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.

Network113.2.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
113.2.64.0
Broadcast address
113.2.127.255
First usable
113.2.64.1
Last usable
113.2.127.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 71024000 · Integer 1895972864 to 1895989247
Reverse DNS zones
64.2.113.in-addr.arpa
65.2.113.in-addr.arpa
66.2.113.in-addr.arpa
67.2.113.in-addr.arpa
68.2.113.in-addr.arpa
69.2.113.in-addr.arpa
70.2.113.in-addr.arpa
71.2.113.in-addr.arpa
72.2.113.in-addr.arpa
73.2.113.in-addr.arpa
74.2.113.in-addr.arpa
75.2.113.in-addr.arpa
76.2.113.in-addr.arpa
77.2.113.in-addr.arpa
78.2.113.in-addr.arpa
79.2.113.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110001.00000010.01000000.00000000113.2.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01110001.00000010.01000000.00000000113.2.64.0
Broadcast01110001.00000010.01111111.11111111113.2.127.255
Split into smaller subnets/30
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

113.2.64.0/18 makes 4,096 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1113.2.64.0/30113.2.64.1 to 113.2.64.2113.2.64.32
2113.2.64.4/30113.2.64.5 to 113.2.64.6113.2.64.72
3113.2.64.8/30113.2.64.9 to 113.2.64.10113.2.64.112
4113.2.64.12/30113.2.64.13 to 113.2.64.14113.2.64.152
5113.2.64.16/30113.2.64.17 to 113.2.64.18113.2.64.192
6113.2.64.20/30113.2.64.21 to 113.2.64.22113.2.64.232
7113.2.64.24/30113.2.64.25 to 113.2.64.26113.2.64.272
8113.2.64.28/30113.2.64.29 to 113.2.64.30113.2.64.312
9113.2.64.32/30113.2.64.33 to 113.2.64.34113.2.64.352
10113.2.64.36/30113.2.64.37 to 113.2.64.38113.2.64.392
11113.2.64.40/30113.2.64.41 to 113.2.64.42113.2.64.432
12113.2.64.44/30113.2.64.45 to 113.2.64.46113.2.64.472
13113.2.64.48/30113.2.64.49 to 113.2.64.50113.2.64.512
14113.2.64.52/30113.2.64.53 to 113.2.64.54113.2.64.552
15113.2.64.56/30113.2.64.57 to 113.2.64.58113.2.64.592
16113.2.64.60/30113.2.64.61 to 113.2.64.62113.2.64.632
17113.2.64.64/30113.2.64.65 to 113.2.64.66113.2.64.672
18113.2.64.68/30113.2.64.69 to 113.2.64.70113.2.64.712
19113.2.64.72/30113.2.64.73 to 113.2.64.74113.2.64.752
20113.2.64.76/30113.2.64.77 to 113.2.64.78113.2.64.792
21113.2.64.80/30113.2.64.81 to 113.2.64.82113.2.64.832
22113.2.64.84/30113.2.64.85 to 113.2.64.86113.2.64.872
23113.2.64.88/30113.2.64.89 to 113.2.64.90113.2.64.912
24113.2.64.92/30113.2.64.93 to 113.2.64.94113.2.64.952
25113.2.64.96/30113.2.64.97 to 113.2.64.98113.2.64.992
26113.2.64.100/30113.2.64.101 to 113.2.64.102113.2.64.1032
27113.2.64.104/30113.2.64.105 to 113.2.64.106113.2.64.1072
28113.2.64.108/30113.2.64.109 to 113.2.64.110113.2.64.1112
29113.2.64.112/30113.2.64.113 to 113.2.64.114113.2.64.1152
