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.

Network10.76.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
10.76.0.0
Broadcast address
10.79.255.255
First usable
10.76.0.1
Last usable
10.79.255.254
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
Private (RFC 1918) 10.0.0.0/8
Office and home networks; not routed on the internet
Old class
A (default /8)
As numbers
Hex 0A4C0000 · Integer 172752896 to 173015039
Reverse DNS zones
76.10.in-addr.arpa
77.10.in-addr.arpa
78.10.in-addr.arpa
79.10.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
Address00001010.01001100.00000000.0000000010.76.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network00001010.01001100.00000000.0000000010.76.0.0
Broadcast00001010.01001111.11111111.1111111110.79.255.255
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)

10.76.0.0/14 makes 256 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
110.76.0.0/2210.76.0.1 to 10.76.3.25410.76.3.2551,022
210.76.4.0/2210.76.4.1 to 10.76.7.25410.76.7.2551,022
310.76.8.0/2210.76.8.1 to 10.76.11.25410.76.11.2551,022
410.76.12.0/2210.76.12.1 to 10.76.15.25410.76.15.2551,022
510.76.16.0/2210.76.16.1 to 10.76.19.25410.76.19.2551,022
610.76.20.0/2210.76.20.1 to 10.76.23.25410.76.23.2551,022
710.76.24.0/2210.76.24.1 to 10.76.27.25410.76.27.2551,022
810.76.28.0/2210.76.28.1 to 10.76.31.25410.76.31.2551,022
910.76.32.0/2210.76.32.1 to 10.76.35.25410.76.35.2551,022
1010.76.36.0/2210.76.36.1 to 10.76.39.25410.76.39.2551,022
1110.76.40.0/2210.76.40.1 to 10.76.43.25410.76.43.2551,022
1210.76.44.0/2210.76.44.1 to 10.76.47.25410.76.47.2551,022
1310.76.48.0/2210.76.48.1 to 10.76.51.25410.76.51.2551,022
1410.76.52.0/2210.76.52.1 to 10.76.55.25410.76.55.2551,022
1510.76.56.0/2210.76.56.1 to 10.76.59.25410.76.59.2551,022
1610.76.60.0/2210.76.60.1 to 10.76.63.25410.76.63.2551,022
1710.76.64.0/2210.76.64.1 to 10.76.67.25410.76.67.2551,022
1810.76.68.0/2210.76.68.1 to 10.76.71.25410.76.71.2551,022
1910.76.72.0/2210.76.72.1 to 10.76.75.25410.76.75.2551,022
2010.76.76.0/2210.76.76.1 to 10.76.79.25410.76.79.2551,022
2110.76.80.0/2210.76.80.1 to 10.76.83.25410.76.83.2551,022
2210.76.84.0/2210.76.84.1 to 10.76.87.25410.76.87.2551,022
2310.76.88.0/2210.76.88.1 to 10.76.91.25410.76.91.2551,022
2410.76.92.0/2210.76.92.1 to 10.76.95.25410.76.95.2551,022
2510.76.96.0/2210.76.96.1 to 10.76.99.25410.76.99.2551,022
2610.76.100.0/2210.76.100.1 to 10.76.103.25410.76.103.2551,022
2710.76.104.0/2210.76.104.1 to 10.76.107.25410.76.107.2551,022
2810.76.108.0/2210.76.108.1 to 10.76.111.25410.76.111.2551,022
2910.76.112.0/2210.76.112.1 to 10.76.115.25410.76.115.2551,022
3010.76.116.0/2210.76.116.1 to 10.76.119.25410.76.119.2551,022
3110.76.120.0/2210.76.120.1 to 10.76.123.25410.76.123.2551,022
3210.76.124.0/2210.76.124.1 to 10.76.127.25410.76.127.2551,022
