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.

Network16.52.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
16.52.0.0
Broadcast address
16.55.255.255
First usable
16.52.0.1
Last usable
16.55.255.254
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 10340000 · Integer 271843328 to 272105471
Reverse DNS zones
52.16.in-addr.arpa
53.16.in-addr.arpa
54.16.in-addr.arpa
55.16.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
Address00010000.00110100.00000000.0000000016.52.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network00010000.00110100.00000000.0000000016.52.0.0
Broadcast00010000.00110111.11111111.1111111116.55.255.255
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)

16.52.0.0/14 makes 1,024 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
116.52.0.0/2416.52.0.1 to 16.52.0.25416.52.0.255254
216.52.1.0/2416.52.1.1 to 16.52.1.25416.52.1.255254
316.52.2.0/2416.52.2.1 to 16.52.2.25416.52.2.255254
416.52.3.0/2416.52.3.1 to 16.52.3.25416.52.3.255254
516.52.4.0/2416.52.4.1 to 16.52.4.25416.52.4.255254
616.52.5.0/2416.52.5.1 to 16.52.5.25416.52.5.255254
716.52.6.0/2416.52.6.1 to 16.52.6.25416.52.6.255254
816.52.7.0/2416.52.7.1 to 16.52.7.25416.52.7.255254
916.52.8.0/2416.52.8.1 to 16.52.8.25416.52.8.255254
1016.52.9.0/2416.52.9.1 to 16.52.9.25416.52.9.255254
1116.52.10.0/2416.52.10.1 to 16.52.10.25416.52.10.255254
1216.52.11.0/2416.52.11.1 to 16.52.11.25416.52.11.255254
1316.52.12.0/2416.52.12.1 to 16.52.12.25416.52.12.255254
1416.52.13.0/2416.52.13.1 to 16.52.13.25416.52.13.255254
1516.52.14.0/2416.52.14.1 to 16.52.14.25416.52.14.255254
1616.52.15.0/2416.52.15.1 to 16.52.15.25416.52.15.255254
1716.52.16.0/2416.52.16.1 to 16.52.16.25416.52.16.255254
1816.52.17.0/2416.52.17.1 to 16.52.17.25416.52.17.255254
1916.52.18.0/2416.52.18.1 to 16.52.18.25416.52.18.255254
2016.52.19.0/2416.52.19.1 to 16.52.19.25416.52.19.255254
2116.52.20.0/2416.52.20.1 to 16.52.20.25416.52.20.255254
2216.52.21.0/2416.52.21.1 to 16.52.21.25416.52.21.255254
2316.52.22.0/2416.52.22.1 to 16.52.22.25416.52.22.255254
2416.52.23.0/2416.52.23.1 to 16.52.23.25416.52.23.255254
2516.52.24.0/2416.52.24.1 to 16.52.24.25416.52.24.255254
2616.52.25.0/2416.52.25.1 to 16.52.25.25416.52.25.255254
2716.52.26.0/2416.52.26.1 to 16.52.26.25416.52.26.255254
2816.52.27.0/2416.52.27.1 to 16.52.27.25416.52.27.255254
2916.52.28.0/2416.52.28.1 to 16.52.28.25416.52.28.255254
3016.52.29.0/2416.52.29.1 to 16.52.29.25416.52.29.255254
3116.52.30.0/2416.52.30.1 to 16.52.30.25416.52.30.255254
3216.52.31.0/2416.52.31.1 to 16.52.31.25416.52.31.255254
3316.52.32.0/2416.52.32.1 to 16.52.32.25416.52.32.255254
3416.52.33.0/2416.52.33.1 to 16.52.33.25416.52.33.255254
