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.

Network84.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
84.0.0.0
Broadcast address
87.255.255.255
First usable
84.0.0.1
Last usable
87.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 54000000 · Integer 1409286144 to 1476395007
Reverse DNS zones
84.in-addr.arpa
85.in-addr.arpa
86.in-addr.arpa
87.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010100.00000000.00000000.0000000084.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01010100.00000000.00000000.0000000084.0.0.0
Broadcast01010111.11111111.11111111.1111111187.255.255.255
Split into smaller subnets/17
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

84.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
184.0.0.0/1784.0.0.1 to 84.0.127.25484.0.127.25532,766
284.0.128.0/1784.0.128.1 to 84.0.255.25484.0.255.25532,766
384.1.0.0/1784.1.0.1 to 84.1.127.25484.1.127.25532,766
484.1.128.0/1784.1.128.1 to 84.1.255.25484.1.255.25532,766
584.2.0.0/1784.2.0.1 to 84.2.127.25484.2.127.25532,766
684.2.128.0/1784.2.128.1 to 84.2.255.25484.2.255.25532,766
784.3.0.0/1784.3.0.1 to 84.3.127.25484.3.127.25532,766
884.3.128.0/1784.3.128.1 to 84.3.255.25484.3.255.25532,766
984.4.0.0/1784.4.0.1 to 84.4.127.25484.4.127.25532,766
1084.4.128.0/1784.4.128.1 to 84.4.255.25484.4.255.25532,766
1184.5.0.0/1784.5.0.1 to 84.5.127.25484.5.127.25532,766
1284.5.128.0/1784.5.128.1 to 84.5.255.25484.5.255.25532,766
1384.6.0.0/1784.6.0.1 to 84.6.127.25484.6.127.25532,766
1484.6.128.0/1784.6.128.1 to 84.6.255.25484.6.255.25532,766
1584.7.0.0/1784.7.0.1 to 84.7.127.25484.7.127.25532,766
1684.7.128.0/1784.7.128.1 to 84.7.255.25484.7.255.25532,766
1784.8.0.0/1784.8.0.1 to 84.8.127.25484.8.127.25532,766
1884.8.128.0/1784.8.128.1 to 84.8.255.25484.8.255.25532,766
1984.9.0.0/1784.9.0.1 to 84.9.127.25484.9.127.25532,766
2084.9.128.0/1784.9.128.1 to 84.9.255.25484.9.255.25532,766
2184.10.0.0/1784.10.0.1 to 84.10.127.25484.10.127.25532,766
2284.10.128.0/1784.10.128.1 to 84.10.255.25484.10.255.25532,766
2384.11.0.0/1784.11.0.1 to 84.11.127.25484.11.127.25532,766
2484.11.128.0/1784.11.128.1 to 84.11.255.25484.11.255.25532,766
2584.12.0.0/1784.12.0.1 to 84.12.127.25484.12.127.25532,766
2684.12.128.0/1784.12.128.1 to 84.12.255.25484.12.255.25532,766
2784.13.0.0/1784.13.0.1 to 84.13.127.25484.13.127.25532,766
2884.13.128.0/1784.13.128.1 to 84.13.255.25484.13.255.25532,766
2984.14.0.0/1784.14.0.1 to 84.14.127.25484.14.127.25532,766
3084.14.128.0/1784.14.128.1 to 84.14.255.25484.14.255.25532,766
3184.15.0.0/1784.15.0.1 to 84.15.127.25484.15.127.25532,766
3284.15.128.0/1784.15.128.1 to 84.15.255.25484.15.255.25532,766
3384.16.0.0/1784.16.0.1 to 84.16.127.25484.16.127.25532,766
3484.16.128.0/1784.16.128.1 to 84.16.255.25484.16.255.25532,766
3584.17.0.0/1784.17.0.1 to 84.17.127.25484.17.127.25532,766
