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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.

Network65.192.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
65.192.0.0
Broadcast address
65.255.255.255
First usable
65.192.0.1
Last usable
65.255.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 41C00000 · Integer 1103101952 to 1107296255
Reverse DNS zones
192.65.in-addr.arpa
193.65.in-addr.arpa
194.65.in-addr.arpa
195.65.in-addr.arpa
196.65.in-addr.arpa
197.65.in-addr.arpa
198.65.in-addr.arpa
199.65.in-addr.arpa
200.65.in-addr.arpa
201.65.in-addr.arpa
202.65.in-addr.arpa
203.65.in-addr.arpa
204.65.in-addr.arpa
205.65.in-addr.arpa
206.65.in-addr.arpa
207.65.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000001.11000000.00000000.0000000065.192.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network01000001.11000000.00000000.0000000065.192.0.0
Broadcast01000001.11111111.11111111.1111111165.255.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

65.192.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
165.192.0.0/1865.192.0.1 to 65.192.63.25465.192.63.25516,382
265.192.64.0/1865.192.64.1 to 65.192.127.25465.192.127.25516,382
365.192.128.0/1865.192.128.1 to 65.192.191.25465.192.191.25516,382
465.192.192.0/1865.192.192.1 to 65.192.255.25465.192.255.25516,382
565.193.0.0/1865.193.0.1 to 65.193.63.25465.193.63.25516,382
665.193.64.0/1865.193.64.1 to 65.193.127.25465.193.127.25516,382
765.193.128.0/1865.193.128.1 to 65.193.191.25465.193.191.25516,382
865.193.192.0/1865.193.192.1 to 65.193.255.25465.193.255.25516,382
965.194.0.0/1865.194.0.1 to 65.194.63.25465.194.63.25516,382
1065.194.64.0/1865.194.64.1 to 65.194.127.25465.194.127.25516,382
1165.194.128.0/1865.194.128.1 to 65.194.191.25465.194.191.25516,382
1265.194.192.0/1865.194.192.1 to 65.194.255.25465.194.255.25516,382
1365.195.0.0/1865.195.0.1 to 65.195.63.25465.195.63.25516,382
1465.195.64.0/1865.195.64.1 to 65.195.127.25465.195.127.25516,382
1565.195.128.0/1865.195.128.1 to 65.195.191.25465.195.191.25516,382
1665.195.192.0/1865.195.192.1 to 65.195.255.25465.195.255.25516,382
1765.196.0.0/1865.196.0.1 to 65.196.63.25465.196.63.25516,382
1865.196.64.0/1865.196.64.1 to 65.196.127.25465.196.127.25516,382
1965.196.128.0/1865.196.128.1 to 65.196.191.25465.196.191.25516,382
2065.196.192.0/1865.196.192.1 to 65.196.255.25465.196.255.25516,382
2165.197.0.0/1865.197.0.1 to 65.197.63.25465.197.63.25516,382
2265.197.64.0/1865.197.64.1 to 65.197.127.25465.197.127.25516,382
2365.197.128.0/1865.197.128.1 to 65.197.191.25465.197.191.25516,382
2465.197.192.0/1865.197.192.1 to 65.197.255.25465.197.255.25516,382
2565.198.0.0/1865.198.0.1 to 65.198.63.25465.198.63.25516,382
2665.198.64.0/1865.198.64.1 to 65.198.127.25465.198.127.25516,382
2765.198.128.0/1865.198.128.1 to 65.198.191.25465.198.191.25516,382
2865.198.192.0/1865.198.192.1 to 65.198.255.25465.198.255.25516,382
2965.199.0.0/1865.199.0.1 to 65.199.63.25465.199.63.25516,382
3065.199.64.0/1865.199.64.1 to 65.199.127.25465.199.127.25516,382
