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.

Network26.201.192.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
26.201.192.0
Broadcast address
26.201.223.255
First usable
26.201.192.1
Last usable
26.201.223.254
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 1AC9C000 · Integer 449429504 to 449437695
Reverse DNS zones
192.201.26.in-addr.arpa
193.201.26.in-addr.arpa
194.201.26.in-addr.arpa
195.201.26.in-addr.arpa
196.201.26.in-addr.arpa
197.201.26.in-addr.arpa
198.201.26.in-addr.arpa
199.201.26.in-addr.arpa
200.201.26.in-addr.arpa
201.201.26.in-addr.arpa
202.201.26.in-addr.arpa
203.201.26.in-addr.arpa
204.201.26.in-addr.arpa
205.201.26.in-addr.arpa
206.201.26.in-addr.arpa
207.201.26.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
Address00011010.11001001.11000000.0000000026.201.192.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00011010.11001001.11000000.0000000026.201.192.0
Broadcast00011010.11001001.11011111.1111111126.201.223.255
Split into smaller subnets/27
/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)

26.201.192.0/19 makes 256 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.201.192.0/2726.201.192.1 to 26.201.192.3026.201.192.3130
226.201.192.32/2726.201.192.33 to 26.201.192.6226.201.192.6330
326.201.192.64/2726.201.192.65 to 26.201.192.9426.201.192.9530
426.201.192.96/2726.201.192.97 to 26.201.192.12626.201.192.12730
526.201.192.128/2726.201.192.129 to 26.201.192.15826.201.192.15930
626.201.192.160/2726.201.192.161 to 26.201.192.19026.201.192.19130
726.201.192.192/2726.201.192.193 to 26.201.192.22226.201.192.22330
826.201.192.224/2726.201.192.225 to 26.201.192.25426.201.192.25530
926.201.193.0/2726.201.193.1 to 26.201.193.3026.201.193.3130
1026.201.193.32/2726.201.193.33 to 26.201.193.6226.201.193.6330
1126.201.193.64/2726.201.193.65 to 26.201.193.9426.201.193.9530
1226.201.193.96/2726.201.193.97 to 26.201.193.12626.201.193.12730
1326.201.193.128/2726.201.193.129 to 26.201.193.15826.201.193.15930
1426.201.193.160/2726.201.193.161 to 26.201.193.19026.201.193.19130
1526.201.193.192/2726.201.193.193 to 26.201.193.22226.201.193.22330
1626.201.193.224/2726.201.193.225 to 26.201.193.25426.201.193.25530
1726.201.194.0/2726.201.194.1 to 26.201.194.3026.201.194.3130
1826.201.194.32/2726.201.194.33 to 26.201.194.6226.201.194.6330
1926.201.194.64/2726.201.194.65 to 26.201.194.9426.201.194.9530
2026.201.194.96/2726.201.194.97 to 26.201.194.12626.201.194.12730
2126.201.194.128/2726.201.194.129 to 26.201.194.15826.201.194.15930
2226.201.194.160/2726.201.194.161 to 26.201.194.19026.201.194.19130
2326.201.194.192/2726.201.194.193 to 26.201.194.22226.201.194.22330
2426.201.194.224/2726.201.194.225 to 26.201.194.25426.201.194.25530
2526.201.195.0/2726.201.195.1 to 26.201.195.3026.201.195.3130
2626.201.195.32/2726.201.195.33 to 26.201.195.6226.201.195.6330
2726.201.195.64/2726.201.195.65 to 26.201.195.9426.201.195.9530
2826.201.195.96/2726.201.195.97 to 26.201.195.12626.201.195.12730
2926.201.195.128/2726.201.195.129 to 26.201.195.15826.201.195.15930
