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.

Network84.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
84.0.0.0
Broadcast address
84.127.255.255
First usable
84.0.0.1
Last usable
84.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 54000000 · Integer 1409286144 to 1417674751
Reverse DNS zones
0.84.in-addr.arpa
1.84.in-addr.arpa
2.84.in-addr.arpa
3.84.in-addr.arpa
4.84.in-addr.arpa
5.84.in-addr.arpa
6.84.in-addr.arpa
7.84.in-addr.arpa
8.84.in-addr.arpa
9.84.in-addr.arpa
10.84.in-addr.arpa
11.84.in-addr.arpa
12.84.in-addr.arpa
13.84.in-addr.arpa
14.84.in-addr.arpa
15.84.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010100.00000000.00000000.0000000084.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01010100.00000000.00000000.0000000084.0.0.0
Broadcast01010100.01111111.11111111.1111111184.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

84.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
184.0.0.0/2084.0.0.1 to 84.0.15.25484.0.15.2554,094
284.0.16.0/2084.0.16.1 to 84.0.31.25484.0.31.2554,094
384.0.32.0/2084.0.32.1 to 84.0.47.25484.0.47.2554,094
484.0.48.0/2084.0.48.1 to 84.0.63.25484.0.63.2554,094
584.0.64.0/2084.0.64.1 to 84.0.79.25484.0.79.2554,094
684.0.80.0/2084.0.80.1 to 84.0.95.25484.0.95.2554,094
784.0.96.0/2084.0.96.1 to 84.0.111.25484.0.111.2554,094
884.0.112.0/2084.0.112.1 to 84.0.127.25484.0.127.2554,094
984.0.128.0/2084.0.128.1 to 84.0.143.25484.0.143.2554,094
1084.0.144.0/2084.0.144.1 to 84.0.159.25484.0.159.2554,094
1184.0.160.0/2084.0.160.1 to 84.0.175.25484.0.175.2554,094
1284.0.176.0/2084.0.176.1 to 84.0.191.25484.0.191.2554,094
1384.0.192.0/2084.0.192.1 to 84.0.207.25484.0.207.2554,094
1484.0.208.0/2084.0.208.1 to 84.0.223.25484.0.223.2554,094
1584.0.224.0/2084.0.224.1 to 84.0.239.25484.0.239.2554,094
1684.0.240.0/2084.0.240.1 to 84.0.255.25484.0.255.2554,094
1784.1.0.0/2084.1.0.1 to 84.1.15.25484.1.15.2554,094
1884.1.16.0/2084.1.16.1 to 84.1.31.25484.1.31.2554,094
1984.1.32.0/2084.1.32.1 to 84.1.47.25484.1.47.2554,094
2084.1.48.0/2084.1.48.1 to 84.1.63.25484.1.63.2554,094
2184.1.64.0/2084.1.64.1 to 84.1.79.25484.1.79.2554,094
2284.1.80.0/2084.1.80.1 to 84.1.95.25484.1.95.2554,094
2384.1.96.0/2084.1.96.1 to 84.1.111.25484.1.111.2554,094
2484.1.112.0/2084.1.112.1 to 84.1.127.25484.1.127.2554,094
2584.1.128.0/2084.1.128.1 to 84.1.143.25484.1.143.2554,094
2684.1.144.0/2084.1.144.1 to 84.1.159.25484.1.159.2554,094
2784.1.160.0/2084.1.160.1 to 84.1.175.25484.1.175.2554,094
2884.1.176.0/2084.1.176.1 to 84.1.191.25484.1.191.2554,094
2984.1.192.0/2084.1.192.1 to 84.1.207.25484.1.207.2554,094
3084.1.208.0/2084.1.208.1 to 84.1.223.25484.1.223.2554,094
3184.1.224.0/2084.1.224.1 to 84.1.239.25484.1.239.2554,094
