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.

Network26.41.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
26.41.0.0
Broadcast address
26.41.255.255
First usable
26.41.0.1
Last usable
26.41.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A290000 · Integer 438894592 to 438960127
Reverse DNS zone
41.26.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.00101001..00000000.0000000026.41.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00011010.00101001..00000000.0000000026.41.0.0
Broadcast00011010.00101001..11111111.1111111126.41.255.255
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

26.41.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.41.0.0/2426.41.0.1 to 26.41.0.25426.41.0.255254
226.41.1.0/2426.41.1.1 to 26.41.1.25426.41.1.255254
326.41.2.0/2426.41.2.1 to 26.41.2.25426.41.2.255254
426.41.3.0/2426.41.3.1 to 26.41.3.25426.41.3.255254
526.41.4.0/2426.41.4.1 to 26.41.4.25426.41.4.255254
626.41.5.0/2426.41.5.1 to 26.41.5.25426.41.5.255254
726.41.6.0/2426.41.6.1 to 26.41.6.25426.41.6.255254
826.41.7.0/2426.41.7.1 to 26.41.7.25426.41.7.255254
926.41.8.0/2426.41.8.1 to 26.41.8.25426.41.8.255254
1026.41.9.0/2426.41.9.1 to 26.41.9.25426.41.9.255254
1126.41.10.0/2426.41.10.1 to 26.41.10.25426.41.10.255254
1226.41.11.0/2426.41.11.1 to 26.41.11.25426.41.11.255254
1326.41.12.0/2426.41.12.1 to 26.41.12.25426.41.12.255254
1426.41.13.0/2426.41.13.1 to 26.41.13.25426.41.13.255254
1526.41.14.0/2426.41.14.1 to 26.41.14.25426.41.14.255254
1626.41.15.0/2426.41.15.1 to 26.41.15.25426.41.15.255254
1726.41.16.0/2426.41.16.1 to 26.41.16.25426.41.16.255254
1826.41.17.0/2426.41.17.1 to 26.41.17.25426.41.17.255254
1926.41.18.0/2426.41.18.1 to 26.41.18.25426.41.18.255254
2026.41.19.0/2426.41.19.1 to 26.41.19.25426.41.19.255254
2126.41.20.0/2426.41.20.1 to 26.41.20.25426.41.20.255254
2226.41.21.0/2426.41.21.1 to 26.41.21.25426.41.21.255254
2326.41.22.0/2426.41.22.1 to 26.41.22.25426.41.22.255254
2426.41.23.0/2426.41.23.1 to 26.41.23.25426.41.23.255254
2526.41.24.0/2426.41.24.1 to 26.41.24.25426.41.24.255254
2626.41.25.0/2426.41.25.1 to 26.41.25.25426.41.25.255254
2726.41.26.0/2426.41.26.1 to 26.41.26.25426.41.26.255254
2826.41.27.0/2426.41.27.1 to 26.41.27.25426.41.27.255254
2926.41.28.0/2426.41.28.1 to 26.41.28.25426.41.28.255254
3026.41.29.0/2426.41.29.1 to 26.41.29.25426.41.29.255254
3126.41.30.0/2426.41.30.1 to 26.41.30.25426.41.30.255254
3226.41.31.0/2426.41.31.1 to 26.41.31.25426.41.31.255254
3326.41.32.0/2426.41.32.1 to 26.41.32.25426.41.32.255254
3426.41.33.0/2426.41.33.1 to 26.41.33.25426.41.33.255254
3526.41.34.0/2426.41.34.1 to 26.41.34.25426.41.34.255254
3626.41.35.0/2426.41.35.1 to 26.41.35.25426.41.35.255254
