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.

Network0.80.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
0.80.0.0
Broadcast address
0.83.255.255
First usable
0.80.0.1
Last usable
0.83.255.254
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
This network 0.0.0.0/8
Not routed; 0.0.0.0 means "any address" in settings
Old class
A (default /8)
As numbers
Hex 00500000 · Integer 5242880 to 5505023
Reverse DNS zones
80.0.in-addr.arpa
81.0.in-addr.arpa
82.0.in-addr.arpa
83.0.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
Address00000000.01010000.00000000.000000000.80.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network00000000.01010000.00000000.000000000.80.0.0
Broadcast00000000.01010011.11111111.111111110.83.255.255
Split into smaller subnets/23
/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)

0.80.0.0/14 makes 512 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.80.0.0/230.80.0.1 to 0.80.1.2540.80.1.255510
20.80.2.0/230.80.2.1 to 0.80.3.2540.80.3.255510
30.80.4.0/230.80.4.1 to 0.80.5.2540.80.5.255510
40.80.6.0/230.80.6.1 to 0.80.7.2540.80.7.255510
50.80.8.0/230.80.8.1 to 0.80.9.2540.80.9.255510
60.80.10.0/230.80.10.1 to 0.80.11.2540.80.11.255510
70.80.12.0/230.80.12.1 to 0.80.13.2540.80.13.255510
80.80.14.0/230.80.14.1 to 0.80.15.2540.80.15.255510
90.80.16.0/230.80.16.1 to 0.80.17.2540.80.17.255510
100.80.18.0/230.80.18.1 to 0.80.19.2540.80.19.255510
110.80.20.0/230.80.20.1 to 0.80.21.2540.80.21.255510
120.80.22.0/230.80.22.1 to 0.80.23.2540.80.23.255510
130.80.24.0/230.80.24.1 to 0.80.25.2540.80.25.255510
140.80.26.0/230.80.26.1 to 0.80.27.2540.80.27.255510
150.80.28.0/230.80.28.1 to 0.80.29.2540.80.29.255510
160.80.30.0/230.80.30.1 to 0.80.31.2540.80.31.255510
170.80.32.0/230.80.32.1 to 0.80.33.2540.80.33.255510
180.80.34.0/230.80.34.1 to 0.80.35.2540.80.35.255510
190.80.36.0/230.80.36.1 to 0.80.37.2540.80.37.255510
200.80.38.0/230.80.38.1 to 0.80.39.2540.80.39.255510
210.80.40.0/230.80.40.1 to 0.80.41.2540.80.41.255510
220.80.42.0/230.80.42.1 to 0.80.43.2540.80.43.255510
230.80.44.0/230.80.44.1 to 0.80.45.2540.80.45.255510
240.80.46.0/230.80.46.1 to 0.80.47.2540.80.47.255510
250.80.48.0/230.80.48.1 to 0.80.49.2540.80.49.255510
260.80.50.0/230.80.50.1 to 0.80.51.2540.80.51.255510
270.80.52.0/230.80.52.1 to 0.80.53.2540.80.53.255510
280.80.54.0/230.80.54.1 to 0.80.55.2540.80.55.255510
290.80.56.0/230.80.56.1 to 0.80.57.2540.80.57.255510
300.80.58.0/230.80.58.1 to 0.80.59.2540.80.59.255510
310.80.60.0/230.80.60.1 to 0.80.61.2540.80.61.255510
320.80.62.0/230.80.62.1 to 0.80.63.2540.80.63.255510
330.80.64.0/230.80.64.1 to 0.80.65.2540.80.65.255510
340.80.66.0/230.80.66.1 to 0.80.67.2540.80.67.255510
350.80.68.0/230.80.68.1 to 0.80.69.2540.80.69.255510
360.80.70.0/230.80.70.1 to 0.80.71.2540.80.71.255510
370.80.72.0/230.80.72.1 to 0.80.73.2540.80.73.255510
380.80.74.0/230.80.74.1 to 0.80.75.2540.80.75.255510
390.80.76.0/230.80.76.1 to 0.80.77.2540.80.77.255510
400.80.78.0/230.80.78.1 to 0.80.79.2540.80.79.255510
410.80.80.0/230.80.80.1 to 0.80.81.2540.80.81.255510