3310.76.128.0/2210.76.128.1 to 10.76.131.25410.76.131.2551,022
3410.76.132.0/2210.76.132.1 to 10.76.135.25410.76.135.2551,022
3510.76.136.0/2210.76.136.1 to 10.76.139.25410.76.139.2551,022
3610.76.140.0/2210.76.140.1 to 10.76.143.25410.76.143.2551,022
3710.76.144.0/2210.76.144.1 to 10.76.147.25410.76.147.2551,022
3810.76.148.0/2210.76.148.1 to 10.76.151.25410.76.151.2551,022
3910.76.152.0/2210.76.152.1 to 10.76.155.25410.76.155.2551,022
4010.76.156.0/2210.76.156.1 to 10.76.159.25410.76.159.2551,022
4110.76.160.0/2210.76.160.1 to 10.76.163.25410.76.163.2551,022
4210.76.164.0/2210.76.164.1 to 10.76.167.25410.76.167.2551,022
4310.76.168.0/2210.76.168.1 to 10.76.171.25410.76.171.2551,022
4410.76.172.0/2210.76.172.1 to 10.76.175.25410.76.175.2551,022
4510.76.176.0/2210.76.176.1 to 10.76.179.25410.76.179.2551,022
4610.76.180.0/2210.76.180.1 to 10.76.183.25410.76.183.2551,022
4710.76.184.0/2210.76.184.1 to 10.76.187.25410.76.187.2551,022
4810.76.188.0/2210.76.188.1 to 10.76.191.25410.76.191.2551,022
4910.76.192.0/2210.76.192.1 to 10.76.195.25410.76.195.2551,022
5010.76.196.0/2210.76.196.1 to 10.76.199.25410.76.199.2551,022
5110.76.200.0/2210.76.200.1 to 10.76.203.25410.76.203.2551,022
5210.76.204.0/2210.76.204.1 to 10.76.207.25410.76.207.2551,022
5310.76.208.0/2210.76.208.1 to 10.76.211.25410.76.211.2551,022
5410.76.212.0/2210.76.212.1 to 10.76.215.25410.76.215.2551,022
5510.76.216.0/2210.76.216.1 to 10.76.219.25410.76.219.2551,022
5610.76.220.0/2210.76.220.1 to 10.76.223.25410.76.223.2551,022
5710.76.224.0/2210.76.224.1 to 10.76.227.25410.76.227.2551,022
5810.76.228.0/2210.76.228.1 to 10.76.231.25410.76.231.2551,022
5910.76.232.0/2210.76.232.1 to 10.76.235.25410.76.235.2551,022
6010.76.236.0/2210.76.236.1 to 10.76.239.25410.76.239.2551,022
6110.76.240.0/2210.76.240.1 to 10.76.243.25410.76.243.2551,022
6210.76.244.0/2210.76.244.1 to 10.76.247.25410.76.247.2551,022
6310.76.248.0/2210.76.248.1 to 10.76.251.25410.76.251.2551,022
6410.76.252.0/2210.76.252.1 to 10.76.255.25410.76.255.2551,022
6510.77.0.0/2210.77.0.1 to 10.77.3.25410.77.3.2551,022
6610.77.4.0/2210.77.4.1 to 10.77.7.25410.77.7.2551,022
6710.77.8.0/2210.77.8.1 to 10.77.11.25410.77.11.2551,022
6810.77.12.0/2210.77.12.1 to 10.77.15.25410.77.15.2551,022
6910.77.16.0/2210.77.16.1 to 10.77.19.25410.77.19.2551,022
7010.77.20.0/2210.77.20.1 to 10.77.23.25410.77.23.2551,022
7110.77.24.0/2210.77.24.1 to 10.77.27.25410.77.27.2551,022
7210.77.28.0/2210.77.28.1 to 10.77.31.25410.77.31.2551,022
7310.77.32.0/2210.77.32.1 to 10.77.35.25410.77.35.2551,022
7410.77.36.0/2210.77.36.1 to 10.77.39.25410.77.39.2551,022
7510.77.40.0/2210.77.40.1 to 10.77.43.25410.77.43.2551,022
7610.77.44.0/2210.77.44.1 to 10.77.47.25410.77.47.2551,022
7710.77.48.0/2210.77.48.1 to 10.77.51.25410.77.51.2551,022
