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.

Network227.228.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
227.228.0.0
Broadcast address
227.231.255.255
First usable
227.228.0.1
Last usable
227.231.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E3E40000 · Integer 3823370240 to 3823632383
Reverse DNS zones
228.227.in-addr.arpa
229.227.in-addr.arpa
230.227.in-addr.arpa
231.227.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
Address11100011.11100100.00000000.00000000227.228.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11100011.11100100.00000000.00000000227.228.0.0
Broadcast11100011.11100111.11111111.11111111227.231.255.255
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)

227.228.0.0/14 makes 1,024 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1227.228.0.0/24227.228.0.1 to 227.228.0.254227.228.0.255254
2227.228.1.0/24227.228.1.1 to 227.228.1.254227.228.1.255254
3227.228.2.0/24227.228.2.1 to 227.228.2.254227.228.2.255254
4227.228.3.0/24227.228.3.1 to 227.228.3.254227.228.3.255254
5227.228.4.0/24227.228.4.1 to 227.228.4.254227.228.4.255254
6227.228.5.0/24227.228.5.1 to 227.228.5.254227.228.5.255254
7227.228.6.0/24227.228.6.1 to 227.228.6.254227.228.6.255254
8227.228.7.0/24227.228.7.1 to 227.228.7.254227.228.7.255254
9227.228.8.0/24227.228.8.1 to 227.228.8.254227.228.8.255254
10227.228.9.0/24227.228.9.1 to 227.228.9.254227.228.9.255254
11227.228.10.0/24227.228.10.1 to 227.228.10.254227.228.10.255254
12227.228.11.0/24227.228.11.1 to 227.228.11.254227.228.11.255254
13227.228.12.0/24227.228.12.1 to 227.228.12.254227.228.12.255254
14227.228.13.0/24227.228.13.1 to 227.228.13.254227.228.13.255254
15227.228.14.0/24227.228.14.1 to 227.228.14.254227.228.14.255254
16227.228.15.0/24227.228.15.1 to 227.228.15.254227.228.15.255254
17227.228.16.0/24227.228.16.1 to 227.228.16.254227.228.16.255254
18227.228.17.0/24227.228.17.1 to 227.228.17.254227.228.17.255254
19227.228.18.0/24227.228.18.1 to 227.228.18.254227.228.18.255254
20227.228.19.0/24227.228.19.1 to 227.228.19.254227.228.19.255254
21227.228.20.0/24227.228.20.1 to 227.228.20.254227.228.20.255254
22227.228.21.0/24227.228.21.1 to 227.228.21.254227.228.21.255254
23227.228.22.0/24227.228.22.1 to 227.228.22.254227.228.22.255254
24227.228.23.0/24227.228.23.1 to 227.228.23.254227.228.23.255254
25227.228.24.0/24227.228.24.1 to 227.228.24.254227.228.24.255254
26227.228.25.0/24227.228.25.1 to 227.228.25.254227.228.25.255254
27227.228.26.0/24227.228.26.1 to 227.228.26.254227.228.26.255254
28227.228.27.0/24227.228.27.1 to 227.228.27.254227.228.27.255254
29227.228.28.0/24227.228.28.1 to 227.228.28.254227.228.28.255254
30227.228.29.0/24227.228.29.1 to 227.228.29.254227.228.29.255254
31227.228.30.0/24227.228.30.1 to 227.228.30.254227.228.30.255254
32227.228.31.0/24227.228.31.1 to 227.228.31.254227.228.31.255254
33227.228.32.0/24227.228.32.1 to 227.228.32.254227.228.32.255254
34227.228.33.0/24227.228.33.1 to 227.228.33.254227.228.33.255254
35227.228.34.0/24227.228.34.1 to 227.228.34.254227.228.34.255254