3516.52.34.0/2416.52.34.1 to 16.52.34.25416.52.34.255254
3616.52.35.0/2416.52.35.1 to 16.52.35.25416.52.35.255254
3716.52.36.0/2416.52.36.1 to 16.52.36.25416.52.36.255254
3816.52.37.0/2416.52.37.1 to 16.52.37.25416.52.37.255254
3916.52.38.0/2416.52.38.1 to 16.52.38.25416.52.38.255254
4016.52.39.0/2416.52.39.1 to 16.52.39.25416.52.39.255254
4116.52.40.0/2416.52.40.1 to 16.52.40.25416.52.40.255254
4216.52.41.0/2416.52.41.1 to 16.52.41.25416.52.41.255254
4316.52.42.0/2416.52.42.1 to 16.52.42.25416.52.42.255254
4416.52.43.0/2416.52.43.1 to 16.52.43.25416.52.43.255254
4516.52.44.0/2416.52.44.1 to 16.52.44.25416.52.44.255254
4616.52.45.0/2416.52.45.1 to 16.52.45.25416.52.45.255254
4716.52.46.0/2416.52.46.1 to 16.52.46.25416.52.46.255254
4816.52.47.0/2416.52.47.1 to 16.52.47.25416.52.47.255254
4916.52.48.0/2416.52.48.1 to 16.52.48.25416.52.48.255254
5016.52.49.0/2416.52.49.1 to 16.52.49.25416.52.49.255254
5116.52.50.0/2416.52.50.1 to 16.52.50.25416.52.50.255254
5216.52.51.0/2416.52.51.1 to 16.52.51.25416.52.51.255254
5316.52.52.0/2416.52.52.1 to 16.52.52.25416.52.52.255254
5416.52.53.0/2416.52.53.1 to 16.52.53.25416.52.53.255254
5516.52.54.0/2416.52.54.1 to 16.52.54.25416.52.54.255254
5616.52.55.0/2416.52.55.1 to 16.52.55.25416.52.55.255254
5716.52.56.0/2416.52.56.1 to 16.52.56.25416.52.56.255254
5816.52.57.0/2416.52.57.1 to 16.52.57.25416.52.57.255254
5916.52.58.0/2416.52.58.1 to 16.52.58.25416.52.58.255254
6016.52.59.0/2416.52.59.1 to 16.52.59.25416.52.59.255254
6116.52.60.0/2416.52.60.1 to 16.52.60.25416.52.60.255254
6216.52.61.0/2416.52.61.1 to 16.52.61.25416.52.61.255254
6316.52.62.0/2416.52.62.1 to 16.52.62.25416.52.62.255254
6416.52.63.0/2416.52.63.1 to 16.52.63.25416.52.63.255254
6516.52.64.0/2416.52.64.1 to 16.52.64.25416.52.64.255254
6616.52.65.0/2416.52.65.1 to 16.52.65.25416.52.65.255254
6716.52.66.0/2416.52.66.1 to 16.52.66.25416.52.66.255254
6816.52.67.0/2416.52.67.1 to 16.52.67.25416.52.67.255254
6916.52.68.0/2416.52.68.1 to 16.52.68.25416.52.68.255254
7016.52.69.0/2416.52.69.1 to 16.52.69.25416.52.69.255254
7116.52.70.0/2416.52.70.1 to 16.52.70.25416.52.70.255254
7216.52.71.0/2416.52.71.1 to 16.52.71.25416.52.71.255254
7316.52.72.0/2416.52.72.1 to 16.52.72.25416.52.72.255254
7416.52.73.0/2416.52.73.1 to 16.52.73.25416.52.73.255254
7516.52.74.0/2416.52.74.1 to 16.52.74.25416.52.74.255254
7616.52.75.0/2416.52.75.1 to 16.52.75.25416.52.75.255254
7716.52.76.0/2416.52.76.1 to 16.52.76.25416.52.76.255254
7816.52.77.0/2416.52.77.1 to 16.52.77.25416.52.77.255254
7916.52.78.0/2416.52.78.1 to 16.52.78.25416.52.78.255254
8016.52.79.0/2416.52.79.1 to 16.52.79.25416.52.79.255254
8116.52.80.0/2416.52.80.1 to 16.52.80.25416.52.80.255254
8216.52.81.0/2416.52.81.1 to 16.52.81.25416.52.81.255254
