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.

Network101.232.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
101.232.0.0
Broadcast address
101.235.255.255
First usable
101.232.0.1
Last usable
101.235.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
A (default /8)
As numbers
Hex 65E80000 · Integer 1709703168 to 1709965311
Reverse DNS zones
232.101.in-addr.arpa
233.101.in-addr.arpa
234.101.in-addr.arpa
235.101.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
Address01100101.11101000.00000000.00000000101.232.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network01100101.11101000.00000000.00000000101.232.0.0
Broadcast01100101.11101011.11111111.11111111101.235.255.255
Split into smaller subnets/24
/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)

101.232.0.0/14 makes 1,024 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1101.232.0.0/24101.232.0.1 to 101.232.0.254101.232.0.255254
2101.232.1.0/24101.232.1.1 to 101.232.1.254101.232.1.255254
3101.232.2.0/24101.232.2.1 to 101.232.2.254101.232.2.255254
4101.232.3.0/24101.232.3.1 to 101.232.3.254101.232.3.255254
5101.232.4.0/24101.232.4.1 to 101.232.4.254101.232.4.255254
6101.232.5.0/24101.232.5.1 to 101.232.5.254101.232.5.255254
7101.232.6.0/24101.232.6.1 to 101.232.6.254101.232.6.255254
8101.232.7.0/24101.232.7.1 to 101.232.7.254101.232.7.255254
9101.232.8.0/24101.232.8.1 to 101.232.8.254101.232.8.255254
10101.232.9.0/24101.232.9.1 to 101.232.9.254101.232.9.255254
11101.232.10.0/24101.232.10.1 to 101.232.10.254101.232.10.255254
12101.232.11.0/24101.232.11.1 to 101.232.11.254101.232.11.255254
13101.232.12.0/24101.232.12.1 to 101.232.12.254101.232.12.255254
14101.232.13.0/24101.232.13.1 to 101.232.13.254101.232.13.255254
15101.232.14.0/24101.232.14.1 to 101.232.14.254101.232.14.255254
16101.232.15.0/24101.232.15.1 to 101.232.15.254101.232.15.255254
17101.232.16.0/24101.232.16.1 to 101.232.16.254101.232.16.255254
18101.232.17.0/24101.232.17.1 to 101.232.17.254101.232.17.255254
19101.232.18.0/24101.232.18.1 to 101.232.18.254101.232.18.255254
20101.232.19.0/24101.232.19.1 to 101.232.19.254101.232.19.255254
21101.232.20.0/24101.232.20.1 to 101.232.20.254101.232.20.255254
22101.232.21.0/24101.232.21.1 to 101.232.21.254101.232.21.255254
23101.232.22.0/24101.232.22.1 to 101.232.22.254101.232.22.255254
24101.232.23.0/24101.232.23.1 to 101.232.23.254101.232.23.255254
25101.232.24.0/24101.232.24.1 to 101.232.24.254101.232.24.255254
26101.232.25.0/24101.232.25.1 to 101.232.25.254101.232.25.255254
27101.232.26.0/24101.232.26.1 to 101.232.26.254101.232.26.255254
28101.232.27.0/24101.232.27.1 to 101.232.27.254101.232.27.255254
29101.232.28.0/24101.232.28.1 to 101.232.28.254101.232.28.255254
30101.232.29.0/24101.232.29.1 to 101.232.29.254101.232.29.255254
31101.232.30.0/24101.232.30.1 to 101.232.30.254101.232.30.255254
32101.232.31.0/24101.232.31.1 to 101.232.31.254101.232.31.255254
33101.232.32.0/24101.232.32.1 to 101.232.32.254101.232.32.255254
34101.232.33.0/24101.232.33.1 to 101.232.33.254101.232.33.255254