3684.17.128.0/1784.17.128.1 to 84.17.255.25484.17.255.25532,766
3784.18.0.0/1784.18.0.1 to 84.18.127.25484.18.127.25532,766
3884.18.128.0/1784.18.128.1 to 84.18.255.25484.18.255.25532,766
3984.19.0.0/1784.19.0.1 to 84.19.127.25484.19.127.25532,766
4084.19.128.0/1784.19.128.1 to 84.19.255.25484.19.255.25532,766
4184.20.0.0/1784.20.0.1 to 84.20.127.25484.20.127.25532,766
4284.20.128.0/1784.20.128.1 to 84.20.255.25484.20.255.25532,766
4384.21.0.0/1784.21.0.1 to 84.21.127.25484.21.127.25532,766
4484.21.128.0/1784.21.128.1 to 84.21.255.25484.21.255.25532,766
4584.22.0.0/1784.22.0.1 to 84.22.127.25484.22.127.25532,766
4684.22.128.0/1784.22.128.1 to 84.22.255.25484.22.255.25532,766
4784.23.0.0/1784.23.0.1 to 84.23.127.25484.23.127.25532,766
4884.23.128.0/1784.23.128.1 to 84.23.255.25484.23.255.25532,766
4984.24.0.0/1784.24.0.1 to 84.24.127.25484.24.127.25532,766
5084.24.128.0/1784.24.128.1 to 84.24.255.25484.24.255.25532,766
5184.25.0.0/1784.25.0.1 to 84.25.127.25484.25.127.25532,766
5284.25.128.0/1784.25.128.1 to 84.25.255.25484.25.255.25532,766
5384.26.0.0/1784.26.0.1 to 84.26.127.25484.26.127.25532,766
5484.26.128.0/1784.26.128.1 to 84.26.255.25484.26.255.25532,766
5584.27.0.0/1784.27.0.1 to 84.27.127.25484.27.127.25532,766
5684.27.128.0/1784.27.128.1 to 84.27.255.25484.27.255.25532,766
5784.28.0.0/1784.28.0.1 to 84.28.127.25484.28.127.25532,766
5884.28.128.0/1784.28.128.1 to 84.28.255.25484.28.255.25532,766
5984.29.0.0/1784.29.0.1 to 84.29.127.25484.29.127.25532,766
6084.29.128.0/1784.29.128.1 to 84.29.255.25484.29.255.25532,766
6184.30.0.0/1784.30.0.1 to 84.30.127.25484.30.127.25532,766
6284.30.128.0/1784.30.128.1 to 84.30.255.25484.30.255.25532,766
6384.31.0.0/1784.31.0.1 to 84.31.127.25484.31.127.25532,766
6484.31.128.0/1784.31.128.1 to 84.31.255.25484.31.255.25532,766
6584.32.0.0/1784.32.0.1 to 84.32.127.25484.32.127.25532,766
6684.32.128.0/1784.32.128.1 to 84.32.255.25484.32.255.25532,766
6784.33.0.0/1784.33.0.1 to 84.33.127.25484.33.127.25532,766
6884.33.128.0/1784.33.128.1 to 84.33.255.25484.33.255.25532,766
6984.34.0.0/1784.34.0.1 to 84.34.127.25484.34.127.25532,766
7084.34.128.0/1784.34.128.1 to 84.34.255.25484.34.255.25532,766
7184.35.0.0/1784.35.0.1 to 84.35.127.25484.35.127.25532,766
7284.35.128.0/1784.35.128.1 to 84.35.255.25484.35.255.25532,766
7384.36.0.0/1784.36.0.1 to 84.36.127.25484.36.127.25532,766
7484.36.128.0/1784.36.128.1 to 84.36.255.25484.36.255.25532,766
7584.37.0.0/1784.37.0.1 to 84.37.127.25484.37.127.25532,766
7684.37.128.0/1784.37.128.1 to 84.37.255.25484.37.255.25532,766
7784.38.0.0/1784.38.0.1 to 84.38.127.25484.38.127.25532,766
7884.38.128.0/1784.38.128.1 to 84.38.255.25484.38.255.25532,766
7984.39.0.0/1784.39.0.1 to 84.39.127.25484.39.127.25532,766
8084.39.128.0/1784.39.128.1 to 84.39.255.25484.39.255.25532,766
8184.40.0.0/1784.40.0.1 to 84.40.127.25484.40.127.25532,766
