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.

Network14.97.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
14.97.64.0
Broadcast address
14.97.127.255
First usable
14.97.64.1
Last usable
14.97.127.254
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 0E614000 · Integer 241254400 to 241270783
Reverse DNS zones
64.97.14.in-addr.arpa
65.97.14.in-addr.arpa
66.97.14.in-addr.arpa
67.97.14.in-addr.arpa
68.97.14.in-addr.arpa
69.97.14.in-addr.arpa
70.97.14.in-addr.arpa
71.97.14.in-addr.arpa
72.97.14.in-addr.arpa
73.97.14.in-addr.arpa
74.97.14.in-addr.arpa
75.97.14.in-addr.arpa
76.97.14.in-addr.arpa
77.97.14.in-addr.arpa
78.97.14.in-addr.arpa
79.97.14.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
Address00001110.01100001.01000000.0000000014.97.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00001110.01100001.01000000.0000000014.97.64.0
Broadcast00001110.01100001.01111111.1111111114.97.127.255
Split into smaller subnets/26
/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)

14.97.64.0/18 makes 256 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
114.97.64.0/2614.97.64.1 to 14.97.64.6214.97.64.6362
214.97.64.64/2614.97.64.65 to 14.97.64.12614.97.64.12762
314.97.64.128/2614.97.64.129 to 14.97.64.19014.97.64.19162
414.97.64.192/2614.97.64.193 to 14.97.64.25414.97.64.25562
514.97.65.0/2614.97.65.1 to 14.97.65.6214.97.65.6362
614.97.65.64/2614.97.65.65 to 14.97.65.12614.97.65.12762
714.97.65.128/2614.97.65.129 to 14.97.65.19014.97.65.19162
814.97.65.192/2614.97.65.193 to 14.97.65.25414.97.65.25562
914.97.66.0/2614.97.66.1 to 14.97.66.6214.97.66.6362
1014.97.66.64/2614.97.66.65 to 14.97.66.12614.97.66.12762
1114.97.66.128/2614.97.66.129 to 14.97.66.19014.97.66.19162
1214.97.66.192/2614.97.66.193 to 14.97.66.25414.97.66.25562
1314.97.67.0/2614.97.67.1 to 14.97.67.6214.97.67.6362
1414.97.67.64/2614.97.67.65 to 14.97.67.12614.97.67.12762
1514.97.67.128/2614.97.67.129 to 14.97.67.19014.97.67.19162
1614.97.67.192/2614.97.67.193 to 14.97.67.25414.97.67.25562
1714.97.68.0/2614.97.68.1 to 14.97.68.6214.97.68.6362
1814.97.68.64/2614.97.68.65 to 14.97.68.12614.97.68.12762
1914.97.68.128/2614.97.68.129 to 14.97.68.19014.97.68.19162
2014.97.68.192/2614.97.68.193 to 14.97.68.25414.97.68.25562
2114.97.69.0/2614.97.69.1 to 14.97.69.6214.97.69.6362
2214.97.69.64/2614.97.69.65 to 14.97.69.12614.97.69.12762
2314.97.69.128/2614.97.69.129 to 14.97.69.19014.97.69.19162
2414.97.69.192/2614.97.69.193 to 14.97.69.25414.97.69.25562
2514.97.70.0/2614.97.70.1 to 14.97.70.6214.97.70.6362
2614.97.70.64/2614.97.70.65 to 14.97.70.12614.97.70.12762
2714.97.70.128/2614.97.70.129 to 14.97.70.19014.97.70.19162
2814.97.70.192/2614.97.70.193 to 14.97.70.25414.97.70.25562
2914.97.71.0/2614.97.71.1 to 14.97.71.6214.97.71.6362
