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.

Network158.0.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
158.0.64.0
Broadcast address
158.0.95.255
First usable
158.0.64.1
Last usable
158.0.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
B (default /16)
As numbers
Hex 9E004000 · Integer 2650816512 to 2650824703
Reverse DNS zones
64.0.158.in-addr.arpa
65.0.158.in-addr.arpa
66.0.158.in-addr.arpa
67.0.158.in-addr.arpa
68.0.158.in-addr.arpa
69.0.158.in-addr.arpa
70.0.158.in-addr.arpa
71.0.158.in-addr.arpa
72.0.158.in-addr.arpa
73.0.158.in-addr.arpa
74.0.158.in-addr.arpa
75.0.158.in-addr.arpa
76.0.158.in-addr.arpa
77.0.158.in-addr.arpa
78.0.158.in-addr.arpa
79.0.158.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011110.00000000.01000000.00000000158.0.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10011110.00000000.01000000.00000000158.0.64.0
Broadcast10011110.00000000.01011111.11111111158.0.95.255
Split into smaller subnets/30
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

158.0.64.0/19 makes 2,048 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1158.0.64.0/30158.0.64.1 to 158.0.64.2158.0.64.32
2158.0.64.4/30158.0.64.5 to 158.0.64.6158.0.64.72
3158.0.64.8/30158.0.64.9 to 158.0.64.10158.0.64.112
4158.0.64.12/30158.0.64.13 to 158.0.64.14158.0.64.152
5158.0.64.16/30158.0.64.17 to 158.0.64.18158.0.64.192
6158.0.64.20/30158.0.64.21 to 158.0.64.22158.0.64.232
7158.0.64.24/30158.0.64.25 to 158.0.64.26158.0.64.272
8158.0.64.28/30158.0.64.29 to 158.0.64.30158.0.64.312
9158.0.64.32/30158.0.64.33 to 158.0.64.34158.0.64.352
10158.0.64.36/30158.0.64.37 to 158.0.64.38158.0.64.392
11158.0.64.40/30158.0.64.41 to 158.0.64.42158.0.64.432
12158.0.64.44/30158.0.64.45 to 158.0.64.46158.0.64.472
13158.0.64.48/30158.0.64.49 to 158.0.64.50158.0.64.512
14158.0.64.52/30158.0.64.53 to 158.0.64.54158.0.64.552
15158.0.64.56/30158.0.64.57 to 158.0.64.58158.0.64.592
16158.0.64.60/30158.0.64.61 to 158.0.64.62158.0.64.632
17158.0.64.64/30158.0.64.65 to 158.0.64.66158.0.64.672
18158.0.64.68/30158.0.64.69 to 158.0.64.70158.0.64.712
19158.0.64.72/30158.0.64.73 to 158.0.64.74158.0.64.752
20158.0.64.76/30158.0.64.77 to 158.0.64.78158.0.64.792
21158.0.64.80/30158.0.64.81 to 158.0.64.82158.0.64.832
22158.0.64.84/30158.0.64.85 to 158.0.64.86158.0.64.872
23158.0.64.88/30158.0.64.89 to 158.0.64.90158.0.64.912
24158.0.64.92/30158.0.64.93 to 158.0.64.94158.0.64.952
25158.0.64.96/30158.0.64.97 to 158.0.64.98158.0.64.992
26158.0.64.100/30158.0.64.101 to 158.0.64.102158.0.64.1032
27158.0.64.104/30158.0.64.105 to 158.0.64.106158.0.64.1072
28158.0.64.108/30158.0.64.109 to 158.0.64.110158.0.64.1112
