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.

Network9.4.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
9.4.0.0
Broadcast address
9.7.255.255
First usable
9.4.0.1
Last usable
9.7.255.254
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 09040000 · Integer 151257088 to 151519231
Reverse DNS zones
4.9.in-addr.arpa
5.9.in-addr.arpa
6.9.in-addr.arpa
7.9.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
Address00001001.00000100.00000000.000000009.4.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network00001001.00000100.00000000.000000009.4.0.0
Broadcast00001001.00000111.11111111.111111119.7.255.255
Split into smaller subnets/22
/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)

9.4.0.0/14 makes 256 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
19.4.0.0/229.4.0.1 to 9.4.3.2549.4.3.2551,022
29.4.4.0/229.4.4.1 to 9.4.7.2549.4.7.2551,022
39.4.8.0/229.4.8.1 to 9.4.11.2549.4.11.2551,022
49.4.12.0/229.4.12.1 to 9.4.15.2549.4.15.2551,022
59.4.16.0/229.4.16.1 to 9.4.19.2549.4.19.2551,022
69.4.20.0/229.4.20.1 to 9.4.23.2549.4.23.2551,022
79.4.24.0/229.4.24.1 to 9.4.27.2549.4.27.2551,022
89.4.28.0/229.4.28.1 to 9.4.31.2549.4.31.2551,022
99.4.32.0/229.4.32.1 to 9.4.35.2549.4.35.2551,022
109.4.36.0/229.4.36.1 to 9.4.39.2549.4.39.2551,022
119.4.40.0/229.4.40.1 to 9.4.43.2549.4.43.2551,022
129.4.44.0/229.4.44.1 to 9.4.47.2549.4.47.2551,022
139.4.48.0/229.4.48.1 to 9.4.51.2549.4.51.2551,022
149.4.52.0/229.4.52.1 to 9.4.55.2549.4.55.2551,022
159.4.56.0/229.4.56.1 to 9.4.59.2549.4.59.2551,022
169.4.60.0/229.4.60.1 to 9.4.63.2549.4.63.2551,022
179.4.64.0/229.4.64.1 to 9.4.67.2549.4.67.2551,022
189.4.68.0/229.4.68.1 to 9.4.71.2549.4.71.2551,022
199.4.72.0/229.4.72.1 to 9.4.75.2549.4.75.2551,022
209.4.76.0/229.4.76.1 to 9.4.79.2549.4.79.2551,022
219.4.80.0/229.4.80.1 to 9.4.83.2549.4.83.2551,022
229.4.84.0/229.4.84.1 to 9.4.87.2549.4.87.2551,022
239.4.88.0/229.4.88.1 to 9.4.91.2549.4.91.2551,022
249.4.92.0/229.4.92.1 to 9.4.95.2549.4.95.2551,022
259.4.96.0/229.4.96.1 to 9.4.99.2549.4.99.2551,022
269.4.100.0/229.4.100.1 to 9.4.103.2549.4.103.2551,022
279.4.104.0/229.4.104.1 to 9.4.107.2549.4.107.2551,022
289.4.108.0/229.4.108.1 to 9.4.111.2549.4.111.2551,022
299.4.112.0/229.4.112.1 to 9.4.115.2549.4.115.2551,022
309.4.116.0/229.4.116.1 to 9.4.119.2549.4.119.2551,022
319.4.120.0/229.4.120.1 to 9.4.123.2549.4.123.2551,022
329.4.124.0/229.4.124.1 to 9.4.127.2549.4.127.2551,022