7810.77.52.0/2210.77.52.1 to 10.77.55.25410.77.55.2551,022
7910.77.56.0/2210.77.56.1 to 10.77.59.25410.77.59.2551,022
8010.77.60.0/2210.77.60.1 to 10.77.63.25410.77.63.2551,022
8110.77.64.0/2210.77.64.1 to 10.77.67.25410.77.67.2551,022
8210.77.68.0/2210.77.68.1 to 10.77.71.25410.77.71.2551,022
8310.77.72.0/2210.77.72.1 to 10.77.75.25410.77.75.2551,022
8410.77.76.0/2210.77.76.1 to 10.77.79.25410.77.79.2551,022
8510.77.80.0/2210.77.80.1 to 10.77.83.25410.77.83.2551,022
8610.77.84.0/2210.77.84.1 to 10.77.87.25410.77.87.2551,022
8710.77.88.0/2210.77.88.1 to 10.77.91.25410.77.91.2551,022
8810.77.92.0/2210.77.92.1 to 10.77.95.25410.77.95.2551,022
8910.77.96.0/2210.77.96.1 to 10.77.99.25410.77.99.2551,022
9010.77.100.0/2210.77.100.1 to 10.77.103.25410.77.103.2551,022
9110.77.104.0/2210.77.104.1 to 10.77.107.25410.77.107.2551,022
9210.77.108.0/2210.77.108.1 to 10.77.111.25410.77.111.2551,022
9310.77.112.0/2210.77.112.1 to 10.77.115.25410.77.115.2551,022
9410.77.116.0/2210.77.116.1 to 10.77.119.25410.77.119.2551,022
9510.77.120.0/2210.77.120.1 to 10.77.123.25410.77.123.2551,022
9610.77.124.0/2210.77.124.1 to 10.77.127.25410.77.127.2551,022
9710.77.128.0/2210.77.128.1 to 10.77.131.25410.77.131.2551,022
9810.77.132.0/2210.77.132.1 to 10.77.135.25410.77.135.2551,022
9910.77.136.0/2210.77.136.1 to 10.77.139.25410.77.139.2551,022
10010.77.140.0/2210.77.140.1 to 10.77.143.25410.77.143.2551,022
10110.77.144.0/2210.77.144.1 to 10.77.147.25410.77.147.2551,022
10210.77.148.0/2210.77.148.1 to 10.77.151.25410.77.151.2551,022
10310.77.152.0/2210.77.152.1 to 10.77.155.25410.77.155.2551,022
10410.77.156.0/2210.77.156.1 to 10.77.159.25410.77.159.2551,022
10510.77.160.0/2210.77.160.1 to 10.77.163.25410.77.163.2551,022
10610.77.164.0/2210.77.164.1 to 10.77.167.25410.77.167.2551,022
10710.77.168.0/2210.77.168.1 to 10.77.171.25410.77.171.2551,022
10810.77.172.0/2210.77.172.1 to 10.77.175.25410.77.175.2551,022
10910.77.176.0/2210.77.176.1 to 10.77.179.25410.77.179.2551,022
11010.77.180.0/2210.77.180.1 to 10.77.183.25410.77.183.2551,022
11110.77.184.0/2210.77.184.1 to 10.77.187.25410.77.187.2551,022
11210.77.188.0/2210.77.188.1 to 10.77.191.25410.77.191.2551,022
11310.77.192.0/2210.77.192.1 to 10.77.195.25410.77.195.2551,022
11410.77.196.0/2210.77.196.1 to 10.77.199.25410.77.199.2551,022
11510.77.200.0/2210.77.200.1 to 10.77.203.25410.77.203.2551,022
11610.77.204.0/2210.77.204.1 to 10.77.207.25410.77.207.2551,022
11710.77.208.0/2210.77.208.1 to 10.77.211.25410.77.211.2551,022
11810.77.212.0/2210.77.212.1 to 10.77.215.25410.77.215.2551,022
11910.77.216.0/2210.77.216.1 to 10.77.219.25410.77.219.2551,022
12010.77.220.0/2210.77.220.1 to 10.77.223.25410.77.223.2551,022
12110.77.224.0/2210.77.224.1 to 10.77.227.25410.77.227.2551,022
12210.77.228.0/2210.77.228.1 to 10.77.231.25410.77.231.2551,022