29158.0.64.112/30158.0.64.113 to 158.0.64.114158.0.64.1152
30158.0.64.116/30158.0.64.117 to 158.0.64.118158.0.64.1192
31158.0.64.120/30158.0.64.121 to 158.0.64.122158.0.64.1232
32158.0.64.124/30158.0.64.125 to 158.0.64.126158.0.64.1272
33158.0.64.128/30158.0.64.129 to 158.0.64.130158.0.64.1312
34158.0.64.132/30158.0.64.133 to 158.0.64.134158.0.64.1352
35158.0.64.136/30158.0.64.137 to 158.0.64.138158.0.64.1392
36158.0.64.140/30158.0.64.141 to 158.0.64.142158.0.64.1432
37158.0.64.144/30158.0.64.145 to 158.0.64.146158.0.64.1472
38158.0.64.148/30158.0.64.149 to 158.0.64.150158.0.64.1512
39158.0.64.152/30158.0.64.153 to 158.0.64.154158.0.64.1552
40158.0.64.156/30158.0.64.157 to 158.0.64.158158.0.64.1592
41158.0.64.160/30158.0.64.161 to 158.0.64.162158.0.64.1632
42158.0.64.164/30158.0.64.165 to 158.0.64.166158.0.64.1672
43158.0.64.168/30158.0.64.169 to 158.0.64.170158.0.64.1712
44158.0.64.172/30158.0.64.173 to 158.0.64.174158.0.64.1752
45158.0.64.176/30158.0.64.177 to 158.0.64.178158.0.64.1792
46158.0.64.180/30158.0.64.181 to 158.0.64.182158.0.64.1832
47158.0.64.184/30158.0.64.185 to 158.0.64.186158.0.64.1872
48158.0.64.188/30158.0.64.189 to 158.0.64.190158.0.64.1912
49158.0.64.192/30158.0.64.193 to 158.0.64.194158.0.64.1952
50158.0.64.196/30158.0.64.197 to 158.0.64.198158.0.64.1992
51158.0.64.200/30158.0.64.201 to 158.0.64.202158.0.64.2032
52158.0.64.204/30158.0.64.205 to 158.0.64.206158.0.64.2072
53158.0.64.208/30158.0.64.209 to 158.0.64.210158.0.64.2112
54158.0.64.212/30158.0.64.213 to 158.0.64.214158.0.64.2152
55158.0.64.216/30158.0.64.217 to 158.0.64.218158.0.64.2192
56158.0.64.220/30158.0.64.221 to 158.0.64.222158.0.64.2232
57158.0.64.224/30158.0.64.225 to 158.0.64.226158.0.64.2272
58158.0.64.228/30158.0.64.229 to 158.0.64.230158.0.64.2312
59158.0.64.232/30158.0.64.233 to 158.0.64.234158.0.64.2352
60158.0.64.236/30158.0.64.237 to 158.0.64.238158.0.64.2392
61158.0.64.240/30158.0.64.241 to 158.0.64.242158.0.64.2432
62158.0.64.244/30158.0.64.245 to 158.0.64.246158.0.64.2472
63158.0.64.248/30158.0.64.249 to 158.0.64.250158.0.64.2512
64158.0.64.252/30158.0.64.253 to 158.0.64.254158.0.64.2552
65158.0.65.0/30158.0.65.1 to 158.0.65.2158.0.65.32
66158.0.65.4/30158.0.65.5 to 158.0.65.6158.0.65.72
67158.0.65.8/30158.0.65.9 to 158.0.65.10158.0.65.112
68158.0.65.12/30158.0.65.13 to 158.0.65.14158.0.65.152
69158.0.65.16/30158.0.65.17 to 158.0.65.18158.0.65.192
70158.0.65.20/30158.0.65.21 to 158.0.65.22158.0.65.232
71158.0.65.24/30158.0.65.25 to 158.0.65.26158.0.65.272
72158.0.65.28/30158.0.65.29 to 158.0.65.30158.0.65.312
73158.0.65.32/30158.0.65.33 to 158.0.65.34158.0.65.352
74158.0.65.36/30158.0.65.37 to 158.0.65.38158.0.65.392
