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.

Network95.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
95.0.0.0
Broadcast address
95.255.255.255
First usable
95.0.0.1
Last usable
95.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 5F000000 · Integer 1593835520 to 1610612735
Reverse DNS zone
95.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01011111..00000000.00000000.0000000095.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01011111..00000000.00000000.0000000095.0.0.0
Broadcast01011111..11111111.11111111.1111111195.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

95.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
195.0.0.0/1895.0.0.1 to 95.0.63.25495.0.63.25516,382
295.0.64.0/1895.0.64.1 to 95.0.127.25495.0.127.25516,382
395.0.128.0/1895.0.128.1 to 95.0.191.25495.0.191.25516,382
495.0.192.0/1895.0.192.1 to 95.0.255.25495.0.255.25516,382
595.1.0.0/1895.1.0.1 to 95.1.63.25495.1.63.25516,382
695.1.64.0/1895.1.64.1 to 95.1.127.25495.1.127.25516,382
795.1.128.0/1895.1.128.1 to 95.1.191.25495.1.191.25516,382
895.1.192.0/1895.1.192.1 to 95.1.255.25495.1.255.25516,382
995.2.0.0/1895.2.0.1 to 95.2.63.25495.2.63.25516,382
1095.2.64.0/1895.2.64.1 to 95.2.127.25495.2.127.25516,382
1195.2.128.0/1895.2.128.1 to 95.2.191.25495.2.191.25516,382
1295.2.192.0/1895.2.192.1 to 95.2.255.25495.2.255.25516,382
1395.3.0.0/1895.3.0.1 to 95.3.63.25495.3.63.25516,382
1495.3.64.0/1895.3.64.1 to 95.3.127.25495.3.127.25516,382
1595.3.128.0/1895.3.128.1 to 95.3.191.25495.3.191.25516,382
1695.3.192.0/1895.3.192.1 to 95.3.255.25495.3.255.25516,382
1795.4.0.0/1895.4.0.1 to 95.4.63.25495.4.63.25516,382
1895.4.64.0/1895.4.64.1 to 95.4.127.25495.4.127.25516,382
1995.4.128.0/1895.4.128.1 to 95.4.191.25495.4.191.25516,382
2095.4.192.0/1895.4.192.1 to 95.4.255.25495.4.255.25516,382
2195.5.0.0/1895.5.0.1 to 95.5.63.25495.5.63.25516,382
2295.5.64.0/1895.5.64.1 to 95.5.127.25495.5.127.25516,382
2395.5.128.0/1895.5.128.1 to 95.5.191.25495.5.191.25516,382
2495.5.192.0/1895.5.192.1 to 95.5.255.25495.5.255.25516,382
2595.6.0.0/1895.6.0.1 to 95.6.63.25495.6.63.25516,382
2695.6.64.0/1895.6.64.1 to 95.6.127.25495.6.127.25516,382
2795.6.128.0/1895.6.128.1 to 95.6.191.25495.6.191.25516,382
2895.6.192.0/1895.6.192.1 to 95.6.255.25495.6.255.25516,382
2995.7.0.0/1895.7.0.1 to 95.7.63.25495.7.63.25516,382
3095.7.64.0/1895.7.64.1 to 95.7.127.25495.7.127.25516,382
3195.7.128.0/1895.7.128.1 to 95.7.191.25495.7.191.25516,382
3295.7.192.0/1895.7.192.1 to 95.7.255.25495.7.255.25516,382
3395.8.0.0/1895.8.0.1 to 95.8.63.25495.8.63.25516,382
3495.8.64.0/1895.8.64.1 to 95.8.127.25495.8.127.25516,382
3595.8.128.0/1895.8.128.1 to 95.8.191.25495.8.191.25516,382
3695.8.192.0/1895.8.192.1 to 95.8.255.25495.8.255.25516,382