3026.201.195.160/2726.201.195.161 to 26.201.195.19026.201.195.19130
3126.201.195.192/2726.201.195.193 to 26.201.195.22226.201.195.22330
3226.201.195.224/2726.201.195.225 to 26.201.195.25426.201.195.25530
3326.201.196.0/2726.201.196.1 to 26.201.196.3026.201.196.3130
3426.201.196.32/2726.201.196.33 to 26.201.196.6226.201.196.6330
3526.201.196.64/2726.201.196.65 to 26.201.196.9426.201.196.9530
3626.201.196.96/2726.201.196.97 to 26.201.196.12626.201.196.12730
3726.201.196.128/2726.201.196.129 to 26.201.196.15826.201.196.15930
3826.201.196.160/2726.201.196.161 to 26.201.196.19026.201.196.19130
3926.201.196.192/2726.201.196.193 to 26.201.196.22226.201.196.22330
4026.201.196.224/2726.201.196.225 to 26.201.196.25426.201.196.25530
4126.201.197.0/2726.201.197.1 to 26.201.197.3026.201.197.3130
4226.201.197.32/2726.201.197.33 to 26.201.197.6226.201.197.6330
4326.201.197.64/2726.201.197.65 to 26.201.197.9426.201.197.9530
4426.201.197.96/2726.201.197.97 to 26.201.197.12626.201.197.12730
4526.201.197.128/2726.201.197.129 to 26.201.197.15826.201.197.15930
4626.201.197.160/2726.201.197.161 to 26.201.197.19026.201.197.19130
4726.201.197.192/2726.201.197.193 to 26.201.197.22226.201.197.22330
4826.201.197.224/2726.201.197.225 to 26.201.197.25426.201.197.25530
4926.201.198.0/2726.201.198.1 to 26.201.198.3026.201.198.3130
5026.201.198.32/2726.201.198.33 to 26.201.198.6226.201.198.6330
5126.201.198.64/2726.201.198.65 to 26.201.198.9426.201.198.9530
5226.201.198.96/2726.201.198.97 to 26.201.198.12626.201.198.12730
5326.201.198.128/2726.201.198.129 to 26.201.198.15826.201.198.15930
5426.201.198.160/2726.201.198.161 to 26.201.198.19026.201.198.19130
5526.201.198.192/2726.201.198.193 to 26.201.198.22226.201.198.22330
5626.201.198.224/2726.201.198.225 to 26.201.198.25426.201.198.25530
5726.201.199.0/2726.201.199.1 to 26.201.199.3026.201.199.3130
5826.201.199.32/2726.201.199.33 to 26.201.199.6226.201.199.6330
5926.201.199.64/2726.201.199.65 to 26.201.199.9426.201.199.9530
6026.201.199.96/2726.201.199.97 to 26.201.199.12626.201.199.12730
6126.201.199.128/2726.201.199.129 to 26.201.199.15826.201.199.15930
6226.201.199.160/2726.201.199.161 to 26.201.199.19026.201.199.19130
6326.201.199.192/2726.201.199.193 to 26.201.199.22226.201.199.22330
6426.201.199.224/2726.201.199.225 to 26.201.199.25426.201.199.25530
6526.201.200.0/2726.201.200.1 to 26.201.200.3026.201.200.3130
6626.201.200.32/2726.201.200.33 to 26.201.200.6226.201.200.6330
6726.201.200.64/2726.201.200.65 to 26.201.200.9426.201.200.9530
6826.201.200.96/2726.201.200.97 to 26.201.200.12626.201.200.12730
6926.201.200.128/2726.201.200.129 to 26.201.200.15826.201.200.15930
7026.201.200.160/2726.201.200.161 to 26.201.200.19026.201.200.19130
7126.201.200.192/2726.201.200.193 to 26.201.200.22226.201.200.22330
7226.201.200.224/2726.201.200.225 to 26.201.200.25426.201.200.25530
7326.201.201.0/2726.201.201.1 to 26.201.201.3026.201.201.3130
7426.201.201.32/2726.201.201.33 to 26.201.201.6226.201.201.6330
7526.201.201.64/2726.201.201.65 to 26.201.201.9426.201.201.9530