3165.199.128.0/1865.199.128.1 to 65.199.191.25465.199.191.25516,382
3265.199.192.0/1865.199.192.1 to 65.199.255.25465.199.255.25516,382
3365.200.0.0/1865.200.0.1 to 65.200.63.25465.200.63.25516,382
3465.200.64.0/1865.200.64.1 to 65.200.127.25465.200.127.25516,382
3565.200.128.0/1865.200.128.1 to 65.200.191.25465.200.191.25516,382
3665.200.192.0/1865.200.192.1 to 65.200.255.25465.200.255.25516,382
3765.201.0.0/1865.201.0.1 to 65.201.63.25465.201.63.25516,382
3865.201.64.0/1865.201.64.1 to 65.201.127.25465.201.127.25516,382
3965.201.128.0/1865.201.128.1 to 65.201.191.25465.201.191.25516,382
4065.201.192.0/1865.201.192.1 to 65.201.255.25465.201.255.25516,382
4165.202.0.0/1865.202.0.1 to 65.202.63.25465.202.63.25516,382
4265.202.64.0/1865.202.64.1 to 65.202.127.25465.202.127.25516,382
4365.202.128.0/1865.202.128.1 to 65.202.191.25465.202.191.25516,382
4465.202.192.0/1865.202.192.1 to 65.202.255.25465.202.255.25516,382
4565.203.0.0/1865.203.0.1 to 65.203.63.25465.203.63.25516,382
4665.203.64.0/1865.203.64.1 to 65.203.127.25465.203.127.25516,382
4765.203.128.0/1865.203.128.1 to 65.203.191.25465.203.191.25516,382
4865.203.192.0/1865.203.192.1 to 65.203.255.25465.203.255.25516,382
4965.204.0.0/1865.204.0.1 to 65.204.63.25465.204.63.25516,382
5065.204.64.0/1865.204.64.1 to 65.204.127.25465.204.127.25516,382
5165.204.128.0/1865.204.128.1 to 65.204.191.25465.204.191.25516,382
5265.204.192.0/1865.204.192.1 to 65.204.255.25465.204.255.25516,382
5365.205.0.0/1865.205.0.1 to 65.205.63.25465.205.63.25516,382
5465.205.64.0/1865.205.64.1 to 65.205.127.25465.205.127.25516,382
5565.205.128.0/1865.205.128.1 to 65.205.191.25465.205.191.25516,382
5665.205.192.0/1865.205.192.1 to 65.205.255.25465.205.255.25516,382
5765.206.0.0/1865.206.0.1 to 65.206.63.25465.206.63.25516,382
5865.206.64.0/1865.206.64.1 to 65.206.127.25465.206.127.25516,382
5965.206.128.0/1865.206.128.1 to 65.206.191.25465.206.191.25516,382
6065.206.192.0/1865.206.192.1 to 65.206.255.25465.206.255.25516,382
6165.207.0.0/1865.207.0.1 to 65.207.63.25465.207.63.25516,382
6265.207.64.0/1865.207.64.1 to 65.207.127.25465.207.127.25516,382
6365.207.128.0/1865.207.128.1 to 65.207.191.25465.207.191.25516,382
6465.207.192.0/1865.207.192.1 to 65.207.255.25465.207.255.25516,382
6565.208.0.0/1865.208.0.1 to 65.208.63.25465.208.63.25516,382
6665.208.64.0/1865.208.64.1 to 65.208.127.25465.208.127.25516,382
6765.208.128.0/1865.208.128.1 to 65.208.191.25465.208.191.25516,382
6865.208.192.0/1865.208.192.1 to 65.208.255.25465.208.255.25516,382
6965.209.0.0/1865.209.0.1 to 65.209.63.25465.209.63.25516,382
7065.209.64.0/1865.209.64.1 to 65.209.127.25465.209.127.25516,382
7165.209.128.0/1865.209.128.1 to 65.209.191.25465.209.191.25516,382
7265.209.192.0/1865.209.192.1 to 65.209.255.25465.209.255.25516,382
7365.210.0.0/1865.210.0.1 to 65.210.63.25465.210.63.25516,382
7465.210.64.0/1865.210.64.1 to 65.210.127.25465.210.127.25516,382
7565.210.128.0/1865.210.128.1 to 65.210.191.25465.210.191.25516,382
7665.210.192.0/1865.210.192.1 to 65.210.255.25465.210.255.25516,382