339.4.128.0/229.4.128.1 to 9.4.131.2549.4.131.2551,022
349.4.132.0/229.4.132.1 to 9.4.135.2549.4.135.2551,022
359.4.136.0/229.4.136.1 to 9.4.139.2549.4.139.2551,022
369.4.140.0/229.4.140.1 to 9.4.143.2549.4.143.2551,022
379.4.144.0/229.4.144.1 to 9.4.147.2549.4.147.2551,022
389.4.148.0/229.4.148.1 to 9.4.151.2549.4.151.2551,022
399.4.152.0/229.4.152.1 to 9.4.155.2549.4.155.2551,022
409.4.156.0/229.4.156.1 to 9.4.159.2549.4.159.2551,022
419.4.160.0/229.4.160.1 to 9.4.163.2549.4.163.2551,022
429.4.164.0/229.4.164.1 to 9.4.167.2549.4.167.2551,022
439.4.168.0/229.4.168.1 to 9.4.171.2549.4.171.2551,022
449.4.172.0/229.4.172.1 to 9.4.175.2549.4.175.2551,022
459.4.176.0/229.4.176.1 to 9.4.179.2549.4.179.2551,022
469.4.180.0/229.4.180.1 to 9.4.183.2549.4.183.2551,022
479.4.184.0/229.4.184.1 to 9.4.187.2549.4.187.2551,022
489.4.188.0/229.4.188.1 to 9.4.191.2549.4.191.2551,022
499.4.192.0/229.4.192.1 to 9.4.195.2549.4.195.2551,022
509.4.196.0/229.4.196.1 to 9.4.199.2549.4.199.2551,022
519.4.200.0/229.4.200.1 to 9.4.203.2549.4.203.2551,022
529.4.204.0/229.4.204.1 to 9.4.207.2549.4.207.2551,022
539.4.208.0/229.4.208.1 to 9.4.211.2549.4.211.2551,022
549.4.212.0/229.4.212.1 to 9.4.215.2549.4.215.2551,022
559.4.216.0/229.4.216.1 to 9.4.219.2549.4.219.2551,022
569.4.220.0/229.4.220.1 to 9.4.223.2549.4.223.2551,022
579.4.224.0/229.4.224.1 to 9.4.227.2549.4.227.2551,022
589.4.228.0/229.4.228.1 to 9.4.231.2549.4.231.2551,022
599.4.232.0/229.4.232.1 to 9.4.235.2549.4.235.2551,022
609.4.236.0/229.4.236.1 to 9.4.239.2549.4.239.2551,022
619.4.240.0/229.4.240.1 to 9.4.243.2549.4.243.2551,022
629.4.244.0/229.4.244.1 to 9.4.247.2549.4.247.2551,022
639.4.248.0/229.4.248.1 to 9.4.251.2549.4.251.2551,022
649.4.252.0/229.4.252.1 to 9.4.255.2549.4.255.2551,022
659.5.0.0/229.5.0.1 to 9.5.3.2549.5.3.2551,022
669.5.4.0/229.5.4.1 to 9.5.7.2549.5.7.2551,022
679.5.8.0/229.5.8.1 to 9.5.11.2549.5.11.2551,022
689.5.12.0/229.5.12.1 to 9.5.15.2549.5.15.2551,022
699.5.16.0/229.5.16.1 to 9.5.19.2549.5.19.2551,022
709.5.20.0/229.5.20.1 to 9.5.23.2549.5.23.2551,022
719.5.24.0/229.5.24.1 to 9.5.27.2549.5.27.2551,022
729.5.28.0/229.5.28.1 to 9.5.31.2549.5.31.2551,022
739.5.32.0/229.5.32.1 to 9.5.35.2549.5.35.2551,022
749.5.36.0/229.5.36.1 to 9.5.39.2549.5.39.2551,022
759.5.40.0/229.5.40.1 to 9.5.43.2549.5.43.2551,022
769.5.44.0/229.5.44.1 to 9.5.47.2549.5.47.2551,022
779.5.48.0/229.5.48.1 to 9.5.51.2549.5.51.2551,022
789.5.52.0/229.5.52.1 to 9.5.55.2549.5.55.2551,022