3726.41.36.0/2426.41.36.1 to 26.41.36.25426.41.36.255254
3826.41.37.0/2426.41.37.1 to 26.41.37.25426.41.37.255254
3926.41.38.0/2426.41.38.1 to 26.41.38.25426.41.38.255254
4026.41.39.0/2426.41.39.1 to 26.41.39.25426.41.39.255254
4126.41.40.0/2426.41.40.1 to 26.41.40.25426.41.40.255254
4226.41.41.0/2426.41.41.1 to 26.41.41.25426.41.41.255254
4326.41.42.0/2426.41.42.1 to 26.41.42.25426.41.42.255254
4426.41.43.0/2426.41.43.1 to 26.41.43.25426.41.43.255254
4526.41.44.0/2426.41.44.1 to 26.41.44.25426.41.44.255254
4626.41.45.0/2426.41.45.1 to 26.41.45.25426.41.45.255254
4726.41.46.0/2426.41.46.1 to 26.41.46.25426.41.46.255254
4826.41.47.0/2426.41.47.1 to 26.41.47.25426.41.47.255254
4926.41.48.0/2426.41.48.1 to 26.41.48.25426.41.48.255254
5026.41.49.0/2426.41.49.1 to 26.41.49.25426.41.49.255254
5126.41.50.0/2426.41.50.1 to 26.41.50.25426.41.50.255254
5226.41.51.0/2426.41.51.1 to 26.41.51.25426.41.51.255254
5326.41.52.0/2426.41.52.1 to 26.41.52.25426.41.52.255254
5426.41.53.0/2426.41.53.1 to 26.41.53.25426.41.53.255254
5526.41.54.0/2426.41.54.1 to 26.41.54.25426.41.54.255254
5626.41.55.0/2426.41.55.1 to 26.41.55.25426.41.55.255254
5726.41.56.0/2426.41.56.1 to 26.41.56.25426.41.56.255254
5826.41.57.0/2426.41.57.1 to 26.41.57.25426.41.57.255254
5926.41.58.0/2426.41.58.1 to 26.41.58.25426.41.58.255254
6026.41.59.0/2426.41.59.1 to 26.41.59.25426.41.59.255254
6126.41.60.0/2426.41.60.1 to 26.41.60.25426.41.60.255254
6226.41.61.0/2426.41.61.1 to 26.41.61.25426.41.61.255254
6326.41.62.0/2426.41.62.1 to 26.41.62.25426.41.62.255254
6426.41.63.0/2426.41.63.1 to 26.41.63.25426.41.63.255254
6526.41.64.0/2426.41.64.1 to 26.41.64.25426.41.64.255254
6626.41.65.0/2426.41.65.1 to 26.41.65.25426.41.65.255254
6726.41.66.0/2426.41.66.1 to 26.41.66.25426.41.66.255254
6826.41.67.0/2426.41.67.1 to 26.41.67.25426.41.67.255254
6926.41.68.0/2426.41.68.1 to 26.41.68.25426.41.68.255254
7026.41.69.0/2426.41.69.1 to 26.41.69.25426.41.69.255254
7126.41.70.0/2426.41.70.1 to 26.41.70.25426.41.70.255254
7226.41.71.0/2426.41.71.1 to 26.41.71.25426.41.71.255254
7326.41.72.0/2426.41.72.1 to 26.41.72.25426.41.72.255254
7426.41.73.0/2426.41.73.1 to 26.41.73.25426.41.73.255254
7526.41.74.0/2426.41.74.1 to 26.41.74.25426.41.74.255254
7626.41.75.0/2426.41.75.1 to 26.41.75.25426.41.75.255254
7726.41.76.0/2426.41.76.1 to 26.41.76.25426.41.76.255254
7826.41.77.0/2426.41.77.1 to 26.41.77.25426.41.77.255254
7926.41.78.0/2426.41.78.1 to 26.41.78.25426.41.78.255254
8026.41.79.0/2426.41.79.1 to 26.41.79.25426.41.79.255254
8126.41.80.0/2426.41.80.1 to 26.41.80.25426.41.80.255254
8226.41.81.0/2426.41.81.1 to 26.41.81.25426.41.81.255254
8326.41.82.0/2426.41.82.1 to 26.41.82.25426.41.82.255254
