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.

Network79.167.3.0/24
Usable hosts254
Subnet mask255.255.255.0
Addresses256
Network address
79.167.3.0
Broadcast address
79.167.3.255
First usable
79.167.3.1
Last usable
79.167.3.254
Usable hosts
254 (256 less the network and broadcast addresses)
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255 (Cisco ACLs, OSPF)
Prefix length
/24
Type
Public public
Old class
A (default /8)
As numbers
Hex 4FA70300 · Integer 1336345344 to 1336345599
Reverse DNS zone
3.167.79.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001111.10100111.00000011..0000000079.167.3.0
Subnet mask11111111.11111111.11111111..00000000255.255.255.0
Network01001111.10100111.00000011..0000000079.167.3.0
Broadcast01001111.10100111.00000011..1111111179.167.3.255
Split into smaller subnets/32
/25 (2)/26 (4)/27 (8)/28 (16)/29 (32)/30 (64)/31 (128)/32 (256)

79.167.3.0/24 makes 256 subnets of /32.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
179.167.3.0/3279.167.3.0 to 79.167.3.0—1
279.167.3.1/3279.167.3.1 to 79.167.3.1—1
379.167.3.2/3279.167.3.2 to 79.167.3.2—1
479.167.3.3/3279.167.3.3 to 79.167.3.3—1
579.167.3.4/3279.167.3.4 to 79.167.3.4—1
679.167.3.5/3279.167.3.5 to 79.167.3.5—1
779.167.3.6/3279.167.3.6 to 79.167.3.6—1
879.167.3.7/3279.167.3.7 to 79.167.3.7—1
979.167.3.8/3279.167.3.8 to 79.167.3.8—1
1079.167.3.9/3279.167.3.9 to 79.167.3.9—1
1179.167.3.10/3279.167.3.10 to 79.167.3.10—1
1279.167.3.11/3279.167.3.11 to 79.167.3.11—1
1379.167.3.12/3279.167.3.12 to 79.167.3.12—1
1479.167.3.13/3279.167.3.13 to 79.167.3.13—1
1579.167.3.14/3279.167.3.14 to 79.167.3.14—1
1679.167.3.15/3279.167.3.15 to 79.167.3.15—1
1779.167.3.16/3279.167.3.16 to 79.167.3.16—1
1879.167.3.17/3279.167.3.17 to 79.167.3.17—1
1979.167.3.18/3279.167.3.18 to 79.167.3.18—1
2079.167.3.19/3279.167.3.19 to 79.167.3.19—1
2179.167.3.20/3279.167.3.20 to 79.167.3.20—1
2279.167.3.21/3279.167.3.21 to 79.167.3.21—1
2379.167.3.22/3279.167.3.22 to 79.167.3.22—1
2479.167.3.23/3279.167.3.23 to 79.167.3.23—1
2579.167.3.24/3279.167.3.24 to 79.167.3.24—1
2679.167.3.25/3279.167.3.25 to 79.167.3.25—1
2779.167.3.26/3279.167.3.26 to 79.167.3.26—1
2879.167.3.27/3279.167.3.27 to 79.167.3.27—1
2979.167.3.28/3279.167.3.28 to 79.167.3.28—1
3079.167.3.29/3279.167.3.29 to 79.167.3.29—1
3179.167.3.30/3279.167.3.30 to 79.167.3.30—1
3279.167.3.31/3279.167.3.31 to 79.167.3.31—1
3379.167.3.32/3279.167.3.32 to 79.167.3.32—1
3479.167.3.33/3279.167.3.33 to 79.167.3.33—1
3579.167.3.34/3279.167.3.34 to 79.167.3.34—1
3679.167.3.35/3279.167.3.35 to 79.167.3.35—1
3779.167.3.36/3279.167.3.36 to 79.167.3.36—1