799.5.56.0/229.5.56.1 to 9.5.59.2549.5.59.2551,022
809.5.60.0/229.5.60.1 to 9.5.63.2549.5.63.2551,022
819.5.64.0/229.5.64.1 to 9.5.67.2549.5.67.2551,022
829.5.68.0/229.5.68.1 to 9.5.71.2549.5.71.2551,022
839.5.72.0/229.5.72.1 to 9.5.75.2549.5.75.2551,022
849.5.76.0/229.5.76.1 to 9.5.79.2549.5.79.2551,022
859.5.80.0/229.5.80.1 to 9.5.83.2549.5.83.2551,022
869.5.84.0/229.5.84.1 to 9.5.87.2549.5.87.2551,022
879.5.88.0/229.5.88.1 to 9.5.91.2549.5.91.2551,022
889.5.92.0/229.5.92.1 to 9.5.95.2549.5.95.2551,022
899.5.96.0/229.5.96.1 to 9.5.99.2549.5.99.2551,022
909.5.100.0/229.5.100.1 to 9.5.103.2549.5.103.2551,022
919.5.104.0/229.5.104.1 to 9.5.107.2549.5.107.2551,022
929.5.108.0/229.5.108.1 to 9.5.111.2549.5.111.2551,022
939.5.112.0/229.5.112.1 to 9.5.115.2549.5.115.2551,022
949.5.116.0/229.5.116.1 to 9.5.119.2549.5.119.2551,022
959.5.120.0/229.5.120.1 to 9.5.123.2549.5.123.2551,022
969.5.124.0/229.5.124.1 to 9.5.127.2549.5.127.2551,022
979.5.128.0/229.5.128.1 to 9.5.131.2549.5.131.2551,022
989.5.132.0/229.5.132.1 to 9.5.135.2549.5.135.2551,022
999.5.136.0/229.5.136.1 to 9.5.139.2549.5.139.2551,022
1009.5.140.0/229.5.140.1 to 9.5.143.2549.5.143.2551,022
1019.5.144.0/229.5.144.1 to 9.5.147.2549.5.147.2551,022
1029.5.148.0/229.5.148.1 to 9.5.151.2549.5.151.2551,022
1039.5.152.0/229.5.152.1 to 9.5.155.2549.5.155.2551,022
1049.5.156.0/229.5.156.1 to 9.5.159.2549.5.159.2551,022
1059.5.160.0/229.5.160.1 to 9.5.163.2549.5.163.2551,022
1069.5.164.0/229.5.164.1 to 9.5.167.2549.5.167.2551,022
1079.5.168.0/229.5.168.1 to 9.5.171.2549.5.171.2551,022
1089.5.172.0/229.5.172.1 to 9.5.175.2549.5.175.2551,022
1099.5.176.0/229.5.176.1 to 9.5.179.2549.5.179.2551,022
1109.5.180.0/229.5.180.1 to 9.5.183.2549.5.183.2551,022
1119.5.184.0/229.5.184.1 to 9.5.187.2549.5.187.2551,022
1129.5.188.0/229.5.188.1 to 9.5.191.2549.5.191.2551,022
1139.5.192.0/229.5.192.1 to 9.5.195.2549.5.195.2551,022
1149.5.196.0/229.5.196.1 to 9.5.199.2549.5.199.2551,022
1159.5.200.0/229.5.200.1 to 9.5.203.2549.5.203.2551,022
1169.5.204.0/229.5.204.1 to 9.5.207.2549.5.207.2551,022
1179.5.208.0/229.5.208.1 to 9.5.211.2549.5.211.2551,022
1189.5.212.0/229.5.212.1 to 9.5.215.2549.5.215.2551,022
1199.5.216.0/229.5.216.1 to 9.5.219.2549.5.219.2551,022
1209.5.220.0/229.5.220.1 to 9.5.223.2549.5.223.2551,022
1219.5.224.0/229.5.224.1 to 9.5.227.2549.5.227.2551,022
1229.5.228.0/229.5.228.1 to 9.5.231.2549.5.231.2551,022