8426.41.83.0/2426.41.83.1 to 26.41.83.25426.41.83.255254
8526.41.84.0/2426.41.84.1 to 26.41.84.25426.41.84.255254
8626.41.85.0/2426.41.85.1 to 26.41.85.25426.41.85.255254
8726.41.86.0/2426.41.86.1 to 26.41.86.25426.41.86.255254
8826.41.87.0/2426.41.87.1 to 26.41.87.25426.41.87.255254
8926.41.88.0/2426.41.88.1 to 26.41.88.25426.41.88.255254
9026.41.89.0/2426.41.89.1 to 26.41.89.25426.41.89.255254
9126.41.90.0/2426.41.90.1 to 26.41.90.25426.41.90.255254
9226.41.91.0/2426.41.91.1 to 26.41.91.25426.41.91.255254
9326.41.92.0/2426.41.92.1 to 26.41.92.25426.41.92.255254
9426.41.93.0/2426.41.93.1 to 26.41.93.25426.41.93.255254
9526.41.94.0/2426.41.94.1 to 26.41.94.25426.41.94.255254
9626.41.95.0/2426.41.95.1 to 26.41.95.25426.41.95.255254
9726.41.96.0/2426.41.96.1 to 26.41.96.25426.41.96.255254
9826.41.97.0/2426.41.97.1 to 26.41.97.25426.41.97.255254
9926.41.98.0/2426.41.98.1 to 26.41.98.25426.41.98.255254
10026.41.99.0/2426.41.99.1 to 26.41.99.25426.41.99.255254
10126.41.100.0/2426.41.100.1 to 26.41.100.25426.41.100.255254
10226.41.101.0/2426.41.101.1 to 26.41.101.25426.41.101.255254
10326.41.102.0/2426.41.102.1 to 26.41.102.25426.41.102.255254
10426.41.103.0/2426.41.103.1 to 26.41.103.25426.41.103.255254
10526.41.104.0/2426.41.104.1 to 26.41.104.25426.41.104.255254
10626.41.105.0/2426.41.105.1 to 26.41.105.25426.41.105.255254
10726.41.106.0/2426.41.106.1 to 26.41.106.25426.41.106.255254
10826.41.107.0/2426.41.107.1 to 26.41.107.25426.41.107.255254
10926.41.108.0/2426.41.108.1 to 26.41.108.25426.41.108.255254
11026.41.109.0/2426.41.109.1 to 26.41.109.25426.41.109.255254
11126.41.110.0/2426.41.110.1 to 26.41.110.25426.41.110.255254
11226.41.111.0/2426.41.111.1 to 26.41.111.25426.41.111.255254
11326.41.112.0/2426.41.112.1 to 26.41.112.25426.41.112.255254
11426.41.113.0/2426.41.113.1 to 26.41.113.25426.41.113.255254
11526.41.114.0/2426.41.114.1 to 26.41.114.25426.41.114.255254
11626.41.115.0/2426.41.115.1 to 26.41.115.25426.41.115.255254
11726.41.116.0/2426.41.116.1 to 26.41.116.25426.41.116.255254
11826.41.117.0/2426.41.117.1 to 26.41.117.25426.41.117.255254
11926.41.118.0/2426.41.118.1 to 26.41.118.25426.41.118.255254
12026.41.119.0/2426.41.119.1 to 26.41.119.25426.41.119.255254
12126.41.120.0/2426.41.120.1 to 26.41.120.25426.41.120.255254
12226.41.121.0/2426.41.121.1 to 26.41.121.25426.41.121.255254
12326.41.122.0/2426.41.122.1 to 26.41.122.25426.41.122.255254
12426.41.123.0/2426.41.123.1 to 26.41.123.25426.41.123.255254
12526.41.124.0/2426.41.124.1 to 26.41.124.25426.41.124.255254
12626.41.125.0/2426.41.125.1 to 26.41.125.25426.41.125.255254
12726.41.126.0/2426.41.126.1 to 26.41.126.25426.41.126.255254