420.80.82.0/230.80.82.1 to 0.80.83.2540.80.83.255510
430.80.84.0/230.80.84.1 to 0.80.85.2540.80.85.255510
440.80.86.0/230.80.86.1 to 0.80.87.2540.80.87.255510
450.80.88.0/230.80.88.1 to 0.80.89.2540.80.89.255510
460.80.90.0/230.80.90.1 to 0.80.91.2540.80.91.255510
470.80.92.0/230.80.92.1 to 0.80.93.2540.80.93.255510
480.80.94.0/230.80.94.1 to 0.80.95.2540.80.95.255510
490.80.96.0/230.80.96.1 to 0.80.97.2540.80.97.255510
500.80.98.0/230.80.98.1 to 0.80.99.2540.80.99.255510
510.80.100.0/230.80.100.1 to 0.80.101.2540.80.101.255510
520.80.102.0/230.80.102.1 to 0.80.103.2540.80.103.255510
530.80.104.0/230.80.104.1 to 0.80.105.2540.80.105.255510
540.80.106.0/230.80.106.1 to 0.80.107.2540.80.107.255510
550.80.108.0/230.80.108.1 to 0.80.109.2540.80.109.255510
560.80.110.0/230.80.110.1 to 0.80.111.2540.80.111.255510
570.80.112.0/230.80.112.1 to 0.80.113.2540.80.113.255510
580.80.114.0/230.80.114.1 to 0.80.115.2540.80.115.255510
590.80.116.0/230.80.116.1 to 0.80.117.2540.80.117.255510
600.80.118.0/230.80.118.1 to 0.80.119.2540.80.119.255510
610.80.120.0/230.80.120.1 to 0.80.121.2540.80.121.255510
620.80.122.0/230.80.122.1 to 0.80.123.2540.80.123.255510
630.80.124.0/230.80.124.1 to 0.80.125.2540.80.125.255510
640.80.126.0/230.80.126.1 to 0.80.127.2540.80.127.255510
650.80.128.0/230.80.128.1 to 0.80.129.2540.80.129.255510
660.80.130.0/230.80.130.1 to 0.80.131.2540.80.131.255510
670.80.132.0/230.80.132.1 to 0.80.133.2540.80.133.255510
680.80.134.0/230.80.134.1 to 0.80.135.2540.80.135.255510
690.80.136.0/230.80.136.1 to 0.80.137.2540.80.137.255510
700.80.138.0/230.80.138.1 to 0.80.139.2540.80.139.255510
710.80.140.0/230.80.140.1 to 0.80.141.2540.80.141.255510
720.80.142.0/230.80.142.1 to 0.80.143.2540.80.143.255510
730.80.144.0/230.80.144.1 to 0.80.145.2540.80.145.255510
740.80.146.0/230.80.146.1 to 0.80.147.2540.80.147.255510
750.80.148.0/230.80.148.1 to 0.80.149.2540.80.149.255510
760.80.150.0/230.80.150.1 to 0.80.151.2540.80.151.255510
770.80.152.0/230.80.152.1 to 0.80.153.2540.80.153.255510
780.80.154.0/230.80.154.1 to 0.80.155.2540.80.155.255510
790.80.156.0/230.80.156.1 to 0.80.157.2540.80.157.255510
800.80.158.0/230.80.158.1 to 0.80.159.2540.80.159.255510
810.80.160.0/230.80.160.1 to 0.80.161.2540.80.161.255510
820.80.162.0/230.80.162.1 to 0.80.163.2540.80.163.255510
830.80.164.0/230.80.164.1 to 0.80.165.2540.80.165.255510
840.80.166.0/230.80.166.1 to 0.80.167.2540.80.167.255510
850.80.168.0/230.80.168.1 to 0.80.169.2540.80.169.255510
860.80.170.0/230.80.170.1 to 0.80.171.2540.80.171.255510
870.80.172.0/230.80.172.1 to 0.80.173.2540.80.173.255510
880.80.174.0/230.80.174.1 to 0.80.175.2540.80.175.255510
890.80.176.0/230.80.176.1 to 0.80.177.2540.80.177.255510
900.80.178.0/230.80.178.1 to 0.80.179.2540.80.179.255510
910.80.180.0/230.80.180.1 to 0.80.181.2540.80.181.255510
920.80.182.0/230.80.182.1 to 0.80.183.2540.80.183.255510
930.80.184.0/230.80.184.1 to 0.80.185.2540.80.185.255510
940.80.186.0/230.80.186.1 to 0.80.187.2540.80.187.255510
950.80.188.0/230.80.188.1 to 0.80.189.2540.80.189.255510