35101.232.34.0/24101.232.34.1 to 101.232.34.254101.232.34.255254
36101.232.35.0/24101.232.35.1 to 101.232.35.254101.232.35.255254
37101.232.36.0/24101.232.36.1 to 101.232.36.254101.232.36.255254
38101.232.37.0/24101.232.37.1 to 101.232.37.254101.232.37.255254
39101.232.38.0/24101.232.38.1 to 101.232.38.254101.232.38.255254
40101.232.39.0/24101.232.39.1 to 101.232.39.254101.232.39.255254
41101.232.40.0/24101.232.40.1 to 101.232.40.254101.232.40.255254
42101.232.41.0/24101.232.41.1 to 101.232.41.254101.232.41.255254
43101.232.42.0/24101.232.42.1 to 101.232.42.254101.232.42.255254
44101.232.43.0/24101.232.43.1 to 101.232.43.254101.232.43.255254
45101.232.44.0/24101.232.44.1 to 101.232.44.254101.232.44.255254
46101.232.45.0/24101.232.45.1 to 101.232.45.254101.232.45.255254
47101.232.46.0/24101.232.46.1 to 101.232.46.254101.232.46.255254
48101.232.47.0/24101.232.47.1 to 101.232.47.254101.232.47.255254
49101.232.48.0/24101.232.48.1 to 101.232.48.254101.232.48.255254
50101.232.49.0/24101.232.49.1 to 101.232.49.254101.232.49.255254
51101.232.50.0/24101.232.50.1 to 101.232.50.254101.232.50.255254
52101.232.51.0/24101.232.51.1 to 101.232.51.254101.232.51.255254
53101.232.52.0/24101.232.52.1 to 101.232.52.254101.232.52.255254
54101.232.53.0/24101.232.53.1 to 101.232.53.254101.232.53.255254
55101.232.54.0/24101.232.54.1 to 101.232.54.254101.232.54.255254
56101.232.55.0/24101.232.55.1 to 101.232.55.254101.232.55.255254
57101.232.56.0/24101.232.56.1 to 101.232.56.254101.232.56.255254
58101.232.57.0/24101.232.57.1 to 101.232.57.254101.232.57.255254
59101.232.58.0/24101.232.58.1 to 101.232.58.254101.232.58.255254
60101.232.59.0/24101.232.59.1 to 101.232.59.254101.232.59.255254
61101.232.60.0/24101.232.60.1 to 101.232.60.254101.232.60.255254
62101.232.61.0/24101.232.61.1 to 101.232.61.254101.232.61.255254
63101.232.62.0/24101.232.62.1 to 101.232.62.254101.232.62.255254
64101.232.63.0/24101.232.63.1 to 101.232.63.254101.232.63.255254
65101.232.64.0/24101.232.64.1 to 101.232.64.254101.232.64.255254
66101.232.65.0/24101.232.65.1 to 101.232.65.254101.232.65.255254
67101.232.66.0/24101.232.66.1 to 101.232.66.254101.232.66.255254
68101.232.67.0/24101.232.67.1 to 101.232.67.254101.232.67.255254
69101.232.68.0/24101.232.68.1 to 101.232.68.254101.232.68.255254
70101.232.69.0/24101.232.69.1 to 101.232.69.254101.232.69.255254
71101.232.70.0/24101.232.70.1 to 101.232.70.254101.232.70.255254
72101.232.71.0/24101.232.71.1 to 101.232.71.254101.232.71.255254
73101.232.72.0/24101.232.72.1 to 101.232.72.254101.232.72.255254
74101.232.73.0/24101.232.73.1 to 101.232.73.254101.232.73.255254
75101.232.74.0/24101.232.74.1 to 101.232.74.254101.232.74.255254
76101.232.75.0/24101.232.75.1 to 101.232.75.254101.232.75.255254
77101.232.76.0/24101.232.76.1 to 101.232.76.254101.232.76.255254
78101.232.77.0/24101.232.77.1 to 101.232.77.254101.232.77.255254
79101.232.78.0/24101.232.78.1 to 101.232.78.254101.232.78.255254
80101.232.79.0/24101.232.79.1 to 101.232.79.254101.232.79.255254
81101.232.80.0/24101.232.80.1 to 101.232.80.254101.232.80.255254