3795.9.0.0/1895.9.0.1 to 95.9.63.25495.9.63.25516,382
3895.9.64.0/1895.9.64.1 to 95.9.127.25495.9.127.25516,382
3995.9.128.0/1895.9.128.1 to 95.9.191.25495.9.191.25516,382
4095.9.192.0/1895.9.192.1 to 95.9.255.25495.9.255.25516,382
4195.10.0.0/1895.10.0.1 to 95.10.63.25495.10.63.25516,382
4295.10.64.0/1895.10.64.1 to 95.10.127.25495.10.127.25516,382
4395.10.128.0/1895.10.128.1 to 95.10.191.25495.10.191.25516,382
4495.10.192.0/1895.10.192.1 to 95.10.255.25495.10.255.25516,382
4595.11.0.0/1895.11.0.1 to 95.11.63.25495.11.63.25516,382
4695.11.64.0/1895.11.64.1 to 95.11.127.25495.11.127.25516,382
4795.11.128.0/1895.11.128.1 to 95.11.191.25495.11.191.25516,382
4895.11.192.0/1895.11.192.1 to 95.11.255.25495.11.255.25516,382
4995.12.0.0/1895.12.0.1 to 95.12.63.25495.12.63.25516,382
5095.12.64.0/1895.12.64.1 to 95.12.127.25495.12.127.25516,382
5195.12.128.0/1895.12.128.1 to 95.12.191.25495.12.191.25516,382
5295.12.192.0/1895.12.192.1 to 95.12.255.25495.12.255.25516,382
5395.13.0.0/1895.13.0.1 to 95.13.63.25495.13.63.25516,382
5495.13.64.0/1895.13.64.1 to 95.13.127.25495.13.127.25516,382
5595.13.128.0/1895.13.128.1 to 95.13.191.25495.13.191.25516,382
5695.13.192.0/1895.13.192.1 to 95.13.255.25495.13.255.25516,382
5795.14.0.0/1895.14.0.1 to 95.14.63.25495.14.63.25516,382
5895.14.64.0/1895.14.64.1 to 95.14.127.25495.14.127.25516,382
5995.14.128.0/1895.14.128.1 to 95.14.191.25495.14.191.25516,382
6095.14.192.0/1895.14.192.1 to 95.14.255.25495.14.255.25516,382
6195.15.0.0/1895.15.0.1 to 95.15.63.25495.15.63.25516,382
6295.15.64.0/1895.15.64.1 to 95.15.127.25495.15.127.25516,382
6395.15.128.0/1895.15.128.1 to 95.15.191.25495.15.191.25516,382
6495.15.192.0/1895.15.192.1 to 95.15.255.25495.15.255.25516,382
6595.16.0.0/1895.16.0.1 to 95.16.63.25495.16.63.25516,382
6695.16.64.0/1895.16.64.1 to 95.16.127.25495.16.127.25516,382
6795.16.128.0/1895.16.128.1 to 95.16.191.25495.16.191.25516,382
6895.16.192.0/1895.16.192.1 to 95.16.255.25495.16.255.25516,382
6995.17.0.0/1895.17.0.1 to 95.17.63.25495.17.63.25516,382
7095.17.64.0/1895.17.64.1 to 95.17.127.25495.17.127.25516,382
7195.17.128.0/1895.17.128.1 to 95.17.191.25495.17.191.25516,382
7295.17.192.0/1895.17.192.1 to 95.17.255.25495.17.255.25516,382
7395.18.0.0/1895.18.0.1 to 95.18.63.25495.18.63.25516,382
7495.18.64.0/1895.18.64.1 to 95.18.127.25495.18.127.25516,382
7595.18.128.0/1895.18.128.1 to 95.18.191.25495.18.191.25516,382
7695.18.192.0/1895.18.192.1 to 95.18.255.25495.18.255.25516,382
7795.19.0.0/1895.19.0.1 to 95.19.63.25495.19.63.25516,382
7895.19.64.0/1895.19.64.1 to 95.19.127.25495.19.127.25516,382
7995.19.128.0/1895.19.128.1 to 95.19.191.25495.19.191.25516,382
8095.19.192.0/1895.19.192.1 to 95.19.255.25495.19.255.25516,382
8195.20.0.0/1895.20.0.1 to 95.20.63.25495.20.63.25516,382