30113.2.64.116/30113.2.64.117 to 113.2.64.118113.2.64.1192
31113.2.64.120/30113.2.64.121 to 113.2.64.122113.2.64.1232
32113.2.64.124/30113.2.64.125 to 113.2.64.126113.2.64.1272
33113.2.64.128/30113.2.64.129 to 113.2.64.130113.2.64.1312
34113.2.64.132/30113.2.64.133 to 113.2.64.134113.2.64.1352
35113.2.64.136/30113.2.64.137 to 113.2.64.138113.2.64.1392
36113.2.64.140/30113.2.64.141 to 113.2.64.142113.2.64.1432
37113.2.64.144/30113.2.64.145 to 113.2.64.146113.2.64.1472
38113.2.64.148/30113.2.64.149 to 113.2.64.150113.2.64.1512
39113.2.64.152/30113.2.64.153 to 113.2.64.154113.2.64.1552
40113.2.64.156/30113.2.64.157 to 113.2.64.158113.2.64.1592
41113.2.64.160/30113.2.64.161 to 113.2.64.162113.2.64.1632
42113.2.64.164/30113.2.64.165 to 113.2.64.166113.2.64.1672
43113.2.64.168/30113.2.64.169 to 113.2.64.170113.2.64.1712
44113.2.64.172/30113.2.64.173 to 113.2.64.174113.2.64.1752
45113.2.64.176/30113.2.64.177 to 113.2.64.178113.2.64.1792
46113.2.64.180/30113.2.64.181 to 113.2.64.182113.2.64.1832
47113.2.64.184/30113.2.64.185 to 113.2.64.186113.2.64.1872
48113.2.64.188/30113.2.64.189 to 113.2.64.190113.2.64.1912
49113.2.64.192/30113.2.64.193 to 113.2.64.194113.2.64.1952
50113.2.64.196/30113.2.64.197 to 113.2.64.198113.2.64.1992
51113.2.64.200/30113.2.64.201 to 113.2.64.202113.2.64.2032
52113.2.64.204/30113.2.64.205 to 113.2.64.206113.2.64.2072
53113.2.64.208/30113.2.64.209 to 113.2.64.210113.2.64.2112
54113.2.64.212/30113.2.64.213 to 113.2.64.214113.2.64.2152
55113.2.64.216/30113.2.64.217 to 113.2.64.218113.2.64.2192
56113.2.64.220/30113.2.64.221 to 113.2.64.222113.2.64.2232
57113.2.64.224/30113.2.64.225 to 113.2.64.226113.2.64.2272
58113.2.64.228/30113.2.64.229 to 113.2.64.230113.2.64.2312
59113.2.64.232/30113.2.64.233 to 113.2.64.234113.2.64.2352
60113.2.64.236/30113.2.64.237 to 113.2.64.238113.2.64.2392
61113.2.64.240/30113.2.64.241 to 113.2.64.242113.2.64.2432
62113.2.64.244/30113.2.64.245 to 113.2.64.246113.2.64.2472
63113.2.64.248/30113.2.64.249 to 113.2.64.250113.2.64.2512
64113.2.64.252/30113.2.64.253 to 113.2.64.254113.2.64.2552
65113.2.65.0/30113.2.65.1 to 113.2.65.2113.2.65.32
66113.2.65.4/30113.2.65.5 to 113.2.65.6113.2.65.72
67113.2.65.8/30113.2.65.9 to 113.2.65.10113.2.65.112
68113.2.65.12/30113.2.65.13 to 113.2.65.14113.2.65.152
69113.2.65.16/30113.2.65.17 to 113.2.65.18113.2.65.192
70113.2.65.20/30113.2.65.21 to 113.2.65.22113.2.65.232
71113.2.65.24/30113.2.65.25 to 113.2.65.26113.2.65.272
72113.2.65.28/30113.2.65.29 to 113.2.65.30113.2.65.312
73113.2.65.32/30113.2.65.33 to 113.2.65.34113.2.65.352
74113.2.65.36/30113.2.65.37 to 113.2.65.38113.2.65.392
75113.2.65.40/30113.2.65.41 to 113.2.65.42113.2.65.432