3879.167.3.37/3279.167.3.37 to 79.167.3.37—1
3979.167.3.38/3279.167.3.38 to 79.167.3.38—1
4079.167.3.39/3279.167.3.39 to 79.167.3.39—1
4179.167.3.40/3279.167.3.40 to 79.167.3.40—1
4279.167.3.41/3279.167.3.41 to 79.167.3.41—1
4379.167.3.42/3279.167.3.42 to 79.167.3.42—1
4479.167.3.43/3279.167.3.43 to 79.167.3.43—1
4579.167.3.44/3279.167.3.44 to 79.167.3.44—1
4679.167.3.45/3279.167.3.45 to 79.167.3.45—1
4779.167.3.46/3279.167.3.46 to 79.167.3.46—1
4879.167.3.47/3279.167.3.47 to 79.167.3.47—1
4979.167.3.48/3279.167.3.48 to 79.167.3.48—1
5079.167.3.49/3279.167.3.49 to 79.167.3.49—1
5179.167.3.50/3279.167.3.50 to 79.167.3.50—1
5279.167.3.51/3279.167.3.51 to 79.167.3.51—1
5379.167.3.52/3279.167.3.52 to 79.167.3.52—1
5479.167.3.53/3279.167.3.53 to 79.167.3.53—1
5579.167.3.54/3279.167.3.54 to 79.167.3.54—1
5679.167.3.55/3279.167.3.55 to 79.167.3.55—1
5779.167.3.56/3279.167.3.56 to 79.167.3.56—1
5879.167.3.57/3279.167.3.57 to 79.167.3.57—1
5979.167.3.58/3279.167.3.58 to 79.167.3.58—1
6079.167.3.59/3279.167.3.59 to 79.167.3.59—1
6179.167.3.60/3279.167.3.60 to 79.167.3.60—1
6279.167.3.61/3279.167.3.61 to 79.167.3.61—1
6379.167.3.62/3279.167.3.62 to 79.167.3.62—1
6479.167.3.63/3279.167.3.63 to 79.167.3.63—1
6579.167.3.64/3279.167.3.64 to 79.167.3.64—1
6679.167.3.65/3279.167.3.65 to 79.167.3.65—1
6779.167.3.66/3279.167.3.66 to 79.167.3.66—1
6879.167.3.67/3279.167.3.67 to 79.167.3.67—1
6979.167.3.68/3279.167.3.68 to 79.167.3.68—1
7079.167.3.69/3279.167.3.69 to 79.167.3.69—1
7179.167.3.70/3279.167.3.70 to 79.167.3.70—1
7279.167.3.71/3279.167.3.71 to 79.167.3.71—1
7379.167.3.72/3279.167.3.72 to 79.167.3.72—1
7479.167.3.73/3279.167.3.73 to 79.167.3.73—1
7579.167.3.74/3279.167.3.74 to 79.167.3.74—1
7679.167.3.75/3279.167.3.75 to 79.167.3.75—1
7779.167.3.76/3279.167.3.76 to 79.167.3.76—1
7879.167.3.77/3279.167.3.77 to 79.167.3.77—1
7979.167.3.78/3279.167.3.78 to 79.167.3.78—1
8079.167.3.79/3279.167.3.79 to 79.167.3.79—1
8179.167.3.80/3279.167.3.80 to 79.167.3.80—1
8279.167.3.81/3279.167.3.81 to 79.167.3.81—1
8379.167.3.82/3279.167.3.82 to 79.167.3.82—1
8479.167.3.83/3279.167.3.83 to 79.167.3.83—1
8579.167.3.84/3279.167.3.84 to 79.167.3.84—1
8679.167.3.85/3279.167.3.85 to 79.167.3.85—1
8779.167.3.86/3279.167.3.86 to 79.167.3.86—1
8879.167.3.87/3279.167.3.87 to 79.167.3.87—1
8979.167.3.88/3279.167.3.88 to 79.167.3.88—1
9079.167.3.89/3279.167.3.89 to 79.167.3.89—1
9179.167.3.90/3279.167.3.90 to 79.167.3.90—1
9279.167.3.91/3279.167.3.91 to 79.167.3.91—1
9379.167.3.92/3279.167.3.92 to 79.167.3.92—1
9479.167.3.93/3279.167.3.93 to 79.167.3.93—1
9579.167.3.94/3279.167.3.94 to 79.167.3.94—1
9679.167.3.95/3279.167.3.95 to 79.167.3.95—1