75158.0.65.40/30158.0.65.41 to 158.0.65.42158.0.65.432
76158.0.65.44/30158.0.65.45 to 158.0.65.46158.0.65.472
77158.0.65.48/30158.0.65.49 to 158.0.65.50158.0.65.512
78158.0.65.52/30158.0.65.53 to 158.0.65.54158.0.65.552
79158.0.65.56/30158.0.65.57 to 158.0.65.58158.0.65.592
80158.0.65.60/30158.0.65.61 to 158.0.65.62158.0.65.632
81158.0.65.64/30158.0.65.65 to 158.0.65.66158.0.65.672
82158.0.65.68/30158.0.65.69 to 158.0.65.70158.0.65.712
83158.0.65.72/30158.0.65.73 to 158.0.65.74158.0.65.752
84158.0.65.76/30158.0.65.77 to 158.0.65.78158.0.65.792
85158.0.65.80/30158.0.65.81 to 158.0.65.82158.0.65.832
86158.0.65.84/30158.0.65.85 to 158.0.65.86158.0.65.872
87158.0.65.88/30158.0.65.89 to 158.0.65.90158.0.65.912
88158.0.65.92/30158.0.65.93 to 158.0.65.94158.0.65.952
89158.0.65.96/30158.0.65.97 to 158.0.65.98158.0.65.992
90158.0.65.100/30158.0.65.101 to 158.0.65.102158.0.65.1032
91158.0.65.104/30158.0.65.105 to 158.0.65.106158.0.65.1072
92158.0.65.108/30158.0.65.109 to 158.0.65.110158.0.65.1112
93158.0.65.112/30158.0.65.113 to 158.0.65.114158.0.65.1152
94158.0.65.116/30158.0.65.117 to 158.0.65.118158.0.65.1192
95158.0.65.120/30158.0.65.121 to 158.0.65.122158.0.65.1232
96158.0.65.124/30158.0.65.125 to 158.0.65.126158.0.65.1272
97158.0.65.128/30158.0.65.129 to 158.0.65.130158.0.65.1312
98158.0.65.132/30158.0.65.133 to 158.0.65.134158.0.65.1352
99158.0.65.136/30158.0.65.137 to 158.0.65.138158.0.65.1392
100158.0.65.140/30158.0.65.141 to 158.0.65.142158.0.65.1432
101158.0.65.144/30158.0.65.145 to 158.0.65.146158.0.65.1472
102158.0.65.148/30158.0.65.149 to 158.0.65.150158.0.65.1512
103158.0.65.152/30158.0.65.153 to 158.0.65.154158.0.65.1552
104158.0.65.156/30158.0.65.157 to 158.0.65.158158.0.65.1592
105158.0.65.160/30158.0.65.161 to 158.0.65.162158.0.65.1632
106158.0.65.164/30158.0.65.165 to 158.0.65.166158.0.65.1672
107158.0.65.168/30158.0.65.169 to 158.0.65.170158.0.65.1712
108158.0.65.172/30158.0.65.173 to 158.0.65.174158.0.65.1752
109158.0.65.176/30158.0.65.177 to 158.0.65.178158.0.65.1792
110158.0.65.180/30158.0.65.181 to 158.0.65.182158.0.65.1832
111158.0.65.184/30158.0.65.185 to 158.0.65.186158.0.65.1872
112158.0.65.188/30158.0.65.189 to 158.0.65.190158.0.65.1912
113158.0.65.192/30158.0.65.193 to 158.0.65.194158.0.65.1952
114158.0.65.196/30158.0.65.197 to 158.0.65.198158.0.65.1992
115158.0.65.200/30158.0.65.201 to 158.0.65.202158.0.65.2032
116158.0.65.204/30158.0.65.205 to 158.0.65.206158.0.65.2072
117158.0.65.208/30158.0.65.209 to 158.0.65.210158.0.65.2112
118158.0.65.212/30158.0.65.213 to 158.0.65.214158.0.65.2152
119158.0.65.216/30158.0.65.217 to 158.0.65.218158.0.65.2192
120158.0.65.220/30158.0.65.221 to 158.0.65.222158.0.65.2232