82101.232.81.0/24101.232.81.1 to 101.232.81.254101.232.81.255254
83101.232.82.0/24101.232.82.1 to 101.232.82.254101.232.82.255254
84101.232.83.0/24101.232.83.1 to 101.232.83.254101.232.83.255254
85101.232.84.0/24101.232.84.1 to 101.232.84.254101.232.84.255254
86101.232.85.0/24101.232.85.1 to 101.232.85.254101.232.85.255254
87101.232.86.0/24101.232.86.1 to 101.232.86.254101.232.86.255254
88101.232.87.0/24101.232.87.1 to 101.232.87.254101.232.87.255254
89101.232.88.0/24101.232.88.1 to 101.232.88.254101.232.88.255254
90101.232.89.0/24101.232.89.1 to 101.232.89.254101.232.89.255254
91101.232.90.0/24101.232.90.1 to 101.232.90.254101.232.90.255254
92101.232.91.0/24101.232.91.1 to 101.232.91.254101.232.91.255254
93101.232.92.0/24101.232.92.1 to 101.232.92.254101.232.92.255254
94101.232.93.0/24101.232.93.1 to 101.232.93.254101.232.93.255254
95101.232.94.0/24101.232.94.1 to 101.232.94.254101.232.94.255254
96101.232.95.0/24101.232.95.1 to 101.232.95.254101.232.95.255254
97101.232.96.0/24101.232.96.1 to 101.232.96.254101.232.96.255254
98101.232.97.0/24101.232.97.1 to 101.232.97.254101.232.97.255254
99101.232.98.0/24101.232.98.1 to 101.232.98.254101.232.98.255254
100101.232.99.0/24101.232.99.1 to 101.232.99.254101.232.99.255254
101101.232.100.0/24101.232.100.1 to 101.232.100.254101.232.100.255254
102101.232.101.0/24101.232.101.1 to 101.232.101.254101.232.101.255254
103101.232.102.0/24101.232.102.1 to 101.232.102.254101.232.102.255254
104101.232.103.0/24101.232.103.1 to 101.232.103.254101.232.103.255254
105101.232.104.0/24101.232.104.1 to 101.232.104.254101.232.104.255254
106101.232.105.0/24101.232.105.1 to 101.232.105.254101.232.105.255254
107101.232.106.0/24101.232.106.1 to 101.232.106.254101.232.106.255254
108101.232.107.0/24101.232.107.1 to 101.232.107.254101.232.107.255254
109101.232.108.0/24101.232.108.1 to 101.232.108.254101.232.108.255254
110101.232.109.0/24101.232.109.1 to 101.232.109.254101.232.109.255254
111101.232.110.0/24101.232.110.1 to 101.232.110.254101.232.110.255254
112101.232.111.0/24101.232.111.1 to 101.232.111.254101.232.111.255254
113101.232.112.0/24101.232.112.1 to 101.232.112.254101.232.112.255254
114101.232.113.0/24101.232.113.1 to 101.232.113.254101.232.113.255254
115101.232.114.0/24101.232.114.1 to 101.232.114.254101.232.114.255254
116101.232.115.0/24101.232.115.1 to 101.232.115.254101.232.115.255254
117101.232.116.0/24101.232.116.1 to 101.232.116.254101.232.116.255254
118101.232.117.0/24101.232.117.1 to 101.232.117.254101.232.117.255254
119101.232.118.0/24101.232.118.1 to 101.232.118.254101.232.118.255254
120101.232.119.0/24101.232.119.1 to 101.232.119.254101.232.119.255254
121101.232.120.0/24101.232.120.1 to 101.232.120.254101.232.120.255254
122101.232.121.0/24101.232.121.1 to 101.232.121.254101.232.121.255254
123101.232.122.0/24101.232.122.1 to 101.232.122.254101.232.122.255254
124101.232.123.0/24101.232.123.1 to 101.232.123.254101.232.123.255254
125101.232.124.0/24101.232.124.1 to 101.232.124.254101.232.124.255254
126101.232.125.0/24101.232.125.1 to 101.232.125.254101.232.125.255254
