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.

Network94.0.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
94.0.64.0
Broadcast address
94.0.95.255
First usable
94.0.64.1
Last usable
94.0.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 5E004000 · Integer 1577074688 to 1577082879
Reverse DNS zones
64.0.94.in-addr.arpa
65.0.94.in-addr.arpa
66.0.94.in-addr.arpa
67.0.94.in-addr.arpa
68.0.94.in-addr.arpa
69.0.94.in-addr.arpa
70.0.94.in-addr.arpa
71.0.94.in-addr.arpa
72.0.94.in-addr.arpa
73.0.94.in-addr.arpa
74.0.94.in-addr.arpa
75.0.94.in-addr.arpa
76.0.94.in-addr.arpa
77.0.94.in-addr.arpa
78.0.94.in-addr.arpa
79.0.94.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01011110.00000000.01000000.0000000094.0.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01011110.00000000.01000000.0000000094.0.64.0
Broadcast01011110.00000000.01011111.1111111194.0.95.255
Split into smaller subnets/30
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

94.0.64.0/19 makes 2,048 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
194.0.64.0/3094.0.64.1 to 94.0.64.294.0.64.32
294.0.64.4/3094.0.64.5 to 94.0.64.694.0.64.72
394.0.64.8/3094.0.64.9 to 94.0.64.1094.0.64.112
494.0.64.12/3094.0.64.13 to 94.0.64.1494.0.64.152
594.0.64.16/3094.0.64.17 to 94.0.64.1894.0.64.192
694.0.64.20/3094.0.64.21 to 94.0.64.2294.0.64.232
794.0.64.24/3094.0.64.25 to 94.0.64.2694.0.64.272
894.0.64.28/3094.0.64.29 to 94.0.64.3094.0.64.312
994.0.64.32/3094.0.64.33 to 94.0.64.3494.0.64.352
1094.0.64.36/3094.0.64.37 to 94.0.64.3894.0.64.392
1194.0.64.40/3094.0.64.41 to 94.0.64.4294.0.64.432
1294.0.64.44/3094.0.64.45 to 94.0.64.4694.0.64.472
1394.0.64.48/3094.0.64.49 to 94.0.64.5094.0.64.512
1494.0.64.52/3094.0.64.53 to 94.0.64.5494.0.64.552
1594.0.64.56/3094.0.64.57 to 94.0.64.5894.0.64.592
1694.0.64.60/3094.0.64.61 to 94.0.64.6294.0.64.632
1794.0.64.64/3094.0.64.65 to 94.0.64.6694.0.64.672
1894.0.64.68/3094.0.64.69 to 94.0.64.7094.0.64.712
1994.0.64.72/3094.0.64.73 to 94.0.64.7494.0.64.752
2094.0.64.76/3094.0.64.77 to 94.0.64.7894.0.64.792
2194.0.64.80/3094.0.64.81 to 94.0.64.8294.0.64.832
2294.0.64.84/3094.0.64.85 to 94.0.64.8694.0.64.872
2394.0.64.88/3094.0.64.89 to 94.0.64.9094.0.64.912
2494.0.64.92/3094.0.64.93 to 94.0.64.9494.0.64.952
2594.0.64.96/3094.0.64.97 to 94.0.64.9894.0.64.992
2694.0.64.100/3094.0.64.101 to 94.0.64.10294.0.64.1032
2794.0.64.104/3094.0.64.105 to 94.0.64.10694.0.64.1072
2894.0.64.108/3094.0.64.109 to 94.0.64.11094.0.64.1112