36227.228.35.0/24227.228.35.1 to 227.228.35.254227.228.35.255254
37227.228.36.0/24227.228.36.1 to 227.228.36.254227.228.36.255254
38227.228.37.0/24227.228.37.1 to 227.228.37.254227.228.37.255254
39227.228.38.0/24227.228.38.1 to 227.228.38.254227.228.38.255254
40227.228.39.0/24227.228.39.1 to 227.228.39.254227.228.39.255254
41227.228.40.0/24227.228.40.1 to 227.228.40.254227.228.40.255254
42227.228.41.0/24227.228.41.1 to 227.228.41.254227.228.41.255254
43227.228.42.0/24227.228.42.1 to 227.228.42.254227.228.42.255254
44227.228.43.0/24227.228.43.1 to 227.228.43.254227.228.43.255254
45227.228.44.0/24227.228.44.1 to 227.228.44.254227.228.44.255254
46227.228.45.0/24227.228.45.1 to 227.228.45.254227.228.45.255254
47227.228.46.0/24227.228.46.1 to 227.228.46.254227.228.46.255254
48227.228.47.0/24227.228.47.1 to 227.228.47.254227.228.47.255254
49227.228.48.0/24227.228.48.1 to 227.228.48.254227.228.48.255254
50227.228.49.0/24227.228.49.1 to 227.228.49.254227.228.49.255254
51227.228.50.0/24227.228.50.1 to 227.228.50.254227.228.50.255254
52227.228.51.0/24227.228.51.1 to 227.228.51.254227.228.51.255254
53227.228.52.0/24227.228.52.1 to 227.228.52.254227.228.52.255254
54227.228.53.0/24227.228.53.1 to 227.228.53.254227.228.53.255254
55227.228.54.0/24227.228.54.1 to 227.228.54.254227.228.54.255254
56227.228.55.0/24227.228.55.1 to 227.228.55.254227.228.55.255254
57227.228.56.0/24227.228.56.1 to 227.228.56.254227.228.56.255254
58227.228.57.0/24227.228.57.1 to 227.228.57.254227.228.57.255254
59227.228.58.0/24227.228.58.1 to 227.228.58.254227.228.58.255254
60227.228.59.0/24227.228.59.1 to 227.228.59.254227.228.59.255254
61227.228.60.0/24227.228.60.1 to 227.228.60.254227.228.60.255254
62227.228.61.0/24227.228.61.1 to 227.228.61.254227.228.61.255254
63227.228.62.0/24227.228.62.1 to 227.228.62.254227.228.62.255254
64227.228.63.0/24227.228.63.1 to 227.228.63.254227.228.63.255254
65227.228.64.0/24227.228.64.1 to 227.228.64.254227.228.64.255254
66227.228.65.0/24227.228.65.1 to 227.228.65.254227.228.65.255254
67227.228.66.0/24227.228.66.1 to 227.228.66.254227.228.66.255254
68227.228.67.0/24227.228.67.1 to 227.228.67.254227.228.67.255254
69227.228.68.0/24227.228.68.1 to 227.228.68.254227.228.68.255254
70227.228.69.0/24227.228.69.1 to 227.228.69.254227.228.69.255254
71227.228.70.0/24227.228.70.1 to 227.228.70.254227.228.70.255254
72227.228.71.0/24227.228.71.1 to 227.228.71.254227.228.71.255254
73227.228.72.0/24227.228.72.1 to 227.228.72.254227.228.72.255254
74227.228.73.0/24227.228.73.1 to 227.228.73.254227.228.73.255254
75227.228.74.0/24227.228.74.1 to 227.228.74.254227.228.74.255254
76227.228.75.0/24227.228.75.1 to 227.228.75.254227.228.75.255254
77227.228.76.0/24227.228.76.1 to 227.228.76.254227.228.76.255254
78227.228.77.0/24227.228.77.1 to 227.228.77.254227.228.77.255254
79227.228.78.0/24227.228.78.1 to 227.228.78.254227.228.78.255254
80227.228.79.0/24227.228.79.1 to 227.228.79.254227.228.79.255254
81227.228.80.0/24227.228.80.1 to 227.228.80.254227.228.80.255254
82227.228.81.0/24227.228.81.1 to 227.228.81.254227.228.81.255254