3284.1.240.0/2084.1.240.1 to 84.1.255.25484.1.255.2554,094
3384.2.0.0/2084.2.0.1 to 84.2.15.25484.2.15.2554,094
3484.2.16.0/2084.2.16.1 to 84.2.31.25484.2.31.2554,094
3584.2.32.0/2084.2.32.1 to 84.2.47.25484.2.47.2554,094
3684.2.48.0/2084.2.48.1 to 84.2.63.25484.2.63.2554,094
3784.2.64.0/2084.2.64.1 to 84.2.79.25484.2.79.2554,094
3884.2.80.0/2084.2.80.1 to 84.2.95.25484.2.95.2554,094
3984.2.96.0/2084.2.96.1 to 84.2.111.25484.2.111.2554,094
4084.2.112.0/2084.2.112.1 to 84.2.127.25484.2.127.2554,094
4184.2.128.0/2084.2.128.1 to 84.2.143.25484.2.143.2554,094
4284.2.144.0/2084.2.144.1 to 84.2.159.25484.2.159.2554,094
4384.2.160.0/2084.2.160.1 to 84.2.175.25484.2.175.2554,094
4484.2.176.0/2084.2.176.1 to 84.2.191.25484.2.191.2554,094
4584.2.192.0/2084.2.192.1 to 84.2.207.25484.2.207.2554,094
4684.2.208.0/2084.2.208.1 to 84.2.223.25484.2.223.2554,094
4784.2.224.0/2084.2.224.1 to 84.2.239.25484.2.239.2554,094
4884.2.240.0/2084.2.240.1 to 84.2.255.25484.2.255.2554,094
4984.3.0.0/2084.3.0.1 to 84.3.15.25484.3.15.2554,094
5084.3.16.0/2084.3.16.1 to 84.3.31.25484.3.31.2554,094
5184.3.32.0/2084.3.32.1 to 84.3.47.25484.3.47.2554,094
5284.3.48.0/2084.3.48.1 to 84.3.63.25484.3.63.2554,094
5384.3.64.0/2084.3.64.1 to 84.3.79.25484.3.79.2554,094
5484.3.80.0/2084.3.80.1 to 84.3.95.25484.3.95.2554,094
5584.3.96.0/2084.3.96.1 to 84.3.111.25484.3.111.2554,094
5684.3.112.0/2084.3.112.1 to 84.3.127.25484.3.127.2554,094
5784.3.128.0/2084.3.128.1 to 84.3.143.25484.3.143.2554,094
5884.3.144.0/2084.3.144.1 to 84.3.159.25484.3.159.2554,094
5984.3.160.0/2084.3.160.1 to 84.3.175.25484.3.175.2554,094
6084.3.176.0/2084.3.176.1 to 84.3.191.25484.3.191.2554,094
6184.3.192.0/2084.3.192.1 to 84.3.207.25484.3.207.2554,094
6284.3.208.0/2084.3.208.1 to 84.3.223.25484.3.223.2554,094
6384.3.224.0/2084.3.224.1 to 84.3.239.25484.3.239.2554,094
6484.3.240.0/2084.3.240.1 to 84.3.255.25484.3.255.2554,094
6584.4.0.0/2084.4.0.1 to 84.4.15.25484.4.15.2554,094
6684.4.16.0/2084.4.16.1 to 84.4.31.25484.4.31.2554,094
6784.4.32.0/2084.4.32.1 to 84.4.47.25484.4.47.2554,094
6884.4.48.0/2084.4.48.1 to 84.4.63.25484.4.63.2554,094
6984.4.64.0/2084.4.64.1 to 84.4.79.25484.4.79.2554,094
7084.4.80.0/2084.4.80.1 to 84.4.95.25484.4.95.2554,094
7184.4.96.0/2084.4.96.1 to 84.4.111.25484.4.111.2554,094
7284.4.112.0/2084.4.112.1 to 84.4.127.25484.4.127.2554,094
7384.4.128.0/2084.4.128.1 to 84.4.143.25484.4.143.2554,094
7484.4.144.0/2084.4.144.1 to 84.4.159.25484.4.159.2554,094
7584.4.160.0/2084.4.160.1 to 84.4.175.25484.4.175.2554,094
7684.4.176.0/2084.4.176.1 to 84.4.191.25484.4.191.2554,094
7784.4.192.0/2084.4.192.1 to 84.4.207.25484.4.207.2554,094
7884.4.208.0/2084.4.208.1 to 84.4.223.25484.4.223.2554,094
