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.

Network11.160.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
11.160.0.0
Broadcast address
11.175.255.255
First usable
11.160.0.1
Last usable
11.175.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 0BA00000 · Integer 195035136 to 196083711
Reverse DNS zones
160.11.in-addr.arpa
161.11.in-addr.arpa
162.11.in-addr.arpa
163.11.in-addr.arpa
164.11.in-addr.arpa
165.11.in-addr.arpa
166.11.in-addr.arpa
167.11.in-addr.arpa
168.11.in-addr.arpa
169.11.in-addr.arpa
170.11.in-addr.arpa
171.11.in-addr.arpa
172.11.in-addr.arpa
173.11.in-addr.arpa
174.11.in-addr.arpa
175.11.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001011.10100000.00000000.0000000011.160.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00001011.10100000.00000000.0000000011.160.0.0
Broadcast00001011.10101111.11111111.1111111111.175.255.255
Split into smaller subnets/20
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

11.160.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
111.160.0.0/2011.160.0.1 to 11.160.15.25411.160.15.2554,094
211.160.16.0/2011.160.16.1 to 11.160.31.25411.160.31.2554,094
311.160.32.0/2011.160.32.1 to 11.160.47.25411.160.47.2554,094
411.160.48.0/2011.160.48.1 to 11.160.63.25411.160.63.2554,094
511.160.64.0/2011.160.64.1 to 11.160.79.25411.160.79.2554,094
611.160.80.0/2011.160.80.1 to 11.160.95.25411.160.95.2554,094
711.160.96.0/2011.160.96.1 to 11.160.111.25411.160.111.2554,094
811.160.112.0/2011.160.112.1 to 11.160.127.25411.160.127.2554,094
911.160.128.0/2011.160.128.1 to 11.160.143.25411.160.143.2554,094
1011.160.144.0/2011.160.144.1 to 11.160.159.25411.160.159.2554,094
1111.160.160.0/2011.160.160.1 to 11.160.175.25411.160.175.2554,094
1211.160.176.0/2011.160.176.1 to 11.160.191.25411.160.191.2554,094
1311.160.192.0/2011.160.192.1 to 11.160.207.25411.160.207.2554,094
1411.160.208.0/2011.160.208.1 to 11.160.223.25411.160.223.2554,094
1511.160.224.0/2011.160.224.1 to 11.160.239.25411.160.239.2554,094
1611.160.240.0/2011.160.240.1 to 11.160.255.25411.160.255.2554,094
1711.161.0.0/2011.161.0.1 to 11.161.15.25411.161.15.2554,094
1811.161.16.0/2011.161.16.1 to 11.161.31.25411.161.31.2554,094
1911.161.32.0/2011.161.32.1 to 11.161.47.25411.161.47.2554,094
2011.161.48.0/2011.161.48.1 to 11.161.63.25411.161.63.2554,094
2111.161.64.0/2011.161.64.1 to 11.161.79.25411.161.79.2554,094
2211.161.80.0/2011.161.80.1 to 11.161.95.25411.161.95.2554,094
2311.161.96.0/2011.161.96.1 to 11.161.111.25411.161.111.2554,094
2411.161.112.0/2011.161.112.1 to 11.161.127.25411.161.127.2554,094
2511.161.128.0/2011.161.128.1 to 11.161.143.25411.161.143.2554,094
2611.161.144.0/2011.161.144.1 to 11.161.159.25411.161.159.2554,094
2711.161.160.0/2011.161.160.1 to 11.161.175.25411.161.175.2554,094
2811.161.176.0/2011.161.176.1 to 11.161.191.25411.161.191.2554,094
2911.161.192.0/2011.161.192.1 to 11.161.207.25411.161.207.2554,094
3011.161.208.0/2011.161.208.1 to 11.161.223.25411.161.223.2554,094