83227.228.82.0/24227.228.82.1 to 227.228.82.254227.228.82.255254
84227.228.83.0/24227.228.83.1 to 227.228.83.254227.228.83.255254
85227.228.84.0/24227.228.84.1 to 227.228.84.254227.228.84.255254
86227.228.85.0/24227.228.85.1 to 227.228.85.254227.228.85.255254
87227.228.86.0/24227.228.86.1 to 227.228.86.254227.228.86.255254
88227.228.87.0/24227.228.87.1 to 227.228.87.254227.228.87.255254
89227.228.88.0/24227.228.88.1 to 227.228.88.254227.228.88.255254
90227.228.89.0/24227.228.89.1 to 227.228.89.254227.228.89.255254
91227.228.90.0/24227.228.90.1 to 227.228.90.254227.228.90.255254
92227.228.91.0/24227.228.91.1 to 227.228.91.254227.228.91.255254
93227.228.92.0/24227.228.92.1 to 227.228.92.254227.228.92.255254
94227.228.93.0/24227.228.93.1 to 227.228.93.254227.228.93.255254
95227.228.94.0/24227.228.94.1 to 227.228.94.254227.228.94.255254
96227.228.95.0/24227.228.95.1 to 227.228.95.254227.228.95.255254
97227.228.96.0/24227.228.96.1 to 227.228.96.254227.228.96.255254
98227.228.97.0/24227.228.97.1 to 227.228.97.254227.228.97.255254
99227.228.98.0/24227.228.98.1 to 227.228.98.254227.228.98.255254
100227.228.99.0/24227.228.99.1 to 227.228.99.254227.228.99.255254
101227.228.100.0/24227.228.100.1 to 227.228.100.254227.228.100.255254
102227.228.101.0/24227.228.101.1 to 227.228.101.254227.228.101.255254
103227.228.102.0/24227.228.102.1 to 227.228.102.254227.228.102.255254
104227.228.103.0/24227.228.103.1 to 227.228.103.254227.228.103.255254
105227.228.104.0/24227.228.104.1 to 227.228.104.254227.228.104.255254
106227.228.105.0/24227.228.105.1 to 227.228.105.254227.228.105.255254
107227.228.106.0/24227.228.106.1 to 227.228.106.254227.228.106.255254
108227.228.107.0/24227.228.107.1 to 227.228.107.254227.228.107.255254
109227.228.108.0/24227.228.108.1 to 227.228.108.254227.228.108.255254
110227.228.109.0/24227.228.109.1 to 227.228.109.254227.228.109.255254
111227.228.110.0/24227.228.110.1 to 227.228.110.254227.228.110.255254
112227.228.111.0/24227.228.111.1 to 227.228.111.254227.228.111.255254
113227.228.112.0/24227.228.112.1 to 227.228.112.254227.228.112.255254
114227.228.113.0/24227.228.113.1 to 227.228.113.254227.228.113.255254
115227.228.114.0/24227.228.114.1 to 227.228.114.254227.228.114.255254
116227.228.115.0/24227.228.115.1 to 227.228.115.254227.228.115.255254
117227.228.116.0/24227.228.116.1 to 227.228.116.254227.228.116.255254
118227.228.117.0/24227.228.117.1 to 227.228.117.254227.228.117.255254
119227.228.118.0/24227.228.118.1 to 227.228.118.254227.228.118.255254
120227.228.119.0/24227.228.119.1 to 227.228.119.254227.228.119.255254
121227.228.120.0/24227.228.120.1 to 227.228.120.254227.228.120.255254
122227.228.121.0/24227.228.121.1 to 227.228.121.254227.228.121.255254
123227.228.122.0/24227.228.122.1 to 227.228.122.254227.228.122.255254
124227.228.123.0/24227.228.123.1 to 227.228.123.254227.228.123.255254
125227.228.124.0/24227.228.124.1 to 227.228.124.254227.228.124.255254
126227.228.125.0/24227.228.125.1 to 227.228.125.254227.228.125.255254
127227.228.126.0/24227.228.126.1 to 227.228.126.254227.228.126.255254