9779.167.3.96/3279.167.3.96 to 79.167.3.96—1
9879.167.3.97/3279.167.3.97 to 79.167.3.97—1
9979.167.3.98/3279.167.3.98 to 79.167.3.98—1
10079.167.3.99/3279.167.3.99 to 79.167.3.99—1
10179.167.3.100/3279.167.3.100 to 79.167.3.100—1
10279.167.3.101/3279.167.3.101 to 79.167.3.101—1
10379.167.3.102/3279.167.3.102 to 79.167.3.102—1
10479.167.3.103/3279.167.3.103 to 79.167.3.103—1
10579.167.3.104/3279.167.3.104 to 79.167.3.104—1
10679.167.3.105/3279.167.3.105 to 79.167.3.105—1
10779.167.3.106/3279.167.3.106 to 79.167.3.106—1
10879.167.3.107/3279.167.3.107 to 79.167.3.107—1
10979.167.3.108/3279.167.3.108 to 79.167.3.108—1
11079.167.3.109/3279.167.3.109 to 79.167.3.109—1
11179.167.3.110/3279.167.3.110 to 79.167.3.110—1
11279.167.3.111/3279.167.3.111 to 79.167.3.111—1
11379.167.3.112/3279.167.3.112 to 79.167.3.112—1
11479.167.3.113/3279.167.3.113 to 79.167.3.113—1
11579.167.3.114/3279.167.3.114 to 79.167.3.114—1
11679.167.3.115/3279.167.3.115 to 79.167.3.115—1
11779.167.3.116/3279.167.3.116 to 79.167.3.116—1
11879.167.3.117/3279.167.3.117 to 79.167.3.117—1
11979.167.3.118/3279.167.3.118 to 79.167.3.118—1
12079.167.3.119/3279.167.3.119 to 79.167.3.119—1
12179.167.3.120/3279.167.3.120 to 79.167.3.120—1
12279.167.3.121/3279.167.3.121 to 79.167.3.121—1
12379.167.3.122/3279.167.3.122 to 79.167.3.122—1
12479.167.3.123/3279.167.3.123 to 79.167.3.123—1
12579.167.3.124/3279.167.3.124 to 79.167.3.124—1
12679.167.3.125/3279.167.3.125 to 79.167.3.125—1
12779.167.3.126/3279.167.3.126 to 79.167.3.126—1
12879.167.3.127/3279.167.3.127 to 79.167.3.127—1
12979.167.3.128/3279.167.3.128 to 79.167.3.128—1
13079.167.3.129/3279.167.3.129 to 79.167.3.129—1
13179.167.3.130/3279.167.3.130 to 79.167.3.130—1
13279.167.3.131/3279.167.3.131 to 79.167.3.131—1
13379.167.3.132/3279.167.3.132 to 79.167.3.132—1
13479.167.3.133/3279.167.3.133 to 79.167.3.133—1
13579.167.3.134/3279.167.3.134 to 79.167.3.134—1
13679.167.3.135/3279.167.3.135 to 79.167.3.135—1
13779.167.3.136/3279.167.3.136 to 79.167.3.136—1
13879.167.3.137/3279.167.3.137 to 79.167.3.137—1
13979.167.3.138/3279.167.3.138 to 79.167.3.138—1
14079.167.3.139/3279.167.3.139 to 79.167.3.139—1
14179.167.3.140/3279.167.3.140 to 79.167.3.140—1
14279.167.3.141/3279.167.3.141 to 79.167.3.141—1
14379.167.3.142/3279.167.3.142 to 79.167.3.142—1
14479.167.3.143/3279.167.3.143 to 79.167.3.143—1
14579.167.3.144/3279.167.3.144 to 79.167.3.144—1
14679.167.3.145/3279.167.3.145 to 79.167.3.145—1
14779.167.3.146/3279.167.3.146 to 79.167.3.146—1
14879.167.3.147/3279.167.3.147 to 79.167.3.147—1
14979.167.3.148/3279.167.3.148 to 79.167.3.148—1
15079.167.3.149/3279.167.3.149 to 79.167.3.149—1