3111.161.224.0/2011.161.224.1 to 11.161.239.25411.161.239.2554,094
3211.161.240.0/2011.161.240.1 to 11.161.255.25411.161.255.2554,094
3311.162.0.0/2011.162.0.1 to 11.162.15.25411.162.15.2554,094
3411.162.16.0/2011.162.16.1 to 11.162.31.25411.162.31.2554,094
3511.162.32.0/2011.162.32.1 to 11.162.47.25411.162.47.2554,094
3611.162.48.0/2011.162.48.1 to 11.162.63.25411.162.63.2554,094
3711.162.64.0/2011.162.64.1 to 11.162.79.25411.162.79.2554,094
3811.162.80.0/2011.162.80.1 to 11.162.95.25411.162.95.2554,094
3911.162.96.0/2011.162.96.1 to 11.162.111.25411.162.111.2554,094
4011.162.112.0/2011.162.112.1 to 11.162.127.25411.162.127.2554,094
4111.162.128.0/2011.162.128.1 to 11.162.143.25411.162.143.2554,094
4211.162.144.0/2011.162.144.1 to 11.162.159.25411.162.159.2554,094
4311.162.160.0/2011.162.160.1 to 11.162.175.25411.162.175.2554,094
4411.162.176.0/2011.162.176.1 to 11.162.191.25411.162.191.2554,094
4511.162.192.0/2011.162.192.1 to 11.162.207.25411.162.207.2554,094
4611.162.208.0/2011.162.208.1 to 11.162.223.25411.162.223.2554,094
4711.162.224.0/2011.162.224.1 to 11.162.239.25411.162.239.2554,094
4811.162.240.0/2011.162.240.1 to 11.162.255.25411.162.255.2554,094
4911.163.0.0/2011.163.0.1 to 11.163.15.25411.163.15.2554,094
5011.163.16.0/2011.163.16.1 to 11.163.31.25411.163.31.2554,094
5111.163.32.0/2011.163.32.1 to 11.163.47.25411.163.47.2554,094
5211.163.48.0/2011.163.48.1 to 11.163.63.25411.163.63.2554,094
5311.163.64.0/2011.163.64.1 to 11.163.79.25411.163.79.2554,094
5411.163.80.0/2011.163.80.1 to 11.163.95.25411.163.95.2554,094
5511.163.96.0/2011.163.96.1 to 11.163.111.25411.163.111.2554,094
5611.163.112.0/2011.163.112.1 to 11.163.127.25411.163.127.2554,094
5711.163.128.0/2011.163.128.1 to 11.163.143.25411.163.143.2554,094
5811.163.144.0/2011.163.144.1 to 11.163.159.25411.163.159.2554,094
5911.163.160.0/2011.163.160.1 to 11.163.175.25411.163.175.2554,094
6011.163.176.0/2011.163.176.1 to 11.163.191.25411.163.191.2554,094
6111.163.192.0/2011.163.192.1 to 11.163.207.25411.163.207.2554,094
6211.163.208.0/2011.163.208.1 to 11.163.223.25411.163.223.2554,094
6311.163.224.0/2011.163.224.1 to 11.163.239.25411.163.239.2554,094
6411.163.240.0/2011.163.240.1 to 11.163.255.25411.163.255.2554,094
6511.164.0.0/2011.164.0.1 to 11.164.15.25411.164.15.2554,094
6611.164.16.0/2011.164.16.1 to 11.164.31.25411.164.31.2554,094
6711.164.32.0/2011.164.32.1 to 11.164.47.25411.164.47.2554,094
6811.164.48.0/2011.164.48.1 to 11.164.63.25411.164.63.2554,094
6911.164.64.0/2011.164.64.1 to 11.164.79.25411.164.79.2554,094
7011.164.80.0/2011.164.80.1 to 11.164.95.25411.164.95.2554,094
7111.164.96.0/2011.164.96.1 to 11.164.111.25411.164.111.2554,094
7211.164.112.0/2011.164.112.1 to 11.164.127.25411.164.127.2554,094
7311.164.128.0/2011.164.128.1 to 11.164.143.25411.164.143.2554,094
7411.164.144.0/2011.164.144.1 to 11.164.159.25411.164.159.2554,094
7511.164.160.0/2011.164.160.1 to 11.164.175.25411.164.175.2554,094
7611.164.176.0/2011.164.176.1 to 11.164.191.25411.164.191.2554,094