8316.52.82.0/2416.52.82.1 to 16.52.82.25416.52.82.255254
8416.52.83.0/2416.52.83.1 to 16.52.83.25416.52.83.255254
8516.52.84.0/2416.52.84.1 to 16.52.84.25416.52.84.255254
8616.52.85.0/2416.52.85.1 to 16.52.85.25416.52.85.255254
8716.52.86.0/2416.52.86.1 to 16.52.86.25416.52.86.255254
8816.52.87.0/2416.52.87.1 to 16.52.87.25416.52.87.255254
8916.52.88.0/2416.52.88.1 to 16.52.88.25416.52.88.255254
9016.52.89.0/2416.52.89.1 to 16.52.89.25416.52.89.255254
9116.52.90.0/2416.52.90.1 to 16.52.90.25416.52.90.255254
9216.52.91.0/2416.52.91.1 to 16.52.91.25416.52.91.255254
9316.52.92.0/2416.52.92.1 to 16.52.92.25416.52.92.255254
9416.52.93.0/2416.52.93.1 to 16.52.93.25416.52.93.255254
9516.52.94.0/2416.52.94.1 to 16.52.94.25416.52.94.255254
9616.52.95.0/2416.52.95.1 to 16.52.95.25416.52.95.255254
9716.52.96.0/2416.52.96.1 to 16.52.96.25416.52.96.255254
9816.52.97.0/2416.52.97.1 to 16.52.97.25416.52.97.255254
9916.52.98.0/2416.52.98.1 to 16.52.98.25416.52.98.255254
10016.52.99.0/2416.52.99.1 to 16.52.99.25416.52.99.255254
10116.52.100.0/2416.52.100.1 to 16.52.100.25416.52.100.255254
10216.52.101.0/2416.52.101.1 to 16.52.101.25416.52.101.255254
10316.52.102.0/2416.52.102.1 to 16.52.102.25416.52.102.255254
10416.52.103.0/2416.52.103.1 to 16.52.103.25416.52.103.255254
10516.52.104.0/2416.52.104.1 to 16.52.104.25416.52.104.255254
10616.52.105.0/2416.52.105.1 to 16.52.105.25416.52.105.255254
10716.52.106.0/2416.52.106.1 to 16.52.106.25416.52.106.255254
10816.52.107.0/2416.52.107.1 to 16.52.107.25416.52.107.255254
10916.52.108.0/2416.52.108.1 to 16.52.108.25416.52.108.255254
11016.52.109.0/2416.52.109.1 to 16.52.109.25416.52.109.255254
11116.52.110.0/2416.52.110.1 to 16.52.110.25416.52.110.255254
11216.52.111.0/2416.52.111.1 to 16.52.111.25416.52.111.255254
11316.52.112.0/2416.52.112.1 to 16.52.112.25416.52.112.255254
11416.52.113.0/2416.52.113.1 to 16.52.113.25416.52.113.255254
11516.52.114.0/2416.52.114.1 to 16.52.114.25416.52.114.255254
11616.52.115.0/2416.52.115.1 to 16.52.115.25416.52.115.255254
11716.52.116.0/2416.52.116.1 to 16.52.116.25416.52.116.255254
11816.52.117.0/2416.52.117.1 to 16.52.117.25416.52.117.255254
11916.52.118.0/2416.52.118.1 to 16.52.118.25416.52.118.255254
12016.52.119.0/2416.52.119.1 to 16.52.119.25416.52.119.255254
12116.52.120.0/2416.52.120.1 to 16.52.120.25416.52.120.255254
12216.52.121.0/2416.52.121.1 to 16.52.121.25416.52.121.255254
12316.52.122.0/2416.52.122.1 to 16.52.122.25416.52.122.255254
12416.52.123.0/2416.52.123.1 to 16.52.123.25416.52.123.255254
12516.52.124.0/2416.52.124.1 to 16.52.124.25416.52.124.255254
12616.52.125.0/2416.52.125.1 to 16.52.125.25416.52.125.255254