2994.0.64.112/3094.0.64.113 to 94.0.64.11494.0.64.1152
3094.0.64.116/3094.0.64.117 to 94.0.64.11894.0.64.1192
3194.0.64.120/3094.0.64.121 to 94.0.64.12294.0.64.1232
3294.0.64.124/3094.0.64.125 to 94.0.64.12694.0.64.1272
3394.0.64.128/3094.0.64.129 to 94.0.64.13094.0.64.1312
3494.0.64.132/3094.0.64.133 to 94.0.64.13494.0.64.1352
3594.0.64.136/3094.0.64.137 to 94.0.64.13894.0.64.1392
3694.0.64.140/3094.0.64.141 to 94.0.64.14294.0.64.1432
3794.0.64.144/3094.0.64.145 to 94.0.64.14694.0.64.1472
3894.0.64.148/3094.0.64.149 to 94.0.64.15094.0.64.1512
3994.0.64.152/3094.0.64.153 to 94.0.64.15494.0.64.1552
4094.0.64.156/3094.0.64.157 to 94.0.64.15894.0.64.1592
4194.0.64.160/3094.0.64.161 to 94.0.64.16294.0.64.1632
4294.0.64.164/3094.0.64.165 to 94.0.64.16694.0.64.1672
4394.0.64.168/3094.0.64.169 to 94.0.64.17094.0.64.1712
4494.0.64.172/3094.0.64.173 to 94.0.64.17494.0.64.1752
4594.0.64.176/3094.0.64.177 to 94.0.64.17894.0.64.1792
4694.0.64.180/3094.0.64.181 to 94.0.64.18294.0.64.1832
4794.0.64.184/3094.0.64.185 to 94.0.64.18694.0.64.1872
4894.0.64.188/3094.0.64.189 to 94.0.64.19094.0.64.1912
4994.0.64.192/3094.0.64.193 to 94.0.64.19494.0.64.1952
5094.0.64.196/3094.0.64.197 to 94.0.64.19894.0.64.1992
5194.0.64.200/3094.0.64.201 to 94.0.64.20294.0.64.2032
5294.0.64.204/3094.0.64.205 to 94.0.64.20694.0.64.2072
5394.0.64.208/3094.0.64.209 to 94.0.64.21094.0.64.2112
5494.0.64.212/3094.0.64.213 to 94.0.64.21494.0.64.2152
5594.0.64.216/3094.0.64.217 to 94.0.64.21894.0.64.2192
5694.0.64.220/3094.0.64.221 to 94.0.64.22294.0.64.2232
5794.0.64.224/3094.0.64.225 to 94.0.64.22694.0.64.2272
5894.0.64.228/3094.0.64.229 to 94.0.64.23094.0.64.2312
5994.0.64.232/3094.0.64.233 to 94.0.64.23494.0.64.2352
6094.0.64.236/3094.0.64.237 to 94.0.64.23894.0.64.2392
6194.0.64.240/3094.0.64.241 to 94.0.64.24294.0.64.2432
6294.0.64.244/3094.0.64.245 to 94.0.64.24694.0.64.2472
6394.0.64.248/3094.0.64.249 to 94.0.64.25094.0.64.2512
6494.0.64.252/3094.0.64.253 to 94.0.64.25494.0.64.2552
6594.0.65.0/3094.0.65.1 to 94.0.65.294.0.65.32
6694.0.65.4/3094.0.65.5 to 94.0.65.694.0.65.72
6794.0.65.8/3094.0.65.9 to 94.0.65.1094.0.65.112
6894.0.65.12/3094.0.65.13 to 94.0.65.1494.0.65.152
6994.0.65.16/3094.0.65.17 to 94.0.65.1894.0.65.192
7094.0.65.20/3094.0.65.21 to 94.0.65.2294.0.65.232
7194.0.65.24/3094.0.65.25 to 94.0.65.2694.0.65.272
7294.0.65.28/3094.0.65.29 to 94.0.65.3094.0.65.312
7394.0.65.32/3094.0.65.33 to 94.0.65.3494.0.65.352
7494.0.65.36/3094.0.65.37 to 94.0.65.3894.0.65.392