7626.201.201.96/2726.201.201.97 to 26.201.201.12626.201.201.12730
7726.201.201.128/2726.201.201.129 to 26.201.201.15826.201.201.15930
7826.201.201.160/2726.201.201.161 to 26.201.201.19026.201.201.19130
7926.201.201.192/2726.201.201.193 to 26.201.201.22226.201.201.22330
8026.201.201.224/2726.201.201.225 to 26.201.201.25426.201.201.25530
8126.201.202.0/2726.201.202.1 to 26.201.202.3026.201.202.3130
8226.201.202.32/2726.201.202.33 to 26.201.202.6226.201.202.6330
8326.201.202.64/2726.201.202.65 to 26.201.202.9426.201.202.9530
8426.201.202.96/2726.201.202.97 to 26.201.202.12626.201.202.12730
8526.201.202.128/2726.201.202.129 to 26.201.202.15826.201.202.15930
8626.201.202.160/2726.201.202.161 to 26.201.202.19026.201.202.19130
8726.201.202.192/2726.201.202.193 to 26.201.202.22226.201.202.22330
8826.201.202.224/2726.201.202.225 to 26.201.202.25426.201.202.25530
8926.201.203.0/2726.201.203.1 to 26.201.203.3026.201.203.3130
9026.201.203.32/2726.201.203.33 to 26.201.203.6226.201.203.6330
9126.201.203.64/2726.201.203.65 to 26.201.203.9426.201.203.9530
9226.201.203.96/2726.201.203.97 to 26.201.203.12626.201.203.12730
9326.201.203.128/2726.201.203.129 to 26.201.203.15826.201.203.15930
9426.201.203.160/2726.201.203.161 to 26.201.203.19026.201.203.19130
9526.201.203.192/2726.201.203.193 to 26.201.203.22226.201.203.22330
9626.201.203.224/2726.201.203.225 to 26.201.203.25426.201.203.25530
9726.201.204.0/2726.201.204.1 to 26.201.204.3026.201.204.3130
9826.201.204.32/2726.201.204.33 to 26.201.204.6226.201.204.6330
9926.201.204.64/2726.201.204.65 to 26.201.204.9426.201.204.9530
10026.201.204.96/2726.201.204.97 to 26.201.204.12626.201.204.12730
10126.201.204.128/2726.201.204.129 to 26.201.204.15826.201.204.15930
10226.201.204.160/2726.201.204.161 to 26.201.204.19026.201.204.19130
10326.201.204.192/2726.201.204.193 to 26.201.204.22226.201.204.22330
10426.201.204.224/2726.201.204.225 to 26.201.204.25426.201.204.25530
10526.201.205.0/2726.201.205.1 to 26.201.205.3026.201.205.3130
10626.201.205.32/2726.201.205.33 to 26.201.205.6226.201.205.6330
10726.201.205.64/2726.201.205.65 to 26.201.205.9426.201.205.9530
10826.201.205.96/2726.201.205.97 to 26.201.205.12626.201.205.12730
10926.201.205.128/2726.201.205.129 to 26.201.205.15826.201.205.15930
11026.201.205.160/2726.201.205.161 to 26.201.205.19026.201.205.19130
11126.201.205.192/2726.201.205.193 to 26.201.205.22226.201.205.22330
11226.201.205.224/2726.201.205.225 to 26.201.205.25426.201.205.25530
11326.201.206.0/2726.201.206.1 to 26.201.206.3026.201.206.3130
11426.201.206.32/2726.201.206.33 to 26.201.206.6226.201.206.6330
11526.201.206.64/2726.201.206.65 to 26.201.206.9426.201.206.9530
11626.201.206.96/2726.201.206.97 to 26.201.206.12626.201.206.12730
11726.201.206.128/2726.201.206.129 to 26.201.206.15826.201.206.15930
11826.201.206.160/2726.201.206.161 to 26.201.206.19026.201.206.19130
11926.201.206.192/2726.201.206.193 to 26.201.206.22226.201.206.22330
12026.201.206.224/2726.201.206.225 to 26.201.206.25426.201.206.25530
12126.201.207.0/2726.201.207.1 to 26.201.207.3026.201.207.3130