12716.52.126.0/2416.52.126.1 to 16.52.126.25416.52.126.255254
12816.52.127.0/2416.52.127.1 to 16.52.127.25416.52.127.255254
12916.52.128.0/2416.52.128.1 to 16.52.128.25416.52.128.255254
13016.52.129.0/2416.52.129.1 to 16.52.129.25416.52.129.255254
13116.52.130.0/2416.52.130.1 to 16.52.130.25416.52.130.255254
13216.52.131.0/2416.52.131.1 to 16.52.131.25416.52.131.255254
13316.52.132.0/2416.52.132.1 to 16.52.132.25416.52.132.255254
13416.52.133.0/2416.52.133.1 to 16.52.133.25416.52.133.255254
13516.52.134.0/2416.52.134.1 to 16.52.134.25416.52.134.255254
13616.52.135.0/2416.52.135.1 to 16.52.135.25416.52.135.255254
13716.52.136.0/2416.52.136.1 to 16.52.136.25416.52.136.255254
13816.52.137.0/2416.52.137.1 to 16.52.137.25416.52.137.255254
13916.52.138.0/2416.52.138.1 to 16.52.138.25416.52.138.255254
14016.52.139.0/2416.52.139.1 to 16.52.139.25416.52.139.255254
14116.52.140.0/2416.52.140.1 to 16.52.140.25416.52.140.255254
14216.52.141.0/2416.52.141.1 to 16.52.141.25416.52.141.255254
14316.52.142.0/2416.52.142.1 to 16.52.142.25416.52.142.255254
14416.52.143.0/2416.52.143.1 to 16.52.143.25416.52.143.255254
14516.52.144.0/2416.52.144.1 to 16.52.144.25416.52.144.255254
14616.52.145.0/2416.52.145.1 to 16.52.145.25416.52.145.255254
14716.52.146.0/2416.52.146.1 to 16.52.146.25416.52.146.255254
14816.52.147.0/2416.52.147.1 to 16.52.147.25416.52.147.255254
14916.52.148.0/2416.52.148.1 to 16.52.148.25416.52.148.255254
15016.52.149.0/2416.52.149.1 to 16.52.149.25416.52.149.255254
15116.52.150.0/2416.52.150.1 to 16.52.150.25416.52.150.255254
15216.52.151.0/2416.52.151.1 to 16.52.151.25416.52.151.255254
15316.52.152.0/2416.52.152.1 to 16.52.152.25416.52.152.255254
15416.52.153.0/2416.52.153.1 to 16.52.153.25416.52.153.255254
15516.52.154.0/2416.52.154.1 to 16.52.154.25416.52.154.255254
15616.52.155.0/2416.52.155.1 to 16.52.155.25416.52.155.255254
15716.52.156.0/2416.52.156.1 to 16.52.156.25416.52.156.255254
15816.52.157.0/2416.52.157.1 to 16.52.157.25416.52.157.255254
15916.52.158.0/2416.52.158.1 to 16.52.158.25416.52.158.255254
16016.52.159.0/2416.52.159.1 to 16.52.159.25416.52.159.255254
16116.52.160.0/2416.52.160.1 to 16.52.160.25416.52.160.255254
16216.52.161.0/2416.52.161.1 to 16.52.161.25416.52.161.255254
16316.52.162.0/2416.52.162.1 to 16.52.162.25416.52.162.255254
16416.52.163.0/2416.52.163.1 to 16.52.163.25416.52.163.255254
16516.52.164.0/2416.52.164.1 to 16.52.164.25416.52.164.255254
16616.52.165.0/2416.52.165.1 to 16.52.165.25416.52.165.255254
16716.52.166.0/2416.52.166.1 to 16.52.166.25416.52.166.255254
16816.52.167.0/2416.52.167.1 to 16.52.167.25416.52.167.255254
16916.52.168.0/2416.52.168.1 to 16.52.168.25416.52.168.255254
17016.52.169.0/2416.52.169.1 to 16.52.169.25416.52.169.255254