7594.0.65.40/3094.0.65.41 to 94.0.65.4294.0.65.432
7694.0.65.44/3094.0.65.45 to 94.0.65.4694.0.65.472
7794.0.65.48/3094.0.65.49 to 94.0.65.5094.0.65.512
7894.0.65.52/3094.0.65.53 to 94.0.65.5494.0.65.552
7994.0.65.56/3094.0.65.57 to 94.0.65.5894.0.65.592
8094.0.65.60/3094.0.65.61 to 94.0.65.6294.0.65.632
8194.0.65.64/3094.0.65.65 to 94.0.65.6694.0.65.672
8294.0.65.68/3094.0.65.69 to 94.0.65.7094.0.65.712
8394.0.65.72/3094.0.65.73 to 94.0.65.7494.0.65.752
8494.0.65.76/3094.0.65.77 to 94.0.65.7894.0.65.792
8594.0.65.80/3094.0.65.81 to 94.0.65.8294.0.65.832
8694.0.65.84/3094.0.65.85 to 94.0.65.8694.0.65.872
8794.0.65.88/3094.0.65.89 to 94.0.65.9094.0.65.912
8894.0.65.92/3094.0.65.93 to 94.0.65.9494.0.65.952
8994.0.65.96/3094.0.65.97 to 94.0.65.9894.0.65.992
9094.0.65.100/3094.0.65.101 to 94.0.65.10294.0.65.1032
9194.0.65.104/3094.0.65.105 to 94.0.65.10694.0.65.1072
9294.0.65.108/3094.0.65.109 to 94.0.65.11094.0.65.1112
9394.0.65.112/3094.0.65.113 to 94.0.65.11494.0.65.1152
9494.0.65.116/3094.0.65.117 to 94.0.65.11894.0.65.1192
9594.0.65.120/3094.0.65.121 to 94.0.65.12294.0.65.1232
9694.0.65.124/3094.0.65.125 to 94.0.65.12694.0.65.1272
9794.0.65.128/3094.0.65.129 to 94.0.65.13094.0.65.1312
9894.0.65.132/3094.0.65.133 to 94.0.65.13494.0.65.1352
9994.0.65.136/3094.0.65.137 to 94.0.65.13894.0.65.1392
10094.0.65.140/3094.0.65.141 to 94.0.65.14294.0.65.1432
10194.0.65.144/3094.0.65.145 to 94.0.65.14694.0.65.1472
10294.0.65.148/3094.0.65.149 to 94.0.65.15094.0.65.1512
10394.0.65.152/3094.0.65.153 to 94.0.65.15494.0.65.1552
10494.0.65.156/3094.0.65.157 to 94.0.65.15894.0.65.1592
10594.0.65.160/3094.0.65.161 to 94.0.65.16294.0.65.1632
10694.0.65.164/3094.0.65.165 to 94.0.65.16694.0.65.1672
10794.0.65.168/3094.0.65.169 to 94.0.65.17094.0.65.1712
10894.0.65.172/3094.0.65.173 to 94.0.65.17494.0.65.1752
10994.0.65.176/3094.0.65.177 to 94.0.65.17894.0.65.1792
11094.0.65.180/3094.0.65.181 to 94.0.65.18294.0.65.1832
11194.0.65.184/3094.0.65.185 to 94.0.65.18694.0.65.1872
11294.0.65.188/3094.0.65.189 to 94.0.65.19094.0.65.1912
11394.0.65.192/3094.0.65.193 to 94.0.65.19494.0.65.1952
11494.0.65.196/3094.0.65.197 to 94.0.65.19894.0.65.1992
11594.0.65.200/3094.0.65.201 to 94.0.65.20294.0.65.2032
11694.0.65.204/3094.0.65.205 to 94.0.65.20694.0.65.2072
11794.0.65.208/3094.0.65.209 to 94.0.65.21094.0.65.2112
11894.0.65.212/3094.0.65.213 to 94.0.65.21494.0.65.2152
11994.0.65.216/3094.0.65.217 to 94.0.65.21894.0.65.2192
12094.0.65.220/3094.0.65.221 to 94.0.65.22294.0.65.2232