128227.228.127.0/24227.228.127.1 to 227.228.127.254227.228.127.255254
129227.228.128.0/24227.228.128.1 to 227.228.128.254227.228.128.255254
130227.228.129.0/24227.228.129.1 to 227.228.129.254227.228.129.255254
131227.228.130.0/24227.228.130.1 to 227.228.130.254227.228.130.255254
132227.228.131.0/24227.228.131.1 to 227.228.131.254227.228.131.255254
133227.228.132.0/24227.228.132.1 to 227.228.132.254227.228.132.255254
134227.228.133.0/24227.228.133.1 to 227.228.133.254227.228.133.255254
135227.228.134.0/24227.228.134.1 to 227.228.134.254227.228.134.255254
136227.228.135.0/24227.228.135.1 to 227.228.135.254227.228.135.255254
137227.228.136.0/24227.228.136.1 to 227.228.136.254227.228.136.255254
138227.228.137.0/24227.228.137.1 to 227.228.137.254227.228.137.255254
139227.228.138.0/24227.228.138.1 to 227.228.138.254227.228.138.255254
140227.228.139.0/24227.228.139.1 to 227.228.139.254227.228.139.255254
141227.228.140.0/24227.228.140.1 to 227.228.140.254227.228.140.255254
142227.228.141.0/24227.228.141.1 to 227.228.141.254227.228.141.255254
143227.228.142.0/24227.228.142.1 to 227.228.142.254227.228.142.255254
144227.228.143.0/24227.228.143.1 to 227.228.143.254227.228.143.255254
145227.228.144.0/24227.228.144.1 to 227.228.144.254227.228.144.255254
146227.228.145.0/24227.228.145.1 to 227.228.145.254227.228.145.255254
147227.228.146.0/24227.228.146.1 to 227.228.146.254227.228.146.255254
148227.228.147.0/24227.228.147.1 to 227.228.147.254227.228.147.255254
149227.228.148.0/24227.228.148.1 to 227.228.148.254227.228.148.255254
150227.228.149.0/24227.228.149.1 to 227.228.149.254227.228.149.255254
151227.228.150.0/24227.228.150.1 to 227.228.150.254227.228.150.255254
152227.228.151.0/24227.228.151.1 to 227.228.151.254227.228.151.255254
153227.228.152.0/24227.228.152.1 to 227.228.152.254227.228.152.255254
154227.228.153.0/24227.228.153.1 to 227.228.153.254227.228.153.255254
155227.228.154.0/24227.228.154.1 to 227.228.154.254227.228.154.255254
156227.228.155.0/24227.228.155.1 to 227.228.155.254227.228.155.255254
157227.228.156.0/24227.228.156.1 to 227.228.156.254227.228.156.255254
158227.228.157.0/24227.228.157.1 to 227.228.157.254227.228.157.255254
159227.228.158.0/24227.228.158.1 to 227.228.158.254227.228.158.255254
160227.228.159.0/24227.228.159.1 to 227.228.159.254227.228.159.255254
161227.228.160.0/24227.228.160.1 to 227.228.160.254227.228.160.255254
162227.228.161.0/24227.228.161.1 to 227.228.161.254227.228.161.255254
163227.228.162.0/24227.228.162.1 to 227.228.162.254227.228.162.255254
164227.228.163.0/24227.228.163.1 to 227.228.163.254227.228.163.255254
165227.228.164.0/24227.228.164.1 to 227.228.164.254227.228.164.255254
166227.228.165.0/24227.228.165.1 to 227.228.165.254227.228.165.255254
167227.228.166.0/24227.228.166.1 to 227.228.166.254227.228.166.255254
168227.228.167.0/24227.228.167.1 to 227.228.167.254227.228.167.255254
169227.228.168.0/24227.228.168.1 to 227.228.168.254227.228.168.255254
170227.228.169.0/24227.228.169.1 to 227.228.169.254227.228.169.255254