3014.97.71.64/2614.97.71.65 to 14.97.71.12614.97.71.12762
3114.97.71.128/2614.97.71.129 to 14.97.71.19014.97.71.19162
3214.97.71.192/2614.97.71.193 to 14.97.71.25414.97.71.25562
3314.97.72.0/2614.97.72.1 to 14.97.72.6214.97.72.6362
3414.97.72.64/2614.97.72.65 to 14.97.72.12614.97.72.12762
3514.97.72.128/2614.97.72.129 to 14.97.72.19014.97.72.19162
3614.97.72.192/2614.97.72.193 to 14.97.72.25414.97.72.25562
3714.97.73.0/2614.97.73.1 to 14.97.73.6214.97.73.6362
3814.97.73.64/2614.97.73.65 to 14.97.73.12614.97.73.12762
3914.97.73.128/2614.97.73.129 to 14.97.73.19014.97.73.19162
4014.97.73.192/2614.97.73.193 to 14.97.73.25414.97.73.25562
4114.97.74.0/2614.97.74.1 to 14.97.74.6214.97.74.6362
4214.97.74.64/2614.97.74.65 to 14.97.74.12614.97.74.12762
4314.97.74.128/2614.97.74.129 to 14.97.74.19014.97.74.19162
4414.97.74.192/2614.97.74.193 to 14.97.74.25414.97.74.25562
4514.97.75.0/2614.97.75.1 to 14.97.75.6214.97.75.6362
4614.97.75.64/2614.97.75.65 to 14.97.75.12614.97.75.12762
4714.97.75.128/2614.97.75.129 to 14.97.75.19014.97.75.19162
4814.97.75.192/2614.97.75.193 to 14.97.75.25414.97.75.25562
4914.97.76.0/2614.97.76.1 to 14.97.76.6214.97.76.6362
5014.97.76.64/2614.97.76.65 to 14.97.76.12614.97.76.12762
5114.97.76.128/2614.97.76.129 to 14.97.76.19014.97.76.19162
5214.97.76.192/2614.97.76.193 to 14.97.76.25414.97.76.25562
5314.97.77.0/2614.97.77.1 to 14.97.77.6214.97.77.6362
5414.97.77.64/2614.97.77.65 to 14.97.77.12614.97.77.12762
5514.97.77.128/2614.97.77.129 to 14.97.77.19014.97.77.19162
5614.97.77.192/2614.97.77.193 to 14.97.77.25414.97.77.25562
5714.97.78.0/2614.97.78.1 to 14.97.78.6214.97.78.6362
5814.97.78.64/2614.97.78.65 to 14.97.78.12614.97.78.12762
5914.97.78.128/2614.97.78.129 to 14.97.78.19014.97.78.19162
6014.97.78.192/2614.97.78.193 to 14.97.78.25414.97.78.25562
6114.97.79.0/2614.97.79.1 to 14.97.79.6214.97.79.6362
6214.97.79.64/2614.97.79.65 to 14.97.79.12614.97.79.12762
6314.97.79.128/2614.97.79.129 to 14.97.79.19014.97.79.19162
6414.97.79.192/2614.97.79.193 to 14.97.79.25414.97.79.25562
6514.97.80.0/2614.97.80.1 to 14.97.80.6214.97.80.6362
6614.97.80.64/2614.97.80.65 to 14.97.80.12614.97.80.12762
6714.97.80.128/2614.97.80.129 to 14.97.80.19014.97.80.19162
6814.97.80.192/2614.97.80.193 to 14.97.80.25414.97.80.25562
6914.97.81.0/2614.97.81.1 to 14.97.81.6214.97.81.6362
7014.97.81.64/2614.97.81.65 to 14.97.81.12614.97.81.12762
7114.97.81.128/2614.97.81.129 to 14.97.81.19014.97.81.19162
7214.97.81.192/2614.97.81.193 to 14.97.81.25414.97.81.25562
7314.97.82.0/2614.97.82.1 to 14.97.82.6214.97.82.6362
7414.97.82.64/2614.97.82.65 to 14.97.82.12614.97.82.12762
7514.97.82.128/2614.97.82.129 to 14.97.82.19014.97.82.19162
7614.97.82.192/2614.97.82.193 to 14.97.82.25414.97.82.25562
7714.97.83.0/2614.97.83.1 to 14.97.83.6214.97.83.6362