12194.0.65.224/3094.0.65.225 to 94.0.65.22694.0.65.2272
12294.0.65.228/3094.0.65.229 to 94.0.65.23094.0.65.2312
12394.0.65.232/3094.0.65.233 to 94.0.65.23494.0.65.2352
12494.0.65.236/3094.0.65.237 to 94.0.65.23894.0.65.2392
12594.0.65.240/3094.0.65.241 to 94.0.65.24294.0.65.2432
12694.0.65.244/3094.0.65.245 to 94.0.65.24694.0.65.2472
12794.0.65.248/3094.0.65.249 to 94.0.65.25094.0.65.2512
12894.0.65.252/3094.0.65.253 to 94.0.65.25494.0.65.2552
12994.0.66.0/3094.0.66.1 to 94.0.66.294.0.66.32
13094.0.66.4/3094.0.66.5 to 94.0.66.694.0.66.72
13194.0.66.8/3094.0.66.9 to 94.0.66.1094.0.66.112
13294.0.66.12/3094.0.66.13 to 94.0.66.1494.0.66.152
13394.0.66.16/3094.0.66.17 to 94.0.66.1894.0.66.192
13494.0.66.20/3094.0.66.21 to 94.0.66.2294.0.66.232
13594.0.66.24/3094.0.66.25 to 94.0.66.2694.0.66.272
13694.0.66.28/3094.0.66.29 to 94.0.66.3094.0.66.312
13794.0.66.32/3094.0.66.33 to 94.0.66.3494.0.66.352
13894.0.66.36/3094.0.66.37 to 94.0.66.3894.0.66.392
13994.0.66.40/3094.0.66.41 to 94.0.66.4294.0.66.432
14094.0.66.44/3094.0.66.45 to 94.0.66.4694.0.66.472
14194.0.66.48/3094.0.66.49 to 94.0.66.5094.0.66.512
14294.0.66.52/3094.0.66.53 to 94.0.66.5494.0.66.552
14394.0.66.56/3094.0.66.57 to 94.0.66.5894.0.66.592
14494.0.66.60/3094.0.66.61 to 94.0.66.6294.0.66.632
14594.0.66.64/3094.0.66.65 to 94.0.66.6694.0.66.672
14694.0.66.68/3094.0.66.69 to 94.0.66.7094.0.66.712
14794.0.66.72/3094.0.66.73 to 94.0.66.7494.0.66.752
14894.0.66.76/3094.0.66.77 to 94.0.66.7894.0.66.792
14994.0.66.80/3094.0.66.81 to 94.0.66.8294.0.66.832
15094.0.66.84/3094.0.66.85 to 94.0.66.8694.0.66.872
15194.0.66.88/3094.0.66.89 to 94.0.66.9094.0.66.912
15294.0.66.92/3094.0.66.93 to 94.0.66.9494.0.66.952
15394.0.66.96/3094.0.66.97 to 94.0.66.9894.0.66.992
15494.0.66.100/3094.0.66.101 to 94.0.66.10294.0.66.1032
15594.0.66.104/3094.0.66.105 to 94.0.66.10694.0.66.1072
15694.0.66.108/3094.0.66.109 to 94.0.66.11094.0.66.1112
15794.0.66.112/3094.0.66.113 to 94.0.66.11494.0.66.1152
15894.0.66.116/3094.0.66.117 to 94.0.66.11894.0.66.1192
15994.0.66.120/3094.0.66.121 to 94.0.66.12294.0.66.1232
16094.0.66.124/3094.0.66.125 to 94.0.66.12694.0.66.1272
16194.0.66.128/3094.0.66.129 to 94.0.66.13094.0.66.1312
16294.0.66.132/3094.0.66.133 to 94.0.66.13494.0.66.1352
16394.0.66.136/3094.0.66.137 to 94.0.66.13894.0.66.1392
16494.0.66.140/3094.0.66.141 to 94.0.66.14294.0.66.1432
16594.0.66.144/3094.0.66.145 to 94.0.66.14694.0.66.1472
16694.0.66.148/3094.0.66.149 to 94.0.66.15094.0.66.1512