7984.4.224.0/2084.4.224.1 to 84.4.239.25484.4.239.2554,094
8084.4.240.0/2084.4.240.1 to 84.4.255.25484.4.255.2554,094
8184.5.0.0/2084.5.0.1 to 84.5.15.25484.5.15.2554,094
8284.5.16.0/2084.5.16.1 to 84.5.31.25484.5.31.2554,094
8384.5.32.0/2084.5.32.1 to 84.5.47.25484.5.47.2554,094
8484.5.48.0/2084.5.48.1 to 84.5.63.25484.5.63.2554,094
8584.5.64.0/2084.5.64.1 to 84.5.79.25484.5.79.2554,094
8684.5.80.0/2084.5.80.1 to 84.5.95.25484.5.95.2554,094
8784.5.96.0/2084.5.96.1 to 84.5.111.25484.5.111.2554,094
8884.5.112.0/2084.5.112.1 to 84.5.127.25484.5.127.2554,094
8984.5.128.0/2084.5.128.1 to 84.5.143.25484.5.143.2554,094
9084.5.144.0/2084.5.144.1 to 84.5.159.25484.5.159.2554,094
9184.5.160.0/2084.5.160.1 to 84.5.175.25484.5.175.2554,094
9284.5.176.0/2084.5.176.1 to 84.5.191.25484.5.191.2554,094
9384.5.192.0/2084.5.192.1 to 84.5.207.25484.5.207.2554,094
9484.5.208.0/2084.5.208.1 to 84.5.223.25484.5.223.2554,094
9584.5.224.0/2084.5.224.1 to 84.5.239.25484.5.239.2554,094
9684.5.240.0/2084.5.240.1 to 84.5.255.25484.5.255.2554,094
9784.6.0.0/2084.6.0.1 to 84.6.15.25484.6.15.2554,094
9884.6.16.0/2084.6.16.1 to 84.6.31.25484.6.31.2554,094
9984.6.32.0/2084.6.32.1 to 84.6.47.25484.6.47.2554,094
10084.6.48.0/2084.6.48.1 to 84.6.63.25484.6.63.2554,094
10184.6.64.0/2084.6.64.1 to 84.6.79.25484.6.79.2554,094
10284.6.80.0/2084.6.80.1 to 84.6.95.25484.6.95.2554,094
10384.6.96.0/2084.6.96.1 to 84.6.111.25484.6.111.2554,094
10484.6.112.0/2084.6.112.1 to 84.6.127.25484.6.127.2554,094
10584.6.128.0/2084.6.128.1 to 84.6.143.25484.6.143.2554,094
10684.6.144.0/2084.6.144.1 to 84.6.159.25484.6.159.2554,094
10784.6.160.0/2084.6.160.1 to 84.6.175.25484.6.175.2554,094
10884.6.176.0/2084.6.176.1 to 84.6.191.25484.6.191.2554,094
10984.6.192.0/2084.6.192.1 to 84.6.207.25484.6.207.2554,094
11084.6.208.0/2084.6.208.1 to 84.6.223.25484.6.223.2554,094
11184.6.224.0/2084.6.224.1 to 84.6.239.25484.6.239.2554,094
11284.6.240.0/2084.6.240.1 to 84.6.255.25484.6.255.2554,094
11384.7.0.0/2084.7.0.1 to 84.7.15.25484.7.15.2554,094
11484.7.16.0/2084.7.16.1 to 84.7.31.25484.7.31.2554,094
11584.7.32.0/2084.7.32.1 to 84.7.47.25484.7.47.2554,094
11684.7.48.0/2084.7.48.1 to 84.7.63.25484.7.63.2554,094
11784.7.64.0/2084.7.64.1 to 84.7.79.25484.7.79.2554,094
11884.7.80.0/2084.7.80.1 to 84.7.95.25484.7.95.2554,094
11984.7.96.0/2084.7.96.1 to 84.7.111.25484.7.111.2554,094
12084.7.112.0/2084.7.112.1 to 84.7.127.25484.7.127.2554,094
12184.7.128.0/2084.7.128.1 to 84.7.143.25484.7.143.2554,094
12284.7.144.0/2084.7.144.1 to 84.7.159.25484.7.159.2554,094
12384.7.160.0/2084.7.160.1 to 84.7.175.25484.7.175.2554,094
12484.7.176.0/2084.7.176.1 to 84.7.191.25484.7.191.2554,094
12584.7.192.0/2084.7.192.1 to 84.7.207.25484.7.207.2554,094