7711.164.192.0/2011.164.192.1 to 11.164.207.25411.164.207.2554,094
7811.164.208.0/2011.164.208.1 to 11.164.223.25411.164.223.2554,094
7911.164.224.0/2011.164.224.1 to 11.164.239.25411.164.239.2554,094
8011.164.240.0/2011.164.240.1 to 11.164.255.25411.164.255.2554,094
8111.165.0.0/2011.165.0.1 to 11.165.15.25411.165.15.2554,094
8211.165.16.0/2011.165.16.1 to 11.165.31.25411.165.31.2554,094
8311.165.32.0/2011.165.32.1 to 11.165.47.25411.165.47.2554,094
8411.165.48.0/2011.165.48.1 to 11.165.63.25411.165.63.2554,094
8511.165.64.0/2011.165.64.1 to 11.165.79.25411.165.79.2554,094
8611.165.80.0/2011.165.80.1 to 11.165.95.25411.165.95.2554,094
8711.165.96.0/2011.165.96.1 to 11.165.111.25411.165.111.2554,094
8811.165.112.0/2011.165.112.1 to 11.165.127.25411.165.127.2554,094
8911.165.128.0/2011.165.128.1 to 11.165.143.25411.165.143.2554,094
9011.165.144.0/2011.165.144.1 to 11.165.159.25411.165.159.2554,094
9111.165.160.0/2011.165.160.1 to 11.165.175.25411.165.175.2554,094
9211.165.176.0/2011.165.176.1 to 11.165.191.25411.165.191.2554,094
9311.165.192.0/2011.165.192.1 to 11.165.207.25411.165.207.2554,094
9411.165.208.0/2011.165.208.1 to 11.165.223.25411.165.223.2554,094
9511.165.224.0/2011.165.224.1 to 11.165.239.25411.165.239.2554,094
9611.165.240.0/2011.165.240.1 to 11.165.255.25411.165.255.2554,094
9711.166.0.0/2011.166.0.1 to 11.166.15.25411.166.15.2554,094
9811.166.16.0/2011.166.16.1 to 11.166.31.25411.166.31.2554,094
9911.166.32.0/2011.166.32.1 to 11.166.47.25411.166.47.2554,094
10011.166.48.0/2011.166.48.1 to 11.166.63.25411.166.63.2554,094
10111.166.64.0/2011.166.64.1 to 11.166.79.25411.166.79.2554,094
10211.166.80.0/2011.166.80.1 to 11.166.95.25411.166.95.2554,094
10311.166.96.0/2011.166.96.1 to 11.166.111.25411.166.111.2554,094
10411.166.112.0/2011.166.112.1 to 11.166.127.25411.166.127.2554,094
10511.166.128.0/2011.166.128.1 to 11.166.143.25411.166.143.2554,094
10611.166.144.0/2011.166.144.1 to 11.166.159.25411.166.159.2554,094
10711.166.160.0/2011.166.160.1 to 11.166.175.25411.166.175.2554,094
10811.166.176.0/2011.166.176.1 to 11.166.191.25411.166.191.2554,094
10911.166.192.0/2011.166.192.1 to 11.166.207.25411.166.207.2554,094
11011.166.208.0/2011.166.208.1 to 11.166.223.25411.166.223.2554,094
11111.166.224.0/2011.166.224.1 to 11.166.239.25411.166.239.2554,094
11211.166.240.0/2011.166.240.1 to 11.166.255.25411.166.255.2554,094
11311.167.0.0/2011.167.0.1 to 11.167.15.25411.167.15.2554,094
11411.167.16.0/2011.167.16.1 to 11.167.31.25411.167.31.2554,094
11511.167.32.0/2011.167.32.1 to 11.167.47.25411.167.47.2554,094
11611.167.48.0/2011.167.48.1 to 11.167.63.25411.167.63.2554,094
11711.167.64.0/2011.167.64.1 to 11.167.79.25411.167.79.2554,094
11811.167.80.0/2011.167.80.1 to 11.167.95.25411.167.95.2554,094
11911.167.96.0/2011.167.96.1 to 11.167.111.25411.167.111.2554,094
12011.167.112.0/2011.167.112.1 to 11.167.127.25411.167.127.2554,094
12111.167.128.0/2011.167.128.1 to 11.167.143.25411.167.143.2554,094
12211.167.144.0/2011.167.144.1 to 11.167.159.25411.167.159.2554,094