8284.40.128.0/1784.40.128.1 to 84.40.255.25484.40.255.25532,766
8384.41.0.0/1784.41.0.1 to 84.41.127.25484.41.127.25532,766
8484.41.128.0/1784.41.128.1 to 84.41.255.25484.41.255.25532,766
8584.42.0.0/1784.42.0.1 to 84.42.127.25484.42.127.25532,766
8684.42.128.0/1784.42.128.1 to 84.42.255.25484.42.255.25532,766
8784.43.0.0/1784.43.0.1 to 84.43.127.25484.43.127.25532,766
8884.43.128.0/1784.43.128.1 to 84.43.255.25484.43.255.25532,766
8984.44.0.0/1784.44.0.1 to 84.44.127.25484.44.127.25532,766
9084.44.128.0/1784.44.128.1 to 84.44.255.25484.44.255.25532,766
9184.45.0.0/1784.45.0.1 to 84.45.127.25484.45.127.25532,766
9284.45.128.0/1784.45.128.1 to 84.45.255.25484.45.255.25532,766
9384.46.0.0/1784.46.0.1 to 84.46.127.25484.46.127.25532,766
9484.46.128.0/1784.46.128.1 to 84.46.255.25484.46.255.25532,766
9584.47.0.0/1784.47.0.1 to 84.47.127.25484.47.127.25532,766
9684.47.128.0/1784.47.128.1 to 84.47.255.25484.47.255.25532,766
9784.48.0.0/1784.48.0.1 to 84.48.127.25484.48.127.25532,766
9884.48.128.0/1784.48.128.1 to 84.48.255.25484.48.255.25532,766
9984.49.0.0/1784.49.0.1 to 84.49.127.25484.49.127.25532,766
10084.49.128.0/1784.49.128.1 to 84.49.255.25484.49.255.25532,766
10184.50.0.0/1784.50.0.1 to 84.50.127.25484.50.127.25532,766
10284.50.128.0/1784.50.128.1 to 84.50.255.25484.50.255.25532,766
10384.51.0.0/1784.51.0.1 to 84.51.127.25484.51.127.25532,766
10484.51.128.0/1784.51.128.1 to 84.51.255.25484.51.255.25532,766
10584.52.0.0/1784.52.0.1 to 84.52.127.25484.52.127.25532,766
10684.52.128.0/1784.52.128.1 to 84.52.255.25484.52.255.25532,766
10784.53.0.0/1784.53.0.1 to 84.53.127.25484.53.127.25532,766
10884.53.128.0/1784.53.128.1 to 84.53.255.25484.53.255.25532,766
10984.54.0.0/1784.54.0.1 to 84.54.127.25484.54.127.25532,766
11084.54.128.0/1784.54.128.1 to 84.54.255.25484.54.255.25532,766
11184.55.0.0/1784.55.0.1 to 84.55.127.25484.55.127.25532,766
11284.55.128.0/1784.55.128.1 to 84.55.255.25484.55.255.25532,766
11384.56.0.0/1784.56.0.1 to 84.56.127.25484.56.127.25532,766
11484.56.128.0/1784.56.128.1 to 84.56.255.25484.56.255.25532,766
11584.57.0.0/1784.57.0.1 to 84.57.127.25484.57.127.25532,766
11684.57.128.0/1784.57.128.1 to 84.57.255.25484.57.255.25532,766
11784.58.0.0/1784.58.0.1 to 84.58.127.25484.58.127.25532,766
11884.58.128.0/1784.58.128.1 to 84.58.255.25484.58.255.25532,766
11984.59.0.0/1784.59.0.1 to 84.59.127.25484.59.127.25532,766
12084.59.128.0/1784.59.128.1 to 84.59.255.25484.59.255.25532,766
12184.60.0.0/1784.60.0.1 to 84.60.127.25484.60.127.25532,766
12284.60.128.0/1784.60.128.1 to 84.60.255.25484.60.255.25532,766
12384.61.0.0/1784.61.0.1 to 84.61.127.25484.61.127.25532,766
12484.61.128.0/1784.61.128.1 to 84.61.255.25484.61.255.25532,766
12584.62.0.0/1784.62.0.1 to 84.62.127.25484.62.127.25532,766
12684.62.128.0/1784.62.128.1 to 84.62.255.25484.62.255.25532,766