171227.228.170.0/24227.228.170.1 to 227.228.170.254227.228.170.255254
172227.228.171.0/24227.228.171.1 to 227.228.171.254227.228.171.255254
173227.228.172.0/24227.228.172.1 to 227.228.172.254227.228.172.255254
174227.228.173.0/24227.228.173.1 to 227.228.173.254227.228.173.255254
175227.228.174.0/24227.228.174.1 to 227.228.174.254227.228.174.255254
176227.228.175.0/24227.228.175.1 to 227.228.175.254227.228.175.255254
177227.228.176.0/24227.228.176.1 to 227.228.176.254227.228.176.255254
178227.228.177.0/24227.228.177.1 to 227.228.177.254227.228.177.255254
179227.228.178.0/24227.228.178.1 to 227.228.178.254227.228.178.255254
180227.228.179.0/24227.228.179.1 to 227.228.179.254227.228.179.255254
181227.228.180.0/24227.228.180.1 to 227.228.180.254227.228.180.255254
182227.228.181.0/24227.228.181.1 to 227.228.181.254227.228.181.255254
183227.228.182.0/24227.228.182.1 to 227.228.182.254227.228.182.255254
184227.228.183.0/24227.228.183.1 to 227.228.183.254227.228.183.255254
185227.228.184.0/24227.228.184.1 to 227.228.184.254227.228.184.255254
186227.228.185.0/24227.228.185.1 to 227.228.185.254227.228.185.255254
187227.228.186.0/24227.228.186.1 to 227.228.186.254227.228.186.255254
188227.228.187.0/24227.228.187.1 to 227.228.187.254227.228.187.255254
189227.228.188.0/24227.228.188.1 to 227.228.188.254227.228.188.255254
190227.228.189.0/24227.228.189.1 to 227.228.189.254227.228.189.255254
191227.228.190.0/24227.228.190.1 to 227.228.190.254227.228.190.255254
192227.228.191.0/24227.228.191.1 to 227.228.191.254227.228.191.255254
193227.228.192.0/24227.228.192.1 to 227.228.192.254227.228.192.255254
194227.228.193.0/24227.228.193.1 to 227.228.193.254227.228.193.255254
195227.228.194.0/24227.228.194.1 to 227.228.194.254227.228.194.255254
196227.228.195.0/24227.228.195.1 to 227.228.195.254227.228.195.255254
197227.228.196.0/24227.228.196.1 to 227.228.196.254227.228.196.255254
198227.228.197.0/24227.228.197.1 to 227.228.197.254227.228.197.255254
199227.228.198.0/24227.228.198.1 to 227.228.198.254227.228.198.255254
200227.228.199.0/24227.228.199.1 to 227.228.199.254227.228.199.255254
201227.228.200.0/24227.228.200.1 to 227.228.200.254227.228.200.255254
202227.228.201.0/24227.228.201.1 to 227.228.201.254227.228.201.255254
203227.228.202.0/24227.228.202.1 to 227.228.202.254227.228.202.255254
204227.228.203.0/24227.228.203.1 to 227.228.203.254227.228.203.255254
205227.228.204.0/24227.228.204.1 to 227.228.204.254227.228.204.255254
206227.228.205.0/24227.228.205.1 to 227.228.205.254227.228.205.255254
207227.228.206.0/24227.228.206.1 to 227.228.206.254227.228.206.255254
208227.228.207.0/24227.228.207.1 to 227.228.207.254227.228.207.255254
209227.228.208.0/24227.228.208.1 to 227.228.208.254227.228.208.255254
210227.228.209.0/24227.228.209.1 to 227.228.209.254227.228.209.255254
211227.228.210.0/24227.228.210.1 to 227.228.210.254227.228.210.255254
212227.228.211.0/24227.228.211.1 to 227.228.211.254227.228.211.255254
213227.228.212.0/24227.228.212.1 to 227.228.212.254227.228.212.255254