12684.7.208.0/2084.7.208.1 to 84.7.223.25484.7.223.2554,094
12784.7.224.0/2084.7.224.1 to 84.7.239.25484.7.239.2554,094
12884.7.240.0/2084.7.240.1 to 84.7.255.25484.7.255.2554,094
12984.8.0.0/2084.8.0.1 to 84.8.15.25484.8.15.2554,094
13084.8.16.0/2084.8.16.1 to 84.8.31.25484.8.31.2554,094
13184.8.32.0/2084.8.32.1 to 84.8.47.25484.8.47.2554,094
13284.8.48.0/2084.8.48.1 to 84.8.63.25484.8.63.2554,094
13384.8.64.0/2084.8.64.1 to 84.8.79.25484.8.79.2554,094
13484.8.80.0/2084.8.80.1 to 84.8.95.25484.8.95.2554,094
13584.8.96.0/2084.8.96.1 to 84.8.111.25484.8.111.2554,094
13684.8.112.0/2084.8.112.1 to 84.8.127.25484.8.127.2554,094
13784.8.128.0/2084.8.128.1 to 84.8.143.25484.8.143.2554,094
13884.8.144.0/2084.8.144.1 to 84.8.159.25484.8.159.2554,094
13984.8.160.0/2084.8.160.1 to 84.8.175.25484.8.175.2554,094
14084.8.176.0/2084.8.176.1 to 84.8.191.25484.8.191.2554,094
14184.8.192.0/2084.8.192.1 to 84.8.207.25484.8.207.2554,094
14284.8.208.0/2084.8.208.1 to 84.8.223.25484.8.223.2554,094
14384.8.224.0/2084.8.224.1 to 84.8.239.25484.8.239.2554,094
14484.8.240.0/2084.8.240.1 to 84.8.255.25484.8.255.2554,094
14584.9.0.0/2084.9.0.1 to 84.9.15.25484.9.15.2554,094
14684.9.16.0/2084.9.16.1 to 84.9.31.25484.9.31.2554,094
14784.9.32.0/2084.9.32.1 to 84.9.47.25484.9.47.2554,094
14884.9.48.0/2084.9.48.1 to 84.9.63.25484.9.63.2554,094
14984.9.64.0/2084.9.64.1 to 84.9.79.25484.9.79.2554,094
15084.9.80.0/2084.9.80.1 to 84.9.95.25484.9.95.2554,094
15184.9.96.0/2084.9.96.1 to 84.9.111.25484.9.111.2554,094
15284.9.112.0/2084.9.112.1 to 84.9.127.25484.9.127.2554,094
15384.9.128.0/2084.9.128.1 to 84.9.143.25484.9.143.2554,094
15484.9.144.0/2084.9.144.1 to 84.9.159.25484.9.159.2554,094
15584.9.160.0/2084.9.160.1 to 84.9.175.25484.9.175.2554,094
15684.9.176.0/2084.9.176.1 to 84.9.191.25484.9.191.2554,094
15784.9.192.0/2084.9.192.1 to 84.9.207.25484.9.207.2554,094
15884.9.208.0/2084.9.208.1 to 84.9.223.25484.9.223.2554,094
15984.9.224.0/2084.9.224.1 to 84.9.239.25484.9.239.2554,094
16084.9.240.0/2084.9.240.1 to 84.9.255.25484.9.255.2554,094
16184.10.0.0/2084.10.0.1 to 84.10.15.25484.10.15.2554,094
16284.10.16.0/2084.10.16.1 to 84.10.31.25484.10.31.2554,094
16384.10.32.0/2084.10.32.1 to 84.10.47.25484.10.47.2554,094
16484.10.48.0/2084.10.48.1 to 84.10.63.25484.10.63.2554,094
16584.10.64.0/2084.10.64.1 to 84.10.79.25484.10.79.2554,094
16684.10.80.0/2084.10.80.1 to 84.10.95.25484.10.95.2554,094
16784.10.96.0/2084.10.96.1 to 84.10.111.25484.10.111.2554,094
16884.10.112.0/2084.10.112.1 to 84.10.127.25484.10.127.2554,094
16984.10.128.0/2084.10.128.1 to 84.10.143.25484.10.143.2554,094
17084.10.144.0/2084.10.144.1 to 84.10.159.25484.10.159.2554,094