12826.41.127.0/2426.41.127.1 to 26.41.127.25426.41.127.255254
12926.41.128.0/2426.41.128.1 to 26.41.128.25426.41.128.255254
13026.41.129.0/2426.41.129.1 to 26.41.129.25426.41.129.255254
13126.41.130.0/2426.41.130.1 to 26.41.130.25426.41.130.255254
13226.41.131.0/2426.41.131.1 to 26.41.131.25426.41.131.255254
13326.41.132.0/2426.41.132.1 to 26.41.132.25426.41.132.255254
13426.41.133.0/2426.41.133.1 to 26.41.133.25426.41.133.255254
13526.41.134.0/2426.41.134.1 to 26.41.134.25426.41.134.255254
13626.41.135.0/2426.41.135.1 to 26.41.135.25426.41.135.255254
13726.41.136.0/2426.41.136.1 to 26.41.136.25426.41.136.255254
13826.41.137.0/2426.41.137.1 to 26.41.137.25426.41.137.255254
13926.41.138.0/2426.41.138.1 to 26.41.138.25426.41.138.255254
14026.41.139.0/2426.41.139.1 to 26.41.139.25426.41.139.255254
14126.41.140.0/2426.41.140.1 to 26.41.140.25426.41.140.255254
14226.41.141.0/2426.41.141.1 to 26.41.141.25426.41.141.255254
14326.41.142.0/2426.41.142.1 to 26.41.142.25426.41.142.255254
14426.41.143.0/2426.41.143.1 to 26.41.143.25426.41.143.255254
14526.41.144.0/2426.41.144.1 to 26.41.144.25426.41.144.255254
14626.41.145.0/2426.41.145.1 to 26.41.145.25426.41.145.255254
14726.41.146.0/2426.41.146.1 to 26.41.146.25426.41.146.255254
14826.41.147.0/2426.41.147.1 to 26.41.147.25426.41.147.255254
14926.41.148.0/2426.41.148.1 to 26.41.148.25426.41.148.255254
15026.41.149.0/2426.41.149.1 to 26.41.149.25426.41.149.255254
15126.41.150.0/2426.41.150.1 to 26.41.150.25426.41.150.255254
15226.41.151.0/2426.41.151.1 to 26.41.151.25426.41.151.255254
15326.41.152.0/2426.41.152.1 to 26.41.152.25426.41.152.255254
15426.41.153.0/2426.41.153.1 to 26.41.153.25426.41.153.255254
15526.41.154.0/2426.41.154.1 to 26.41.154.25426.41.154.255254
15626.41.155.0/2426.41.155.1 to 26.41.155.25426.41.155.255254
15726.41.156.0/2426.41.156.1 to 26.41.156.25426.41.156.255254
15826.41.157.0/2426.41.157.1 to 26.41.157.25426.41.157.255254
15926.41.158.0/2426.41.158.1 to 26.41.158.25426.41.158.255254
16026.41.159.0/2426.41.159.1 to 26.41.159.25426.41.159.255254
16126.41.160.0/2426.41.160.1 to 26.41.160.25426.41.160.255254
16226.41.161.0/2426.41.161.1 to 26.41.161.25426.41.161.255254
16326.41.162.0/2426.41.162.1 to 26.41.162.25426.41.162.255254
16426.41.163.0/2426.41.163.1 to 26.41.163.25426.41.163.255254
16526.41.164.0/2426.41.164.1 to 26.41.164.25426.41.164.255254
16626.41.165.0/2426.41.165.1 to 26.41.165.25426.41.165.255254
16726.41.166.0/2426.41.166.1 to 26.41.166.25426.41.166.255254
16826.41.167.0/2426.41.167.1 to 26.41.167.25426.41.167.255254
16926.41.168.0/2426.41.168.1 to 26.41.168.25426.41.168.255254
17026.41.169.0/2426.41.169.1 to 26.41.169.25426.41.169.255254
17126.41.170.0/2426.41.170.1 to 26.41.170.25426.41.170.255254