1239.5.232.0/229.5.232.1 to 9.5.235.2549.5.235.2551,022
1249.5.236.0/229.5.236.1 to 9.5.239.2549.5.239.2551,022
1259.5.240.0/229.5.240.1 to 9.5.243.2549.5.243.2551,022
1269.5.244.0/229.5.244.1 to 9.5.247.2549.5.247.2551,022
1279.5.248.0/229.5.248.1 to 9.5.251.2549.5.251.2551,022
1289.5.252.0/229.5.252.1 to 9.5.255.2549.5.255.2551,022
1299.6.0.0/229.6.0.1 to 9.6.3.2549.6.3.2551,022
1309.6.4.0/229.6.4.1 to 9.6.7.2549.6.7.2551,022
1319.6.8.0/229.6.8.1 to 9.6.11.2549.6.11.2551,022
1329.6.12.0/229.6.12.1 to 9.6.15.2549.6.15.2551,022
1339.6.16.0/229.6.16.1 to 9.6.19.2549.6.19.2551,022
1349.6.20.0/229.6.20.1 to 9.6.23.2549.6.23.2551,022
1359.6.24.0/229.6.24.1 to 9.6.27.2549.6.27.2551,022
1369.6.28.0/229.6.28.1 to 9.6.31.2549.6.31.2551,022
1379.6.32.0/229.6.32.1 to 9.6.35.2549.6.35.2551,022
1389.6.36.0/229.6.36.1 to 9.6.39.2549.6.39.2551,022
1399.6.40.0/229.6.40.1 to 9.6.43.2549.6.43.2551,022
1409.6.44.0/229.6.44.1 to 9.6.47.2549.6.47.2551,022
1419.6.48.0/229.6.48.1 to 9.6.51.2549.6.51.2551,022
1429.6.52.0/229.6.52.1 to 9.6.55.2549.6.55.2551,022
1439.6.56.0/229.6.56.1 to 9.6.59.2549.6.59.2551,022
1449.6.60.0/229.6.60.1 to 9.6.63.2549.6.63.2551,022
1459.6.64.0/229.6.64.1 to 9.6.67.2549.6.67.2551,022
1469.6.68.0/229.6.68.1 to 9.6.71.2549.6.71.2551,022
1479.6.72.0/229.6.72.1 to 9.6.75.2549.6.75.2551,022
1489.6.76.0/229.6.76.1 to 9.6.79.2549.6.79.2551,022
1499.6.80.0/229.6.80.1 to 9.6.83.2549.6.83.2551,022
1509.6.84.0/229.6.84.1 to 9.6.87.2549.6.87.2551,022
1519.6.88.0/229.6.88.1 to 9.6.91.2549.6.91.2551,022
1529.6.92.0/229.6.92.1 to 9.6.95.2549.6.95.2551,022
1539.6.96.0/229.6.96.1 to 9.6.99.2549.6.99.2551,022
1549.6.100.0/229.6.100.1 to 9.6.103.2549.6.103.2551,022
1559.6.104.0/229.6.104.1 to 9.6.107.2549.6.107.2551,022
1569.6.108.0/229.6.108.1 to 9.6.111.2549.6.111.2551,022
1579.6.112.0/229.6.112.1 to 9.6.115.2549.6.115.2551,022
1589.6.116.0/229.6.116.1 to 9.6.119.2549.6.119.2551,022
1599.6.120.0/229.6.120.1 to 9.6.123.2549.6.123.2551,022
1609.6.124.0/229.6.124.1 to 9.6.127.2549.6.127.2551,022
1619.6.128.0/229.6.128.1 to 9.6.131.2549.6.131.2551,022
1629.6.132.0/229.6.132.1 to 9.6.135.2549.6.135.2551,022
1639.6.136.0/229.6.136.1 to 9.6.139.2549.6.139.2551,022
1649.6.140.0/229.6.140.1 to 9.6.143.2549.6.143.2551,022
1659.6.144.0/229.6.144.1 to 9.6.147.2549.6.147.2551,022
1669.6.148.0/229.6.148.1 to 9.6.151.2549.6.151.2551,022
1679.6.152.0/229.6.152.1 to 9.6.155.2549.6.155.2551,022
1689.6.156.0/229.6.156.1 to 9.6.159.2549.6.159.2551,022