12226.201.207.32/2726.201.207.33 to 26.201.207.6226.201.207.6330
12326.201.207.64/2726.201.207.65 to 26.201.207.9426.201.207.9530
12426.201.207.96/2726.201.207.97 to 26.201.207.12626.201.207.12730
12526.201.207.128/2726.201.207.129 to 26.201.207.15826.201.207.15930
12626.201.207.160/2726.201.207.161 to 26.201.207.19026.201.207.19130
12726.201.207.192/2726.201.207.193 to 26.201.207.22226.201.207.22330
12826.201.207.224/2726.201.207.225 to 26.201.207.25426.201.207.25530
12926.201.208.0/2726.201.208.1 to 26.201.208.3026.201.208.3130
13026.201.208.32/2726.201.208.33 to 26.201.208.6226.201.208.6330
13126.201.208.64/2726.201.208.65 to 26.201.208.9426.201.208.9530
13226.201.208.96/2726.201.208.97 to 26.201.208.12626.201.208.12730
13326.201.208.128/2726.201.208.129 to 26.201.208.15826.201.208.15930
13426.201.208.160/2726.201.208.161 to 26.201.208.19026.201.208.19130
13526.201.208.192/2726.201.208.193 to 26.201.208.22226.201.208.22330
13626.201.208.224/2726.201.208.225 to 26.201.208.25426.201.208.25530
13726.201.209.0/2726.201.209.1 to 26.201.209.3026.201.209.3130
13826.201.209.32/2726.201.209.33 to 26.201.209.6226.201.209.6330
13926.201.209.64/2726.201.209.65 to 26.201.209.9426.201.209.9530
14026.201.209.96/2726.201.209.97 to 26.201.209.12626.201.209.12730
14126.201.209.128/2726.201.209.129 to 26.201.209.15826.201.209.15930
14226.201.209.160/2726.201.209.161 to 26.201.209.19026.201.209.19130
14326.201.209.192/2726.201.209.193 to 26.201.209.22226.201.209.22330
14426.201.209.224/2726.201.209.225 to 26.201.209.25426.201.209.25530
14526.201.210.0/2726.201.210.1 to 26.201.210.3026.201.210.3130
14626.201.210.32/2726.201.210.33 to 26.201.210.6226.201.210.6330
14726.201.210.64/2726.201.210.65 to 26.201.210.9426.201.210.9530
14826.201.210.96/2726.201.210.97 to 26.201.210.12626.201.210.12730
14926.201.210.128/2726.201.210.129 to 26.201.210.15826.201.210.15930
15026.201.210.160/2726.201.210.161 to 26.201.210.19026.201.210.19130
15126.201.210.192/2726.201.210.193 to 26.201.210.22226.201.210.22330
15226.201.210.224/2726.201.210.225 to 26.201.210.25426.201.210.25530
15326.201.211.0/2726.201.211.1 to 26.201.211.3026.201.211.3130
15426.201.211.32/2726.201.211.33 to 26.201.211.6226.201.211.6330
15526.201.211.64/2726.201.211.65 to 26.201.211.9426.201.211.9530
15626.201.211.96/2726.201.211.97 to 26.201.211.12626.201.211.12730
15726.201.211.128/2726.201.211.129 to 26.201.211.15826.201.211.15930
15826.201.211.160/2726.201.211.161 to 26.201.211.19026.201.211.19130
15926.201.211.192/2726.201.211.193 to 26.201.211.22226.201.211.22330
16026.201.211.224/2726.201.211.225 to 26.201.211.25426.201.211.25530
16126.201.212.0/2726.201.212.1 to 26.201.212.3026.201.212.3130
16226.201.212.32/2726.201.212.33 to 26.201.212.6226.201.212.6330
16326.201.212.64/2726.201.212.65 to 26.201.212.9426.201.212.9530
16426.201.212.96/2726.201.212.97 to 26.201.212.12626.201.212.12730
16526.201.212.128/2726.201.212.129 to 26.201.212.15826.201.212.15930
16626.201.212.160/2726.201.212.161 to 26.201.212.19026.201.212.19130