12311.167.160.0/2011.167.160.1 to 11.167.175.25411.167.175.2554,094
12411.167.176.0/2011.167.176.1 to 11.167.191.25411.167.191.2554,094
12511.167.192.0/2011.167.192.1 to 11.167.207.25411.167.207.2554,094
12611.167.208.0/2011.167.208.1 to 11.167.223.25411.167.223.2554,094
12711.167.224.0/2011.167.224.1 to 11.167.239.25411.167.239.2554,094
12811.167.240.0/2011.167.240.1 to 11.167.255.25411.167.255.2554,094
12911.168.0.0/2011.168.0.1 to 11.168.15.25411.168.15.2554,094
13011.168.16.0/2011.168.16.1 to 11.168.31.25411.168.31.2554,094
13111.168.32.0/2011.168.32.1 to 11.168.47.25411.168.47.2554,094
13211.168.48.0/2011.168.48.1 to 11.168.63.25411.168.63.2554,094
13311.168.64.0/2011.168.64.1 to 11.168.79.25411.168.79.2554,094
13411.168.80.0/2011.168.80.1 to 11.168.95.25411.168.95.2554,094
13511.168.96.0/2011.168.96.1 to 11.168.111.25411.168.111.2554,094
13611.168.112.0/2011.168.112.1 to 11.168.127.25411.168.127.2554,094
13711.168.128.0/2011.168.128.1 to 11.168.143.25411.168.143.2554,094
13811.168.144.0/2011.168.144.1 to 11.168.159.25411.168.159.2554,094
13911.168.160.0/2011.168.160.1 to 11.168.175.25411.168.175.2554,094
14011.168.176.0/2011.168.176.1 to 11.168.191.25411.168.191.2554,094
14111.168.192.0/2011.168.192.1 to 11.168.207.25411.168.207.2554,094
14211.168.208.0/2011.168.208.1 to 11.168.223.25411.168.223.2554,094
14311.168.224.0/2011.168.224.1 to 11.168.239.25411.168.239.2554,094
14411.168.240.0/2011.168.240.1 to 11.168.255.25411.168.255.2554,094
14511.169.0.0/2011.169.0.1 to 11.169.15.25411.169.15.2554,094
14611.169.16.0/2011.169.16.1 to 11.169.31.25411.169.31.2554,094
14711.169.32.0/2011.169.32.1 to 11.169.47.25411.169.47.2554,094
14811.169.48.0/2011.169.48.1 to 11.169.63.25411.169.63.2554,094
14911.169.64.0/2011.169.64.1 to 11.169.79.25411.169.79.2554,094
15011.169.80.0/2011.169.80.1 to 11.169.95.25411.169.95.2554,094
15111.169.96.0/2011.169.96.1 to 11.169.111.25411.169.111.2554,094
15211.169.112.0/2011.169.112.1 to 11.169.127.25411.169.127.2554,094
15311.169.128.0/2011.169.128.1 to 11.169.143.25411.169.143.2554,094
15411.169.144.0/2011.169.144.1 to 11.169.159.25411.169.159.2554,094
15511.169.160.0/2011.169.160.1 to 11.169.175.25411.169.175.2554,094
15611.169.176.0/2011.169.176.1 to 11.169.191.25411.169.191.2554,094
15711.169.192.0/2011.169.192.1 to 11.169.207.25411.169.207.2554,094
15811.169.208.0/2011.169.208.1 to 11.169.223.25411.169.223.2554,094
15911.169.224.0/2011.169.224.1 to 11.169.239.25411.169.239.2554,094
16011.169.240.0/2011.169.240.1 to 11.169.255.25411.169.255.2554,094
16111.170.0.0/2011.170.0.1 to 11.170.15.25411.170.15.2554,094
16211.170.16.0/2011.170.16.1 to 11.170.31.25411.170.31.2554,094
16311.170.32.0/2011.170.32.1 to 11.170.47.25411.170.47.2554,094
16411.170.48.0/2011.170.48.1 to 11.170.63.25411.170.63.2554,094
16511.170.64.0/2011.170.64.1 to 11.170.79.25411.170.79.2554,094
16611.170.80.0/2011.170.80.1 to 11.170.95.25411.170.95.2554,094
16711.170.96.0/2011.170.96.1 to 11.170.111.25411.170.111.2554,094