1699.6.160.0/229.6.160.1 to 9.6.163.2549.6.163.2551,022
1709.6.164.0/229.6.164.1 to 9.6.167.2549.6.167.2551,022
1719.6.168.0/229.6.168.1 to 9.6.171.2549.6.171.2551,022
1729.6.172.0/229.6.172.1 to 9.6.175.2549.6.175.2551,022
1739.6.176.0/229.6.176.1 to 9.6.179.2549.6.179.2551,022
1749.6.180.0/229.6.180.1 to 9.6.183.2549.6.183.2551,022
1759.6.184.0/229.6.184.1 to 9.6.187.2549.6.187.2551,022
1769.6.188.0/229.6.188.1 to 9.6.191.2549.6.191.2551,022
1779.6.192.0/229.6.192.1 to 9.6.195.2549.6.195.2551,022
1789.6.196.0/229.6.196.1 to 9.6.199.2549.6.199.2551,022
1799.6.200.0/229.6.200.1 to 9.6.203.2549.6.203.2551,022
1809.6.204.0/229.6.204.1 to 9.6.207.2549.6.207.2551,022
1819.6.208.0/229.6.208.1 to 9.6.211.2549.6.211.2551,022
1829.6.212.0/229.6.212.1 to 9.6.215.2549.6.215.2551,022
1839.6.216.0/229.6.216.1 to 9.6.219.2549.6.219.2551,022
1849.6.220.0/229.6.220.1 to 9.6.223.2549.6.223.2551,022
1859.6.224.0/229.6.224.1 to 9.6.227.2549.6.227.2551,022
1869.6.228.0/229.6.228.1 to 9.6.231.2549.6.231.2551,022
1879.6.232.0/229.6.232.1 to 9.6.235.2549.6.235.2551,022
1889.6.236.0/229.6.236.1 to 9.6.239.2549.6.239.2551,022
1899.6.240.0/229.6.240.1 to 9.6.243.2549.6.243.2551,022
1909.6.244.0/229.6.244.1 to 9.6.247.2549.6.247.2551,022
1919.6.248.0/229.6.248.1 to 9.6.251.2549.6.251.2551,022
1929.6.252.0/229.6.252.1 to 9.6.255.2549.6.255.2551,022
1939.7.0.0/229.7.0.1 to 9.7.3.2549.7.3.2551,022
1949.7.4.0/229.7.4.1 to 9.7.7.2549.7.7.2551,022
1959.7.8.0/229.7.8.1 to 9.7.11.2549.7.11.2551,022
1969.7.12.0/229.7.12.1 to 9.7.15.2549.7.15.2551,022
1979.7.16.0/229.7.16.1 to 9.7.19.2549.7.19.2551,022
1989.7.20.0/229.7.20.1 to 9.7.23.2549.7.23.2551,022
1999.7.24.0/229.7.24.1 to 9.7.27.2549.7.27.2551,022
2009.7.28.0/229.7.28.1 to 9.7.31.2549.7.31.2551,022
2019.7.32.0/229.7.32.1 to 9.7.35.2549.7.35.2551,022
2029.7.36.0/229.7.36.1 to 9.7.39.2549.7.39.2551,022
2039.7.40.0/229.7.40.1 to 9.7.43.2549.7.43.2551,022
2049.7.44.0/229.7.44.1 to 9.7.47.2549.7.47.2551,022
2059.7.48.0/229.7.48.1 to 9.7.51.2549.7.51.2551,022
2069.7.52.0/229.7.52.1 to 9.7.55.2549.7.55.2551,022
2079.7.56.0/229.7.56.1 to 9.7.59.2549.7.59.2551,022
2089.7.60.0/229.7.60.1 to 9.7.63.2549.7.63.2551,022
2099.7.64.0/229.7.64.1 to 9.7.67.2549.7.67.2551,022
2109.7.68.0/229.7.68.1 to 9.7.71.2549.7.71.2551,022
2119.7.72.0/229.7.72.1 to 9.7.75.2549.7.75.2551,022
2129.7.76.0/229.7.76.1 to 9.7.79.2549.7.79.2551,022
2139.7.80.0/229.7.80.1 to 9.7.83.2549.7.83.2551,022