7765.211.0.0/1865.211.0.1 to 65.211.63.25465.211.63.25516,382
7865.211.64.0/1865.211.64.1 to 65.211.127.25465.211.127.25516,382
7965.211.128.0/1865.211.128.1 to 65.211.191.25465.211.191.25516,382
8065.211.192.0/1865.211.192.1 to 65.211.255.25465.211.255.25516,382
8165.212.0.0/1865.212.0.1 to 65.212.63.25465.212.63.25516,382
8265.212.64.0/1865.212.64.1 to 65.212.127.25465.212.127.25516,382
8365.212.128.0/1865.212.128.1 to 65.212.191.25465.212.191.25516,382
8465.212.192.0/1865.212.192.1 to 65.212.255.25465.212.255.25516,382
8565.213.0.0/1865.213.0.1 to 65.213.63.25465.213.63.25516,382
8665.213.64.0/1865.213.64.1 to 65.213.127.25465.213.127.25516,382
8765.213.128.0/1865.213.128.1 to 65.213.191.25465.213.191.25516,382
8865.213.192.0/1865.213.192.1 to 65.213.255.25465.213.255.25516,382
8965.214.0.0/1865.214.0.1 to 65.214.63.25465.214.63.25516,382
9065.214.64.0/1865.214.64.1 to 65.214.127.25465.214.127.25516,382
9165.214.128.0/1865.214.128.1 to 65.214.191.25465.214.191.25516,382
9265.214.192.0/1865.214.192.1 to 65.214.255.25465.214.255.25516,382
9365.215.0.0/1865.215.0.1 to 65.215.63.25465.215.63.25516,382
9465.215.64.0/1865.215.64.1 to 65.215.127.25465.215.127.25516,382
9565.215.128.0/1865.215.128.1 to 65.215.191.25465.215.191.25516,382
9665.215.192.0/1865.215.192.1 to 65.215.255.25465.215.255.25516,382
9765.216.0.0/1865.216.0.1 to 65.216.63.25465.216.63.25516,382
9865.216.64.0/1865.216.64.1 to 65.216.127.25465.216.127.25516,382
9965.216.128.0/1865.216.128.1 to 65.216.191.25465.216.191.25516,382
10065.216.192.0/1865.216.192.1 to 65.216.255.25465.216.255.25516,382
10165.217.0.0/1865.217.0.1 to 65.217.63.25465.217.63.25516,382
10265.217.64.0/1865.217.64.1 to 65.217.127.25465.217.127.25516,382
10365.217.128.0/1865.217.128.1 to 65.217.191.25465.217.191.25516,382
10465.217.192.0/1865.217.192.1 to 65.217.255.25465.217.255.25516,382
10565.218.0.0/1865.218.0.1 to 65.218.63.25465.218.63.25516,382
10665.218.64.0/1865.218.64.1 to 65.218.127.25465.218.127.25516,382
10765.218.128.0/1865.218.128.1 to 65.218.191.25465.218.191.25516,382
10865.218.192.0/1865.218.192.1 to 65.218.255.25465.218.255.25516,382
10965.219.0.0/1865.219.0.1 to 65.219.63.25465.219.63.25516,382
11065.219.64.0/1865.219.64.1 to 65.219.127.25465.219.127.25516,382
11165.219.128.0/1865.219.128.1 to 65.219.191.25465.219.191.25516,382
11265.219.192.0/1865.219.192.1 to 65.219.255.25465.219.255.25516,382
11365.220.0.0/1865.220.0.1 to 65.220.63.25465.220.63.25516,382
11465.220.64.0/1865.220.64.1 to 65.220.127.25465.220.127.25516,382
11565.220.128.0/1865.220.128.1 to 65.220.191.25465.220.191.25516,382
11665.220.192.0/1865.220.192.1 to 65.220.255.25465.220.255.25516,382
11765.221.0.0/1865.221.0.1 to 65.221.63.25465.221.63.25516,382
11865.221.64.0/1865.221.64.1 to 65.221.127.25465.221.127.25516,382
11965.221.128.0/1865.221.128.1 to 65.221.191.25465.221.191.25516,382
12065.221.192.0/1865.221.192.1 to 65.221.255.25465.221.255.25516,382
12165.222.0.0/1865.222.0.1 to 65.222.63.25465.222.63.25516,382