12310.77.232.0/2210.77.232.1 to 10.77.235.25410.77.235.2551,022
12410.77.236.0/2210.77.236.1 to 10.77.239.25410.77.239.2551,022
12510.77.240.0/2210.77.240.1 to 10.77.243.25410.77.243.2551,022
12610.77.244.0/2210.77.244.1 to 10.77.247.25410.77.247.2551,022
12710.77.248.0/2210.77.248.1 to 10.77.251.25410.77.251.2551,022
12810.77.252.0/2210.77.252.1 to 10.77.255.25410.77.255.2551,022
12910.78.0.0/2210.78.0.1 to 10.78.3.25410.78.3.2551,022
13010.78.4.0/2210.78.4.1 to 10.78.7.25410.78.7.2551,022
13110.78.8.0/2210.78.8.1 to 10.78.11.25410.78.11.2551,022
13210.78.12.0/2210.78.12.1 to 10.78.15.25410.78.15.2551,022
13310.78.16.0/2210.78.16.1 to 10.78.19.25410.78.19.2551,022
13410.78.20.0/2210.78.20.1 to 10.78.23.25410.78.23.2551,022
13510.78.24.0/2210.78.24.1 to 10.78.27.25410.78.27.2551,022
13610.78.28.0/2210.78.28.1 to 10.78.31.25410.78.31.2551,022
13710.78.32.0/2210.78.32.1 to 10.78.35.25410.78.35.2551,022
13810.78.36.0/2210.78.36.1 to 10.78.39.25410.78.39.2551,022
13910.78.40.0/2210.78.40.1 to 10.78.43.25410.78.43.2551,022
14010.78.44.0/2210.78.44.1 to 10.78.47.25410.78.47.2551,022
14110.78.48.0/2210.78.48.1 to 10.78.51.25410.78.51.2551,022
14210.78.52.0/2210.78.52.1 to 10.78.55.25410.78.55.2551,022
14310.78.56.0/2210.78.56.1 to 10.78.59.25410.78.59.2551,022
14410.78.60.0/2210.78.60.1 to 10.78.63.25410.78.63.2551,022
14510.78.64.0/2210.78.64.1 to 10.78.67.25410.78.67.2551,022
14610.78.68.0/2210.78.68.1 to 10.78.71.25410.78.71.2551,022
14710.78.72.0/2210.78.72.1 to 10.78.75.25410.78.75.2551,022
14810.78.76.0/2210.78.76.1 to 10.78.79.25410.78.79.2551,022
14910.78.80.0/2210.78.80.1 to 10.78.83.25410.78.83.2551,022
15010.78.84.0/2210.78.84.1 to 10.78.87.25410.78.87.2551,022
15110.78.88.0/2210.78.88.1 to 10.78.91.25410.78.91.2551,022
15210.78.92.0/2210.78.92.1 to 10.78.95.25410.78.95.2551,022
15310.78.96.0/2210.78.96.1 to 10.78.99.25410.78.99.2551,022
15410.78.100.0/2210.78.100.1 to 10.78.103.25410.78.103.2551,022
15510.78.104.0/2210.78.104.1 to 10.78.107.25410.78.107.2551,022
15610.78.108.0/2210.78.108.1 to 10.78.111.25410.78.111.2551,022
15710.78.112.0/2210.78.112.1 to 10.78.115.25410.78.115.2551,022
15810.78.116.0/2210.78.116.1 to 10.78.119.25410.78.119.2551,022
15910.78.120.0/2210.78.120.1 to 10.78.123.25410.78.123.2551,022
16010.78.124.0/2210.78.124.1 to 10.78.127.25410.78.127.2551,022
16110.78.128.0/2210.78.128.1 to 10.78.131.25410.78.131.2551,022
16210.78.132.0/2210.78.132.1 to 10.78.135.25410.78.135.2551,022
16310.78.136.0/2210.78.136.1 to 10.78.139.25410.78.139.2551,022
16410.78.140.0/2210.78.140.1 to 10.78.143.25410.78.143.2551,022
16510.78.144.0/2210.78.144.1 to 10.78.147.25410.78.147.2551,022
16610.78.148.0/2210.78.148.1 to 10.78.151.25410.78.151.2551,022
16710.78.152.0/2210.78.152.1 to 10.78.155.25410.78.155.2551,022
16810.78.156.0/2210.78.156.1 to 10.78.159.25410.78.159.2551,022