16811.170.112.0/2011.170.112.1 to 11.170.127.25411.170.127.2554,094
16911.170.128.0/2011.170.128.1 to 11.170.143.25411.170.143.2554,094
17011.170.144.0/2011.170.144.1 to 11.170.159.25411.170.159.2554,094
17111.170.160.0/2011.170.160.1 to 11.170.175.25411.170.175.2554,094
17211.170.176.0/2011.170.176.1 to 11.170.191.25411.170.191.2554,094
17311.170.192.0/2011.170.192.1 to 11.170.207.25411.170.207.2554,094
17411.170.208.0/2011.170.208.1 to 11.170.223.25411.170.223.2554,094
17511.170.224.0/2011.170.224.1 to 11.170.239.25411.170.239.2554,094
17611.170.240.0/2011.170.240.1 to 11.170.255.25411.170.255.2554,094
17711.171.0.0/2011.171.0.1 to 11.171.15.25411.171.15.2554,094
17811.171.16.0/2011.171.16.1 to 11.171.31.25411.171.31.2554,094
17911.171.32.0/2011.171.32.1 to 11.171.47.25411.171.47.2554,094
18011.171.48.0/2011.171.48.1 to 11.171.63.25411.171.63.2554,094
18111.171.64.0/2011.171.64.1 to 11.171.79.25411.171.79.2554,094
18211.171.80.0/2011.171.80.1 to 11.171.95.25411.171.95.2554,094
18311.171.96.0/2011.171.96.1 to 11.171.111.25411.171.111.2554,094
18411.171.112.0/2011.171.112.1 to 11.171.127.25411.171.127.2554,094
18511.171.128.0/2011.171.128.1 to 11.171.143.25411.171.143.2554,094
18611.171.144.0/2011.171.144.1 to 11.171.159.25411.171.159.2554,094
18711.171.160.0/2011.171.160.1 to 11.171.175.25411.171.175.2554,094
18811.171.176.0/2011.171.176.1 to 11.171.191.25411.171.191.2554,094
18911.171.192.0/2011.171.192.1 to 11.171.207.25411.171.207.2554,094
19011.171.208.0/2011.171.208.1 to 11.171.223.25411.171.223.2554,094
19111.171.224.0/2011.171.224.1 to 11.171.239.25411.171.239.2554,094
19211.171.240.0/2011.171.240.1 to 11.171.255.25411.171.255.2554,094
19311.172.0.0/2011.172.0.1 to 11.172.15.25411.172.15.2554,094
19411.172.16.0/2011.172.16.1 to 11.172.31.25411.172.31.2554,094
19511.172.32.0/2011.172.32.1 to 11.172.47.25411.172.47.2554,094
19611.172.48.0/2011.172.48.1 to 11.172.63.25411.172.63.2554,094
19711.172.64.0/2011.172.64.1 to 11.172.79.25411.172.79.2554,094
19811.172.80.0/2011.172.80.1 to 11.172.95.25411.172.95.2554,094
19911.172.96.0/2011.172.96.1 to 11.172.111.25411.172.111.2554,094
20011.172.112.0/2011.172.112.1 to 11.172.127.25411.172.127.2554,094
20111.172.128.0/2011.172.128.1 to 11.172.143.25411.172.143.2554,094
20211.172.144.0/2011.172.144.1 to 11.172.159.25411.172.159.2554,094
20311.172.160.0/2011.172.160.1 to 11.172.175.25411.172.175.2554,094
20411.172.176.0/2011.172.176.1 to 11.172.191.25411.172.191.2554,094
20511.172.192.0/2011.172.192.1 to 11.172.207.25411.172.207.2554,094
20611.172.208.0/2011.172.208.1 to 11.172.223.25411.172.223.2554,094
20711.172.224.0/2011.172.224.1 to 11.172.239.25411.172.239.2554,094
20811.172.240.0/2011.172.240.1 to 11.172.255.25411.172.255.2554,094
20911.173.0.0/2011.173.0.1 to 11.173.15.25411.173.15.2554,094
21011.173.16.0/2011.173.16.1 to 11.173.31.25411.173.31.2554,094
21111.173.32.0/2011.173.32.1 to 11.173.47.25411.173.47.2554,094
21211.173.48.0/2011.173.48.1 to 11.173.63.25411.173.63.2554,094