960.80.190.0/230.80.190.1 to 0.80.191.2540.80.191.255510
970.80.192.0/230.80.192.1 to 0.80.193.2540.80.193.255510
980.80.194.0/230.80.194.1 to 0.80.195.2540.80.195.255510
990.80.196.0/230.80.196.1 to 0.80.197.2540.80.197.255510
1000.80.198.0/230.80.198.1 to 0.80.199.2540.80.199.255510
1010.80.200.0/230.80.200.1 to 0.80.201.2540.80.201.255510
1020.80.202.0/230.80.202.1 to 0.80.203.2540.80.203.255510
1030.80.204.0/230.80.204.1 to 0.80.205.2540.80.205.255510
1040.80.206.0/230.80.206.1 to 0.80.207.2540.80.207.255510
1050.80.208.0/230.80.208.1 to 0.80.209.2540.80.209.255510
1060.80.210.0/230.80.210.1 to 0.80.211.2540.80.211.255510
1070.80.212.0/230.80.212.1 to 0.80.213.2540.80.213.255510
1080.80.214.0/230.80.214.1 to 0.80.215.2540.80.215.255510
1090.80.216.0/230.80.216.1 to 0.80.217.2540.80.217.255510
1100.80.218.0/230.80.218.1 to 0.80.219.2540.80.219.255510
1110.80.220.0/230.80.220.1 to 0.80.221.2540.80.221.255510
1120.80.222.0/230.80.222.1 to 0.80.223.2540.80.223.255510
1130.80.224.0/230.80.224.1 to 0.80.225.2540.80.225.255510
1140.80.226.0/230.80.226.1 to 0.80.227.2540.80.227.255510
1150.80.228.0/230.80.228.1 to 0.80.229.2540.80.229.255510
1160.80.230.0/230.80.230.1 to 0.80.231.2540.80.231.255510
1170.80.232.0/230.80.232.1 to 0.80.233.2540.80.233.255510
1180.80.234.0/230.80.234.1 to 0.80.235.2540.80.235.255510
1190.80.236.0/230.80.236.1 to 0.80.237.2540.80.237.255510
1200.80.238.0/230.80.238.1 to 0.80.239.2540.80.239.255510
1210.80.240.0/230.80.240.1 to 0.80.241.2540.80.241.255510
1220.80.242.0/230.80.242.1 to 0.80.243.2540.80.243.255510
1230.80.244.0/230.80.244.1 to 0.80.245.2540.80.245.255510
1240.80.246.0/230.80.246.1 to 0.80.247.2540.80.247.255510
1250.80.248.0/230.80.248.1 to 0.80.249.2540.80.249.255510
1260.80.250.0/230.80.250.1 to 0.80.251.2540.80.251.255510
1270.80.252.0/230.80.252.1 to 0.80.253.2540.80.253.255510
1280.80.254.0/230.80.254.1 to 0.80.255.2540.80.255.255510
1290.81.0.0/230.81.0.1 to 0.81.1.2540.81.1.255510
1300.81.2.0/230.81.2.1 to 0.81.3.2540.81.3.255510
1310.81.4.0/230.81.4.1 to 0.81.5.2540.81.5.255510
1320.81.6.0/230.81.6.1 to 0.81.7.2540.81.7.255510
1330.81.8.0/230.81.8.1 to 0.81.9.2540.81.9.255510
1340.81.10.0/230.81.10.1 to 0.81.11.2540.81.11.255510
1350.81.12.0/230.81.12.1 to 0.81.13.2540.81.13.255510
1360.81.14.0/230.81.14.1 to 0.81.15.2540.81.15.255510
1370.81.16.0/230.81.16.1 to 0.81.17.2540.81.17.255510
1380.81.18.0/230.81.18.1 to 0.81.19.2540.81.19.255510
1390.81.20.0/230.81.20.1 to 0.81.21.2540.81.21.255510
1400.81.22.0/230.81.22.1 to 0.81.23.2540.81.23.255510
1410.81.24.0/230.81.24.1 to 0.81.25.2540.81.25.255510
1420.81.26.0/230.81.26.1 to 0.81.27.2540.81.27.255510
1430.81.28.0/230.81.28.1 to 0.81.29.2540.81.29.255510
1440.81.30.0/230.81.30.1 to 0.81.31.2540.81.31.255510
1450.81.32.0/230.81.32.1 to 0.81.33.2540.81.33.255510
1460.81.34.0/230.81.34.1 to 0.81.35.2540.81.35.255510
1470.81.36.0/230.81.36.1 to 0.81.37.2540.81.37.255510
1480.81.38.0/230.81.38.1 to 0.81.39.2540.81.39.255510
1490.81.40.0/230.81.40.1 to 0.81.41.2540.81.41.255510
1500.81.42.0/230.81.42.1 to 0.81.43.2540.81.43.255510