121158.0.65.224/30158.0.65.225 to 158.0.65.226158.0.65.2272
122158.0.65.228/30158.0.65.229 to 158.0.65.230158.0.65.2312
123158.0.65.232/30158.0.65.233 to 158.0.65.234158.0.65.2352
124158.0.65.236/30158.0.65.237 to 158.0.65.238158.0.65.2392
125158.0.65.240/30158.0.65.241 to 158.0.65.242158.0.65.2432
126158.0.65.244/30158.0.65.245 to 158.0.65.246158.0.65.2472
127158.0.65.248/30158.0.65.249 to 158.0.65.250158.0.65.2512
128158.0.65.252/30158.0.65.253 to 158.0.65.254158.0.65.2552
129158.0.66.0/30158.0.66.1 to 158.0.66.2158.0.66.32
130158.0.66.4/30158.0.66.5 to 158.0.66.6158.0.66.72
131158.0.66.8/30158.0.66.9 to 158.0.66.10158.0.66.112
132158.0.66.12/30158.0.66.13 to 158.0.66.14158.0.66.152
133158.0.66.16/30158.0.66.17 to 158.0.66.18158.0.66.192
134158.0.66.20/30158.0.66.21 to 158.0.66.22158.0.66.232
135158.0.66.24/30158.0.66.25 to 158.0.66.26158.0.66.272
136158.0.66.28/30158.0.66.29 to 158.0.66.30158.0.66.312
137158.0.66.32/30158.0.66.33 to 158.0.66.34158.0.66.352
138158.0.66.36/30158.0.66.37 to 158.0.66.38158.0.66.392
139158.0.66.40/30158.0.66.41 to 158.0.66.42158.0.66.432
140158.0.66.44/30158.0.66.45 to 158.0.66.46158.0.66.472
141158.0.66.48/30158.0.66.49 to 158.0.66.50158.0.66.512
142158.0.66.52/30158.0.66.53 to 158.0.66.54158.0.66.552
143158.0.66.56/30158.0.66.57 to 158.0.66.58158.0.66.592
144158.0.66.60/30158.0.66.61 to 158.0.66.62158.0.66.632
145158.0.66.64/30158.0.66.65 to 158.0.66.66158.0.66.672
146158.0.66.68/30158.0.66.69 to 158.0.66.70158.0.66.712
147158.0.66.72/30158.0.66.73 to 158.0.66.74158.0.66.752
148158.0.66.76/30158.0.66.77 to 158.0.66.78158.0.66.792
149158.0.66.80/30158.0.66.81 to 158.0.66.82158.0.66.832
150158.0.66.84/30158.0.66.85 to 158.0.66.86158.0.66.872
151158.0.66.88/30158.0.66.89 to 158.0.66.90158.0.66.912
152158.0.66.92/30158.0.66.93 to 158.0.66.94158.0.66.952
153158.0.66.96/30158.0.66.97 to 158.0.66.98158.0.66.992
154158.0.66.100/30158.0.66.101 to 158.0.66.102158.0.66.1032
155158.0.66.104/30158.0.66.105 to 158.0.66.106158.0.66.1072
156158.0.66.108/30158.0.66.109 to 158.0.66.110158.0.66.1112
157158.0.66.112/30158.0.66.113 to 158.0.66.114158.0.66.1152
158158.0.66.116/30158.0.66.117 to 158.0.66.118158.0.66.1192
159158.0.66.120/30158.0.66.121 to 158.0.66.122158.0.66.1232
160158.0.66.124/30158.0.66.125 to 158.0.66.126158.0.66.1272
161158.0.66.128/30158.0.66.129 to 158.0.66.130158.0.66.1312
162158.0.66.132/30158.0.66.133 to 158.0.66.134158.0.66.1352
163158.0.66.136/30158.0.66.137 to 158.0.66.138158.0.66.1392
164158.0.66.140/30158.0.66.141 to 158.0.66.142158.0.66.1432
165158.0.66.144/30158.0.66.145 to 158.0.66.146158.0.66.1472
166158.0.66.148/30158.0.66.149 to 158.0.66.150158.0.66.1512