16910.78.160.0/2210.78.160.1 to 10.78.163.25410.78.163.2551,022
17010.78.164.0/2210.78.164.1 to 10.78.167.25410.78.167.2551,022
17110.78.168.0/2210.78.168.1 to 10.78.171.25410.78.171.2551,022
17210.78.172.0/2210.78.172.1 to 10.78.175.25410.78.175.2551,022
17310.78.176.0/2210.78.176.1 to 10.78.179.25410.78.179.2551,022
17410.78.180.0/2210.78.180.1 to 10.78.183.25410.78.183.2551,022
17510.78.184.0/2210.78.184.1 to 10.78.187.25410.78.187.2551,022
17610.78.188.0/2210.78.188.1 to 10.78.191.25410.78.191.2551,022
17710.78.192.0/2210.78.192.1 to 10.78.195.25410.78.195.2551,022
17810.78.196.0/2210.78.196.1 to 10.78.199.25410.78.199.2551,022
17910.78.200.0/2210.78.200.1 to 10.78.203.25410.78.203.2551,022
18010.78.204.0/2210.78.204.1 to 10.78.207.25410.78.207.2551,022
18110.78.208.0/2210.78.208.1 to 10.78.211.25410.78.211.2551,022
18210.78.212.0/2210.78.212.1 to 10.78.215.25410.78.215.2551,022
18310.78.216.0/2210.78.216.1 to 10.78.219.25410.78.219.2551,022
18410.78.220.0/2210.78.220.1 to 10.78.223.25410.78.223.2551,022
18510.78.224.0/2210.78.224.1 to 10.78.227.25410.78.227.2551,022
18610.78.228.0/2210.78.228.1 to 10.78.231.25410.78.231.2551,022
18710.78.232.0/2210.78.232.1 to 10.78.235.25410.78.235.2551,022
18810.78.236.0/2210.78.236.1 to 10.78.239.25410.78.239.2551,022
18910.78.240.0/2210.78.240.1 to 10.78.243.25410.78.243.2551,022
19010.78.244.0/2210.78.244.1 to 10.78.247.25410.78.247.2551,022
19110.78.248.0/2210.78.248.1 to 10.78.251.25410.78.251.2551,022
19210.78.252.0/2210.78.252.1 to 10.78.255.25410.78.255.2551,022
19310.79.0.0/2210.79.0.1 to 10.79.3.25410.79.3.2551,022
19410.79.4.0/2210.79.4.1 to 10.79.7.25410.79.7.2551,022
19510.79.8.0/2210.79.8.1 to 10.79.11.25410.79.11.2551,022
19610.79.12.0/2210.79.12.1 to 10.79.15.25410.79.15.2551,022
19710.79.16.0/2210.79.16.1 to 10.79.19.25410.79.19.2551,022
19810.79.20.0/2210.79.20.1 to 10.79.23.25410.79.23.2551,022
19910.79.24.0/2210.79.24.1 to 10.79.27.25410.79.27.2551,022
20010.79.28.0/2210.79.28.1 to 10.79.31.25410.79.31.2551,022
20110.79.32.0/2210.79.32.1 to 10.79.35.25410.79.35.2551,022
20210.79.36.0/2210.79.36.1 to 10.79.39.25410.79.39.2551,022
20310.79.40.0/2210.79.40.1 to 10.79.43.25410.79.43.2551,022
20410.79.44.0/2210.79.44.1 to 10.79.47.25410.79.47.2551,022
20510.79.48.0/2210.79.48.1 to 10.79.51.25410.79.51.2551,022
20610.79.52.0/2210.79.52.1 to 10.79.55.25410.79.55.2551,022
20710.79.56.0/2210.79.56.1 to 10.79.59.25410.79.59.2551,022
20810.79.60.0/2210.79.60.1 to 10.79.63.25410.79.63.2551,022
20910.79.64.0/2210.79.64.1 to 10.79.67.25410.79.67.2551,022
21010.79.68.0/2210.79.68.1 to 10.79.71.25410.79.71.2551,022
21110.79.72.0/2210.79.72.1 to 10.79.75.25410.79.75.2551,022
21210.79.76.0/2210.79.76.1 to 10.79.79.25410.79.79.2551,022
21310.79.80.0/2210.79.80.1 to 10.79.83.25410.79.83.2551,022