127101.232.126.0/24101.232.126.1 to 101.232.126.254101.232.126.255254
128101.232.127.0/24101.232.127.1 to 101.232.127.254101.232.127.255254
129101.232.128.0/24101.232.128.1 to 101.232.128.254101.232.128.255254
130101.232.129.0/24101.232.129.1 to 101.232.129.254101.232.129.255254
131101.232.130.0/24101.232.130.1 to 101.232.130.254101.232.130.255254
132101.232.131.0/24101.232.131.1 to 101.232.131.254101.232.131.255254
133101.232.132.0/24101.232.132.1 to 101.232.132.254101.232.132.255254
134101.232.133.0/24101.232.133.1 to 101.232.133.254101.232.133.255254
135101.232.134.0/24101.232.134.1 to 101.232.134.254101.232.134.255254
136101.232.135.0/24101.232.135.1 to 101.232.135.254101.232.135.255254
137101.232.136.0/24101.232.136.1 to 101.232.136.254101.232.136.255254
138101.232.137.0/24101.232.137.1 to 101.232.137.254101.232.137.255254
139101.232.138.0/24101.232.138.1 to 101.232.138.254101.232.138.255254
140101.232.139.0/24101.232.139.1 to 101.232.139.254101.232.139.255254
141101.232.140.0/24101.232.140.1 to 101.232.140.254101.232.140.255254
142101.232.141.0/24101.232.141.1 to 101.232.141.254101.232.141.255254
143101.232.142.0/24101.232.142.1 to 101.232.142.254101.232.142.255254
144101.232.143.0/24101.232.143.1 to 101.232.143.254101.232.143.255254
145101.232.144.0/24101.232.144.1 to 101.232.144.254101.232.144.255254
146101.232.145.0/24101.232.145.1 to 101.232.145.254101.232.145.255254
147101.232.146.0/24101.232.146.1 to 101.232.146.254101.232.146.255254
148101.232.147.0/24101.232.147.1 to 101.232.147.254101.232.147.255254
149101.232.148.0/24101.232.148.1 to 101.232.148.254101.232.148.255254
150101.232.149.0/24101.232.149.1 to 101.232.149.254101.232.149.255254
151101.232.150.0/24101.232.150.1 to 101.232.150.254101.232.150.255254
152101.232.151.0/24101.232.151.1 to 101.232.151.254101.232.151.255254
153101.232.152.0/24101.232.152.1 to 101.232.152.254101.232.152.255254
154101.232.153.0/24101.232.153.1 to 101.232.153.254101.232.153.255254
155101.232.154.0/24101.232.154.1 to 101.232.154.254101.232.154.255254
156101.232.155.0/24101.232.155.1 to 101.232.155.254101.232.155.255254
157101.232.156.0/24101.232.156.1 to 101.232.156.254101.232.156.255254
158101.232.157.0/24101.232.157.1 to 101.232.157.254101.232.157.255254
159101.232.158.0/24101.232.158.1 to 101.232.158.254101.232.158.255254
160101.232.159.0/24101.232.159.1 to 101.232.159.254101.232.159.255254
161101.232.160.0/24101.232.160.1 to 101.232.160.254101.232.160.255254
162101.232.161.0/24101.232.161.1 to 101.232.161.254101.232.161.255254
163101.232.162.0/24101.232.162.1 to 101.232.162.254101.232.162.255254
164101.232.163.0/24101.232.163.1 to 101.232.163.254101.232.163.255254
165101.232.164.0/24101.232.164.1 to 101.232.164.254101.232.164.255254
166101.232.165.0/24101.232.165.1 to 101.232.165.254101.232.165.255254
167101.232.166.0/24101.232.166.1 to 101.232.166.254101.232.166.255254
168101.232.167.0/24101.232.167.1 to 101.232.167.254101.232.167.255254
169101.232.168.0/24101.232.168.1 to 101.232.168.254101.232.168.255254
170101.232.169.0/24101.232.169.1 to 101.232.169.254101.232.169.255254