76113.2.65.44/30113.2.65.45 to 113.2.65.46113.2.65.472
77113.2.65.48/30113.2.65.49 to 113.2.65.50113.2.65.512
78113.2.65.52/30113.2.65.53 to 113.2.65.54113.2.65.552
79113.2.65.56/30113.2.65.57 to 113.2.65.58113.2.65.592
80113.2.65.60/30113.2.65.61 to 113.2.65.62113.2.65.632
81113.2.65.64/30113.2.65.65 to 113.2.65.66113.2.65.672
82113.2.65.68/30113.2.65.69 to 113.2.65.70113.2.65.712
83113.2.65.72/30113.2.65.73 to 113.2.65.74113.2.65.752
84113.2.65.76/30113.2.65.77 to 113.2.65.78113.2.65.792
85113.2.65.80/30113.2.65.81 to 113.2.65.82113.2.65.832
86113.2.65.84/30113.2.65.85 to 113.2.65.86113.2.65.872
87113.2.65.88/30113.2.65.89 to 113.2.65.90113.2.65.912
88113.2.65.92/30113.2.65.93 to 113.2.65.94113.2.65.952
89113.2.65.96/30113.2.65.97 to 113.2.65.98113.2.65.992
90113.2.65.100/30113.2.65.101 to 113.2.65.102113.2.65.1032
91113.2.65.104/30113.2.65.105 to 113.2.65.106113.2.65.1072
92113.2.65.108/30113.2.65.109 to 113.2.65.110113.2.65.1112
93113.2.65.112/30113.2.65.113 to 113.2.65.114113.2.65.1152
94113.2.65.116/30113.2.65.117 to 113.2.65.118113.2.65.1192
95113.2.65.120/30113.2.65.121 to 113.2.65.122113.2.65.1232
96113.2.65.124/30113.2.65.125 to 113.2.65.126113.2.65.1272
97113.2.65.128/30113.2.65.129 to 113.2.65.130113.2.65.1312
98113.2.65.132/30113.2.65.133 to 113.2.65.134113.2.65.1352
99113.2.65.136/30113.2.65.137 to 113.2.65.138113.2.65.1392
100113.2.65.140/30113.2.65.141 to 113.2.65.142113.2.65.1432
101113.2.65.144/30113.2.65.145 to 113.2.65.146113.2.65.1472
102113.2.65.148/30113.2.65.149 to 113.2.65.150113.2.65.1512
103113.2.65.152/30113.2.65.153 to 113.2.65.154113.2.65.1552
104113.2.65.156/30113.2.65.157 to 113.2.65.158113.2.65.1592
105113.2.65.160/30113.2.65.161 to 113.2.65.162113.2.65.1632
106113.2.65.164/30113.2.65.165 to 113.2.65.166113.2.65.1672
107113.2.65.168/30113.2.65.169 to 113.2.65.170113.2.65.1712
108113.2.65.172/30113.2.65.173 to 113.2.65.174113.2.65.1752
109113.2.65.176/30113.2.65.177 to 113.2.65.178113.2.65.1792
110113.2.65.180/30113.2.65.181 to 113.2.65.182113.2.65.1832
111113.2.65.184/30113.2.65.185 to 113.2.65.186113.2.65.1872
112113.2.65.188/30113.2.65.189 to 113.2.65.190113.2.65.1912
113113.2.65.192/30113.2.65.193 to 113.2.65.194113.2.65.1952
114113.2.65.196/30113.2.65.197 to 113.2.65.198113.2.65.1992
115113.2.65.200/30113.2.65.201 to 113.2.65.202113.2.65.2032
116113.2.65.204/30113.2.65.205 to 113.2.65.206113.2.65.2072
117113.2.65.208/30113.2.65.209 to 113.2.65.210113.2.65.2112
118113.2.65.212/30113.2.65.213 to 113.2.65.214113.2.65.2152
119113.2.65.216/30113.2.65.217 to 113.2.65.218113.2.65.2192
120113.2.65.220/30113.2.65.221 to 113.2.65.222113.2.65.2232
