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.

Network95.72.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
95.72.0.0
Broadcast address
95.79.255.255
First usable
95.72.0.1
Last usable
95.79.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 5F480000 · Integer 1598554112 to 1599078399
Reverse DNS zones
72.95.in-addr.arpa
73.95.in-addr.arpa
74.95.in-addr.arpa
75.95.in-addr.arpa
76.95.in-addr.arpa
77.95.in-addr.arpa
78.95.in-addr.arpa
79.95.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01011111.01001000.00000000.0000000095.72.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network01011111.01001000.00000000.0000000095.72.0.0
Broadcast01011111.01001111.11111111.1111111195.79.255.255
Split into smaller subnets/22
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

95.72.0.0/13 makes 512 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
195.72.0.0/2295.72.0.1 to 95.72.3.25495.72.3.2551,022
295.72.4.0/2295.72.4.1 to 95.72.7.25495.72.7.2551,022
395.72.8.0/2295.72.8.1 to 95.72.11.25495.72.11.2551,022
495.72.12.0/2295.72.12.1 to 95.72.15.25495.72.15.2551,022
595.72.16.0/2295.72.16.1 to 95.72.19.25495.72.19.2551,022
695.72.20.0/2295.72.20.1 to 95.72.23.25495.72.23.2551,022
795.72.24.0/2295.72.24.1 to 95.72.27.25495.72.27.2551,022
895.72.28.0/2295.72.28.1 to 95.72.31.25495.72.31.2551,022
995.72.32.0/2295.72.32.1 to 95.72.35.25495.72.35.2551,022
1095.72.36.0/2295.72.36.1 to 95.72.39.25495.72.39.2551,022
1195.72.40.0/2295.72.40.1 to 95.72.43.25495.72.43.2551,022
1295.72.44.0/2295.72.44.1 to 95.72.47.25495.72.47.2551,022
1395.72.48.0/2295.72.48.1 to 95.72.51.25495.72.51.2551,022
1495.72.52.0/2295.72.52.1 to 95.72.55.25495.72.55.2551,022
1595.72.56.0/2295.72.56.1 to 95.72.59.25495.72.59.2551,022
1695.72.60.0/2295.72.60.1 to 95.72.63.25495.72.63.2551,022
1795.72.64.0/2295.72.64.1 to 95.72.67.25495.72.67.2551,022
1895.72.68.0/2295.72.68.1 to 95.72.71.25495.72.71.2551,022
1995.72.72.0/2295.72.72.1 to 95.72.75.25495.72.75.2551,022
2095.72.76.0/2295.72.76.1 to 95.72.79.25495.72.79.2551,022
2195.72.80.0/2295.72.80.1 to 95.72.83.25495.72.83.2551,022
2295.72.84.0/2295.72.84.1 to 95.72.87.25495.72.87.2551,022
2395.72.88.0/2295.72.88.1 to 95.72.91.25495.72.91.2551,022
2495.72.92.0/2295.72.92.1 to 95.72.95.25495.72.95.2551,022
2595.72.96.0/2295.72.96.1 to 95.72.99.25495.72.99.2551,022
2695.72.100.0/2295.72.100.1 to 95.72.103.25495.72.103.2551,022
2795.72.104.0/2295.72.104.1 to 95.72.107.25495.72.107.2551,022
2895.72.108.0/2295.72.108.1 to 95.72.111.25495.72.111.2551,022
2995.72.112.0/2295.72.112.1 to 95.72.115.25495.72.115.2551,022
3095.72.116.0/2295.72.116.1 to 95.72.119.25495.72.119.2551,022
3195.72.120.0/2295.72.120.1 to 95.72.123.25495.72.123.2551,022
3295.72.124.0/2295.72.124.1 to 95.72.127.25495.72.127.2551,022