17184.10.160.0/2084.10.160.1 to 84.10.175.25484.10.175.2554,094
17284.10.176.0/2084.10.176.1 to 84.10.191.25484.10.191.2554,094
17384.10.192.0/2084.10.192.1 to 84.10.207.25484.10.207.2554,094
17484.10.208.0/2084.10.208.1 to 84.10.223.25484.10.223.2554,094
17584.10.224.0/2084.10.224.1 to 84.10.239.25484.10.239.2554,094
17684.10.240.0/2084.10.240.1 to 84.10.255.25484.10.255.2554,094
17784.11.0.0/2084.11.0.1 to 84.11.15.25484.11.15.2554,094
17884.11.16.0/2084.11.16.1 to 84.11.31.25484.11.31.2554,094
17984.11.32.0/2084.11.32.1 to 84.11.47.25484.11.47.2554,094
18084.11.48.0/2084.11.48.1 to 84.11.63.25484.11.63.2554,094
18184.11.64.0/2084.11.64.1 to 84.11.79.25484.11.79.2554,094
18284.11.80.0/2084.11.80.1 to 84.11.95.25484.11.95.2554,094
18384.11.96.0/2084.11.96.1 to 84.11.111.25484.11.111.2554,094
18484.11.112.0/2084.11.112.1 to 84.11.127.25484.11.127.2554,094
18584.11.128.0/2084.11.128.1 to 84.11.143.25484.11.143.2554,094
18684.11.144.0/2084.11.144.1 to 84.11.159.25484.11.159.2554,094
18784.11.160.0/2084.11.160.1 to 84.11.175.25484.11.175.2554,094
18884.11.176.0/2084.11.176.1 to 84.11.191.25484.11.191.2554,094
18984.11.192.0/2084.11.192.1 to 84.11.207.25484.11.207.2554,094
19084.11.208.0/2084.11.208.1 to 84.11.223.25484.11.223.2554,094
19184.11.224.0/2084.11.224.1 to 84.11.239.25484.11.239.2554,094
19284.11.240.0/2084.11.240.1 to 84.11.255.25484.11.255.2554,094
19384.12.0.0/2084.12.0.1 to 84.12.15.25484.12.15.2554,094
19484.12.16.0/2084.12.16.1 to 84.12.31.25484.12.31.2554,094
19584.12.32.0/2084.12.32.1 to 84.12.47.25484.12.47.2554,094
19684.12.48.0/2084.12.48.1 to 84.12.63.25484.12.63.2554,094
19784.12.64.0/2084.12.64.1 to 84.12.79.25484.12.79.2554,094
19884.12.80.0/2084.12.80.1 to 84.12.95.25484.12.95.2554,094
19984.12.96.0/2084.12.96.1 to 84.12.111.25484.12.111.2554,094
20084.12.112.0/2084.12.112.1 to 84.12.127.25484.12.127.2554,094
20184.12.128.0/2084.12.128.1 to 84.12.143.25484.12.143.2554,094
20284.12.144.0/2084.12.144.1 to 84.12.159.25484.12.159.2554,094
20384.12.160.0/2084.12.160.1 to 84.12.175.25484.12.175.2554,094
20484.12.176.0/2084.12.176.1 to 84.12.191.25484.12.191.2554,094
20584.12.192.0/2084.12.192.1 to 84.12.207.25484.12.207.2554,094
20684.12.208.0/2084.12.208.1 to 84.12.223.25484.12.223.2554,094
20784.12.224.0/2084.12.224.1 to 84.12.239.25484.12.239.2554,094
20884.12.240.0/2084.12.240.1 to 84.12.255.25484.12.255.2554,094
20984.13.0.0/2084.13.0.1 to 84.13.15.25484.13.15.2554,094
21084.13.16.0/2084.13.16.1 to 84.13.31.25484.13.31.2554,094
21184.13.32.0/2084.13.32.1 to 84.13.47.25484.13.47.2554,094
21284.13.48.0/2084.13.48.1 to 84.13.63.25484.13.63.2554,094
21384.13.64.0/2084.13.64.1 to 84.13.79.25484.13.79.2554,094
21484.13.80.0/2084.13.80.1 to 84.13.95.25484.13.95.2554,094