16794.0.66.152/3094.0.66.153 to 94.0.66.15494.0.66.1552
16894.0.66.156/3094.0.66.157 to 94.0.66.15894.0.66.1592
16994.0.66.160/3094.0.66.161 to 94.0.66.16294.0.66.1632
17094.0.66.164/3094.0.66.165 to 94.0.66.16694.0.66.1672
17194.0.66.168/3094.0.66.169 to 94.0.66.17094.0.66.1712
17294.0.66.172/3094.0.66.173 to 94.0.66.17494.0.66.1752
17394.0.66.176/3094.0.66.177 to 94.0.66.17894.0.66.1792
17494.0.66.180/3094.0.66.181 to 94.0.66.18294.0.66.1832
17594.0.66.184/3094.0.66.185 to 94.0.66.18694.0.66.1872
17694.0.66.188/3094.0.66.189 to 94.0.66.19094.0.66.1912
17794.0.66.192/3094.0.66.193 to 94.0.66.19494.0.66.1952
17894.0.66.196/3094.0.66.197 to 94.0.66.19894.0.66.1992
17994.0.66.200/3094.0.66.201 to 94.0.66.20294.0.66.2032
18094.0.66.204/3094.0.66.205 to 94.0.66.20694.0.66.2072
18194.0.66.208/3094.0.66.209 to 94.0.66.21094.0.66.2112
18294.0.66.212/3094.0.66.213 to 94.0.66.21494.0.66.2152
18394.0.66.216/3094.0.66.217 to 94.0.66.21894.0.66.2192
18494.0.66.220/3094.0.66.221 to 94.0.66.22294.0.66.2232
18594.0.66.224/3094.0.66.225 to 94.0.66.22694.0.66.2272
18694.0.66.228/3094.0.66.229 to 94.0.66.23094.0.66.2312
18794.0.66.232/3094.0.66.233 to 94.0.66.23494.0.66.2352
18894.0.66.236/3094.0.66.237 to 94.0.66.23894.0.66.2392
18994.0.66.240/3094.0.66.241 to 94.0.66.24294.0.66.2432
19094.0.66.244/3094.0.66.245 to 94.0.66.24694.0.66.2472
19194.0.66.248/3094.0.66.249 to 94.0.66.25094.0.66.2512
19294.0.66.252/3094.0.66.253 to 94.0.66.25494.0.66.2552
19394.0.67.0/3094.0.67.1 to 94.0.67.294.0.67.32
19494.0.67.4/3094.0.67.5 to 94.0.67.694.0.67.72
19594.0.67.8/3094.0.67.9 to 94.0.67.1094.0.67.112
19694.0.67.12/3094.0.67.13 to 94.0.67.1494.0.67.152
19794.0.67.16/3094.0.67.17 to 94.0.67.1894.0.67.192
19894.0.67.20/3094.0.67.21 to 94.0.67.2294.0.67.232
19994.0.67.24/3094.0.67.25 to 94.0.67.2694.0.67.272
20094.0.67.28/3094.0.67.29 to 94.0.67.3094.0.67.312
20194.0.67.32/3094.0.67.33 to 94.0.67.3494.0.67.352
20294.0.67.36/3094.0.67.37 to 94.0.67.3894.0.67.392
20394.0.67.40/3094.0.67.41 to 94.0.67.4294.0.67.432
20494.0.67.44/3094.0.67.45 to 94.0.67.4694.0.67.472
20594.0.67.48/3094.0.67.49 to 94.0.67.5094.0.67.512
20694.0.67.52/3094.0.67.53 to 94.0.67.5494.0.67.552
20794.0.67.56/3094.0.67.57 to 94.0.67.5894.0.67.592
20894.0.67.60/3094.0.67.61 to 94.0.67.6294.0.67.632
20994.0.67.64/3094.0.67.65 to 94.0.67.6694.0.67.672
21094.0.67.68/3094.0.67.69 to 94.0.67.7094.0.67.712
21194.0.67.72/3094.0.67.73 to 94.0.67.7494.0.67.752
21294.0.67.76/3094.0.67.77 to 94.0.67.7894.0.67.792