8295.20.64.0/1895.20.64.1 to 95.20.127.25495.20.127.25516,382
8395.20.128.0/1895.20.128.1 to 95.20.191.25495.20.191.25516,382
8495.20.192.0/1895.20.192.1 to 95.20.255.25495.20.255.25516,382
8595.21.0.0/1895.21.0.1 to 95.21.63.25495.21.63.25516,382
8695.21.64.0/1895.21.64.1 to 95.21.127.25495.21.127.25516,382
8795.21.128.0/1895.21.128.1 to 95.21.191.25495.21.191.25516,382
8895.21.192.0/1895.21.192.1 to 95.21.255.25495.21.255.25516,382
8995.22.0.0/1895.22.0.1 to 95.22.63.25495.22.63.25516,382
9095.22.64.0/1895.22.64.1 to 95.22.127.25495.22.127.25516,382
9195.22.128.0/1895.22.128.1 to 95.22.191.25495.22.191.25516,382
9295.22.192.0/1895.22.192.1 to 95.22.255.25495.22.255.25516,382
9395.23.0.0/1895.23.0.1 to 95.23.63.25495.23.63.25516,382
9495.23.64.0/1895.23.64.1 to 95.23.127.25495.23.127.25516,382
9595.23.128.0/1895.23.128.1 to 95.23.191.25495.23.191.25516,382
9695.23.192.0/1895.23.192.1 to 95.23.255.25495.23.255.25516,382
9795.24.0.0/1895.24.0.1 to 95.24.63.25495.24.63.25516,382
9895.24.64.0/1895.24.64.1 to 95.24.127.25495.24.127.25516,382
9995.24.128.0/1895.24.128.1 to 95.24.191.25495.24.191.25516,382
10095.24.192.0/1895.24.192.1 to 95.24.255.25495.24.255.25516,382
10195.25.0.0/1895.25.0.1 to 95.25.63.25495.25.63.25516,382
10295.25.64.0/1895.25.64.1 to 95.25.127.25495.25.127.25516,382
10395.25.128.0/1895.25.128.1 to 95.25.191.25495.25.191.25516,382
10495.25.192.0/1895.25.192.1 to 95.25.255.25495.25.255.25516,382
10595.26.0.0/1895.26.0.1 to 95.26.63.25495.26.63.25516,382
10695.26.64.0/1895.26.64.1 to 95.26.127.25495.26.127.25516,382
10795.26.128.0/1895.26.128.1 to 95.26.191.25495.26.191.25516,382
10895.26.192.0/1895.26.192.1 to 95.26.255.25495.26.255.25516,382
10995.27.0.0/1895.27.0.1 to 95.27.63.25495.27.63.25516,382
11095.27.64.0/1895.27.64.1 to 95.27.127.25495.27.127.25516,382
11195.27.128.0/1895.27.128.1 to 95.27.191.25495.27.191.25516,382
11295.27.192.0/1895.27.192.1 to 95.27.255.25495.27.255.25516,382
11395.28.0.0/1895.28.0.1 to 95.28.63.25495.28.63.25516,382
11495.28.64.0/1895.28.64.1 to 95.28.127.25495.28.127.25516,382
11595.28.128.0/1895.28.128.1 to 95.28.191.25495.28.191.25516,382
11695.28.192.0/1895.28.192.1 to 95.28.255.25495.28.255.25516,382
11795.29.0.0/1895.29.0.1 to 95.29.63.25495.29.63.25516,382
11895.29.64.0/1895.29.64.1 to 95.29.127.25495.29.127.25516,382
11995.29.128.0/1895.29.128.1 to 95.29.191.25495.29.191.25516,382
12095.29.192.0/1895.29.192.1 to 95.29.255.25495.29.255.25516,382
12195.30.0.0/1895.30.0.1 to 95.30.63.25495.30.63.25516,382
12295.30.64.0/1895.30.64.1 to 95.30.127.25495.30.127.25516,382
12395.30.128.0/1895.30.128.1 to 95.30.191.25495.30.191.25516,382
12495.30.192.0/1895.30.192.1 to 95.30.255.25495.30.255.25516,382
12595.31.0.0/1895.31.0.1 to 95.31.63.25495.31.63.25516,382