171101.232.170.0/24101.232.170.1 to 101.232.170.254101.232.170.255254
172101.232.171.0/24101.232.171.1 to 101.232.171.254101.232.171.255254
173101.232.172.0/24101.232.172.1 to 101.232.172.254101.232.172.255254
174101.232.173.0/24101.232.173.1 to 101.232.173.254101.232.173.255254
175101.232.174.0/24101.232.174.1 to 101.232.174.254101.232.174.255254
176101.232.175.0/24101.232.175.1 to 101.232.175.254101.232.175.255254
177101.232.176.0/24101.232.176.1 to 101.232.176.254101.232.176.255254
178101.232.177.0/24101.232.177.1 to 101.232.177.254101.232.177.255254
179101.232.178.0/24101.232.178.1 to 101.232.178.254101.232.178.255254
180101.232.179.0/24101.232.179.1 to 101.232.179.254101.232.179.255254
181101.232.180.0/24101.232.180.1 to 101.232.180.254101.232.180.255254
182101.232.181.0/24101.232.181.1 to 101.232.181.254101.232.181.255254
183101.232.182.0/24101.232.182.1 to 101.232.182.254101.232.182.255254
184101.232.183.0/24101.232.183.1 to 101.232.183.254101.232.183.255254
185101.232.184.0/24101.232.184.1 to 101.232.184.254101.232.184.255254
186101.232.185.0/24101.232.185.1 to 101.232.185.254101.232.185.255254
187101.232.186.0/24101.232.186.1 to 101.232.186.254101.232.186.255254
188101.232.187.0/24101.232.187.1 to 101.232.187.254101.232.187.255254
189101.232.188.0/24101.232.188.1 to 101.232.188.254101.232.188.255254
190101.232.189.0/24101.232.189.1 to 101.232.189.254101.232.189.255254
191101.232.190.0/24101.232.190.1 to 101.232.190.254101.232.190.255254
192101.232.191.0/24101.232.191.1 to 101.232.191.254101.232.191.255254
193101.232.192.0/24101.232.192.1 to 101.232.192.254101.232.192.255254
194101.232.193.0/24101.232.193.1 to 101.232.193.254101.232.193.255254
195101.232.194.0/24101.232.194.1 to 101.232.194.254101.232.194.255254
196101.232.195.0/24101.232.195.1 to 101.232.195.254101.232.195.255254
197101.232.196.0/24101.232.196.1 to 101.232.196.254101.232.196.255254
198101.232.197.0/24101.232.197.1 to 101.232.197.254101.232.197.255254
199101.232.198.0/24101.232.198.1 to 101.232.198.254101.232.198.255254
200101.232.199.0/24101.232.199.1 to 101.232.199.254101.232.199.255254
201101.232.200.0/24101.232.200.1 to 101.232.200.254101.232.200.255254
202101.232.201.0/24101.232.201.1 to 101.232.201.254101.232.201.255254
203101.232.202.0/24101.232.202.1 to 101.232.202.254101.232.202.255254
204101.232.203.0/24101.232.203.1 to 101.232.203.254101.232.203.255254
205101.232.204.0/24101.232.204.1 to 101.232.204.254101.232.204.255254
206101.232.205.0/24101.232.205.1 to 101.232.205.254101.232.205.255254
207101.232.206.0/24101.232.206.1 to 101.232.206.254101.232.206.255254
208101.232.207.0/24101.232.207.1 to 101.232.207.254101.232.207.255254
209101.232.208.0/24101.232.208.1 to 101.232.208.254101.232.208.255254
210101.232.209.0/24101.232.209.1 to 101.232.209.254101.232.209.255254
211101.232.210.0/24101.232.210.1 to 101.232.210.254101.232.210.255254
212101.232.211.0/24101.232.211.1 to 101.232.211.254101.232.211.255254
213101.232.212.0/24101.232.212.1 to 101.232.212.254101.232.212.255254