121113.2.65.224/30113.2.65.225 to 113.2.65.226113.2.65.2272
122113.2.65.228/30113.2.65.229 to 113.2.65.230113.2.65.2312
123113.2.65.232/30113.2.65.233 to 113.2.65.234113.2.65.2352
124113.2.65.236/30113.2.65.237 to 113.2.65.238113.2.65.2392
125113.2.65.240/30113.2.65.241 to 113.2.65.242113.2.65.2432
126113.2.65.244/30113.2.65.245 to 113.2.65.246113.2.65.2472
127113.2.65.248/30113.2.65.249 to 113.2.65.250113.2.65.2512
128113.2.65.252/30113.2.65.253 to 113.2.65.254113.2.65.2552
129113.2.66.0/30113.2.66.1 to 113.2.66.2113.2.66.32
130113.2.66.4/30113.2.66.5 to 113.2.66.6113.2.66.72
131113.2.66.8/30113.2.66.9 to 113.2.66.10113.2.66.112
132113.2.66.12/30113.2.66.13 to 113.2.66.14113.2.66.152
133113.2.66.16/30113.2.66.17 to 113.2.66.18113.2.66.192
134113.2.66.20/30113.2.66.21 to 113.2.66.22113.2.66.232
135113.2.66.24/30113.2.66.25 to 113.2.66.26113.2.66.272
136113.2.66.28/30113.2.66.29 to 113.2.66.30113.2.66.312
137113.2.66.32/30113.2.66.33 to 113.2.66.34113.2.66.352
138113.2.66.36/30113.2.66.37 to 113.2.66.38113.2.66.392
139113.2.66.40/30113.2.66.41 to 113.2.66.42113.2.66.432
140113.2.66.44/30113.2.66.45 to 113.2.66.46113.2.66.472
141113.2.66.48/30113.2.66.49 to 113.2.66.50113.2.66.512
142113.2.66.52/30113.2.66.53 to 113.2.66.54113.2.66.552
143113.2.66.56/30113.2.66.57 to 113.2.66.58113.2.66.592
144113.2.66.60/30113.2.66.61 to 113.2.66.62113.2.66.632
145113.2.66.64/30113.2.66.65 to 113.2.66.66113.2.66.672
146113.2.66.68/30113.2.66.69 to 113.2.66.70113.2.66.712
147113.2.66.72/30113.2.66.73 to 113.2.66.74113.2.66.752
148113.2.66.76/30113.2.66.77 to 113.2.66.78113.2.66.792
149113.2.66.80/30113.2.66.81 to 113.2.66.82113.2.66.832
150113.2.66.84/30113.2.66.85 to 113.2.66.86113.2.66.872
151113.2.66.88/30113.2.66.89 to 113.2.66.90113.2.66.912
152113.2.66.92/30113.2.66.93 to 113.2.66.94113.2.66.952
153113.2.66.96/30113.2.66.97 to 113.2.66.98113.2.66.992
154113.2.66.100/30113.2.66.101 to 113.2.66.102113.2.66.1032
155113.2.66.104/30113.2.66.105 to 113.2.66.106113.2.66.1072
156113.2.66.108/30113.2.66.109 to 113.2.66.110113.2.66.1112
157113.2.66.112/30113.2.66.113 to 113.2.66.114113.2.66.1152
158113.2.66.116/30113.2.66.117 to 113.2.66.118113.2.66.1192
159113.2.66.120/30113.2.66.121 to 113.2.66.122113.2.66.1232
160113.2.66.124/30113.2.66.125 to 113.2.66.126113.2.66.1272
161113.2.66.128/30113.2.66.129 to 113.2.66.130113.2.66.1312
162113.2.66.132/30113.2.66.133 to 113.2.66.134113.2.66.1352
163113.2.66.136/30113.2.66.137 to 113.2.66.138113.2.66.1392
164113.2.66.140/30113.2.66.141 to 113.2.66.142113.2.66.1432
165113.2.66.144/30113.2.66.145 to 113.2.66.146113.2.66.1472
166113.2.66.148/30113.2.66.149 to 113.2.66.150113.2.66.1512