12695.31.64.0/1895.31.64.1 to 95.31.127.25495.31.127.25516,382
12795.31.128.0/1895.31.128.1 to 95.31.191.25495.31.191.25516,382
12895.31.192.0/1895.31.192.1 to 95.31.255.25495.31.255.25516,382
12995.32.0.0/1895.32.0.1 to 95.32.63.25495.32.63.25516,382
13095.32.64.0/1895.32.64.1 to 95.32.127.25495.32.127.25516,382
13195.32.128.0/1895.32.128.1 to 95.32.191.25495.32.191.25516,382
13295.32.192.0/1895.32.192.1 to 95.32.255.25495.32.255.25516,382
13395.33.0.0/1895.33.0.1 to 95.33.63.25495.33.63.25516,382
13495.33.64.0/1895.33.64.1 to 95.33.127.25495.33.127.25516,382
13595.33.128.0/1895.33.128.1 to 95.33.191.25495.33.191.25516,382
13695.33.192.0/1895.33.192.1 to 95.33.255.25495.33.255.25516,382
13795.34.0.0/1895.34.0.1 to 95.34.63.25495.34.63.25516,382
13895.34.64.0/1895.34.64.1 to 95.34.127.25495.34.127.25516,382
13995.34.128.0/1895.34.128.1 to 95.34.191.25495.34.191.25516,382
14095.34.192.0/1895.34.192.1 to 95.34.255.25495.34.255.25516,382
14195.35.0.0/1895.35.0.1 to 95.35.63.25495.35.63.25516,382
14295.35.64.0/1895.35.64.1 to 95.35.127.25495.35.127.25516,382
14395.35.128.0/1895.35.128.1 to 95.35.191.25495.35.191.25516,382
14495.35.192.0/1895.35.192.1 to 95.35.255.25495.35.255.25516,382
14595.36.0.0/1895.36.0.1 to 95.36.63.25495.36.63.25516,382
14695.36.64.0/1895.36.64.1 to 95.36.127.25495.36.127.25516,382
14795.36.128.0/1895.36.128.1 to 95.36.191.25495.36.191.25516,382
14895.36.192.0/1895.36.192.1 to 95.36.255.25495.36.255.25516,382
14995.37.0.0/1895.37.0.1 to 95.37.63.25495.37.63.25516,382
15095.37.64.0/1895.37.64.1 to 95.37.127.25495.37.127.25516,382
15195.37.128.0/1895.37.128.1 to 95.37.191.25495.37.191.25516,382
15295.37.192.0/1895.37.192.1 to 95.37.255.25495.37.255.25516,382
15395.38.0.0/1895.38.0.1 to 95.38.63.25495.38.63.25516,382
15495.38.64.0/1895.38.64.1 to 95.38.127.25495.38.127.25516,382
15595.38.128.0/1895.38.128.1 to 95.38.191.25495.38.191.25516,382
15695.38.192.0/1895.38.192.1 to 95.38.255.25495.38.255.25516,382
15795.39.0.0/1895.39.0.1 to 95.39.63.25495.39.63.25516,382
15895.39.64.0/1895.39.64.1 to 95.39.127.25495.39.127.25516,382
15995.39.128.0/1895.39.128.1 to 95.39.191.25495.39.191.25516,382
16095.39.192.0/1895.39.192.1 to 95.39.255.25495.39.255.25516,382
16195.40.0.0/1895.40.0.1 to 95.40.63.25495.40.63.25516,382
16295.40.64.0/1895.40.64.1 to 95.40.127.25495.40.127.25516,382
16395.40.128.0/1895.40.128.1 to 95.40.191.25495.40.191.25516,382
16495.40.192.0/1895.40.192.1 to 95.40.255.25495.40.255.25516,382
16595.41.0.0/1895.41.0.1 to 95.41.63.25495.41.63.25516,382
16695.41.64.0/1895.41.64.1 to 95.41.127.25495.41.127.25516,382
16795.41.128.0/1895.41.128.1 to 95.41.191.25495.41.191.25516,382
16895.41.192.0/1895.41.192.1 to 95.41.255.25495.41.255.25516,382
16995.42.0.0/1895.42.0.1 to 95.42.63.25495.42.63.25516,382