17116.52.170.0/2416.52.170.1 to 16.52.170.25416.52.170.255254
17216.52.171.0/2416.52.171.1 to 16.52.171.25416.52.171.255254
17316.52.172.0/2416.52.172.1 to 16.52.172.25416.52.172.255254
17416.52.173.0/2416.52.173.1 to 16.52.173.25416.52.173.255254
17516.52.174.0/2416.52.174.1 to 16.52.174.25416.52.174.255254
17616.52.175.0/2416.52.175.1 to 16.52.175.25416.52.175.255254
17716.52.176.0/2416.52.176.1 to 16.52.176.25416.52.176.255254
17816.52.177.0/2416.52.177.1 to 16.52.177.25416.52.177.255254
17916.52.178.0/2416.52.178.1 to 16.52.178.25416.52.178.255254
18016.52.179.0/2416.52.179.1 to 16.52.179.25416.52.179.255254
18116.52.180.0/2416.52.180.1 to 16.52.180.25416.52.180.255254
18216.52.181.0/2416.52.181.1 to 16.52.181.25416.52.181.255254
18316.52.182.0/2416.52.182.1 to 16.52.182.25416.52.182.255254
18416.52.183.0/2416.52.183.1 to 16.52.183.25416.52.183.255254
18516.52.184.0/2416.52.184.1 to 16.52.184.25416.52.184.255254
18616.52.185.0/2416.52.185.1 to 16.52.185.25416.52.185.255254
18716.52.186.0/2416.52.186.1 to 16.52.186.25416.52.186.255254
18816.52.187.0/2416.52.187.1 to 16.52.187.25416.52.187.255254
18916.52.188.0/2416.52.188.1 to 16.52.188.25416.52.188.255254
19016.52.189.0/2416.52.189.1 to 16.52.189.25416.52.189.255254
19116.52.190.0/2416.52.190.1 to 16.52.190.25416.52.190.255254
19216.52.191.0/2416.52.191.1 to 16.52.191.25416.52.191.255254
19316.52.192.0/2416.52.192.1 to 16.52.192.25416.52.192.255254
19416.52.193.0/2416.52.193.1 to 16.52.193.25416.52.193.255254
19516.52.194.0/2416.52.194.1 to 16.52.194.25416.52.194.255254
19616.52.195.0/2416.52.195.1 to 16.52.195.25416.52.195.255254
19716.52.196.0/2416.52.196.1 to 16.52.196.25416.52.196.255254
19816.52.197.0/2416.52.197.1 to 16.52.197.25416.52.197.255254
19916.52.198.0/2416.52.198.1 to 16.52.198.25416.52.198.255254
20016.52.199.0/2416.52.199.1 to 16.52.199.25416.52.199.255254
20116.52.200.0/2416.52.200.1 to 16.52.200.25416.52.200.255254
20216.52.201.0/2416.52.201.1 to 16.52.201.25416.52.201.255254
20316.52.202.0/2416.52.202.1 to 16.52.202.25416.52.202.255254
20416.52.203.0/2416.52.203.1 to 16.52.203.25416.52.203.255254
20516.52.204.0/2416.52.204.1 to 16.52.204.25416.52.204.255254
20616.52.205.0/2416.52.205.1 to 16.52.205.25416.52.205.255254
20716.52.206.0/2416.52.206.1 to 16.52.206.25416.52.206.255254
20816.52.207.0/2416.52.207.1 to 16.52.207.25416.52.207.255254
20916.52.208.0/2416.52.208.1 to 16.52.208.25416.52.208.255254
21016.52.209.0/2416.52.209.1 to 16.52.209.25416.52.209.255254
21116.52.210.0/2416.52.210.1 to 16.52.210.25416.52.210.255254
21216.52.211.0/2416.52.211.1 to 16.52.211.25416.52.211.255254
21316.52.212.0/2416.52.212.1 to 16.52.212.25416.52.212.255254