3395.72.128.0/2295.72.128.1 to 95.72.131.25495.72.131.2551,022
3495.72.132.0/2295.72.132.1 to 95.72.135.25495.72.135.2551,022
3595.72.136.0/2295.72.136.1 to 95.72.139.25495.72.139.2551,022
3695.72.140.0/2295.72.140.1 to 95.72.143.25495.72.143.2551,022
3795.72.144.0/2295.72.144.1 to 95.72.147.25495.72.147.2551,022
3895.72.148.0/2295.72.148.1 to 95.72.151.25495.72.151.2551,022
3995.72.152.0/2295.72.152.1 to 95.72.155.25495.72.155.2551,022
4095.72.156.0/2295.72.156.1 to 95.72.159.25495.72.159.2551,022
4195.72.160.0/2295.72.160.1 to 95.72.163.25495.72.163.2551,022
4295.72.164.0/2295.72.164.1 to 95.72.167.25495.72.167.2551,022
4395.72.168.0/2295.72.168.1 to 95.72.171.25495.72.171.2551,022
4495.72.172.0/2295.72.172.1 to 95.72.175.25495.72.175.2551,022
4595.72.176.0/2295.72.176.1 to 95.72.179.25495.72.179.2551,022
4695.72.180.0/2295.72.180.1 to 95.72.183.25495.72.183.2551,022
4795.72.184.0/2295.72.184.1 to 95.72.187.25495.72.187.2551,022
4895.72.188.0/2295.72.188.1 to 95.72.191.25495.72.191.2551,022
4995.72.192.0/2295.72.192.1 to 95.72.195.25495.72.195.2551,022
5095.72.196.0/2295.72.196.1 to 95.72.199.25495.72.199.2551,022
5195.72.200.0/2295.72.200.1 to 95.72.203.25495.72.203.2551,022
5295.72.204.0/2295.72.204.1 to 95.72.207.25495.72.207.2551,022
5395.72.208.0/2295.72.208.1 to 95.72.211.25495.72.211.2551,022
5495.72.212.0/2295.72.212.1 to 95.72.215.25495.72.215.2551,022
5595.72.216.0/2295.72.216.1 to 95.72.219.25495.72.219.2551,022
5695.72.220.0/2295.72.220.1 to 95.72.223.25495.72.223.2551,022
5795.72.224.0/2295.72.224.1 to 95.72.227.25495.72.227.2551,022
5895.72.228.0/2295.72.228.1 to 95.72.231.25495.72.231.2551,022
5995.72.232.0/2295.72.232.1 to 95.72.235.25495.72.235.2551,022
6095.72.236.0/2295.72.236.1 to 95.72.239.25495.72.239.2551,022
6195.72.240.0/2295.72.240.1 to 95.72.243.25495.72.243.2551,022
6295.72.244.0/2295.72.244.1 to 95.72.247.25495.72.247.2551,022
6395.72.248.0/2295.72.248.1 to 95.72.251.25495.72.251.2551,022
6495.72.252.0/2295.72.252.1 to 95.72.255.25495.72.255.2551,022
6595.73.0.0/2295.73.0.1 to 95.73.3.25495.73.3.2551,022
6695.73.4.0/2295.73.4.1 to 95.73.7.25495.73.7.2551,022
6795.73.8.0/2295.73.8.1 to 95.73.11.25495.73.11.2551,022
6895.73.12.0/2295.73.12.1 to 95.73.15.25495.73.15.2551,022
6995.73.16.0/2295.73.16.1 to 95.73.19.25495.73.19.2551,022
7095.73.20.0/2295.73.20.1 to 95.73.23.25495.73.23.2551,022
7195.73.24.0/2295.73.24.1 to 95.73.27.25495.73.27.2551,022
7295.73.28.0/2295.73.28.1 to 95.73.31.25495.73.31.2551,022
7395.73.32.0/2295.73.32.1 to 95.73.35.25495.73.35.2551,022
7495.73.36.0/2295.73.36.1 to 95.73.39.25495.73.39.2551,022
7595.73.40.0/2295.73.40.1 to 95.73.43.25495.73.43.2551,022
7695.73.44.0/2295.73.44.1 to 95.73.47.25495.73.47.2551,022
7795.73.48.0/2295.73.48.1 to 95.73.51.25495.73.51.2551,022
7895.73.52.0/2295.73.52.1 to 95.73.55.25495.73.55.2551,022