12784.63.0.0/1784.63.0.1 to 84.63.127.25484.63.127.25532,766
12884.63.128.0/1784.63.128.1 to 84.63.255.25484.63.255.25532,766
12984.64.0.0/1784.64.0.1 to 84.64.127.25484.64.127.25532,766
13084.64.128.0/1784.64.128.1 to 84.64.255.25484.64.255.25532,766
13184.65.0.0/1784.65.0.1 to 84.65.127.25484.65.127.25532,766
13284.65.128.0/1784.65.128.1 to 84.65.255.25484.65.255.25532,766
13384.66.0.0/1784.66.0.1 to 84.66.127.25484.66.127.25532,766
13484.66.128.0/1784.66.128.1 to 84.66.255.25484.66.255.25532,766
13584.67.0.0/1784.67.0.1 to 84.67.127.25484.67.127.25532,766
13684.67.128.0/1784.67.128.1 to 84.67.255.25484.67.255.25532,766
13784.68.0.0/1784.68.0.1 to 84.68.127.25484.68.127.25532,766
13884.68.128.0/1784.68.128.1 to 84.68.255.25484.68.255.25532,766
13984.69.0.0/1784.69.0.1 to 84.69.127.25484.69.127.25532,766
14084.69.128.0/1784.69.128.1 to 84.69.255.25484.69.255.25532,766
14184.70.0.0/1784.70.0.1 to 84.70.127.25484.70.127.25532,766
14284.70.128.0/1784.70.128.1 to 84.70.255.25484.70.255.25532,766
14384.71.0.0/1784.71.0.1 to 84.71.127.25484.71.127.25532,766
14484.71.128.0/1784.71.128.1 to 84.71.255.25484.71.255.25532,766
14584.72.0.0/1784.72.0.1 to 84.72.127.25484.72.127.25532,766
14684.72.128.0/1784.72.128.1 to 84.72.255.25484.72.255.25532,766
14784.73.0.0/1784.73.0.1 to 84.73.127.25484.73.127.25532,766
14884.73.128.0/1784.73.128.1 to 84.73.255.25484.73.255.25532,766
14984.74.0.0/1784.74.0.1 to 84.74.127.25484.74.127.25532,766
15084.74.128.0/1784.74.128.1 to 84.74.255.25484.74.255.25532,766
15184.75.0.0/1784.75.0.1 to 84.75.127.25484.75.127.25532,766
15284.75.128.0/1784.75.128.1 to 84.75.255.25484.75.255.25532,766
15384.76.0.0/1784.76.0.1 to 84.76.127.25484.76.127.25532,766
15484.76.128.0/1784.76.128.1 to 84.76.255.25484.76.255.25532,766
15584.77.0.0/1784.77.0.1 to 84.77.127.25484.77.127.25532,766
15684.77.128.0/1784.77.128.1 to 84.77.255.25484.77.255.25532,766
15784.78.0.0/1784.78.0.1 to 84.78.127.25484.78.127.25532,766
15884.78.128.0/1784.78.128.1 to 84.78.255.25484.78.255.25532,766
15984.79.0.0/1784.79.0.1 to 84.79.127.25484.79.127.25532,766
16084.79.128.0/1784.79.128.1 to 84.79.255.25484.79.255.25532,766
16184.80.0.0/1784.80.0.1 to 84.80.127.25484.80.127.25532,766
16284.80.128.0/1784.80.128.1 to 84.80.255.25484.80.255.25532,766
16384.81.0.0/1784.81.0.1 to 84.81.127.25484.81.127.25532,766
16484.81.128.0/1784.81.128.1 to 84.81.255.25484.81.255.25532,766
16584.82.0.0/1784.82.0.1 to 84.82.127.25484.82.127.25532,766
16684.82.128.0/1784.82.128.1 to 84.82.255.25484.82.255.25532,766
16784.83.0.0/1784.83.0.1 to 84.83.127.25484.83.127.25532,766
16884.83.128.0/1784.83.128.1 to 84.83.255.25484.83.255.25532,766
16984.84.0.0/1784.84.0.1 to 84.84.127.25484.84.127.25532,766
17084.84.128.0/1784.84.128.1 to 84.84.255.25484.84.255.25532,766
17184.85.0.0/1784.85.0.1 to 84.85.127.25484.85.127.25532,766