16726.201.212.192/2726.201.212.193 to 26.201.212.22226.201.212.22330
16826.201.212.224/2726.201.212.225 to 26.201.212.25426.201.212.25530
16926.201.213.0/2726.201.213.1 to 26.201.213.3026.201.213.3130
17026.201.213.32/2726.201.213.33 to 26.201.213.6226.201.213.6330
17126.201.213.64/2726.201.213.65 to 26.201.213.9426.201.213.9530
17226.201.213.96/2726.201.213.97 to 26.201.213.12626.201.213.12730
17326.201.213.128/2726.201.213.129 to 26.201.213.15826.201.213.15930
17426.201.213.160/2726.201.213.161 to 26.201.213.19026.201.213.19130
17526.201.213.192/2726.201.213.193 to 26.201.213.22226.201.213.22330
17626.201.213.224/2726.201.213.225 to 26.201.213.25426.201.213.25530
17726.201.214.0/2726.201.214.1 to 26.201.214.3026.201.214.3130
17826.201.214.32/2726.201.214.33 to 26.201.214.6226.201.214.6330
17926.201.214.64/2726.201.214.65 to 26.201.214.9426.201.214.9530
18026.201.214.96/2726.201.214.97 to 26.201.214.12626.201.214.12730
18126.201.214.128/2726.201.214.129 to 26.201.214.15826.201.214.15930
18226.201.214.160/2726.201.214.161 to 26.201.214.19026.201.214.19130
18326.201.214.192/2726.201.214.193 to 26.201.214.22226.201.214.22330
18426.201.214.224/2726.201.214.225 to 26.201.214.25426.201.214.25530
18526.201.215.0/2726.201.215.1 to 26.201.215.3026.201.215.3130
18626.201.215.32/2726.201.215.33 to 26.201.215.6226.201.215.6330
18726.201.215.64/2726.201.215.65 to 26.201.215.9426.201.215.9530
18826.201.215.96/2726.201.215.97 to 26.201.215.12626.201.215.12730
18926.201.215.128/2726.201.215.129 to 26.201.215.15826.201.215.15930
19026.201.215.160/2726.201.215.161 to 26.201.215.19026.201.215.19130
19126.201.215.192/2726.201.215.193 to 26.201.215.22226.201.215.22330
19226.201.215.224/2726.201.215.225 to 26.201.215.25426.201.215.25530
19326.201.216.0/2726.201.216.1 to 26.201.216.3026.201.216.3130
19426.201.216.32/2726.201.216.33 to 26.201.216.6226.201.216.6330
19526.201.216.64/2726.201.216.65 to 26.201.216.9426.201.216.9530
19626.201.216.96/2726.201.216.97 to 26.201.216.12626.201.216.12730
19726.201.216.128/2726.201.216.129 to 26.201.216.15826.201.216.15930
19826.201.216.160/2726.201.216.161 to 26.201.216.19026.201.216.19130
19926.201.216.192/2726.201.216.193 to 26.201.216.22226.201.216.22330
20026.201.216.224/2726.201.216.225 to 26.201.216.25426.201.216.25530
20126.201.217.0/2726.201.217.1 to 26.201.217.3026.201.217.3130
20226.201.217.32/2726.201.217.33 to 26.201.217.6226.201.217.6330
20326.201.217.64/2726.201.217.65 to 26.201.217.9426.201.217.9530
20426.201.217.96/2726.201.217.97 to 26.201.217.12626.201.217.12730
20526.201.217.128/2726.201.217.129 to 26.201.217.15826.201.217.15930
20626.201.217.160/2726.201.217.161 to 26.201.217.19026.201.217.19130
20726.201.217.192/2726.201.217.193 to 26.201.217.22226.201.217.22330
20826.201.217.224/2726.201.217.225 to 26.201.217.25426.201.217.25530
20926.201.218.0/2726.201.218.1 to 26.201.218.3026.201.218.3130
21026.201.218.32/2726.201.218.33 to 26.201.218.6226.201.218.6330
21126.201.218.64/2726.201.218.65 to 26.201.218.9426.201.218.9530
21226.201.218.96/2726.201.218.97 to 26.201.218.12626.201.218.12730