1510.81.44.0/230.81.44.1 to 0.81.45.2540.81.45.255510
1520.81.46.0/230.81.46.1 to 0.81.47.2540.81.47.255510
1530.81.48.0/230.81.48.1 to 0.81.49.2540.81.49.255510
1540.81.50.0/230.81.50.1 to 0.81.51.2540.81.51.255510
1550.81.52.0/230.81.52.1 to 0.81.53.2540.81.53.255510
1560.81.54.0/230.81.54.1 to 0.81.55.2540.81.55.255510
1570.81.56.0/230.81.56.1 to 0.81.57.2540.81.57.255510
1580.81.58.0/230.81.58.1 to 0.81.59.2540.81.59.255510
1590.81.60.0/230.81.60.1 to 0.81.61.2540.81.61.255510
1600.81.62.0/230.81.62.1 to 0.81.63.2540.81.63.255510
1610.81.64.0/230.81.64.1 to 0.81.65.2540.81.65.255510
1620.81.66.0/230.81.66.1 to 0.81.67.2540.81.67.255510
1630.81.68.0/230.81.68.1 to 0.81.69.2540.81.69.255510
1640.81.70.0/230.81.70.1 to 0.81.71.2540.81.71.255510
1650.81.72.0/230.81.72.1 to 0.81.73.2540.81.73.255510
1660.81.74.0/230.81.74.1 to 0.81.75.2540.81.75.255510
1670.81.76.0/230.81.76.1 to 0.81.77.2540.81.77.255510
1680.81.78.0/230.81.78.1 to 0.81.79.2540.81.79.255510
1690.81.80.0/230.81.80.1 to 0.81.81.2540.81.81.255510
1700.81.82.0/230.81.82.1 to 0.81.83.2540.81.83.255510
1710.81.84.0/230.81.84.1 to 0.81.85.2540.81.85.255510
1720.81.86.0/230.81.86.1 to 0.81.87.2540.81.87.255510
1730.81.88.0/230.81.88.1 to 0.81.89.2540.81.89.255510
1740.81.90.0/230.81.90.1 to 0.81.91.2540.81.91.255510
1750.81.92.0/230.81.92.1 to 0.81.93.2540.81.93.255510
1760.81.94.0/230.81.94.1 to 0.81.95.2540.81.95.255510
1770.81.96.0/230.81.96.1 to 0.81.97.2540.81.97.255510
1780.81.98.0/230.81.98.1 to 0.81.99.2540.81.99.255510
1790.81.100.0/230.81.100.1 to 0.81.101.2540.81.101.255510
1800.81.102.0/230.81.102.1 to 0.81.103.2540.81.103.255510
1810.81.104.0/230.81.104.1 to 0.81.105.2540.81.105.255510
1820.81.106.0/230.81.106.1 to 0.81.107.2540.81.107.255510
1830.81.108.0/230.81.108.1 to 0.81.109.2540.81.109.255510
1840.81.110.0/230.81.110.1 to 0.81.111.2540.81.111.255510
1850.81.112.0/230.81.112.1 to 0.81.113.2540.81.113.255510
1860.81.114.0/230.81.114.1 to 0.81.115.2540.81.115.255510
1870.81.116.0/230.81.116.1 to 0.81.117.2540.81.117.255510
1880.81.118.0/230.81.118.1 to 0.81.119.2540.81.119.255510
1890.81.120.0/230.81.120.1 to 0.81.121.2540.81.121.255510
1900.81.122.0/230.81.122.1 to 0.81.123.2540.81.123.255510
1910.81.124.0/230.81.124.1 to 0.81.125.2540.81.125.255510
1920.81.126.0/230.81.126.1 to 0.81.127.2540.81.127.255510
1930.81.128.0/230.81.128.1 to 0.81.129.2540.81.129.255510
1940.81.130.0/230.81.130.1 to 0.81.131.2540.81.131.255510
1950.81.132.0/230.81.132.1 to 0.81.133.2540.81.133.255510
1960.81.134.0/230.81.134.1 to 0.81.135.2540.81.135.255510
1970.81.136.0/230.81.136.1 to 0.81.137.2540.81.137.255510
1980.81.138.0/230.81.138.1 to 0.81.139.2540.81.139.255510
1990.81.140.0/230.81.140.1 to 0.81.141.2540.81.141.255510
2000.81.142.0/230.81.142.1 to 0.81.143.2540.81.143.255510
2010.81.144.0/230.81.144.1 to 0.81.145.2540.81.145.255510
2020.81.146.0/230.81.146.1 to 0.81.147.2540.81.147.255510
2030.81.148.0/230.81.148.1 to 0.81.149.2540.81.149.255510
2040.81.150.0/230.81.150.1 to 0.81.151.2540.81.151.255510