17284.85.128.0/1784.85.128.1 to 84.85.255.25484.85.255.25532,766
17384.86.0.0/1784.86.0.1 to 84.86.127.25484.86.127.25532,766
17484.86.128.0/1784.86.128.1 to 84.86.255.25484.86.255.25532,766
17584.87.0.0/1784.87.0.1 to 84.87.127.25484.87.127.25532,766
17684.87.128.0/1784.87.128.1 to 84.87.255.25484.87.255.25532,766
17784.88.0.0/1784.88.0.1 to 84.88.127.25484.88.127.25532,766
17884.88.128.0/1784.88.128.1 to 84.88.255.25484.88.255.25532,766
17984.89.0.0/1784.89.0.1 to 84.89.127.25484.89.127.25532,766
18084.89.128.0/1784.89.128.1 to 84.89.255.25484.89.255.25532,766
18184.90.0.0/1784.90.0.1 to 84.90.127.25484.90.127.25532,766
18284.90.128.0/1784.90.128.1 to 84.90.255.25484.90.255.25532,766
18384.91.0.0/1784.91.0.1 to 84.91.127.25484.91.127.25532,766
18484.91.128.0/1784.91.128.1 to 84.91.255.25484.91.255.25532,766
18584.92.0.0/1784.92.0.1 to 84.92.127.25484.92.127.25532,766
18684.92.128.0/1784.92.128.1 to 84.92.255.25484.92.255.25532,766
18784.93.0.0/1784.93.0.1 to 84.93.127.25484.93.127.25532,766
18884.93.128.0/1784.93.128.1 to 84.93.255.25484.93.255.25532,766
18984.94.0.0/1784.94.0.1 to 84.94.127.25484.94.127.25532,766
19084.94.128.0/1784.94.128.1 to 84.94.255.25484.94.255.25532,766
19184.95.0.0/1784.95.0.1 to 84.95.127.25484.95.127.25532,766
19284.95.128.0/1784.95.128.1 to 84.95.255.25484.95.255.25532,766
19384.96.0.0/1784.96.0.1 to 84.96.127.25484.96.127.25532,766
19484.96.128.0/1784.96.128.1 to 84.96.255.25484.96.255.25532,766
19584.97.0.0/1784.97.0.1 to 84.97.127.25484.97.127.25532,766
19684.97.128.0/1784.97.128.1 to 84.97.255.25484.97.255.25532,766
19784.98.0.0/1784.98.0.1 to 84.98.127.25484.98.127.25532,766
19884.98.128.0/1784.98.128.1 to 84.98.255.25484.98.255.25532,766
19984.99.0.0/1784.99.0.1 to 84.99.127.25484.99.127.25532,766
20084.99.128.0/1784.99.128.1 to 84.99.255.25484.99.255.25532,766
20184.100.0.0/1784.100.0.1 to 84.100.127.25484.100.127.25532,766
20284.100.128.0/1784.100.128.1 to 84.100.255.25484.100.255.25532,766
20384.101.0.0/1784.101.0.1 to 84.101.127.25484.101.127.25532,766
20484.101.128.0/1784.101.128.1 to 84.101.255.25484.101.255.25532,766
20584.102.0.0/1784.102.0.1 to 84.102.127.25484.102.127.25532,766
20684.102.128.0/1784.102.128.1 to 84.102.255.25484.102.255.25532,766
20784.103.0.0/1784.103.0.1 to 84.103.127.25484.103.127.25532,766
20884.103.128.0/1784.103.128.1 to 84.103.255.25484.103.255.25532,766
20984.104.0.0/1784.104.0.1 to 84.104.127.25484.104.127.25532,766
21084.104.128.0/1784.104.128.1 to 84.104.255.25484.104.255.25532,766
21184.105.0.0/1784.105.0.1 to 84.105.127.25484.105.127.25532,766
21284.105.128.0/1784.105.128.1 to 84.105.255.25484.105.255.25532,766
21384.106.0.0/1784.106.0.1 to 84.106.127.25484.106.127.25532,766
21484.106.128.0/1784.106.128.1 to 84.106.255.25484.106.255.25532,766
21584.107.0.0/1784.107.0.1 to 84.107.127.25484.107.127.25532,766