214227.228.213.0/24227.228.213.1 to 227.228.213.254227.228.213.255254
215227.228.214.0/24227.228.214.1 to 227.228.214.254227.228.214.255254
216227.228.215.0/24227.228.215.1 to 227.228.215.254227.228.215.255254
217227.228.216.0/24227.228.216.1 to 227.228.216.254227.228.216.255254
218227.228.217.0/24227.228.217.1 to 227.228.217.254227.228.217.255254
219227.228.218.0/24227.228.218.1 to 227.228.218.254227.228.218.255254
220227.228.219.0/24227.228.219.1 to 227.228.219.254227.228.219.255254
221227.228.220.0/24227.228.220.1 to 227.228.220.254227.228.220.255254
222227.228.221.0/24227.228.221.1 to 227.228.221.254227.228.221.255254
223227.228.222.0/24227.228.222.1 to 227.228.222.254227.228.222.255254
224227.228.223.0/24227.228.223.1 to 227.228.223.254227.228.223.255254
225227.228.224.0/24227.228.224.1 to 227.228.224.254227.228.224.255254
226227.228.225.0/24227.228.225.1 to 227.228.225.254227.228.225.255254
227227.228.226.0/24227.228.226.1 to 227.228.226.254227.228.226.255254
228227.228.227.0/24227.228.227.1 to 227.228.227.254227.228.227.255254
229227.228.228.0/24227.228.228.1 to 227.228.228.254227.228.228.255254
230227.228.229.0/24227.228.229.1 to 227.228.229.254227.228.229.255254
231227.228.230.0/24227.228.230.1 to 227.228.230.254227.228.230.255254
232227.228.231.0/24227.228.231.1 to 227.228.231.254227.228.231.255254
233227.228.232.0/24227.228.232.1 to 227.228.232.254227.228.232.255254
234227.228.233.0/24227.228.233.1 to 227.228.233.254227.228.233.255254
235227.228.234.0/24227.228.234.1 to 227.228.234.254227.228.234.255254
236227.228.235.0/24227.228.235.1 to 227.228.235.254227.228.235.255254
237227.228.236.0/24227.228.236.1 to 227.228.236.254227.228.236.255254
238227.228.237.0/24227.228.237.1 to 227.228.237.254227.228.237.255254
239227.228.238.0/24227.228.238.1 to 227.228.238.254227.228.238.255254
240227.228.239.0/24227.228.239.1 to 227.228.239.254227.228.239.255254
241227.228.240.0/24227.228.240.1 to 227.228.240.254227.228.240.255254
242227.228.241.0/24227.228.241.1 to 227.228.241.254227.228.241.255254
243227.228.242.0/24227.228.242.1 to 227.228.242.254227.228.242.255254
244227.228.243.0/24227.228.243.1 to 227.228.243.254227.228.243.255254
245227.228.244.0/24227.228.244.1 to 227.228.244.254227.228.244.255254
246227.228.245.0/24227.228.245.1 to 227.228.245.254227.228.245.255254
247227.228.246.0/24227.228.246.1 to 227.228.246.254227.228.246.255254
248227.228.247.0/24227.228.247.1 to 227.228.247.254227.228.247.255254
249227.228.248.0/24227.228.248.1 to 227.228.248.254227.228.248.255254
250227.228.249.0/24227.228.249.1 to 227.228.249.254227.228.249.255254
251227.228.250.0/24227.228.250.1 to 227.228.250.254227.228.250.255254
252227.228.251.0/24227.228.251.1 to 227.228.251.254227.228.251.255254
253227.228.252.0/24227.228.252.1 to 227.228.252.254227.228.252.255254
254227.228.253.0/24227.228.253.1 to 227.228.253.254227.228.253.255254
255227.228.254.0/24227.228.254.1 to 227.228.254.254227.228.254.255254
256227.228.255.0/24227.228.255.1 to 227.228.255.254227.228.255.255254

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.