167158.0.66.152/30158.0.66.153 to 158.0.66.154158.0.66.1552
168158.0.66.156/30158.0.66.157 to 158.0.66.158158.0.66.1592
169158.0.66.160/30158.0.66.161 to 158.0.66.162158.0.66.1632
170158.0.66.164/30158.0.66.165 to 158.0.66.166158.0.66.1672
171158.0.66.168/30158.0.66.169 to 158.0.66.170158.0.66.1712
172158.0.66.172/30158.0.66.173 to 158.0.66.174158.0.66.1752
173158.0.66.176/30158.0.66.177 to 158.0.66.178158.0.66.1792
174158.0.66.180/30158.0.66.181 to 158.0.66.182158.0.66.1832
175158.0.66.184/30158.0.66.185 to 158.0.66.186158.0.66.1872
176158.0.66.188/30158.0.66.189 to 158.0.66.190158.0.66.1912
177158.0.66.192/30158.0.66.193 to 158.0.66.194158.0.66.1952
178158.0.66.196/30158.0.66.197 to 158.0.66.198158.0.66.1992
179158.0.66.200/30158.0.66.201 to 158.0.66.202158.0.66.2032
180158.0.66.204/30158.0.66.205 to 158.0.66.206158.0.66.2072
181158.0.66.208/30158.0.66.209 to 158.0.66.210158.0.66.2112
182158.0.66.212/30158.0.66.213 to 158.0.66.214158.0.66.2152
183158.0.66.216/30158.0.66.217 to 158.0.66.218158.0.66.2192
184158.0.66.220/30158.0.66.221 to 158.0.66.222158.0.66.2232
185158.0.66.224/30158.0.66.225 to 158.0.66.226158.0.66.2272
186158.0.66.228/30158.0.66.229 to 158.0.66.230158.0.66.2312
187158.0.66.232/30158.0.66.233 to 158.0.66.234158.0.66.2352
188158.0.66.236/30158.0.66.237 to 158.0.66.238158.0.66.2392
189158.0.66.240/30158.0.66.241 to 158.0.66.242158.0.66.2432
190158.0.66.244/30158.0.66.245 to 158.0.66.246158.0.66.2472
191158.0.66.248/30158.0.66.249 to 158.0.66.250158.0.66.2512
192158.0.66.252/30158.0.66.253 to 158.0.66.254158.0.66.2552
193158.0.67.0/30158.0.67.1 to 158.0.67.2158.0.67.32
194158.0.67.4/30158.0.67.5 to 158.0.67.6158.0.67.72
195158.0.67.8/30158.0.67.9 to 158.0.67.10158.0.67.112
196158.0.67.12/30158.0.67.13 to 158.0.67.14158.0.67.152
197158.0.67.16/30158.0.67.17 to 158.0.67.18158.0.67.192
198158.0.67.20/30158.0.67.21 to 158.0.67.22158.0.67.232
199158.0.67.24/30158.0.67.25 to 158.0.67.26158.0.67.272
200158.0.67.28/30158.0.67.29 to 158.0.67.30158.0.67.312
201158.0.67.32/30158.0.67.33 to 158.0.67.34158.0.67.352
202158.0.67.36/30158.0.67.37 to 158.0.67.38158.0.67.392
203158.0.67.40/30158.0.67.41 to 158.0.67.42158.0.67.432
204158.0.67.44/30158.0.67.45 to 158.0.67.46158.0.67.472
205158.0.67.48/30158.0.67.49 to 158.0.67.50158.0.67.512
206158.0.67.52/30158.0.67.53 to 158.0.67.54158.0.67.552
207158.0.67.56/30158.0.67.57 to 158.0.67.58158.0.67.592
208158.0.67.60/30158.0.67.61 to 158.0.67.62158.0.67.632
209158.0.67.64/30158.0.67.65 to 158.0.67.66158.0.67.672
210158.0.67.68/30158.0.67.69 to 158.0.67.70158.0.67.712
211158.0.67.72/30158.0.67.73 to 158.0.67.74158.0.67.752
212158.0.67.76/30158.0.67.77 to 158.0.67.78158.0.67.792