21684.107.128.0/1784.107.128.1 to 84.107.255.25484.107.255.25532,766
21784.108.0.0/1784.108.0.1 to 84.108.127.25484.108.127.25532,766
21884.108.128.0/1784.108.128.1 to 84.108.255.25484.108.255.25532,766
21984.109.0.0/1784.109.0.1 to 84.109.127.25484.109.127.25532,766
22084.109.128.0/1784.109.128.1 to 84.109.255.25484.109.255.25532,766
22184.110.0.0/1784.110.0.1 to 84.110.127.25484.110.127.25532,766
22284.110.128.0/1784.110.128.1 to 84.110.255.25484.110.255.25532,766
22384.111.0.0/1784.111.0.1 to 84.111.127.25484.111.127.25532,766
22484.111.128.0/1784.111.128.1 to 84.111.255.25484.111.255.25532,766
22584.112.0.0/1784.112.0.1 to 84.112.127.25484.112.127.25532,766
22684.112.128.0/1784.112.128.1 to 84.112.255.25484.112.255.25532,766
22784.113.0.0/1784.113.0.1 to 84.113.127.25484.113.127.25532,766
22884.113.128.0/1784.113.128.1 to 84.113.255.25484.113.255.25532,766
22984.114.0.0/1784.114.0.1 to 84.114.127.25484.114.127.25532,766
23084.114.128.0/1784.114.128.1 to 84.114.255.25484.114.255.25532,766
23184.115.0.0/1784.115.0.1 to 84.115.127.25484.115.127.25532,766
23284.115.128.0/1784.115.128.1 to 84.115.255.25484.115.255.25532,766
23384.116.0.0/1784.116.0.1 to 84.116.127.25484.116.127.25532,766
23484.116.128.0/1784.116.128.1 to 84.116.255.25484.116.255.25532,766
23584.117.0.0/1784.117.0.1 to 84.117.127.25484.117.127.25532,766
23684.117.128.0/1784.117.128.1 to 84.117.255.25484.117.255.25532,766
23784.118.0.0/1784.118.0.1 to 84.118.127.25484.118.127.25532,766
23884.118.128.0/1784.118.128.1 to 84.118.255.25484.118.255.25532,766
23984.119.0.0/1784.119.0.1 to 84.119.127.25484.119.127.25532,766
24084.119.128.0/1784.119.128.1 to 84.119.255.25484.119.255.25532,766
24184.120.0.0/1784.120.0.1 to 84.120.127.25484.120.127.25532,766
24284.120.128.0/1784.120.128.1 to 84.120.255.25484.120.255.25532,766
24384.121.0.0/1784.121.0.1 to 84.121.127.25484.121.127.25532,766
24484.121.128.0/1784.121.128.1 to 84.121.255.25484.121.255.25532,766
24584.122.0.0/1784.122.0.1 to 84.122.127.25484.122.127.25532,766
24684.122.128.0/1784.122.128.1 to 84.122.255.25484.122.255.25532,766
24784.123.0.0/1784.123.0.1 to 84.123.127.25484.123.127.25532,766
24884.123.128.0/1784.123.128.1 to 84.123.255.25484.123.255.25532,766
24984.124.0.0/1784.124.0.1 to 84.124.127.25484.124.127.25532,766
25084.124.128.0/1784.124.128.1 to 84.124.255.25484.124.255.25532,766
25184.125.0.0/1784.125.0.1 to 84.125.127.25484.125.127.25532,766
25284.125.128.0/1784.125.128.1 to 84.125.255.25484.125.255.25532,766
25384.126.0.0/1784.126.0.1 to 84.126.127.25484.126.127.25532,766
25484.126.128.0/1784.126.128.1 to 84.126.255.25484.126.255.25532,766
25584.127.0.0/1784.127.0.1 to 84.127.127.25484.127.127.25532,766
25684.127.128.0/1784.127.128.1 to 84.127.255.25484.127.255.25532,766

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.