.3130
114149.48.14.32/27149.48.14.33 to 149.48.14.62149.48.14.6330
115149.48.14.64/27149.48.14.65 to 149.48.14.94149.48.14.9530
116149.48.14.96/27149.48.14.97 to 149.48.14.126149.48.14.12730
117149.48.14.128/27149.48.14.129 to 149.48.14.158149.48.14.15930
118149.48.14.160/27149.48.14.161 to 149.48.14.190149.48.14.19130
119149.48.14.192/27149.48.14.193 to 149.48.14.222149.48.14.22330
120149.48.14.224/27149.48.14.225 to 149.48.14.254149.48.14.25530
121149.48.15.0/27149.48.15.1 to 149.48.15.30149.48.15.3130
122149.48.15.32/27149.48.15.33 to 149.48.15.62149.48.15.6330
123149.48.15.64/27149.48.15.65 to 149.48.15.94149.48.15.9530
124149.48.15.96/27149.48.15.97 to 149.48.15.126149.48.15.12730
125149.48.15.128/27149.48.15.129 to 149.48.15.158149.48.15.15930
126149.48.15.160/27149.48.15.161 to 149.48.15.190149.48.15.19130
127149.48.15.192/27149.48.15.193 to 149.48.15.222149.48.15.22330
128149.48.15.224/27149.48.15.225 to 149.48.15.254149.48.15.25530
129149.48.16.0/27149.48.16.1 to 149.48.16.30149.48.16.3130
130149.48.16.32/27149.48.16.33 to 149.48.16.62149.48.16.6330
131149.48.16.64/27149.48.16.65 to 149.48.16.94149.48.16.9530
132149.48.16.96/27149.48.16.97 to 149.48.16.126149.48.16.12730
133149.48.16.128/27149.48.16.129 to 149.48.16.158149.48.16.15930
134149.48.16.160/27149.48.16.161 to 149.48.16.190149.48.16.19130
135149.48.16.192/27149.48.16.193 to 149.48.16.222149.48.16.22330
136149.48.16.224/27149.48.16.225 to 149.48.16.254149.48.16.25530
137149.48.17.0/27149.48.17.1 to 149.48.17.30149.48.17.3130
138149.48.17.32/27149.48.17.33 to 149.48.17.62149.48.17.6330
139149.48.17.64/27149.48.17.65 to 149.48.17.94149.48.17.9530
140149.48.17.96/27149.48.17.97 to 149.48.17.126149.48.17.12730
141149.48.17.128/27149.48.17.129 to 149.48.17.158149.48.17.15930
142149.48.17.160/27149.48.17.161 to 149.48.17.190149.48.17.19130
143149.48.17.192/27149.48.17.193 to 149.48.17.222149.48.17.22330
144149.48.17.224/27149.48.17.225 to 149.48.17.254149.48.17.25530
145149.48.18.0/27149.48.18.1 to 149.48.18.30149.48.18.3130
146149.48.18.32/27149.48.18.33 to 149.48.18.62149.48.18.6330
147149.48.18.64/27149.48.18.65 to 149.48.18.94149.48.18.9530
148149.48.18.96/27149.48.18.97 to 149.48.18.126149.48.18.12730
149149.48.18.128/27149.48.18.129 to 149.48.18.158149.48.18.15930
150149.48.18.160/27149.48.18.161 to 149.48.18.190149.48.18.19130
151149.48.18.192/27149.48.18.193 to 149.48.18.222149.48.18.22330
152149.48.18.224/27149.48.18.225 to 149.48.18.254149.48.18.25530
153149.48.19.0/27149.48.19.1 to 149.48.19.30149.48.19.3130
154149.48.19.32/27149.48.19.33 to 149.48.19.62149.48.19.6330
155149.48.19.64/27149.48.19.65 to 149.48.19.94149.48.19.9530
156149.48.19.96/27149.48.19.97 to 149.48.19.126149.48.19.12730
157149.48.19.128/27149.48.19.129 to 149.48.19.158149.48.19.15930
158149.48.19.160/27149.48.19.161 to 149.48.19.190149.48.19.19130
159149.48.19.192/27149.48.19.193 to 149.48.19.222149.48.19.22330
160149.48.19.224/27149.48.19.225 to 149.48.19.254149.48.19.25530
161149.48.20.0/27149.48.20.1 to 149.48.20.30149.48.20.3130