15179.167.3.150/3279.167.3.150 to 79.167.3.150—1
15279.167.3.151/3279.167.3.151 to 79.167.3.151—1
15379.167.3.152/3279.167.3.152 to 79.167.3.152—1
15479.167.3.153/3279.167.3.153 to 79.167.3.153—1
15579.167.3.154/3279.167.3.154 to 79.167.3.154—1
15679.167.3.155/3279.167.3.155 to 79.167.3.155—1
15779.167.3.156/3279.167.3.156 to 79.167.3.156—1
15879.167.3.157/3279.167.3.157 to 79.167.3.157—1
15979.167.3.158/3279.167.3.158 to 79.167.3.158—1
16079.167.3.159/3279.167.3.159 to 79.167.3.159—1
16179.167.3.160/3279.167.3.160 to 79.167.3.160—1
16279.167.3.161/3279.167.3.161 to 79.167.3.161—1
16379.167.3.162/3279.167.3.162 to 79.167.3.162—1
16479.167.3.163/3279.167.3.163 to 79.167.3.163—1
16579.167.3.164/3279.167.3.164 to 79.167.3.164—1
16679.167.3.165/3279.167.3.165 to 79.167.3.165—1
16779.167.3.166/3279.167.3.166 to 79.167.3.166—1
16879.167.3.167/3279.167.3.167 to 79.167.3.167—1
16979.167.3.168/3279.167.3.168 to 79.167.3.168—1
17079.167.3.169/3279.167.3.169 to 79.167.3.169—1
17179.167.3.170/3279.167.3.170 to 79.167.3.170—1
17279.167.3.171/3279.167.3.171 to 79.167.3.171—1
17379.167.3.172/3279.167.3.172 to 79.167.3.172—1
17479.167.3.173/3279.167.3.173 to 79.167.3.173—1
17579.167.3.174/3279.167.3.174 to 79.167.3.174—1
17679.167.3.175/3279.167.3.175 to 79.167.3.175—1
17779.167.3.176/3279.167.3.176 to 79.167.3.176—1
17879.167.3.177/3279.167.3.177 to 79.167.3.177—1
17979.167.3.178/3279.167.3.178 to 79.167.3.178—1
18079.167.3.179/3279.167.3.179 to 79.167.3.179—1
18179.167.3.180/3279.167.3.180 to 79.167.3.180—1
18279.167.3.181/3279.167.3.181 to 79.167.3.181—1
18379.167.3.182/3279.167.3.182 to 79.167.3.182—1
18479.167.3.183/3279.167.3.183 to 79.167.3.183—1
18579.167.3.184/3279.167.3.184 to 79.167.3.184—1
18679.167.3.185/3279.167.3.185 to 79.167.3.185—1
18779.167.3.186/3279.167.3.186 to 79.167.3.186—1
18879.167.3.187/3279.167.3.187 to 79.167.3.187—1
18979.167.3.188/3279.167.3.188 to 79.167.3.188—1
19079.167.3.189/3279.167.3.189 to 79.167.3.189—1
19179.167.3.190/3279.167.3.190 to 79.167.3.190—1
19279.167.3.191/3279.167.3.191 to 79.167.3.191—1
19379.167.3.192/3279.167.3.192 to 79.167.3.192—1
19479.167.3.193/3279.167.3.193 to 79.167.3.193—1
19579.167.3.194/3279.167.3.194 to 79.167.3.194—1
19679.167.3.195/3279.167.3.195 to 79.167.3.195—1
19779.167.3.196/3279.167.3.196 to 79.167.3.196—1
19879.167.3.197/3279.167.3.197 to 79.167.3.197—1
19979.167.3.198/3279.167.3.198 to 79.167.3.198—1
20079.167.3.199/3279.167.3.199 to 79.167.3.199—1
20179.167.3.200/3279.167.3.200 to 79.167.3.200—1
20279.167.3.201/3279.167.3.201 to 79.167.3.201—1
20379.167.3.202/3279.167.3.202 to 79.167.3.202—1