21311.173.64.0/2011.173.64.1 to 11.173.79.25411.173.79.2554,094
21411.173.80.0/2011.173.80.1 to 11.173.95.25411.173.95.2554,094
21511.173.96.0/2011.173.96.1 to 11.173.111.25411.173.111.2554,094
21611.173.112.0/2011.173.112.1 to 11.173.127.25411.173.127.2554,094
21711.173.128.0/2011.173.128.1 to 11.173.143.25411.173.143.2554,094
21811.173.144.0/2011.173.144.1 to 11.173.159.25411.173.159.2554,094
21911.173.160.0/2011.173.160.1 to 11.173.175.25411.173.175.2554,094
22011.173.176.0/2011.173.176.1 to 11.173.191.25411.173.191.2554,094
22111.173.192.0/2011.173.192.1 to 11.173.207.25411.173.207.2554,094
22211.173.208.0/2011.173.208.1 to 11.173.223.25411.173.223.2554,094
22311.173.224.0/2011.173.224.1 to 11.173.239.25411.173.239.2554,094
22411.173.240.0/2011.173.240.1 to 11.173.255.25411.173.255.2554,094
22511.174.0.0/2011.174.0.1 to 11.174.15.25411.174.15.2554,094
22611.174.16.0/2011.174.16.1 to 11.174.31.25411.174.31.2554,094
22711.174.32.0/2011.174.32.1 to 11.174.47.25411.174.47.2554,094
22811.174.48.0/2011.174.48.1 to 11.174.63.25411.174.63.2554,094
22911.174.64.0/2011.174.64.1 to 11.174.79.25411.174.79.2554,094
23011.174.80.0/2011.174.80.1 to 11.174.95.25411.174.95.2554,094
23111.174.96.0/2011.174.96.1 to 11.174.111.25411.174.111.2554,094
23211.174.112.0/2011.174.112.1 to 11.174.127.25411.174.127.2554,094
23311.174.128.0/2011.174.128.1 to 11.174.143.25411.174.143.2554,094
23411.174.144.0/2011.174.144.1 to 11.174.159.25411.174.159.2554,094
23511.174.160.0/2011.174.160.1 to 11.174.175.25411.174.175.2554,094
23611.174.176.0/2011.174.176.1 to 11.174.191.25411.174.191.2554,094
23711.174.192.0/2011.174.192.1 to 11.174.207.25411.174.207.2554,094
23811.174.208.0/2011.174.208.1 to 11.174.223.25411.174.223.2554,094
23911.174.224.0/2011.174.224.1 to 11.174.239.25411.174.239.2554,094
24011.174.240.0/2011.174.240.1 to 11.174.255.25411.174.255.2554,094
24111.175.0.0/2011.175.0.1 to 11.175.15.25411.175.15.2554,094
24211.175.16.0/2011.175.16.1 to 11.175.31.25411.175.31.2554,094
24311.175.32.0/2011.175.32.1 to 11.175.47.25411.175.47.2554,094
24411.175.48.0/2011.175.48.1 to 11.175.63.25411.175.63.2554,094
24511.175.64.0/2011.175.64.1 to 11.175.79.25411.175.79.2554,094
24611.175.80.0/2011.175.80.1 to 11.175.95.25411.175.95.2554,094
24711.175.96.0/2011.175.96.1 to 11.175.111.25411.175.111.2554,094
24811.175.112.0/2011.175.112.1 to 11.175.127.25411.175.127.2554,094
24911.175.128.0/2011.175.128.1 to 11.175.143.25411.175.143.2554,094
25011.175.144.0/2011.175.144.1 to 11.175.159.25411.175.159.2554,094
25111.175.160.0/2011.175.160.1 to 11.175.175.25411.175.175.2554,094
25211.175.176.0/2011.175.176.1 to 11.175.191.25411.175.191.2554,094
25311.175.192.0/2011.175.192.1 to 11.175.207.25411.175.207.2554,094
25411.175.208.0/2011.175.208.1 to 11.175.223.25411.175.223.2554,094
25511.175.224.0/2011.175.224.1 to 11.175.239.25411.175.239.2554,094
25611.175.240.0/2011.175.240.1 to 11.175.255.25411.175.255.2554,094

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.