2050.81.152.0/230.81.152.1 to 0.81.153.2540.81.153.255510
2060.81.154.0/230.81.154.1 to 0.81.155.2540.81.155.255510
2070.81.156.0/230.81.156.1 to 0.81.157.2540.81.157.255510
2080.81.158.0/230.81.158.1 to 0.81.159.2540.81.159.255510
2090.81.160.0/230.81.160.1 to 0.81.161.2540.81.161.255510
2100.81.162.0/230.81.162.1 to 0.81.163.2540.81.163.255510
2110.81.164.0/230.81.164.1 to 0.81.165.2540.81.165.255510
2120.81.166.0/230.81.166.1 to 0.81.167.2540.81.167.255510
2130.81.168.0/230.81.168.1 to 0.81.169.2540.81.169.255510
2140.81.170.0/230.81.170.1 to 0.81.171.2540.81.171.255510
2150.81.172.0/230.81.172.1 to 0.81.173.2540.81.173.255510
2160.81.174.0/230.81.174.1 to 0.81.175.2540.81.175.255510
2170.81.176.0/230.81.176.1 to 0.81.177.2540.81.177.255510
2180.81.178.0/230.81.178.1 to 0.81.179.2540.81.179.255510
2190.81.180.0/230.81.180.1 to 0.81.181.2540.81.181.255510
2200.81.182.0/230.81.182.1 to 0.81.183.2540.81.183.255510
2210.81.184.0/230.81.184.1 to 0.81.185.2540.81.185.255510
2220.81.186.0/230.81.186.1 to 0.81.187.2540.81.187.255510
2230.81.188.0/230.81.188.1 to 0.81.189.2540.81.189.255510
2240.81.190.0/230.81.190.1 to 0.81.191.2540.81.191.255510
2250.81.192.0/230.81.192.1 to 0.81.193.2540.81.193.255510
2260.81.194.0/230.81.194.1 to 0.81.195.2540.81.195.255510
2270.81.196.0/230.81.196.1 to 0.81.197.2540.81.197.255510
2280.81.198.0/230.81.198.1 to 0.81.199.2540.81.199.255510
2290.81.200.0/230.81.200.1 to 0.81.201.2540.81.201.255510
2300.81.202.0/230.81.202.1 to 0.81.203.2540.81.203.255510
2310.81.204.0/230.81.204.1 to 0.81.205.2540.81.205.255510
2320.81.206.0/230.81.206.1 to 0.81.207.2540.81.207.255510
2330.81.208.0/230.81.208.1 to 0.81.209.2540.81.209.255510
2340.81.210.0/230.81.210.1 to 0.81.211.2540.81.211.255510
2350.81.212.0/230.81.212.1 to 0.81.213.2540.81.213.255510
2360.81.214.0/230.81.214.1 to 0.81.215.2540.81.215.255510
2370.81.216.0/230.81.216.1 to 0.81.217.2540.81.217.255510
2380.81.218.0/230.81.218.1 to 0.81.219.2540.81.219.255510
2390.81.220.0/230.81.220.1 to 0.81.221.2540.81.221.255510
2400.81.222.0/230.81.222.1 to 0.81.223.2540.81.223.255510
2410.81.224.0/230.81.224.1 to 0.81.225.2540.81.225.255510
2420.81.226.0/230.81.226.1 to 0.81.227.2540.81.227.255510
2430.81.228.0/230.81.228.1 to 0.81.229.2540.81.229.255510
2440.81.230.0/230.81.230.1 to 0.81.231.2540.81.231.255510
2450.81.232.0/230.81.232.1 to 0.81.233.2540.81.233.255510
2460.81.234.0/230.81.234.1 to 0.81.235.2540.81.235.255510
2470.81.236.0/230.81.236.1 to 0.81.237.2540.81.237.255510
2480.81.238.0/230.81.238.1 to 0.81.239.2540.81.239.255510
2490.81.240.0/230.81.240.1 to 0.81.241.2540.81.241.255510
2500.81.242.0/230.81.242.1 to 0.81.243.2540.81.243.255510
2510.81.244.0/230.81.244.1 to 0.81.245.2540.81.245.255510
2520.81.246.0/230.81.246.1 to 0.81.247.2540.81.247.255510
2530.81.248.0/230.81.248.1 to 0.81.249.2540.81.249.255510
2540.81.250.0/230.81.250.1 to 0.81.251.2540.81.251.255510
2550.81.252.0/230.81.252.1 to 0.81.253.2540.81.253.255510
2560.81.254.0/230.81.254.1 to 0.81.255.2540.81.255.255510

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.