21326.201.218.128/2726.201.218.129 to 26.201.218.15826.201.218.15930
21426.201.218.160/2726.201.218.161 to 26.201.218.19026.201.218.19130
21526.201.218.192/2726.201.218.193 to 26.201.218.22226.201.218.22330
21626.201.218.224/2726.201.218.225 to 26.201.218.25426.201.218.25530
21726.201.219.0/2726.201.219.1 to 26.201.219.3026.201.219.3130
21826.201.219.32/2726.201.219.33 to 26.201.219.6226.201.219.6330
21926.201.219.64/2726.201.219.65 to 26.201.219.9426.201.219.9530
22026.201.219.96/2726.201.219.97 to 26.201.219.12626.201.219.12730
22126.201.219.128/2726.201.219.129 to 26.201.219.15826.201.219.15930
22226.201.219.160/2726.201.219.161 to 26.201.219.19026.201.219.19130
22326.201.219.192/2726.201.219.193 to 26.201.219.22226.201.219.22330
22426.201.219.224/2726.201.219.225 to 26.201.219.25426.201.219.25530
22526.201.220.0/2726.201.220.1 to 26.201.220.3026.201.220.3130
22626.201.220.32/2726.201.220.33 to 26.201.220.6226.201.220.6330
22726.201.220.64/2726.201.220.65 to 26.201.220.9426.201.220.9530
22826.201.220.96/2726.201.220.97 to 26.201.220.12626.201.220.12730
22926.201.220.128/2726.201.220.129 to 26.201.220.15826.201.220.15930
23026.201.220.160/2726.201.220.161 to 26.201.220.19026.201.220.19130
23126.201.220.192/2726.201.220.193 to 26.201.220.22226.201.220.22330
23226.201.220.224/2726.201.220.225 to 26.201.220.25426.201.220.25530
23326.201.221.0/2726.201.221.1 to 26.201.221.3026.201.221.3130
23426.201.221.32/2726.201.221.33 to 26.201.221.6226.201.221.6330
23526.201.221.64/2726.201.221.65 to 26.201.221.9426.201.221.9530
23626.201.221.96/2726.201.221.97 to 26.201.221.12626.201.221.12730
23726.201.221.128/2726.201.221.129 to 26.201.221.15826.201.221.15930
23826.201.221.160/2726.201.221.161 to 26.201.221.19026.201.221.19130
23926.201.221.192/2726.201.221.193 to 26.201.221.22226.201.221.22330
24026.201.221.224/2726.201.221.225 to 26.201.221.25426.201.221.25530
24126.201.222.0/2726.201.222.1 to 26.201.222.3026.201.222.3130
24226.201.222.32/2726.201.222.33 to 26.201.222.6226.201.222.6330
24326.201.222.64/2726.201.222.65 to 26.201.222.9426.201.222.9530
24426.201.222.96/2726.201.222.97 to 26.201.222.12626.201.222.12730
24526.201.222.128/2726.201.222.129 to 26.201.222.15826.201.222.15930
24626.201.222.160/2726.201.222.161 to 26.201.222.19026.201.222.19130
24726.201.222.192/2726.201.222.193 to 26.201.222.22226.201.222.22330
24826.201.222.224/2726.201.222.225 to 26.201.222.25426.201.222.25530
24926.201.223.0/2726.201.223.1 to 26.201.223.3026.201.223.3130
25026.201.223.32/2726.201.223.33 to 26.201.223.6226.201.223.6330
25126.201.223.64/2726.201.223.65 to 26.201.223.9426.201.223.9530
25226.201.223.96/2726.201.223.97 to 26.201.223.12626.201.223.12730
25326.201.223.128/2726.201.223.129 to 26.201.223.15826.201.223.15930
25426.201.223.160/2726.201.223.161 to 26.201.223.19026.201.223.19130
25526.201.223.192/2726.201.223.193 to 26.201.223.22226.201.223.22330
25626.201.223.224/2726.201.223.225 to 26.201.223.25426.201.223.25530

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.