214101.232.213.0/24101.232.213.1 to 101.232.213.254101.232.213.255254
215101.232.214.0/24101.232.214.1 to 101.232.214.254101.232.214.255254
216101.232.215.0/24101.232.215.1 to 101.232.215.254101.232.215.255254
217101.232.216.0/24101.232.216.1 to 101.232.216.254101.232.216.255254
218101.232.217.0/24101.232.217.1 to 101.232.217.254101.232.217.255254
219101.232.218.0/24101.232.218.1 to 101.232.218.254101.232.218.255254
220101.232.219.0/24101.232.219.1 to 101.232.219.254101.232.219.255254
221101.232.220.0/24101.232.220.1 to 101.232.220.254101.232.220.255254
222101.232.221.0/24101.232.221.1 to 101.232.221.254101.232.221.255254
223101.232.222.0/24101.232.222.1 to 101.232.222.254101.232.222.255254
224101.232.223.0/24101.232.223.1 to 101.232.223.254101.232.223.255254
225101.232.224.0/24101.232.224.1 to 101.232.224.254101.232.224.255254
226101.232.225.0/24101.232.225.1 to 101.232.225.254101.232.225.255254
227101.232.226.0/24101.232.226.1 to 101.232.226.254101.232.226.255254
228101.232.227.0/24101.232.227.1 to 101.232.227.254101.232.227.255254
229101.232.228.0/24101.232.228.1 to 101.232.228.254101.232.228.255254
230101.232.229.0/24101.232.229.1 to 101.232.229.254101.232.229.255254
231101.232.230.0/24101.232.230.1 to 101.232.230.254101.232.230.255254
232101.232.231.0/24101.232.231.1 to 101.232.231.254101.232.231.255254
233101.232.232.0/24101.232.232.1 to 101.232.232.254101.232.232.255254
234101.232.233.0/24101.232.233.1 to 101.232.233.254101.232.233.255254
235101.232.234.0/24101.232.234.1 to 101.232.234.254101.232.234.255254
236101.232.235.0/24101.232.235.1 to 101.232.235.254101.232.235.255254
237101.232.236.0/24101.232.236.1 to 101.232.236.254101.232.236.255254
238101.232.237.0/24101.232.237.1 to 101.232.237.254101.232.237.255254
239101.232.238.0/24101.232.238.1 to 101.232.238.254101.232.238.255254
240101.232.239.0/24101.232.239.1 to 101.232.239.254101.232.239.255254
241101.232.240.0/24101.232.240.1 to 101.232.240.254101.232.240.255254
242101.232.241.0/24101.232.241.1 to 101.232.241.254101.232.241.255254
243101.232.242.0/24101.232.242.1 to 101.232.242.254101.232.242.255254
244101.232.243.0/24101.232.243.1 to 101.232.243.254101.232.243.255254
245101.232.244.0/24101.232.244.1 to 101.232.244.254101.232.244.255254
246101.232.245.0/24101.232.245.1 to 101.232.245.254101.232.245.255254
247101.232.246.0/24101.232.246.1 to 101.232.246.254101.232.246.255254
248101.232.247.0/24101.232.247.1 to 101.232.247.254101.232.247.255254
249101.232.248.0/24101.232.248.1 to 101.232.248.254101.232.248.255254
250101.232.249.0/24101.232.249.1 to 101.232.249.254101.232.249.255254
251101.232.250.0/24101.232.250.1 to 101.232.250.254101.232.250.255254
252101.232.251.0/24101.232.251.1 to 101.232.251.254101.232.251.255254
253101.232.252.0/24101.232.252.1 to 101.232.252.254101.232.252.255254
254101.232.253.0/24101.232.253.1 to 101.232.253.254101.232.253.255254
255101.232.254.0/24101.232.254.1 to 101.232.254.254101.232.254.255254
256101.232.255.0/24101.232.255.1 to 101.232.255.254101.232.255.255254

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.