12265.222.64.0/1865.222.64.1 to 65.222.127.25465.222.127.25516,382
12365.222.128.0/1865.222.128.1 to 65.222.191.25465.222.191.25516,382
12465.222.192.0/1865.222.192.1 to 65.222.255.25465.222.255.25516,382
12565.223.0.0/1865.223.0.1 to 65.223.63.25465.223.63.25516,382
12665.223.64.0/1865.223.64.1 to 65.223.127.25465.223.127.25516,382
12765.223.128.0/1865.223.128.1 to 65.223.191.25465.223.191.25516,382
12865.223.192.0/1865.223.192.1 to 65.223.255.25465.223.255.25516,382
12965.224.0.0/1865.224.0.1 to 65.224.63.25465.224.63.25516,382
13065.224.64.0/1865.224.64.1 to 65.224.127.25465.224.127.25516,382
13165.224.128.0/1865.224.128.1 to 65.224.191.25465.224.191.25516,382
13265.224.192.0/1865.224.192.1 to 65.224.255.25465.224.255.25516,382
13365.225.0.0/1865.225.0.1 to 65.225.63.25465.225.63.25516,382
13465.225.64.0/1865.225.64.1 to 65.225.127.25465.225.127.25516,382
13565.225.128.0/1865.225.128.1 to 65.225.191.25465.225.191.25516,382
13665.225.192.0/1865.225.192.1 to 65.225.255.25465.225.255.25516,382
13765.226.0.0/1865.226.0.1 to 65.226.63.25465.226.63.25516,382
13865.226.64.0/1865.226.64.1 to 65.226.127.25465.226.127.25516,382
13965.226.128.0/1865.226.128.1 to 65.226.191.25465.226.191.25516,382
14065.226.192.0/1865.226.192.1 to 65.226.255.25465.226.255.25516,382
14165.227.0.0/1865.227.0.1 to 65.227.63.25465.227.63.25516,382
14265.227.64.0/1865.227.64.1 to 65.227.127.25465.227.127.25516,382
14365.227.128.0/1865.227.128.1 to 65.227.191.25465.227.191.25516,382
14465.227.192.0/1865.227.192.1 to 65.227.255.25465.227.255.25516,382
14565.228.0.0/1865.228.0.1 to 65.228.63.25465.228.63.25516,382
14665.228.64.0/1865.228.64.1 to 65.228.127.25465.228.127.25516,382
14765.228.128.0/1865.228.128.1 to 65.228.191.25465.228.191.25516,382
14865.228.192.0/1865.228.192.1 to 65.228.255.25465.228.255.25516,382
14965.229.0.0/1865.229.0.1 to 65.229.63.25465.229.63.25516,382
15065.229.64.0/1865.229.64.1 to 65.229.127.25465.229.127.25516,382
15165.229.128.0/1865.229.128.1 to 65.229.191.25465.229.191.25516,382
15265.229.192.0/1865.229.192.1 to 65.229.255.25465.229.255.25516,382
15365.230.0.0/1865.230.0.1 to 65.230.63.25465.230.63.25516,382
15465.230.64.0/1865.230.64.1 to 65.230.127.25465.230.127.25516,382
15565.230.128.0/1865.230.128.1 to 65.230.191.25465.230.191.25516,382
15665.230.192.0/1865.230.192.1 to 65.230.255.25465.230.255.25516,382
15765.231.0.0/1865.231.0.1 to 65.231.63.25465.231.63.25516,382
15865.231.64.0/1865.231.64.1 to 65.231.127.25465.231.127.25516,382
15965.231.128.0/1865.231.128.1 to 65.231.191.25465.231.191.25516,382
16065.231.192.0/1865.231.192.1 to 65.231.255.25465.231.255.25516,382
16165.232.0.0/1865.232.0.1 to 65.232.63.25465.232.63.25516,382
16265.232.64.0/1865.232.64.1 to 65.232.127.25465.232.127.25516,382
16365.232.128.0/1865.232.128.1 to 65.232.191.25465.232.191.25516,382
16465.232.192.0/1865.232.192.1 to 65.232.255.25465.232.255.25516,382
16565.233.0.0/1865.233.0.1 to 65.233.63.25465.233.63.25516,382
16665.233.64.0/1865.233.64.1 to 65.233.127.25465.233.127.25516,382
16765.233.128.0/1865.233.128.1 to 65.233.191.25465.233.191.25516,382