7995.73.56.0/2295.73.56.1 to 95.73.59.25495.73.59.2551,022
8095.73.60.0/2295.73.60.1 to 95.73.63.25495.73.63.2551,022
8195.73.64.0/2295.73.64.1 to 95.73.67.25495.73.67.2551,022
8295.73.68.0/2295.73.68.1 to 95.73.71.25495.73.71.2551,022
8395.73.72.0/2295.73.72.1 to 95.73.75.25495.73.75.2551,022
8495.73.76.0/2295.73.76.1 to 95.73.79.25495.73.79.2551,022
8595.73.80.0/2295.73.80.1 to 95.73.83.25495.73.83.2551,022
8695.73.84.0/2295.73.84.1 to 95.73.87.25495.73.87.2551,022
8795.73.88.0/2295.73.88.1 to 95.73.91.25495.73.91.2551,022
8895.73.92.0/2295.73.92.1 to 95.73.95.25495.73.95.2551,022
8995.73.96.0/2295.73.96.1 to 95.73.99.25495.73.99.2551,022
9095.73.100.0/2295.73.100.1 to 95.73.103.25495.73.103.2551,022
9195.73.104.0/2295.73.104.1 to 95.73.107.25495.73.107.2551,022
9295.73.108.0/2295.73.108.1 to 95.73.111.25495.73.111.2551,022
9395.73.112.0/2295.73.112.1 to 95.73.115.25495.73.115.2551,022
9495.73.116.0/2295.73.116.1 to 95.73.119.25495.73.119.2551,022
9595.73.120.0/2295.73.120.1 to 95.73.123.25495.73.123.2551,022
9695.73.124.0/2295.73.124.1 to 95.73.127.25495.73.127.2551,022
9795.73.128.0/2295.73.128.1 to 95.73.131.25495.73.131.2551,022
9895.73.132.0/2295.73.132.1 to 95.73.135.25495.73.135.2551,022
9995.73.136.0/2295.73.136.1 to 95.73.139.25495.73.139.2551,022
10095.73.140.0/2295.73.140.1 to 95.73.143.25495.73.143.2551,022
10195.73.144.0/2295.73.144.1 to 95.73.147.25495.73.147.2551,022
10295.73.148.0/2295.73.148.1 to 95.73.151.25495.73.151.2551,022
10395.73.152.0/2295.73.152.1 to 95.73.155.25495.73.155.2551,022
10495.73.156.0/2295.73.156.1 to 95.73.159.25495.73.159.2551,022
10595.73.160.0/2295.73.160.1 to 95.73.163.25495.73.163.2551,022
10695.73.164.0/2295.73.164.1 to 95.73.167.25495.73.167.2551,022
10795.73.168.0/2295.73.168.1 to 95.73.171.25495.73.171.2551,022
10895.73.172.0/2295.73.172.1 to 95.73.175.25495.73.175.2551,022
10995.73.176.0/2295.73.176.1 to 95.73.179.25495.73.179.2551,022
11095.73.180.0/2295.73.180.1 to 95.73.183.25495.73.183.2551,022
11195.73.184.0/2295.73.184.1 to 95.73.187.25495.73.187.2551,022
11295.73.188.0/2295.73.188.1 to 95.73.191.25495.73.191.2551,022
11395.73.192.0/2295.73.192.1 to 95.73.195.25495.73.195.2551,022
11495.73.196.0/2295.73.196.1 to 95.73.199.25495.73.199.2551,022
11595.73.200.0/2295.73.200.1 to 95.73.203.25495.73.203.2551,022
11695.73.204.0/2295.73.204.1 to 95.73.207.25495.73.207.2551,022
11795.73.208.0/2295.73.208.1 to 95.73.211.25495.73.211.2551,022
11895.73.212.0/2295.73.212.1 to 95.73.215.25495.73.215.2551,022
11995.73.216.0/2295.73.216.1 to 95.73.219.25495.73.219.2551,022
12095.73.220.0/2295.73.220.1 to 95.73.223.25495.73.223.2551,022
12195.73.224.0/2295.73.224.1 to 95.73.227.25495.73.227.2551,022
12295.73.228.0/2295.73.228.1 to 95.73.231.25495.73.231.2551,022