7814.97.83.64/2614.97.83.65 to 14.97.83.12614.97.83.12762
7914.97.83.128/2614.97.83.129 to 14.97.83.19014.97.83.19162
8014.97.83.192/2614.97.83.193 to 14.97.83.25414.97.83.25562
8114.97.84.0/2614.97.84.1 to 14.97.84.6214.97.84.6362
8214.97.84.64/2614.97.84.65 to 14.97.84.12614.97.84.12762
8314.97.84.128/2614.97.84.129 to 14.97.84.19014.97.84.19162
8414.97.84.192/2614.97.84.193 to 14.97.84.25414.97.84.25562
8514.97.85.0/2614.97.85.1 to 14.97.85.6214.97.85.6362
8614.97.85.64/2614.97.85.65 to 14.97.85.12614.97.85.12762
8714.97.85.128/2614.97.85.129 to 14.97.85.19014.97.85.19162
8814.97.85.192/2614.97.85.193 to 14.97.85.25414.97.85.25562
8914.97.86.0/2614.97.86.1 to 14.97.86.6214.97.86.6362
9014.97.86.64/2614.97.86.65 to 14.97.86.12614.97.86.12762
9114.97.86.128/2614.97.86.129 to 14.97.86.19014.97.86.19162
9214.97.86.192/2614.97.86.193 to 14.97.86.25414.97.86.25562
9314.97.87.0/2614.97.87.1 to 14.97.87.6214.97.87.6362
9414.97.87.64/2614.97.87.65 to 14.97.87.12614.97.87.12762
9514.97.87.128/2614.97.87.129 to 14.97.87.19014.97.87.19162
9614.97.87.192/2614.97.87.193 to 14.97.87.25414.97.87.25562
9714.97.88.0/2614.97.88.1 to 14.97.88.6214.97.88.6362
9814.97.88.64/2614.97.88.65 to 14.97.88.12614.97.88.12762
9914.97.88.128/2614.97.88.129 to 14.97.88.19014.97.88.19162
10014.97.88.192/2614.97.88.193 to 14.97.88.25414.97.88.25562
10114.97.89.0/2614.97.89.1 to 14.97.89.6214.97.89.6362
10214.97.89.64/2614.97.89.65 to 14.97.89.12614.97.89.12762
10314.97.89.128/2614.97.89.129 to 14.97.89.19014.97.89.19162
10414.97.89.192/2614.97.89.193 to 14.97.89.25414.97.89.25562
10514.97.90.0/2614.97.90.1 to 14.97.90.6214.97.90.6362
10614.97.90.64/2614.97.90.65 to 14.97.90.12614.97.90.12762
10714.97.90.128/2614.97.90.129 to 14.97.90.19014.97.90.19162
10814.97.90.192/2614.97.90.193 to 14.97.90.25414.97.90.25562
10914.97.91.0/2614.97.91.1 to 14.97.91.6214.97.91.6362
11014.97.91.64/2614.97.91.65 to 14.97.91.12614.97.91.12762
11114.97.91.128/2614.97.91.129 to 14.97.91.19014.97.91.19162
11214.97.91.192/2614.97.91.193 to 14.97.91.25414.97.91.25562
11314.97.92.0/2614.97.92.1 to 14.97.92.6214.97.92.6362
11414.97.92.64/2614.97.92.65 to 14.97.92.12614.97.92.12762
11514.97.92.128/2614.97.92.129 to 14.97.92.19014.97.92.19162
11614.97.92.192/2614.97.92.193 to 14.97.92.25414.97.92.25562
11714.97.93.0/2614.97.93.1 to 14.97.93.6214.97.93.6362
11814.97.93.64/2614.97.93.65 to 14.97.93.12614.97.93.12762
11914.97.93.128/2614.97.93.129 to 14.97.93.19014.97.93.19162
12014.97.93.192/2614.97.93.193 to 14.97.93.25414.97.93.25562
12114.97.94.0/2614.97.94.1 to 14.97.94.6214.97.94.6362
12214.97.94.64/2614.97.94.65 to 14.97.94.12614.97.94.12762
12314.97.94.128/2614.97.94.129 to 14.97.94.19014.97.94.19162
12414.97.94.192/2614.97.94.193 to 14.97.94.25414.97.94.25562