17095.42.64.0/1895.42.64.1 to 95.42.127.25495.42.127.25516,382
17195.42.128.0/1895.42.128.1 to 95.42.191.25495.42.191.25516,382
17295.42.192.0/1895.42.192.1 to 95.42.255.25495.42.255.25516,382
17395.43.0.0/1895.43.0.1 to 95.43.63.25495.43.63.25516,382
17495.43.64.0/1895.43.64.1 to 95.43.127.25495.43.127.25516,382
17595.43.128.0/1895.43.128.1 to 95.43.191.25495.43.191.25516,382
17695.43.192.0/1895.43.192.1 to 95.43.255.25495.43.255.25516,382
17795.44.0.0/1895.44.0.1 to 95.44.63.25495.44.63.25516,382
17895.44.64.0/1895.44.64.1 to 95.44.127.25495.44.127.25516,382
17995.44.128.0/1895.44.128.1 to 95.44.191.25495.44.191.25516,382
18095.44.192.0/1895.44.192.1 to 95.44.255.25495.44.255.25516,382
18195.45.0.0/1895.45.0.1 to 95.45.63.25495.45.63.25516,382
18295.45.64.0/1895.45.64.1 to 95.45.127.25495.45.127.25516,382
18395.45.128.0/1895.45.128.1 to 95.45.191.25495.45.191.25516,382
18495.45.192.0/1895.45.192.1 to 95.45.255.25495.45.255.25516,382
18595.46.0.0/1895.46.0.1 to 95.46.63.25495.46.63.25516,382
18695.46.64.0/1895.46.64.1 to 95.46.127.25495.46.127.25516,382
18795.46.128.0/1895.46.128.1 to 95.46.191.25495.46.191.25516,382
18895.46.192.0/1895.46.192.1 to 95.46.255.25495.46.255.25516,382
18995.47.0.0/1895.47.0.1 to 95.47.63.25495.47.63.25516,382
19095.47.64.0/1895.47.64.1 to 95.47.127.25495.47.127.25516,382
19195.47.128.0/1895.47.128.1 to 95.47.191.25495.47.191.25516,382
19295.47.192.0/1895.47.192.1 to 95.47.255.25495.47.255.25516,382
19395.48.0.0/1895.48.0.1 to 95.48.63.25495.48.63.25516,382
19495.48.64.0/1895.48.64.1 to 95.48.127.25495.48.127.25516,382
19595.48.128.0/1895.48.128.1 to 95.48.191.25495.48.191.25516,382
19695.48.192.0/1895.48.192.1 to 95.48.255.25495.48.255.25516,382
19795.49.0.0/1895.49.0.1 to 95.49.63.25495.49.63.25516,382
19895.49.64.0/1895.49.64.1 to 95.49.127.25495.49.127.25516,382
19995.49.128.0/1895.49.128.1 to 95.49.191.25495.49.191.25516,382
20095.49.192.0/1895.49.192.1 to 95.49.255.25495.49.255.25516,382
20195.50.0.0/1895.50.0.1 to 95.50.63.25495.50.63.25516,382
20295.50.64.0/1895.50.64.1 to 95.50.127.25495.50.127.25516,382
20395.50.128.0/1895.50.128.1 to 95.50.191.25495.50.191.25516,382
20495.50.192.0/1895.50.192.1 to 95.50.255.25495.50.255.25516,382
20595.51.0.0/1895.51.0.1 to 95.51.63.25495.51.63.25516,382
20695.51.64.0/1895.51.64.1 to 95.51.127.25495.51.127.25516,382
20795.51.128.0/1895.51.128.1 to 95.51.191.25495.51.191.25516,382
20895.51.192.0/1895.51.192.1 to 95.51.255.25495.51.255.25516,382
20995.52.0.0/1895.52.0.1 to 95.52.63.25495.52.63.25516,382
21095.52.64.0/1895.52.64.1 to 95.52.127.25495.52.127.25516,382
21195.52.128.0/1895.52.128.1 to 95.52.191.25495.52.191.25516,382
21295.52.192.0/1895.52.192.1 to 95.52.255.25495.52.255.25516,382
21395.53.0.0/1895.53.0.1 to 95.53.63.25495.53.63.25516,382