12395.73.232.0/2295.73.232.1 to 95.73.235.25495.73.235.2551,022
12495.73.236.0/2295.73.236.1 to 95.73.239.25495.73.239.2551,022
12595.73.240.0/2295.73.240.1 to 95.73.243.25495.73.243.2551,022
12695.73.244.0/2295.73.244.1 to 95.73.247.25495.73.247.2551,022
12795.73.248.0/2295.73.248.1 to 95.73.251.25495.73.251.2551,022
12895.73.252.0/2295.73.252.1 to 95.73.255.25495.73.255.2551,022
12995.74.0.0/2295.74.0.1 to 95.74.3.25495.74.3.2551,022
13095.74.4.0/2295.74.4.1 to 95.74.7.25495.74.7.2551,022
13195.74.8.0/2295.74.8.1 to 95.74.11.25495.74.11.2551,022
13295.74.12.0/2295.74.12.1 to 95.74.15.25495.74.15.2551,022
13395.74.16.0/2295.74.16.1 to 95.74.19.25495.74.19.2551,022
13495.74.20.0/2295.74.20.1 to 95.74.23.25495.74.23.2551,022
13595.74.24.0/2295.74.24.1 to 95.74.27.25495.74.27.2551,022
13695.74.28.0/2295.74.28.1 to 95.74.31.25495.74.31.2551,022
13795.74.32.0/2295.74.32.1 to 95.74.35.25495.74.35.2551,022
13895.74.36.0/2295.74.36.1 to 95.74.39.25495.74.39.2551,022
13995.74.40.0/2295.74.40.1 to 95.74.43.25495.74.43.2551,022
14095.74.44.0/2295.74.44.1 to 95.74.47.25495.74.47.2551,022
14195.74.48.0/2295.74.48.1 to 95.74.51.25495.74.51.2551,022
14295.74.52.0/2295.74.52.1 to 95.74.55.25495.74.55.2551,022
14395.74.56.0/2295.74.56.1 to 95.74.59.25495.74.59.2551,022
14495.74.60.0/2295.74.60.1 to 95.74.63.25495.74.63.2551,022
14595.74.64.0/2295.74.64.1 to 95.74.67.25495.74.67.2551,022
14695.74.68.0/2295.74.68.1 to 95.74.71.25495.74.71.2551,022
14795.74.72.0/2295.74.72.1 to 95.74.75.25495.74.75.2551,022
14895.74.76.0/2295.74.76.1 to 95.74.79.25495.74.79.2551,022
14995.74.80.0/2295.74.80.1 to 95.74.83.25495.74.83.2551,022
15095.74.84.0/2295.74.84.1 to 95.74.87.25495.74.87.2551,022
15195.74.88.0/2295.74.88.1 to 95.74.91.25495.74.91.2551,022
15295.74.92.0/2295.74.92.1 to 95.74.95.25495.74.95.2551,022
15395.74.96.0/2295.74.96.1 to 95.74.99.25495.74.99.2551,022
15495.74.100.0/2295.74.100.1 to 95.74.103.25495.74.103.2551,022
15595.74.104.0/2295.74.104.1 to 95.74.107.25495.74.107.2551,022
15695.74.108.0/2295.74.108.1 to 95.74.111.25495.74.111.2551,022
15795.74.112.0/2295.74.112.1 to 95.74.115.25495.74.115.2551,022
15895.74.116.0/2295.74.116.1 to 95.74.119.25495.74.119.2551,022
15995.74.120.0/2295.74.120.1 to 95.74.123.25495.74.123.2551,022
16095.74.124.0/2295.74.124.1 to 95.74.127.25495.74.127.2551,022
16195.74.128.0/2295.74.128.1 to 95.74.131.25495.74.131.2551,022
16295.74.132.0/2295.74.132.1 to 95.74.135.25495.74.135.2551,022
16395.74.136.0/2295.74.136.1 to 95.74.139.25495.74.139.2551,022
16495.74.140.0/2295.74.140.1 to 95.74.143.25495.74.143.2551,022
16595.74.144.0/2295.74.144.1 to 95.74.147.25495.74.147.2551,022
16695.74.148.0/2295.74.148.1 to 95.74.151.25495.74.151.2551,022
16795.74.152.0/2295.74.152.1 to 95.74.155.25495.74.155.2551,022
16895.74.156.0/2295.74.156.1 to 95.74.159.25495.74.159.2551,022