12514.97.95.0/2614.97.95.1 to 14.97.95.6214.97.95.6362
12614.97.95.64/2614.97.95.65 to 14.97.95.12614.97.95.12762
12714.97.95.128/2614.97.95.129 to 14.97.95.19014.97.95.19162
12814.97.95.192/2614.97.95.193 to 14.97.95.25414.97.95.25562
12914.97.96.0/2614.97.96.1 to 14.97.96.6214.97.96.6362
13014.97.96.64/2614.97.96.65 to 14.97.96.12614.97.96.12762
13114.97.96.128/2614.97.96.129 to 14.97.96.19014.97.96.19162
13214.97.96.192/2614.97.96.193 to 14.97.96.25414.97.96.25562
13314.97.97.0/2614.97.97.1 to 14.97.97.6214.97.97.6362
13414.97.97.64/2614.97.97.65 to 14.97.97.12614.97.97.12762
13514.97.97.128/2614.97.97.129 to 14.97.97.19014.97.97.19162
13614.97.97.192/2614.97.97.193 to 14.97.97.25414.97.97.25562
13714.97.98.0/2614.97.98.1 to 14.97.98.6214.97.98.6362
13814.97.98.64/2614.97.98.65 to 14.97.98.12614.97.98.12762
13914.97.98.128/2614.97.98.129 to 14.97.98.19014.97.98.19162
14014.97.98.192/2614.97.98.193 to 14.97.98.25414.97.98.25562
14114.97.99.0/2614.97.99.1 to 14.97.99.6214.97.99.6362
14214.97.99.64/2614.97.99.65 to 14.97.99.12614.97.99.12762
14314.97.99.128/2614.97.99.129 to 14.97.99.19014.97.99.19162
14414.97.99.192/2614.97.99.193 to 14.97.99.25414.97.99.25562
14514.97.100.0/2614.97.100.1 to 14.97.100.6214.97.100.6362
14614.97.100.64/2614.97.100.65 to 14.97.100.12614.97.100.12762
14714.97.100.128/2614.97.100.129 to 14.97.100.19014.97.100.19162
14814.97.100.192/2614.97.100.193 to 14.97.100.25414.97.100.25562
14914.97.101.0/2614.97.101.1 to 14.97.101.6214.97.101.6362
15014.97.101.64/2614.97.101.65 to 14.97.101.12614.97.101.12762
15114.97.101.128/2614.97.101.129 to 14.97.101.19014.97.101.19162
15214.97.101.192/2614.97.101.193 to 14.97.101.25414.97.101.25562
15314.97.102.0/2614.97.102.1 to 14.97.102.6214.97.102.6362
15414.97.102.64/2614.97.102.65 to 14.97.102.12614.97.102.12762
15514.97.102.128/2614.97.102.129 to 14.97.102.19014.97.102.19162
15614.97.102.192/2614.97.102.193 to 14.97.102.25414.97.102.25562
15714.97.103.0/2614.97.103.1 to 14.97.103.6214.97.103.6362
15814.97.103.64/2614.97.103.65 to 14.97.103.12614.97.103.12762
15914.97.103.128/2614.97.103.129 to 14.97.103.19014.97.103.19162
16014.97.103.192/2614.97.103.193 to 14.97.103.25414.97.103.25562
16114.97.104.0/2614.97.104.1 to 14.97.104.6214.97.104.6362
16214.97.104.64/2614.97.104.65 to 14.97.104.12614.97.104.12762
16314.97.104.128/2614.97.104.129 to 14.97.104.19014.97.104.19162
16414.97.104.192/2614.97.104.193 to 14.97.104.25414.97.104.25562
16514.97.105.0/2614.97.105.1 to 14.97.105.6214.97.105.6362
16614.97.105.64/2614.97.105.65 to 14.97.105.12614.97.105.12762
16714.97.105.128/2614.97.105.129 to 14.97.105.19014.97.105.19162
16814.97.105.192/2614.97.105.193 to 14.97.105.25414.97.105.25562
16914.97.106.0/2614.97.106.1 to 14.97.106.6214.97.106.6362