162149.48.20.32/27149.48.20.33 to 149.48.20.62149.48.20.6330
163149.48.20.64/27149.48.20.65 to 149.48.20.94149.48.20.9530
164149.48.20.96/27149.48.20.97 to 149.48.20.126149.48.20.12730
165149.48.20.128/27149.48.20.129 to 149.48.20.158149.48.20.15930
166149.48.20.160/27149.48.20.161 to 149.48.20.190149.48.20.19130
167149.48.20.192/27149.48.20.193 to 149.48.20.222149.48.20.22330
168149.48.20.224/27149.48.20.225 to 149.48.20.254149.48.20.25530
169149.48.21.0/27149.48.21.1 to 149.48.21.30149.48.21.3130
170149.48.21.32/27149.48.21.33 to 149.48.21.62149.48.21.6330
171149.48.21.64/27149.48.21.65 to 149.48.21.94149.48.21.9530
172149.48.21.96/27149.48.21.97 to 149.48.21.126149.48.21.12730
173149.48.21.128/27149.48.21.129 to 149.48.21.158149.48.21.15930
174149.48.21.160/27149.48.21.161 to 149.48.21.190149.48.21.19130
175149.48.21.192/27149.48.21.193 to 149.48.21.222149.48.21.22330
176149.48.21.224/27149.48.21.225 to 149.48.21.254149.48.21.25530
177149.48.22.0/27149.48.22.1 to 149.48.22.30149.48.22.3130
178149.48.22.32/27149.48.22.33 to 149.48.22.62149.48.22.6330
179149.48.22.64/27149.48.22.65 to 149.48.22.94149.48.22.9530
180149.48.22.96/27149.48.22.97 to 149.48.22.126149.48.22.12730
181149.48.22.128/27149.48.22.129 to 149.48.22.158149.48.22.15930
182149.48.22.160/27149.48.22.161 to 149.48.22.190149.48.22.19130
183149.48.22.192/27149.48.22.193 to 149.48.22.222149.48.22.22330
184149.48.22.224/27149.48.22.225 to 149.48.22.254149.48.22.25530
185149.48.23.0/27149.48.23.1 to 149.48.23.30149.48.23.3130
186149.48.23.32/27149.48.23.33 to 149.48.23.62149.48.23.6330
187149.48.23.64/27149.48.23.65 to 149.48.23.94149.48.23.9530
188149.48.23.96/27149.48.23.97 to 149.48.23.126149.48.23.12730
189149.48.23.128/27149.48.23.129 to 149.48.23.158149.48.23.15930
190149.48.23.160/27149.48.23.161 to 149.48.23.190149.48.23.19130
191149.48.23.192/27149.48.23.193 to 149.48.23.222149.48.23.22330
192149.48.23.224/27149.48.23.225 to 149.48.23.254149.48.23.25530
193149.48.24.0/27149.48.24.1 to 149.48.24.30149.48.24.3130
194149.48.24.32/27149.48.24.33 to 149.48.24.62149.48.24.6330
195149.48.24.64/27149.48.24.65 to 149.48.24.94149.48.24.9530
196149.48.24.96/27149.48.24.97 to 149.48.24.126149.48.24.12730
197149.48.24.128/27149.48.24.129 to 149.48.24.158149.48.24.15930
198149.48.24.160/27149.48.24.161 to 149.48.24.190149.48.24.19130
199149.48.24.192/27149.48.24.193 to 149.48.24.222149.48.24.22330
200149.48.24.224/27149.48.24.225 to 149.48.24.254149.48.24.25530
201149.48.25.0/27149.48.25.1 to 149.48.25.30149.48.25.3130
202149.48.25.32/27149.48.25.33 to 149.48.25.62149.48.25.6330
203149.48.25.64/27149.48.25.65 to 149.48.25.94149.48.25.9530
204149.48.25.96/27149.48.25.97 to 149.48.25.126149.48.25.12730
205149.48.25.128/27149.48.25.129 to 149.48.25.158149.48.25.15930
206149.48.25.160/27149.48.25.161 to 149.48.25.190149.48.25.19130
207149.48.25.192/27149.48.25.193 to 149.48.25.222149.48.25.22330
208149.48.25.224/27149.48.25.225 to 149.48.25.254149.48.25.25530
209149.48.26.0/27149.48.26.1 to 149.48.26.30149.48.26.3130