21410.79.84.0/2210.79.84.1 to 10.79.87.25410.79.87.2551,022
21510.79.88.0/2210.79.88.1 to 10.79.91.25410.79.91.2551,022
21610.79.92.0/2210.79.92.1 to 10.79.95.25410.79.95.2551,022
21710.79.96.0/2210.79.96.1 to 10.79.99.25410.79.99.2551,022
21810.79.100.0/2210.79.100.1 to 10.79.103.25410.79.103.2551,022
21910.79.104.0/2210.79.104.1 to 10.79.107.25410.79.107.2551,022
22010.79.108.0/2210.79.108.1 to 10.79.111.25410.79.111.2551,022
22110.79.112.0/2210.79.112.1 to 10.79.115.25410.79.115.2551,022
22210.79.116.0/2210.79.116.1 to 10.79.119.25410.79.119.2551,022
22310.79.120.0/2210.79.120.1 to 10.79.123.25410.79.123.2551,022
22410.79.124.0/2210.79.124.1 to 10.79.127.25410.79.127.2551,022
22510.79.128.0/2210.79.128.1 to 10.79.131.25410.79.131.2551,022
22610.79.132.0/2210.79.132.1 to 10.79.135.25410.79.135.2551,022
22710.79.136.0/2210.79.136.1 to 10.79.139.25410.79.139.2551,022
22810.79.140.0/2210.79.140.1 to 10.79.143.25410.79.143.2551,022
22910.79.144.0/2210.79.144.1 to 10.79.147.25410.79.147.2551,022
23010.79.148.0/2210.79.148.1 to 10.79.151.25410.79.151.2551,022
23110.79.152.0/2210.79.152.1 to 10.79.155.25410.79.155.2551,022
23210.79.156.0/2210.79.156.1 to 10.79.159.25410.79.159.2551,022
23310.79.160.0/2210.79.160.1 to 10.79.163.25410.79.163.2551,022
23410.79.164.0/2210.79.164.1 to 10.79.167.25410.79.167.2551,022
23510.79.168.0/2210.79.168.1 to 10.79.171.25410.79.171.2551,022
23610.79.172.0/2210.79.172.1 to 10.79.175.25410.79.175.2551,022
23710.79.176.0/2210.79.176.1 to 10.79.179.25410.79.179.2551,022
23810.79.180.0/2210.79.180.1 to 10.79.183.25410.79.183.2551,022
23910.79.184.0/2210.79.184.1 to 10.79.187.25410.79.187.2551,022
24010.79.188.0/2210.79.188.1 to 10.79.191.25410.79.191.2551,022
24110.79.192.0/2210.79.192.1 to 10.79.195.25410.79.195.2551,022
24210.79.196.0/2210.79.196.1 to 10.79.199.25410.79.199.2551,022
24310.79.200.0/2210.79.200.1 to 10.79.203.25410.79.203.2551,022
24410.79.204.0/2210.79.204.1 to 10.79.207.25410.79.207.2551,022
24510.79.208.0/2210.79.208.1 to 10.79.211.25410.79.211.2551,022
24610.79.212.0/2210.79.212.1 to 10.79.215.25410.79.215.2551,022
24710.79.216.0/2210.79.216.1 to 10.79.219.25410.79.219.2551,022
24810.79.220.0/2210.79.220.1 to 10.79.223.25410.79.223.2551,022
24910.79.224.0/2210.79.224.1 to 10.79.227.25410.79.227.2551,022
25010.79.228.0/2210.79.228.1 to 10.79.231.25410.79.231.2551,022
25110.79.232.0/2210.79.232.1 to 10.79.235.25410.79.235.2551,022
25210.79.236.0/2210.79.236.1 to 10.79.239.25410.79.239.2551,022
25310.79.240.0/2210.79.240.1 to 10.79.243.25410.79.243.2551,022
25410.79.244.0/2210.79.244.1 to 10.79.247.25410.79.247.2551,022
25510.79.248.0/2210.79.248.1 to 10.79.251.25410.79.251.2551,022
25610.79.252.0/2210.79.252.1 to 10.79.255.25410.79.255.2551,022

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.