17014.97.106.64/2614.97.106.65 to 14.97.106.12614.97.106.12762
17114.97.106.128/2614.97.106.129 to 14.97.106.19014.97.106.19162
17214.97.106.192/2614.97.106.193 to 14.97.106.25414.97.106.25562
17314.97.107.0/2614.97.107.1 to 14.97.107.6214.97.107.6362
17414.97.107.64/2614.97.107.65 to 14.97.107.12614.97.107.12762
17514.97.107.128/2614.97.107.129 to 14.97.107.19014.97.107.19162
17614.97.107.192/2614.97.107.193 to 14.97.107.25414.97.107.25562
17714.97.108.0/2614.97.108.1 to 14.97.108.6214.97.108.6362
17814.97.108.64/2614.97.108.65 to 14.97.108.12614.97.108.12762
17914.97.108.128/2614.97.108.129 to 14.97.108.19014.97.108.19162
18014.97.108.192/2614.97.108.193 to 14.97.108.25414.97.108.25562
18114.97.109.0/2614.97.109.1 to 14.97.109.6214.97.109.6362
18214.97.109.64/2614.97.109.65 to 14.97.109.12614.97.109.12762
18314.97.109.128/2614.97.109.129 to 14.97.109.19014.97.109.19162
18414.97.109.192/2614.97.109.193 to 14.97.109.25414.97.109.25562
18514.97.110.0/2614.97.110.1 to 14.97.110.6214.97.110.6362
18614.97.110.64/2614.97.110.65 to 14.97.110.12614.97.110.12762
18714.97.110.128/2614.97.110.129 to 14.97.110.19014.97.110.19162
18814.97.110.192/2614.97.110.193 to 14.97.110.25414.97.110.25562
18914.97.111.0/2614.97.111.1 to 14.97.111.6214.97.111.6362
19014.97.111.64/2614.97.111.65 to 14.97.111.12614.97.111.12762
19114.97.111.128/2614.97.111.129 to 14.97.111.19014.97.111.19162
19214.97.111.192/2614.97.111.193 to 14.97.111.25414.97.111.25562
19314.97.112.0/2614.97.112.1 to 14.97.112.6214.97.112.6362
19414.97.112.64/2614.97.112.65 to 14.97.112.12614.97.112.12762
19514.97.112.128/2614.97.112.129 to 14.97.112.19014.97.112.19162
19614.97.112.192/2614.97.112.193 to 14.97.112.25414.97.112.25562
19714.97.113.0/2614.97.113.1 to 14.97.113.6214.97.113.6362
19814.97.113.64/2614.97.113.65 to 14.97.113.12614.97.113.12762
19914.97.113.128/2614.97.113.129 to 14.97.113.19014.97.113.19162
20014.97.113.192/2614.97.113.193 to 14.97.113.25414.97.113.25562
20114.97.114.0/2614.97.114.1 to 14.97.114.6214.97.114.6362
20214.97.114.64/2614.97.114.65 to 14.97.114.12614.97.114.12762
20314.97.114.128/2614.97.114.129 to 14.97.114.19014.97.114.19162
20414.97.114.192/2614.97.114.193 to 14.97.114.25414.97.114.25562
20514.97.115.0/2614.97.115.1 to 14.97.115.6214.97.115.6362
20614.97.115.64/2614.97.115.65 to 14.97.115.12614.97.115.12762
20714.97.115.128/2614.97.115.129 to 14.97.115.19014.97.115.19162
20814.97.115.192/2614.97.115.193 to 14.97.115.25414.97.115.25562
20914.97.116.0/2614.97.116.1 to 14.97.116.6214.97.116.6362
21014.97.116.64/2614.97.116.65 to 14.97.116.12614.97.116.12762
21114.97.116.128/2614.97.116.129 to 14.97.116.19014.97.116.19162
21214.97.116.192/2614.97.116.193 to 14.97.116.25414.97.116.25562
21314.97.117.0/2614.97.117.1 to 14.97.117.6214.97.117.6362