16865.233.192.0/1865.233.192.1 to 65.233.255.25465.233.255.25516,382
16965.234.0.0/1865.234.0.1 to 65.234.63.25465.234.63.25516,382
17065.234.64.0/1865.234.64.1 to 65.234.127.25465.234.127.25516,382
17165.234.128.0/1865.234.128.1 to 65.234.191.25465.234.191.25516,382
17265.234.192.0/1865.234.192.1 to 65.234.255.25465.234.255.25516,382
17365.235.0.0/1865.235.0.1 to 65.235.63.25465.235.63.25516,382
17465.235.64.0/1865.235.64.1 to 65.235.127.25465.235.127.25516,382
17565.235.128.0/1865.235.128.1 to 65.235.191.25465.235.191.25516,382
17665.235.192.0/1865.235.192.1 to 65.235.255.25465.235.255.25516,382
17765.236.0.0/1865.236.0.1 to 65.236.63.25465.236.63.25516,382
17865.236.64.0/1865.236.64.1 to 65.236.127.25465.236.127.25516,382
17965.236.128.0/1865.236.128.1 to 65.236.191.25465.236.191.25516,382
18065.236.192.0/1865.236.192.1 to 65.236.255.25465.236.255.25516,382
18165.237.0.0/1865.237.0.1 to 65.237.63.25465.237.63.25516,382
18265.237.64.0/1865.237.64.1 to 65.237.127.25465.237.127.25516,382
18365.237.128.0/1865.237.128.1 to 65.237.191.25465.237.191.25516,382
18465.237.192.0/1865.237.192.1 to 65.237.255.25465.237.255.25516,382
18565.238.0.0/1865.238.0.1 to 65.238.63.25465.238.63.25516,382
18665.238.64.0/1865.238.64.1 to 65.238.127.25465.238.127.25516,382
18765.238.128.0/1865.238.128.1 to 65.238.191.25465.238.191.25516,382
18865.238.192.0/1865.238.192.1 to 65.238.255.25465.238.255.25516,382
18965.239.0.0/1865.239.0.1 to 65.239.63.25465.239.63.25516,382
19065.239.64.0/1865.239.64.1 to 65.239.127.25465.239.127.25516,382
19165.239.128.0/1865.239.128.1 to 65.239.191.25465.239.191.25516,382
19265.239.192.0/1865.239.192.1 to 65.239.255.25465.239.255.25516,382
19365.240.0.0/1865.240.0.1 to 65.240.63.25465.240.63.25516,382
19465.240.64.0/1865.240.64.1 to 65.240.127.25465.240.127.25516,382
19565.240.128.0/1865.240.128.1 to 65.240.191.25465.240.191.25516,382
19665.240.192.0/1865.240.192.1 to 65.240.255.25465.240.255.25516,382
19765.241.0.0/1865.241.0.1 to 65.241.63.25465.241.63.25516,382
19865.241.64.0/1865.241.64.1 to 65.241.127.25465.241.127.25516,382
19965.241.128.0/1865.241.128.1 to 65.241.191.25465.241.191.25516,382
20065.241.192.0/1865.241.192.1 to 65.241.255.25465.241.255.25516,382
20165.242.0.0/1865.242.0.1 to 65.242.63.25465.242.63.25516,382
20265.242.64.0/1865.242.64.1 to 65.242.127.25465.242.127.25516,382
20365.242.128.0/1865.242.128.1 to 65.242.191.25465.242.191.25516,382
20465.242.192.0/1865.242.192.1 to 65.242.255.25465.242.255.25516,382
20565.243.0.0/1865.243.0.1 to 65.243.63.25465.243.63.25516,382
20665.243.64.0/1865.243.64.1 to 65.243.127.25465.243.127.25516,382
20765.243.128.0/1865.243.128.1 to 65.243.191.25465.243.191.25516,382
20865.243.192.0/1865.243.192.1 to 65.243.255.25465.243.255.25516,382
20965.244.0.0/1865.244.0.1 to 65.244.63.25465.244.63.25516,382
21065.244.64.0/1865.244.64.1 to 65.244.127.25465.244.127.25516,382
21165.244.128.0/1865.244.128.1 to 65.244.191.25465.244.191.25516,382
21265.244.192.0/1865.244.192.1 to 65.244.255.25465.244.255.25516,382