16995.74.160.0/2295.74.160.1 to 95.74.163.25495.74.163.2551,022
17095.74.164.0/2295.74.164.1 to 95.74.167.25495.74.167.2551,022
17195.74.168.0/2295.74.168.1 to 95.74.171.25495.74.171.2551,022
17295.74.172.0/2295.74.172.1 to 95.74.175.25495.74.175.2551,022
17395.74.176.0/2295.74.176.1 to 95.74.179.25495.74.179.2551,022
17495.74.180.0/2295.74.180.1 to 95.74.183.25495.74.183.2551,022
17595.74.184.0/2295.74.184.1 to 95.74.187.25495.74.187.2551,022
17695.74.188.0/2295.74.188.1 to 95.74.191.25495.74.191.2551,022
17795.74.192.0/2295.74.192.1 to 95.74.195.25495.74.195.2551,022
17895.74.196.0/2295.74.196.1 to 95.74.199.25495.74.199.2551,022
17995.74.200.0/2295.74.200.1 to 95.74.203.25495.74.203.2551,022
18095.74.204.0/2295.74.204.1 to 95.74.207.25495.74.207.2551,022
18195.74.208.0/2295.74.208.1 to 95.74.211.25495.74.211.2551,022
18295.74.212.0/2295.74.212.1 to 95.74.215.25495.74.215.2551,022
18395.74.216.0/2295.74.216.1 to 95.74.219.25495.74.219.2551,022
18495.74.220.0/2295.74.220.1 to 95.74.223.25495.74.223.2551,022
18595.74.224.0/2295.74.224.1 to 95.74.227.25495.74.227.2551,022
18695.74.228.0/2295.74.228.1 to 95.74.231.25495.74.231.2551,022
18795.74.232.0/2295.74.232.1 to 95.74.235.25495.74.235.2551,022
18895.74.236.0/2295.74.236.1 to 95.74.239.25495.74.239.2551,022
18995.74.240.0/2295.74.240.1 to 95.74.243.25495.74.243.2551,022
19095.74.244.0/2295.74.244.1 to 95.74.247.25495.74.247.2551,022
19195.74.248.0/2295.74.248.1 to 95.74.251.25495.74.251.2551,022
19295.74.252.0/2295.74.252.1 to 95.74.255.25495.74.255.2551,022
19395.75.0.0/2295.75.0.1 to 95.75.3.25495.75.3.2551,022
19495.75.4.0/2295.75.4.1 to 95.75.7.25495.75.7.2551,022
19595.75.8.0/2295.75.8.1 to 95.75.11.25495.75.11.2551,022
19695.75.12.0/2295.75.12.1 to 95.75.15.25495.75.15.2551,022
19795.75.16.0/2295.75.16.1 to 95.75.19.25495.75.19.2551,022
19895.75.20.0/2295.75.20.1 to 95.75.23.25495.75.23.2551,022
19995.75.24.0/2295.75.24.1 to 95.75.27.25495.75.27.2551,022
20095.75.28.0/2295.75.28.1 to 95.75.31.25495.75.31.2551,022
20195.75.32.0/2295.75.32.1 to 95.75.35.25495.75.35.2551,022
20295.75.36.0/2295.75.36.1 to 95.75.39.25495.75.39.2551,022
20395.75.40.0/2295.75.40.1 to 95.75.43.25495.75.43.2551,022
20495.75.44.0/2295.75.44.1 to 95.75.47.25495.75.47.2551,022
20595.75.48.0/2295.75.48.1 to 95.75.51.25495.75.51.2551,022
20695.75.52.0/2295.75.52.1 to 95.75.55.25495.75.55.2551,022
20795.75.56.0/2295.75.56.1 to 95.75.59.25495.75.59.2551,022
20895.75.60.0/2295.75.60.1 to 95.75.63.25495.75.63.2551,022
20995.75.64.0/2295.75.64.1 to 95.75.67.25495.75.67.2551,022
21095.75.68.0/2295.75.68.1 to 95.75.71.25495.75.71.2551,022
21195.75.72.0/2295.75.72.1 to 95.75.75.25495.75.75.2551,022
21295.75.76.0/2295.75.76.1 to 95.75.79.25495.75.79.2551,022
21395.75.80.0/2295.75.80.1 to 95.75.83.25495.75.83.2551,022