17226.41.171.0/2426.41.171.1 to 26.41.171.25426.41.171.255254
17326.41.172.0/2426.41.172.1 to 26.41.172.25426.41.172.255254
17426.41.173.0/2426.41.173.1 to 26.41.173.25426.41.173.255254
17526.41.174.0/2426.41.174.1 to 26.41.174.25426.41.174.255254
17626.41.175.0/2426.41.175.1 to 26.41.175.25426.41.175.255254
17726.41.176.0/2426.41.176.1 to 26.41.176.25426.41.176.255254
17826.41.177.0/2426.41.177.1 to 26.41.177.25426.41.177.255254
17926.41.178.0/2426.41.178.1 to 26.41.178.25426.41.178.255254
18026.41.179.0/2426.41.179.1 to 26.41.179.25426.41.179.255254
18126.41.180.0/2426.41.180.1 to 26.41.180.25426.41.180.255254
18226.41.181.0/2426.41.181.1 to 26.41.181.25426.41.181.255254
18326.41.182.0/2426.41.182.1 to 26.41.182.25426.41.182.255254
18426.41.183.0/2426.41.183.1 to 26.41.183.25426.41.183.255254
18526.41.184.0/2426.41.184.1 to 26.41.184.25426.41.184.255254
18626.41.185.0/2426.41.185.1 to 26.41.185.25426.41.185.255254
18726.41.186.0/2426.41.186.1 to 26.41.186.25426.41.186.255254
18826.41.187.0/2426.41.187.1 to 26.41.187.25426.41.187.255254
18926.41.188.0/2426.41.188.1 to 26.41.188.25426.41.188.255254
19026.41.189.0/2426.41.189.1 to 26.41.189.25426.41.189.255254
19126.41.190.0/2426.41.190.1 to 26.41.190.25426.41.190.255254
19226.41.191.0/2426.41.191.1 to 26.41.191.25426.41.191.255254
19326.41.192.0/2426.41.192.1 to 26.41.192.25426.41.192.255254
19426.41.193.0/2426.41.193.1 to 26.41.193.25426.41.193.255254
19526.41.194.0/2426.41.194.1 to 26.41.194.25426.41.194.255254
19626.41.195.0/2426.41.195.1 to 26.41.195.25426.41.195.255254
19726.41.196.0/2426.41.196.1 to 26.41.196.25426.41.196.255254
19826.41.197.0/2426.41.197.1 to 26.41.197.25426.41.197.255254
19926.41.198.0/2426.41.198.1 to 26.41.198.25426.41.198.255254
20026.41.199.0/2426.41.199.1 to 26.41.199.25426.41.199.255254
20126.41.200.0/2426.41.200.1 to 26.41.200.25426.41.200.255254
20226.41.201.0/2426.41.201.1 to 26.41.201.25426.41.201.255254
20326.41.202.0/2426.41.202.1 to 26.41.202.25426.41.202.255254
20426.41.203.0/2426.41.203.1 to 26.41.203.25426.41.203.255254
20526.41.204.0/2426.41.204.1 to 26.41.204.25426.41.204.255254
20626.41.205.0/2426.41.205.1 to 26.41.205.25426.41.205.255254
20726.41.206.0/2426.41.206.1 to 26.41.206.25426.41.206.255254
20826.41.207.0/2426.41.207.1 to 26.41.207.25426.41.207.255254
20926.41.208.0/2426.41.208.1 to 26.41.208.25426.41.208.255254
21026.41.209.0/2426.41.209.1 to 26.41.209.25426.41.209.255254
21126.41.210.0/2426.41.210.1 to 26.41.210.25426.41.210.255254
21226.41.211.0/2426.41.211.1 to 26.41.211.25426.41.211.255254
21326.41.212.0/2426.41.212.1 to 26.41.212.25426.41.212.255254
21426.41.213.0/2426.41.213.1 to 26.41.213.25426.41.213.255254