20479.167.3.203/3279.167.3.203 to 79.167.3.203—1
20579.167.3.204/3279.167.3.204 to 79.167.3.204—1
20679.167.3.205/3279.167.3.205 to 79.167.3.205—1
20779.167.3.206/3279.167.3.206 to 79.167.3.206—1
20879.167.3.207/3279.167.3.207 to 79.167.3.207—1
20979.167.3.208/3279.167.3.208 to 79.167.3.208—1
21079.167.3.209/3279.167.3.209 to 79.167.3.209—1
21179.167.3.210/3279.167.3.210 to 79.167.3.210—1
21279.167.3.211/3279.167.3.211 to 79.167.3.211—1
21379.167.3.212/3279.167.3.212 to 79.167.3.212—1
21479.167.3.213/3279.167.3.213 to 79.167.3.213—1
21579.167.3.214/3279.167.3.214 to 79.167.3.214—1
21679.167.3.215/3279.167.3.215 to 79.167.3.215—1
21779.167.3.216/3279.167.3.216 to 79.167.3.216—1
21879.167.3.217/3279.167.3.217 to 79.167.3.217—1
21979.167.3.218/3279.167.3.218 to 79.167.3.218—1
22079.167.3.219/3279.167.3.219 to 79.167.3.219—1
22179.167.3.220/3279.167.3.220 to 79.167.3.220—1
22279.167.3.221/3279.167.3.221 to 79.167.3.221—1
22379.167.3.222/3279.167.3.222 to 79.167.3.222—1
22479.167.3.223/3279.167.3.223 to 79.167.3.223—1
22579.167.3.224/3279.167.3.224 to 79.167.3.224—1
22679.167.3.225/3279.167.3.225 to 79.167.3.225—1
22779.167.3.226/3279.167.3.226 to 79.167.3.226—1
22879.167.3.227/3279.167.3.227 to 79.167.3.227—1
22979.167.3.228/3279.167.3.228 to 79.167.3.228—1
23079.167.3.229/3279.167.3.229 to 79.167.3.229—1
23179.167.3.230/3279.167.3.230 to 79.167.3.230—1
23279.167.3.231/3279.167.3.231 to 79.167.3.231—1
23379.167.3.232/3279.167.3.232 to 79.167.3.232—1
23479.167.3.233/3279.167.3.233 to 79.167.3.233—1
23579.167.3.234/3279.167.3.234 to 79.167.3.234—1
23679.167.3.235/3279.167.3.235 to 79.167.3.235—1
23779.167.3.236/3279.167.3.236 to 79.167.3.236—1
23879.167.3.237/3279.167.3.237 to 79.167.3.237—1
23979.167.3.238/3279.167.3.238 to 79.167.3.238—1
24079.167.3.239/3279.167.3.239 to 79.167.3.239—1
24179.167.3.240/3279.167.3.240 to 79.167.3.240—1
24279.167.3.241/3279.167.3.241 to 79.167.3.241—1
24379.167.3.242/3279.167.3.242 to 79.167.3.242—1
24479.167.3.243/3279.167.3.243 to 79.167.3.243—1
24579.167.3.244/3279.167.3.244 to 79.167.3.244—1
24679.167.3.245/3279.167.3.245 to 79.167.3.245—1
24779.167.3.246/3279.167.3.246 to 79.167.3.246—1
24879.167.3.247/3279.167.3.247 to 79.167.3.247—1
24979.167.3.248/3279.167.3.248 to 79.167.3.248—1
25079.167.3.249/3279.167.3.249 to 79.167.3.249—1
25179.167.3.250/3279.167.3.250 to 79.167.3.250—1
25279.167.3.251/3279.167.3.251 to 79.167.3.251—1
25379.167.3.252/3279.167.3.252 to 79.167.3.252—1
25479.167.3.253/3279.167.3.253 to 79.167.3.253—1
25579.167.3.254/3279.167.3.254 to 79.167.3.254—1
25679.167.3.255/3279.167.3.255 to 79.167.3.255—1

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.