167113.2.66.152/30113.2.66.153 to 113.2.66.154113.2.66.1552
168113.2.66.156/30113.2.66.157 to 113.2.66.158113.2.66.1592
169113.2.66.160/30113.2.66.161 to 113.2.66.162113.2.66.1632
170113.2.66.164/30113.2.66.165 to 113.2.66.166113.2.66.1672
171113.2.66.168/30113.2.66.169 to 113.2.66.170113.2.66.1712
172113.2.66.172/30113.2.66.173 to 113.2.66.174113.2.66.1752
173113.2.66.176/30113.2.66.177 to 113.2.66.178113.2.66.1792
174113.2.66.180/30113.2.66.181 to 113.2.66.182113.2.66.1832
175113.2.66.184/30113.2.66.185 to 113.2.66.186113.2.66.1872
176113.2.66.188/30113.2.66.189 to 113.2.66.190113.2.66.1912
177113.2.66.192/30113.2.66.193 to 113.2.66.194113.2.66.1952
178113.2.66.196/30113.2.66.197 to 113.2.66.198113.2.66.1992
179113.2.66.200/30113.2.66.201 to 113.2.66.202113.2.66.2032
180113.2.66.204/30113.2.66.205 to 113.2.66.206113.2.66.2072
181113.2.66.208/30113.2.66.209 to 113.2.66.210113.2.66.2112
182113.2.66.212/30113.2.66.213 to 113.2.66.214113.2.66.2152
183113.2.66.216/30113.2.66.217 to 113.2.66.218113.2.66.2192
184113.2.66.220/30113.2.66.221 to 113.2.66.222113.2.66.2232
185113.2.66.224/30113.2.66.225 to 113.2.66.226113.2.66.2272
186113.2.66.228/30113.2.66.229 to 113.2.66.230113.2.66.2312
187113.2.66.232/30113.2.66.233 to 113.2.66.234113.2.66.2352
188113.2.66.236/30113.2.66.237 to 113.2.66.238113.2.66.2392
189113.2.66.240/30113.2.66.241 to 113.2.66.242113.2.66.2432
190113.2.66.244/30113.2.66.245 to 113.2.66.246113.2.66.2472
191113.2.66.248/30113.2.66.249 to 113.2.66.250113.2.66.2512
192113.2.66.252/30113.2.66.253 to 113.2.66.254113.2.66.2552
193113.2.67.0/30113.2.67.1 to 113.2.67.2113.2.67.32
194113.2.67.4/30113.2.67.5 to 113.2.67.6113.2.67.72
195113.2.67.8/30113.2.67.9 to 113.2.67.10113.2.67.112
196113.2.67.12/30113.2.67.13 to 113.2.67.14113.2.67.152
197113.2.67.16/30113.2.67.17 to 113.2.67.18113.2.67.192
198113.2.67.20/30113.2.67.21 to 113.2.67.22113.2.67.232
199113.2.67.24/30113.2.67.25 to 113.2.67.26113.2.67.272
200113.2.67.28/30113.2.67.29 to 113.2.67.30113.2.67.312
201113.2.67.32/30113.2.67.33 to 113.2.67.34113.2.67.352
202113.2.67.36/30113.2.67.37 to 113.2.67.38113.2.67.392
203113.2.67.40/30113.2.67.41 to 113.2.67.42113.2.67.432
204113.2.67.44/30113.2.67.45 to 113.2.67.46113.2.67.472
205113.2.67.48/30113.2.67.49 to 113.2.67.50113.2.67.512
206113.2.67.52/30113.2.67.53 to 113.2.67.54113.2.67.552
207113.2.67.56/30113.2.67.57 to 113.2.67.58113.2.67.592
208113.2.67.60/30113.2.67.61 to 113.2.67.62113.2.67.632
209113.2.67.64/30113.2.67.65 to 113.2.67.66113.2.67.672
210113.2.67.68/30113.2.67.69 to 113.2.67.70113.2.67.712
211113.2.67.72/30113.2.67.73 to 113.2.67.74113.2.67.752
212113.2.67.76/30113.2.67.77 to 113.2.67.78113.2.67.792