21526.41.214.0/2426.41.214.1 to 26.41.214.25426.41.214.255254
21626.41.215.0/2426.41.215.1 to 26.41.215.25426.41.215.255254
21726.41.216.0/2426.41.216.1 to 26.41.216.25426.41.216.255254
21826.41.217.0/2426.41.217.1 to 26.41.217.25426.41.217.255254
21926.41.218.0/2426.41.218.1 to 26.41.218.25426.41.218.255254
22026.41.219.0/2426.41.219.1 to 26.41.219.25426.41.219.255254
22126.41.220.0/2426.41.220.1 to 26.41.220.25426.41.220.255254
22226.41.221.0/2426.41.221.1 to 26.41.221.25426.41.221.255254
22326.41.222.0/2426.41.222.1 to 26.41.222.25426.41.222.255254
22426.41.223.0/2426.41.223.1 to 26.41.223.25426.41.223.255254
22526.41.224.0/2426.41.224.1 to 26.41.224.25426.41.224.255254
22626.41.225.0/2426.41.225.1 to 26.41.225.25426.41.225.255254
22726.41.226.0/2426.41.226.1 to 26.41.226.25426.41.226.255254
22826.41.227.0/2426.41.227.1 to 26.41.227.25426.41.227.255254
22926.41.228.0/2426.41.228.1 to 26.41.228.25426.41.228.255254
23026.41.229.0/2426.41.229.1 to 26.41.229.25426.41.229.255254
23126.41.230.0/2426.41.230.1 to 26.41.230.25426.41.230.255254
23226.41.231.0/2426.41.231.1 to 26.41.231.25426.41.231.255254
23326.41.232.0/2426.41.232.1 to 26.41.232.25426.41.232.255254
23426.41.233.0/2426.41.233.1 to 26.41.233.25426.41.233.255254
23526.41.234.0/2426.41.234.1 to 26.41.234.25426.41.234.255254
23626.41.235.0/2426.41.235.1 to 26.41.235.25426.41.235.255254
23726.41.236.0/2426.41.236.1 to 26.41.236.25426.41.236.255254
23826.41.237.0/2426.41.237.1 to 26.41.237.25426.41.237.255254
23926.41.238.0/2426.41.238.1 to 26.41.238.25426.41.238.255254
24026.41.239.0/2426.41.239.1 to 26.41.239.25426.41.239.255254
24126.41.240.0/2426.41.240.1 to 26.41.240.25426.41.240.255254
24226.41.241.0/2426.41.241.1 to 26.41.241.25426.41.241.255254
24326.41.242.0/2426.41.242.1 to 26.41.242.25426.41.242.255254
24426.41.243.0/2426.41.243.1 to 26.41.243.25426.41.243.255254
24526.41.244.0/2426.41.244.1 to 26.41.244.25426.41.244.255254
24626.41.245.0/2426.41.245.1 to 26.41.245.25426.41.245.255254
24726.41.246.0/2426.41.246.1 to 26.41.246.25426.41.246.255254
24826.41.247.0/2426.41.247.1 to 26.41.247.25426.41.247.255254
24926.41.248.0/2426.41.248.1 to 26.41.248.25426.41.248.255254
25026.41.249.0/2426.41.249.1 to 26.41.249.25426.41.249.255254
25126.41.250.0/2426.41.250.1 to 26.41.250.25426.41.250.255254
25226.41.251.0/2426.41.251.1 to 26.41.251.25426.41.251.255254
25326.41.252.0/2426.41.252.1 to 26.41.252.25426.41.252.255254
25426.41.253.0/2426.41.253.1 to 26.41.253.25426.41.253.255254
25526.41.254.0/2426.41.254.1 to 26.41.254.25426.41.254.255254
25626.41.255.0/2426.41.255.1 to 26.41.255.25426.41.255.255254

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.