21495.53.64.0/1895.53.64.1 to 95.53.127.25495.53.127.25516,382
21595.53.128.0/1895.53.128.1 to 95.53.191.25495.53.191.25516,382
21695.53.192.0/1895.53.192.1 to 95.53.255.25495.53.255.25516,382
21795.54.0.0/1895.54.0.1 to 95.54.63.25495.54.63.25516,382
21895.54.64.0/1895.54.64.1 to 95.54.127.25495.54.127.25516,382
21995.54.128.0/1895.54.128.1 to 95.54.191.25495.54.191.25516,382
22095.54.192.0/1895.54.192.1 to 95.54.255.25495.54.255.25516,382
22195.55.0.0/1895.55.0.1 to 95.55.63.25495.55.63.25516,382
22295.55.64.0/1895.55.64.1 to 95.55.127.25495.55.127.25516,382
22395.55.128.0/1895.55.128.1 to 95.55.191.25495.55.191.25516,382
22495.55.192.0/1895.55.192.1 to 95.55.255.25495.55.255.25516,382
22595.56.0.0/1895.56.0.1 to 95.56.63.25495.56.63.25516,382
22695.56.64.0/1895.56.64.1 to 95.56.127.25495.56.127.25516,382
22795.56.128.0/1895.56.128.1 to 95.56.191.25495.56.191.25516,382
22895.56.192.0/1895.56.192.1 to 95.56.255.25495.56.255.25516,382
22995.57.0.0/1895.57.0.1 to 95.57.63.25495.57.63.25516,382
23095.57.64.0/1895.57.64.1 to 95.57.127.25495.57.127.25516,382
23195.57.128.0/1895.57.128.1 to 95.57.191.25495.57.191.25516,382
23295.57.192.0/1895.57.192.1 to 95.57.255.25495.57.255.25516,382
23395.58.0.0/1895.58.0.1 to 95.58.63.25495.58.63.25516,382
23495.58.64.0/1895.58.64.1 to 95.58.127.25495.58.127.25516,382
23595.58.128.0/1895.58.128.1 to 95.58.191.25495.58.191.25516,382
23695.58.192.0/1895.58.192.1 to 95.58.255.25495.58.255.25516,382
23795.59.0.0/1895.59.0.1 to 95.59.63.25495.59.63.25516,382
23895.59.64.0/1895.59.64.1 to 95.59.127.25495.59.127.25516,382
23995.59.128.0/1895.59.128.1 to 95.59.191.25495.59.191.25516,382
24095.59.192.0/1895.59.192.1 to 95.59.255.25495.59.255.25516,382
24195.60.0.0/1895.60.0.1 to 95.60.63.25495.60.63.25516,382
24295.60.64.0/1895.60.64.1 to 95.60.127.25495.60.127.25516,382
24395.60.128.0/1895.60.128.1 to 95.60.191.25495.60.191.25516,382
24495.60.192.0/1895.60.192.1 to 95.60.255.25495.60.255.25516,382
24595.61.0.0/1895.61.0.1 to 95.61.63.25495.61.63.25516,382
24695.61.64.0/1895.61.64.1 to 95.61.127.25495.61.127.25516,382
24795.61.128.0/1895.61.128.1 to 95.61.191.25495.61.191.25516,382
24895.61.192.0/1895.61.192.1 to 95.61.255.25495.61.255.25516,382
24995.62.0.0/1895.62.0.1 to 95.62.63.25495.62.63.25516,382
25095.62.64.0/1895.62.64.1 to 95.62.127.25495.62.127.25516,382
25195.62.128.0/1895.62.128.1 to 95.62.191.25495.62.191.25516,382
25295.62.192.0/1895.62.192.1 to 95.62.255.25495.62.255.25516,382
25395.63.0.0/1895.63.0.1 to 95.63.63.25495.63.63.25516,382
25495.63.64.0/1895.63.64.1 to 95.63.127.25495.63.127.25516,382
25595.63.128.0/1895.63.128.1 to 95.63.191.25495.63.191.25516,382
25695.63.192.0/1895.63.192.1 to 95.63.255.25495.63.255.25516,382

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.