213113.2.67.80/30113.2.67.81 to 113.2.67.82113.2.67.832
214113.2.67.84/30113.2.67.85 to 113.2.67.86113.2.67.872
215113.2.67.88/30113.2.67.89 to 113.2.67.90113.2.67.912
216113.2.67.92/30113.2.67.93 to 113.2.67.94113.2.67.952
217113.2.67.96/30113.2.67.97 to 113.2.67.98113.2.67.992
218113.2.67.100/30113.2.67.101 to 113.2.67.102113.2.67.1032
219113.2.67.104/30113.2.67.105 to 113.2.67.106113.2.67.1072
220113.2.67.108/30113.2.67.109 to 113.2.67.110113.2.67.1112
221113.2.67.112/30113.2.67.113 to 113.2.67.114113.2.67.1152
222113.2.67.116/30113.2.67.117 to 113.2.67.118113.2.67.1192
223113.2.67.120/30113.2.67.121 to 113.2.67.122113.2.67.1232
224113.2.67.124/30113.2.67.125 to 113.2.67.126113.2.67.1272
225113.2.67.128/30113.2.67.129 to 113.2.67.130113.2.67.1312
226113.2.67.132/30113.2.67.133 to 113.2.67.134113.2.67.1352
227113.2.67.136/30113.2.67.137 to 113.2.67.138113.2.67.1392
228113.2.67.140/30113.2.67.141 to 113.2.67.142113.2.67.1432
229113.2.67.144/30113.2.67.145 to 113.2.67.146113.2.67.1472
230113.2.67.148/30113.2.67.149 to 113.2.67.150113.2.67.1512
231113.2.67.152/30113.2.67.153 to 113.2.67.154113.2.67.1552
232113.2.67.156/30113.2.67.157 to 113.2.67.158113.2.67.1592
233113.2.67.160/30113.2.67.161 to 113.2.67.162113.2.67.1632
234113.2.67.164/30113.2.67.165 to 113.2.67.166113.2.67.1672
235113.2.67.168/30113.2.67.169 to 113.2.67.170113.2.67.1712
236113.2.67.172/30113.2.67.173 to 113.2.67.174113.2.67.1752
237113.2.67.176/30113.2.67.177 to 113.2.67.178113.2.67.1792
238113.2.67.180/30113.2.67.181 to 113.2.67.182113.2.67.1832
239113.2.67.184/30113.2.67.185 to 113.2.67.186113.2.67.1872
240113.2.67.188/30113.2.67.189 to 113.2.67.190113.2.67.1912
241113.2.67.192/30113.2.67.193 to 113.2.67.194113.2.67.1952
242113.2.67.196/30113.2.67.197 to 113.2.67.198113.2.67.1992
243113.2.67.200/30113.2.67.201 to 113.2.67.202113.2.67.2032
244113.2.67.204/30113.2.67.205 to 113.2.67.206113.2.67.2072
245113.2.67.208/30113.2.67.209 to 113.2.67.210113.2.67.2112
246113.2.67.212/30113.2.67.213 to 113.2.67.214113.2.67.2152
247113.2.67.216/30113.2.67.217 to 113.2.67.218113.2.67.2192
248113.2.67.220/30113.2.67.221 to 113.2.67.222113.2.67.2232
249113.2.67.224/30113.2.67.225 to 113.2.67.226113.2.67.2272
250113.2.67.228/30113.2.67.229 to 113.2.67.230113.2.67.2312
251113.2.67.232/30113.2.67.233 to 113.2.67.234113.2.67.2352
252113.2.67.236/30113.2.67.237 to 113.2.67.238113.2.67.2392
253113.2.67.240/30113.2.67.241 to 113.2.67.242113.2.67.2432
254113.2.67.244/30113.2.67.245 to 113.2.67.246113.2.67.2472
255113.2.67.248/30113.2.67.249 to 113.2.67.250113.2.67.2512
256113.2.67.252/30113.2.67.253 to 113.2.67.254113.2.67.2552

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.