21584.13.96.0/2084.13.96.1 to 84.13.111.25484.13.111.2554,094
21684.13.112.0/2084.13.112.1 to 84.13.127.25484.13.127.2554,094
21784.13.128.0/2084.13.128.1 to 84.13.143.25484.13.143.2554,094
21884.13.144.0/2084.13.144.1 to 84.13.159.25484.13.159.2554,094
21984.13.160.0/2084.13.160.1 to 84.13.175.25484.13.175.2554,094
22084.13.176.0/2084.13.176.1 to 84.13.191.25484.13.191.2554,094
22184.13.192.0/2084.13.192.1 to 84.13.207.25484.13.207.2554,094
22284.13.208.0/2084.13.208.1 to 84.13.223.25484.13.223.2554,094
22384.13.224.0/2084.13.224.1 to 84.13.239.25484.13.239.2554,094
22484.13.240.0/2084.13.240.1 to 84.13.255.25484.13.255.2554,094
22584.14.0.0/2084.14.0.1 to 84.14.15.25484.14.15.2554,094
22684.14.16.0/2084.14.16.1 to 84.14.31.25484.14.31.2554,094
22784.14.32.0/2084.14.32.1 to 84.14.47.25484.14.47.2554,094
22884.14.48.0/2084.14.48.1 to 84.14.63.25484.14.63.2554,094
22984.14.64.0/2084.14.64.1 to 84.14.79.25484.14.79.2554,094
23084.14.80.0/2084.14.80.1 to 84.14.95.25484.14.95.2554,094
23184.14.96.0/2084.14.96.1 to 84.14.111.25484.14.111.2554,094
23284.14.112.0/2084.14.112.1 to 84.14.127.25484.14.127.2554,094
23384.14.128.0/2084.14.128.1 to 84.14.143.25484.14.143.2554,094
23484.14.144.0/2084.14.144.1 to 84.14.159.25484.14.159.2554,094
23584.14.160.0/2084.14.160.1 to 84.14.175.25484.14.175.2554,094
23684.14.176.0/2084.14.176.1 to 84.14.191.25484.14.191.2554,094
23784.14.192.0/2084.14.192.1 to 84.14.207.25484.14.207.2554,094
23884.14.208.0/2084.14.208.1 to 84.14.223.25484.14.223.2554,094
23984.14.224.0/2084.14.224.1 to 84.14.239.25484.14.239.2554,094
24084.14.240.0/2084.14.240.1 to 84.14.255.25484.14.255.2554,094
24184.15.0.0/2084.15.0.1 to 84.15.15.25484.15.15.2554,094
24284.15.16.0/2084.15.16.1 to 84.15.31.25484.15.31.2554,094
24384.15.32.0/2084.15.32.1 to 84.15.47.25484.15.47.2554,094
24484.15.48.0/2084.15.48.1 to 84.15.63.25484.15.63.2554,094
24584.15.64.0/2084.15.64.1 to 84.15.79.25484.15.79.2554,094
24684.15.80.0/2084.15.80.1 to 84.15.95.25484.15.95.2554,094
24784.15.96.0/2084.15.96.1 to 84.15.111.25484.15.111.2554,094
24884.15.112.0/2084.15.112.1 to 84.15.127.25484.15.127.2554,094
24984.15.128.0/2084.15.128.1 to 84.15.143.25484.15.143.2554,094
25084.15.144.0/2084.15.144.1 to 84.15.159.25484.15.159.2554,094
25184.15.160.0/2084.15.160.1 to 84.15.175.25484.15.175.2554,094
25284.15.176.0/2084.15.176.1 to 84.15.191.25484.15.191.2554,094
25384.15.192.0/2084.15.192.1 to 84.15.207.25484.15.207.2554,094
25484.15.208.0/2084.15.208.1 to 84.15.223.25484.15.223.2554,094
25584.15.224.0/2084.15.224.1 to 84.15.239.25484.15.239.2554,094
25684.15.240.0/2084.15.240.1 to 84.15.255.25484.15.255.2554,094

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.