21416.52.213.0/2416.52.213.1 to 16.52.213.25416.52.213.255254
21516.52.214.0/2416.52.214.1 to 16.52.214.25416.52.214.255254
21616.52.215.0/2416.52.215.1 to 16.52.215.25416.52.215.255254
21716.52.216.0/2416.52.216.1 to 16.52.216.25416.52.216.255254
21816.52.217.0/2416.52.217.1 to 16.52.217.25416.52.217.255254
21916.52.218.0/2416.52.218.1 to 16.52.218.25416.52.218.255254
22016.52.219.0/2416.52.219.1 to 16.52.219.25416.52.219.255254
22116.52.220.0/2416.52.220.1 to 16.52.220.25416.52.220.255254
22216.52.221.0/2416.52.221.1 to 16.52.221.25416.52.221.255254
22316.52.222.0/2416.52.222.1 to 16.52.222.25416.52.222.255254
22416.52.223.0/2416.52.223.1 to 16.52.223.25416.52.223.255254
22516.52.224.0/2416.52.224.1 to 16.52.224.25416.52.224.255254
22616.52.225.0/2416.52.225.1 to 16.52.225.25416.52.225.255254
22716.52.226.0/2416.52.226.1 to 16.52.226.25416.52.226.255254
22816.52.227.0/2416.52.227.1 to 16.52.227.25416.52.227.255254
22916.52.228.0/2416.52.228.1 to 16.52.228.25416.52.228.255254
23016.52.229.0/2416.52.229.1 to 16.52.229.25416.52.229.255254
23116.52.230.0/2416.52.230.1 to 16.52.230.25416.52.230.255254
23216.52.231.0/2416.52.231.1 to 16.52.231.25416.52.231.255254
23316.52.232.0/2416.52.232.1 to 16.52.232.25416.52.232.255254
23416.52.233.0/2416.52.233.1 to 16.52.233.25416.52.233.255254
23516.52.234.0/2416.52.234.1 to 16.52.234.25416.52.234.255254
23616.52.235.0/2416.52.235.1 to 16.52.235.25416.52.235.255254
23716.52.236.0/2416.52.236.1 to 16.52.236.25416.52.236.255254
23816.52.237.0/2416.52.237.1 to 16.52.237.25416.52.237.255254
23916.52.238.0/2416.52.238.1 to 16.52.238.25416.52.238.255254
24016.52.239.0/2416.52.239.1 to 16.52.239.25416.52.239.255254
24116.52.240.0/2416.52.240.1 to 16.52.240.25416.52.240.255254
24216.52.241.0/2416.52.241.1 to 16.52.241.25416.52.241.255254
24316.52.242.0/2416.52.242.1 to 16.52.242.25416.52.242.255254
24416.52.243.0/2416.52.243.1 to 16.52.243.25416.52.243.255254
24516.52.244.0/2416.52.244.1 to 16.52.244.25416.52.244.255254
24616.52.245.0/2416.52.245.1 to 16.52.245.25416.52.245.255254
24716.52.246.0/2416.52.246.1 to 16.52.246.25416.52.246.255254
24816.52.247.0/2416.52.247.1 to 16.52.247.25416.52.247.255254
24916.52.248.0/2416.52.248.1 to 16.52.248.25416.52.248.255254
25016.52.249.0/2416.52.249.1 to 16.52.249.25416.52.249.255254
25116.52.250.0/2416.52.250.1 to 16.52.250.25416.52.250.255254
25216.52.251.0/2416.52.251.1 to 16.52.251.25416.52.251.255254
25316.52.252.0/2416.52.252.1 to 16.52.252.25416.52.252.255254
25416.52.253.0/2416.52.253.1 to 16.52.253.25416.52.253.255254
25516.52.254.0/2416.52.254.1 to 16.52.254.25416.52.254.255254
25616.52.255.0/2416.52.255.1 to 16.52.255.25416.52.255.255254

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.