21414.97.117.64/2614.97.117.65 to 14.97.117.12614.97.117.12762
21514.97.117.128/2614.97.117.129 to 14.97.117.19014.97.117.19162
21614.97.117.192/2614.97.117.193 to 14.97.117.25414.97.117.25562
21714.97.118.0/2614.97.118.1 to 14.97.118.6214.97.118.6362
21814.97.118.64/2614.97.118.65 to 14.97.118.12614.97.118.12762
21914.97.118.128/2614.97.118.129 to 14.97.118.19014.97.118.19162
22014.97.118.192/2614.97.118.193 to 14.97.118.25414.97.118.25562
22114.97.119.0/2614.97.119.1 to 14.97.119.6214.97.119.6362
22214.97.119.64/2614.97.119.65 to 14.97.119.12614.97.119.12762
22314.97.119.128/2614.97.119.129 to 14.97.119.19014.97.119.19162
22414.97.119.192/2614.97.119.193 to 14.97.119.25414.97.119.25562
22514.97.120.0/2614.97.120.1 to 14.97.120.6214.97.120.6362
22614.97.120.64/2614.97.120.65 to 14.97.120.12614.97.120.12762
22714.97.120.128/2614.97.120.129 to 14.97.120.19014.97.120.19162
22814.97.120.192/2614.97.120.193 to 14.97.120.25414.97.120.25562
22914.97.121.0/2614.97.121.1 to 14.97.121.6214.97.121.6362
23014.97.121.64/2614.97.121.65 to 14.97.121.12614.97.121.12762
23114.97.121.128/2614.97.121.129 to 14.97.121.19014.97.121.19162
23214.97.121.192/2614.97.121.193 to 14.97.121.25414.97.121.25562
23314.97.122.0/2614.97.122.1 to 14.97.122.6214.97.122.6362
23414.97.122.64/2614.97.122.65 to 14.97.122.12614.97.122.12762
23514.97.122.128/2614.97.122.129 to 14.97.122.19014.97.122.19162
23614.97.122.192/2614.97.122.193 to 14.97.122.25414.97.122.25562
23714.97.123.0/2614.97.123.1 to 14.97.123.6214.97.123.6362
23814.97.123.64/2614.97.123.65 to 14.97.123.12614.97.123.12762
23914.97.123.128/2614.97.123.129 to 14.97.123.19014.97.123.19162
24014.97.123.192/2614.97.123.193 to 14.97.123.25414.97.123.25562
24114.97.124.0/2614.97.124.1 to 14.97.124.6214.97.124.6362
24214.97.124.64/2614.97.124.65 to 14.97.124.12614.97.124.12762
24314.97.124.128/2614.97.124.129 to 14.97.124.19014.97.124.19162
24414.97.124.192/2614.97.124.193 to 14.97.124.25414.97.124.25562
24514.97.125.0/2614.97.125.1 to 14.97.125.6214.97.125.6362
24614.97.125.64/2614.97.125.65 to 14.97.125.12614.97.125.12762
24714.97.125.128/2614.97.125.129 to 14.97.125.19014.97.125.19162
24814.97.125.192/2614.97.125.193 to 14.97.125.25414.97.125.25562
24914.97.126.0/2614.97.126.1 to 14.97.126.6214.97.126.6362
25014.97.126.64/2614.97.126.65 to 14.97.126.12614.97.126.12762
25114.97.126.128/2614.97.126.129 to 14.97.126.19014.97.126.19162
25214.97.126.192/2614.97.126.193 to 14.97.126.25414.97.126.25562
25314.97.127.0/2614.97.127.1 to 14.97.127.6214.97.127.6362
25414.97.127.64/2614.97.127.65 to 14.97.127.12614.97.127.12762
25514.97.127.128/2614.97.127.129 to 14.97.127.19014.97.127.19162
25614.97.127.192/2614.97.127.193 to 14.97.127.25414.97.127.25562

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.