210149.48.26.32/27149.48.26.33 to 149.48.26.62149.48.26.6330
211149.48.26.64/27149.48.26.65 to 149.48.26.94149.48.26.9530
212149.48.26.96/27149.48.26.97 to 149.48.26.126149.48.26.12730
213149.48.26.128/27149.48.26.129 to 149.48.26.158149.48.26.15930
214149.48.26.160/27149.48.26.161 to 149.48.26.190149.48.26.19130
215149.48.26.192/27149.48.26.193 to 149.48.26.222149.48.26.22330
216149.48.26.224/27149.48.26.225 to 149.48.26.254149.48.26.25530
217149.48.27.0/27149.48.27.1 to 149.48.27.30149.48.27.3130
218149.48.27.32/27149.48.27.33 to 149.48.27.62149.48.27.6330
219149.48.27.64/27149.48.27.65 to 149.48.27.94149.48.27.9530
220149.48.27.96/27149.48.27.97 to 149.48.27.126149.48.27.12730
221149.48.27.128/27149.48.27.129 to 149.48.27.158149.48.27.15930
222149.48.27.160/27149.48.27.161 to 149.48.27.190149.48.27.19130
223149.48.27.192/27149.48.27.193 to 149.48.27.222149.48.27.22330
224149.48.27.224/27149.48.27.225 to 149.48.27.254149.48.27.25530
225149.48.28.0/27149.48.28.1 to 149.48.28.30149.48.28.3130
226149.48.28.32/27149.48.28.33 to 149.48.28.62149.48.28.6330
227149.48.28.64/27149.48.28.65 to 149.48.28.94149.48.28.9530
228149.48.28.96/27149.48.28.97 to 149.48.28.126149.48.28.12730
229149.48.28.128/27149.48.28.129 to 149.48.28.158149.48.28.15930
230149.48.28.160/27149.48.28.161 to 149.48.28.190149.48.28.19130
231149.48.28.192/27149.48.28.193 to 149.48.28.222149.48.28.22330
232149.48.28.224/27149.48.28.225 to 149.48.28.254149.48.28.25530
233149.48.29.0/27149.48.29.1 to 149.48.29.30149.48.29.3130
234149.48.29.32/27149.48.29.33 to 149.48.29.62149.48.29.6330
235149.48.29.64/27149.48.29.65 to 149.48.29.94149.48.29.9530
236149.48.29.96/27149.48.29.97 to 149.48.29.126149.48.29.12730
237149.48.29.128/27149.48.29.129 to 149.48.29.158149.48.29.15930
238149.48.29.160/27149.48.29.161 to 149.48.29.190149.48.29.19130
239149.48.29.192/27149.48.29.193 to 149.48.29.222149.48.29.22330
240149.48.29.224/27149.48.29.225 to 149.48.29.254149.48.29.25530
241149.48.30.0/27149.48.30.1 to 149.48.30.30149.48.30.3130
242149.48.30.32/27149.48.30.33 to 149.48.30.62149.48.30.6330
243149.48.30.64/27149.48.30.65 to 149.48.30.94149.48.30.9530
244149.48.30.96/27149.48.30.97 to 149.48.30.126149.48.30.12730
245149.48.30.128/27149.48.30.129 to 149.48.30.158149.48.30.15930
246149.48.30.160/27149.48.30.161 to 149.48.30.190149.48.30.19130
247149.48.30.192/27149.48.30.193 to 149.48.30.222149.48.30.22330
248149.48.30.224/27149.48.30.225 to 149.48.30.254149.48.30.25530
249149.48.31.0/27149.48.31.1 to 149.48.31.30149.48.31.3130
250149.48.31.32/27149.48.31.33 to 149.48.31.62149.48.31.6330
251149.48.31.64/27149.48.31.65 to 149.48.31.94149.48.31.9530
252149.48.31.96/27149.48.31.97 to 149.48.31.126149.48.31.12730
253149.48.31.128/27149.48.31.129 to 149.48.31.158149.48.31.15930
254149.48.31.160/27149.48.31.161 to 149.48.31.190149.48.31.19130
255149.48.31.192/27149.48.31.193 to 149.48.31.222149.48.31.22330
256149.48.31.224/27149.48.31.225 to 149.48.31.254149.48.31.25530

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.