21394.0.67.80/3094.0.67.81 to 94.0.67.8294.0.67.832
21494.0.67.84/3094.0.67.85 to 94.0.67.8694.0.67.872
21594.0.67.88/3094.0.67.89 to 94.0.67.9094.0.67.912
21694.0.67.92/3094.0.67.93 to 94.0.67.9494.0.67.952
21794.0.67.96/3094.0.67.97 to 94.0.67.9894.0.67.992
21894.0.67.100/3094.0.67.101 to 94.0.67.10294.0.67.1032
21994.0.67.104/3094.0.67.105 to 94.0.67.10694.0.67.1072
22094.0.67.108/3094.0.67.109 to 94.0.67.11094.0.67.1112
22194.0.67.112/3094.0.67.113 to 94.0.67.11494.0.67.1152
22294.0.67.116/3094.0.67.117 to 94.0.67.11894.0.67.1192
22394.0.67.120/3094.0.67.121 to 94.0.67.12294.0.67.1232
22494.0.67.124/3094.0.67.125 to 94.0.67.12694.0.67.1272
22594.0.67.128/3094.0.67.129 to 94.0.67.13094.0.67.1312
22694.0.67.132/3094.0.67.133 to 94.0.67.13494.0.67.1352
22794.0.67.136/3094.0.67.137 to 94.0.67.13894.0.67.1392
22894.0.67.140/3094.0.67.141 to 94.0.67.14294.0.67.1432
22994.0.67.144/3094.0.67.145 to 94.0.67.14694.0.67.1472
23094.0.67.148/3094.0.67.149 to 94.0.67.15094.0.67.1512
23194.0.67.152/3094.0.67.153 to 94.0.67.15494.0.67.1552
23294.0.67.156/3094.0.67.157 to 94.0.67.15894.0.67.1592
23394.0.67.160/3094.0.67.161 to 94.0.67.16294.0.67.1632
23494.0.67.164/3094.0.67.165 to 94.0.67.16694.0.67.1672
23594.0.67.168/3094.0.67.169 to 94.0.67.17094.0.67.1712
23694.0.67.172/3094.0.67.173 to 94.0.67.17494.0.67.1752
23794.0.67.176/3094.0.67.177 to 94.0.67.17894.0.67.1792
23894.0.67.180/3094.0.67.181 to 94.0.67.18294.0.67.1832
23994.0.67.184/3094.0.67.185 to 94.0.67.18694.0.67.1872
24094.0.67.188/3094.0.67.189 to 94.0.67.19094.0.67.1912
24194.0.67.192/3094.0.67.193 to 94.0.67.19494.0.67.1952
24294.0.67.196/3094.0.67.197 to 94.0.67.19894.0.67.1992
24394.0.67.200/3094.0.67.201 to 94.0.67.20294.0.67.2032
24494.0.67.204/3094.0.67.205 to 94.0.67.20694.0.67.2072
24594.0.67.208/3094.0.67.209 to 94.0.67.21094.0.67.2112
24694.0.67.212/3094.0.67.213 to 94.0.67.21494.0.67.2152
24794.0.67.216/3094.0.67.217 to 94.0.67.21894.0.67.2192
24894.0.67.220/3094.0.67.221 to 94.0.67.22294.0.67.2232
24994.0.67.224/3094.0.67.225 to 94.0.67.22694.0.67.2272
25094.0.67.228/3094.0.67.229 to 94.0.67.23094.0.67.2312
25194.0.67.232/3094.0.67.233 to 94.0.67.23494.0.67.2352
25294.0.67.236/3094.0.67.237 to 94.0.67.23894.0.67.2392
25394.0.67.240/3094.0.67.241 to 94.0.67.24294.0.67.2432
25494.0.67.244/3094.0.67.245 to 94.0.67.24694.0.67.2472
25594.0.67.248/3094.0.67.249 to 94.0.67.25094.0.67.2512
25694.0.67.252/3094.0.67.253 to 94.0.67.25494.0.67.2552

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.