21495.75.84.0/2295.75.84.1 to 95.75.87.25495.75.87.2551,022
21595.75.88.0/2295.75.88.1 to 95.75.91.25495.75.91.2551,022
21695.75.92.0/2295.75.92.1 to 95.75.95.25495.75.95.2551,022
21795.75.96.0/2295.75.96.1 to 95.75.99.25495.75.99.2551,022
21895.75.100.0/2295.75.100.1 to 95.75.103.25495.75.103.2551,022
21995.75.104.0/2295.75.104.1 to 95.75.107.25495.75.107.2551,022
22095.75.108.0/2295.75.108.1 to 95.75.111.25495.75.111.2551,022
22195.75.112.0/2295.75.112.1 to 95.75.115.25495.75.115.2551,022
22295.75.116.0/2295.75.116.1 to 95.75.119.25495.75.119.2551,022
22395.75.120.0/2295.75.120.1 to 95.75.123.25495.75.123.2551,022
22495.75.124.0/2295.75.124.1 to 95.75.127.25495.75.127.2551,022
22595.75.128.0/2295.75.128.1 to 95.75.131.25495.75.131.2551,022
22695.75.132.0/2295.75.132.1 to 95.75.135.25495.75.135.2551,022
22795.75.136.0/2295.75.136.1 to 95.75.139.25495.75.139.2551,022
22895.75.140.0/2295.75.140.1 to 95.75.143.25495.75.143.2551,022
22995.75.144.0/2295.75.144.1 to 95.75.147.25495.75.147.2551,022
23095.75.148.0/2295.75.148.1 to 95.75.151.25495.75.151.2551,022
23195.75.152.0/2295.75.152.1 to 95.75.155.25495.75.155.2551,022
23295.75.156.0/2295.75.156.1 to 95.75.159.25495.75.159.2551,022
23395.75.160.0/2295.75.160.1 to 95.75.163.25495.75.163.2551,022
23495.75.164.0/2295.75.164.1 to 95.75.167.25495.75.167.2551,022
23595.75.168.0/2295.75.168.1 to 95.75.171.25495.75.171.2551,022
23695.75.172.0/2295.75.172.1 to 95.75.175.25495.75.175.2551,022
23795.75.176.0/2295.75.176.1 to 95.75.179.25495.75.179.2551,022
23895.75.180.0/2295.75.180.1 to 95.75.183.25495.75.183.2551,022
23995.75.184.0/2295.75.184.1 to 95.75.187.25495.75.187.2551,022
24095.75.188.0/2295.75.188.1 to 95.75.191.25495.75.191.2551,022
24195.75.192.0/2295.75.192.1 to 95.75.195.25495.75.195.2551,022
24295.75.196.0/2295.75.196.1 to 95.75.199.25495.75.199.2551,022
24395.75.200.0/2295.75.200.1 to 95.75.203.25495.75.203.2551,022
24495.75.204.0/2295.75.204.1 to 95.75.207.25495.75.207.2551,022
24595.75.208.0/2295.75.208.1 to 95.75.211.25495.75.211.2551,022
24695.75.212.0/2295.75.212.1 to 95.75.215.25495.75.215.2551,022
24795.75.216.0/2295.75.216.1 to 95.75.219.25495.75.219.2551,022
24895.75.220.0/2295.75.220.1 to 95.75.223.25495.75.223.2551,022
24995.75.224.0/2295.75.224.1 to 95.75.227.25495.75.227.2551,022
25095.75.228.0/2295.75.228.1 to 95.75.231.25495.75.231.2551,022
25195.75.232.0/2295.75.232.1 to 95.75.235.25495.75.235.2551,022
25295.75.236.0/2295.75.236.1 to 95.75.239.25495.75.239.2551,022
25395.75.240.0/2295.75.240.1 to 95.75.243.25495.75.243.2551,022
25495.75.244.0/2295.75.244.1 to 95.75.247.25495.75.247.2551,022
25595.75.248.0/2295.75.248.1 to 95.75.251.25495.75.251.2551,022
25695.75.252.0/2295.75.252.1 to 95.75.255.25495.75.255.2551,022

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.