213158.0.67.80/30158.0.67.81 to 158.0.67.82158.0.67.832
214158.0.67.84/30158.0.67.85 to 158.0.67.86158.0.67.872
215158.0.67.88/30158.0.67.89 to 158.0.67.90158.0.67.912
216158.0.67.92/30158.0.67.93 to 158.0.67.94158.0.67.952
217158.0.67.96/30158.0.67.97 to 158.0.67.98158.0.67.992
218158.0.67.100/30158.0.67.101 to 158.0.67.102158.0.67.1032
219158.0.67.104/30158.0.67.105 to 158.0.67.106158.0.67.1072
220158.0.67.108/30158.0.67.109 to 158.0.67.110158.0.67.1112
221158.0.67.112/30158.0.67.113 to 158.0.67.114158.0.67.1152
222158.0.67.116/30158.0.67.117 to 158.0.67.118158.0.67.1192
223158.0.67.120/30158.0.67.121 to 158.0.67.122158.0.67.1232
224158.0.67.124/30158.0.67.125 to 158.0.67.126158.0.67.1272
225158.0.67.128/30158.0.67.129 to 158.0.67.130158.0.67.1312
226158.0.67.132/30158.0.67.133 to 158.0.67.134158.0.67.1352
227158.0.67.136/30158.0.67.137 to 158.0.67.138158.0.67.1392
228158.0.67.140/30158.0.67.141 to 158.0.67.142158.0.67.1432
229158.0.67.144/30158.0.67.145 to 158.0.67.146158.0.67.1472
230158.0.67.148/30158.0.67.149 to 158.0.67.150158.0.67.1512
231158.0.67.152/30158.0.67.153 to 158.0.67.154158.0.67.1552
232158.0.67.156/30158.0.67.157 to 158.0.67.158158.0.67.1592
233158.0.67.160/30158.0.67.161 to 158.0.67.162158.0.67.1632
234158.0.67.164/30158.0.67.165 to 158.0.67.166158.0.67.1672
235158.0.67.168/30158.0.67.169 to 158.0.67.170158.0.67.1712
236158.0.67.172/30158.0.67.173 to 158.0.67.174158.0.67.1752
237158.0.67.176/30158.0.67.177 to 158.0.67.178158.0.67.1792
238158.0.67.180/30158.0.67.181 to 158.0.67.182158.0.67.1832
239158.0.67.184/30158.0.67.185 to 158.0.67.186158.0.67.1872
240158.0.67.188/30158.0.67.189 to 158.0.67.190158.0.67.1912
241158.0.67.192/30158.0.67.193 to 158.0.67.194158.0.67.1952
242158.0.67.196/30158.0.67.197 to 158.0.67.198158.0.67.1992
243158.0.67.200/30158.0.67.201 to 158.0.67.202158.0.67.2032
244158.0.67.204/30158.0.67.205 to 158.0.67.206158.0.67.2072
245158.0.67.208/30158.0.67.209 to 158.0.67.210158.0.67.2112
246158.0.67.212/30158.0.67.213 to 158.0.67.214158.0.67.2152
247158.0.67.216/30158.0.67.217 to 158.0.67.218158.0.67.2192
248158.0.67.220/30158.0.67.221 to 158.0.67.222158.0.67.2232
249158.0.67.224/30158.0.67.225 to 158.0.67.226158.0.67.2272
250158.0.67.228/30158.0.67.229 to 158.0.67.230158.0.67.2312
251158.0.67.232/30158.0.67.233 to 158.0.67.234158.0.67.2352
252158.0.67.236/30158.0.67.237 to 158.0.67.238158.0.67.2392
253158.0.67.240/30158.0.67.241 to 158.0.67.242158.0.67.2432
254158.0.67.244/30158.0.67.245 to 158.0.67.246158.0.67.2472
255158.0.67.248/30158.0.67.249 to 158.0.67.250158.0.67.2512
256158.0.67.252/30158.0.67.253 to 158.0.67.254158.0.67.2552

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.