21365.245.0.0/1865.245.0.1 to 65.245.63.25465.245.63.25516,382
21465.245.64.0/1865.245.64.1 to 65.245.127.25465.245.127.25516,382
21565.245.128.0/1865.245.128.1 to 65.245.191.25465.245.191.25516,382
21665.245.192.0/1865.245.192.1 to 65.245.255.25465.245.255.25516,382
21765.246.0.0/1865.246.0.1 to 65.246.63.25465.246.63.25516,382
21865.246.64.0/1865.246.64.1 to 65.246.127.25465.246.127.25516,382
21965.246.128.0/1865.246.128.1 to 65.246.191.25465.246.191.25516,382
22065.246.192.0/1865.246.192.1 to 65.246.255.25465.246.255.25516,382
22165.247.0.0/1865.247.0.1 to 65.247.63.25465.247.63.25516,382
22265.247.64.0/1865.247.64.1 to 65.247.127.25465.247.127.25516,382
22365.247.128.0/1865.247.128.1 to 65.247.191.25465.247.191.25516,382
22465.247.192.0/1865.247.192.1 to 65.247.255.25465.247.255.25516,382
22565.248.0.0/1865.248.0.1 to 65.248.63.25465.248.63.25516,382
22665.248.64.0/1865.248.64.1 to 65.248.127.25465.248.127.25516,382
22765.248.128.0/1865.248.128.1 to 65.248.191.25465.248.191.25516,382
22865.248.192.0/1865.248.192.1 to 65.248.255.25465.248.255.25516,382
22965.249.0.0/1865.249.0.1 to 65.249.63.25465.249.63.25516,382
23065.249.64.0/1865.249.64.1 to 65.249.127.25465.249.127.25516,382
23165.249.128.0/1865.249.128.1 to 65.249.191.25465.249.191.25516,382
23265.249.192.0/1865.249.192.1 to 65.249.255.25465.249.255.25516,382
23365.250.0.0/1865.250.0.1 to 65.250.63.25465.250.63.25516,382
23465.250.64.0/1865.250.64.1 to 65.250.127.25465.250.127.25516,382
23565.250.128.0/1865.250.128.1 to 65.250.191.25465.250.191.25516,382
23665.250.192.0/1865.250.192.1 to 65.250.255.25465.250.255.25516,382
23765.251.0.0/1865.251.0.1 to 65.251.63.25465.251.63.25516,382
23865.251.64.0/1865.251.64.1 to 65.251.127.25465.251.127.25516,382
23965.251.128.0/1865.251.128.1 to 65.251.191.25465.251.191.25516,382
24065.251.192.0/1865.251.192.1 to 65.251.255.25465.251.255.25516,382
24165.252.0.0/1865.252.0.1 to 65.252.63.25465.252.63.25516,382
24265.252.64.0/1865.252.64.1 to 65.252.127.25465.252.127.25516,382
24365.252.128.0/1865.252.128.1 to 65.252.191.25465.252.191.25516,382
24465.252.192.0/1865.252.192.1 to 65.252.255.25465.252.255.25516,382
24565.253.0.0/1865.253.0.1 to 65.253.63.25465.253.63.25516,382
24665.253.64.0/1865.253.64.1 to 65.253.127.25465.253.127.25516,382
24765.253.128.0/1865.253.128.1 to 65.253.191.25465.253.191.25516,382
24865.253.192.0/1865.253.192.1 to 65.253.255.25465.253.255.25516,382
24965.254.0.0/1865.254.0.1 to 65.254.63.25465.254.63.25516,382
25065.254.64.0/1865.254.64.1 to 65.254.127.25465.254.127.25516,382
25165.254.128.0/1865.254.128.1 to 65.254.191.25465.254.191.25516,382
25265.254.192.0/1865.254.192.1 to 65.254.255.25465.254.255.25516,382
25365.255.0.0/1865.255.0.1 to 65.255.63.25465.255.63.25516,382
25465.255.64.0/1865.255.64.1 to 65.255.127.25465.255.127.25516,382
25565.255.128.0/1865.255.128.1 to 65.255.191.25465.255.191.25516,382
25665.255.192.0/1865.255.192.1 to 65.255.255.25465.255.255.25516,382

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.