2149.7.84.0/229.7.84.1 to 9.7.87.2549.7.87.2551,022
2159.7.88.0/229.7.88.1 to 9.7.91.2549.7.91.2551,022
2169.7.92.0/229.7.92.1 to 9.7.95.2549.7.95.2551,022
2179.7.96.0/229.7.96.1 to 9.7.99.2549.7.99.2551,022
2189.7.100.0/229.7.100.1 to 9.7.103.2549.7.103.2551,022
2199.7.104.0/229.7.104.1 to 9.7.107.2549.7.107.2551,022
2209.7.108.0/229.7.108.1 to 9.7.111.2549.7.111.2551,022
2219.7.112.0/229.7.112.1 to 9.7.115.2549.7.115.2551,022
2229.7.116.0/229.7.116.1 to 9.7.119.2549.7.119.2551,022
2239.7.120.0/229.7.120.1 to 9.7.123.2549.7.123.2551,022
2249.7.124.0/229.7.124.1 to 9.7.127.2549.7.127.2551,022
2259.7.128.0/229.7.128.1 to 9.7.131.2549.7.131.2551,022
2269.7.132.0/229.7.132.1 to 9.7.135.2549.7.135.2551,022
2279.7.136.0/229.7.136.1 to 9.7.139.2549.7.139.2551,022
2289.7.140.0/229.7.140.1 to 9.7.143.2549.7.143.2551,022
2299.7.144.0/229.7.144.1 to 9.7.147.2549.7.147.2551,022
2309.7.148.0/229.7.148.1 to 9.7.151.2549.7.151.2551,022
2319.7.152.0/229.7.152.1 to 9.7.155.2549.7.155.2551,022
2329.7.156.0/229.7.156.1 to 9.7.159.2549.7.159.2551,022
2339.7.160.0/229.7.160.1 to 9.7.163.2549.7.163.2551,022
2349.7.164.0/229.7.164.1 to 9.7.167.2549.7.167.2551,022
2359.7.168.0/229.7.168.1 to 9.7.171.2549.7.171.2551,022
2369.7.172.0/229.7.172.1 to 9.7.175.2549.7.175.2551,022
2379.7.176.0/229.7.176.1 to 9.7.179.2549.7.179.2551,022
2389.7.180.0/229.7.180.1 to 9.7.183.2549.7.183.2551,022
2399.7.184.0/229.7.184.1 to 9.7.187.2549.7.187.2551,022
2409.7.188.0/229.7.188.1 to 9.7.191.2549.7.191.2551,022
2419.7.192.0/229.7.192.1 to 9.7.195.2549.7.195.2551,022
2429.7.196.0/229.7.196.1 to 9.7.199.2549.7.199.2551,022
2439.7.200.0/229.7.200.1 to 9.7.203.2549.7.203.2551,022
2449.7.204.0/229.7.204.1 to 9.7.207.2549.7.207.2551,022
2459.7.208.0/229.7.208.1 to 9.7.211.2549.7.211.2551,022
2469.7.212.0/229.7.212.1 to 9.7.215.2549.7.215.2551,022
2479.7.216.0/229.7.216.1 to 9.7.219.2549.7.219.2551,022
2489.7.220.0/229.7.220.1 to 9.7.223.2549.7.223.2551,022
2499.7.224.0/229.7.224.1 to 9.7.227.2549.7.227.2551,022
2509.7.228.0/229.7.228.1 to 9.7.231.2549.7.231.2551,022
2519.7.232.0/229.7.232.1 to 9.7.235.2549.7.235.2551,022
2529.7.236.0/229.7.236.1 to 9.7.239.2549.7.239.2551,022
2539.7.240.0/229.7.240.1 to 9.7.243.2549.7.243.2551,022
2549.7.244.0/229.7.244.1 to 9.7.247.2549.7.247.2551,022
2559.7.248.0/229.7.248.1 to 9.7.251.2549.7.251.2551,022
2569.7.252.0/229.7.252.1 to 9.7.255.2549.7.255.2551,022

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.