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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.

Network74.64.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
74.64.0.0
Broadcast address
74.79.255.255
First usable
74.64.0.1
Last usable
74.79.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 4A400000 · Integer 1245708288 to 1246756863
Reverse DNS zones
64.74.in-addr.arpa
65.74.in-addr.arpa
66.74.in-addr.arpa
67.74.in-addr.arpa
68.74.in-addr.arpa
69.74.in-addr.arpa
70.74.in-addr.arpa
71.74.in-addr.arpa
72.74.in-addr.arpa
73.74.in-addr.arpa
74.74.in-addr.arpa
75.74.in-addr.arpa
76.74.in-addr.arpa
77.74.in-addr.arpa
78.74.in-addr.arpa
79.74.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001010.01000000.00000000.0000000074.64.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01001010.01000000.00000000.0000000074.64.0.0
Broadcast01001010.01001111.11111111.1111111174.79.255.255
Split into smaller subnets/21
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

74.64.0.0/12 makes 512 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
174.64.0.0/2174.64.0.1 to 74.64.7.25474.64.7.2552,046
274.64.8.0/2174.64.8.1 to 74.64.15.25474.64.15.2552,046
374.64.16.0/2174.64.16.1 to 74.64.23.25474.64.23.2552,046
474.64.24.0/2174.64.24.1 to 74.64.31.25474.64.31.2552,046
574.64.32.0/2174.64.32.1 to 74.64.39.25474.64.39.2552,046
674.64.40.0/2174.64.40.1 to 74.64.47.25474.64.47.2552,046
774.64.48.0/2174.64.48.1 to 74.64.55.25474.64.55.2552,046
874.64.56.0/2174.64.56.1 to 74.64.63.25474.64.63.2552,046
974.64.64.0/2174.64.64.1 to 74.64.71.25474.64.71.2552,046
1074.64.72.0/2174.64.72.1 to 74.64.79.25474.64.79.2552,046
1174.64.80.0/2174.64.80.1 to 74.64.87.25474.64.87.2552,046
1274.64.88.0/2174.64.88.1 to 74.64.95.25474.64.95.2552,046
1374.64.96.0/2174.64.96.1 to 74.64.103.25474.64.103.2552,046
1474.64.104.0/2174.64.104.1 to 74.64.111.25474.64.111.2552,046
1574.64.112.0/2174.64.112.1 to 74.64.119.25474.64.119.2552,046
1674.64.120.0/2174.64.120.1 to 74.64.127.25474.64.127.2552,046
1774.64.128.0/2174.64.128.1 to 74.64.135.25474.64.135.2552,046
1874.64.136.0/2174.64.136.1 to 74.64.143.25474.64.143.2552,046
1974.64.144.0/2174.64.144.1 to 74.64.151.25474.64.151.2552,046
2074.64.152.0/2174.64.152.1 to 74.64.159.25474.64.159.2552,046
2174.64.160.0/2174.64.160.1 to 74.64.167.25474.64.167.2552,046
2274.64.168.0/2174.64.168.1 to 74.64.175.25474.64.175.2552,046
2374.64.176.0/2174.64.176.1 to 74.64.183.25474.64.183.2552,046
2474.64.184.0/2174.64.184.1 to 74.64.191.25474.64.191.2552,046
2574.64.192.0/2174.64.192.1 to 74.64.199.25474.64.199.2552,046
2674.64.200.0/2174.64.200.1 to 74.64.207.25474.64.207.2552,046
2774.64.208.0/2174.64.208.1 to 74.64.215.25474.64.215.2552,046
2874.64.216.0/2174.64.216.1 to 74.64.223.25474.64.223.2552,046
2974.64.224.0/2174.64.224.1 to 74.64.231.25474.64.231.2552,046
3074.64.232.0/2174.64.232.1 to 74.64.239.25474.64.239.2552,046
3174.64.240.0/2174.64.240.1 to 74.64.247.25474.64.247.2552,046
3274.64.248.0/2174.64.248.1 to 74.64.255.25474.64.255.2552,046
3374.65.0.0/2174.65.0.1 to 74.65.7.25474.65.7.2552,046
3474.65.8.0/2174.65.8.1 to 74.65.15.25474.65.15.2552,046
3574.65.16.0/2174.65.16.1 to 74.65.23.25474.65.23.2552,046
3674.65.24.0/2174.65.24.1 to 74.65.31.25474.65.31.2552,046
3774.65.32.0/2174.65.32.1 to 74.65.39.25474.65.39.2552,046
3874.65.40.0/2174.65.40.1 to 74.65.47.25474.65.47.2552,046
3974.65.48.0/2174.65.48.1 to 74.65.55.25474.65.55.2552,046
4074.65.56.0/2174.65.56.1 to 74.65.63.25474.65.63.2552,046
4174.65.64.0/2174.65.64.1 to 74.65.71.25474.65.71.2552,046
4274.65.72.0/2174.65.72.1 to 74.65.79.25474.65.79.2552,046
4374.65.80.0/2174.65.80.1 to 74.65.87.25474.65.87.2552,046
4474.65.88.0/2174.65.88.1 to 74.65.95.25474.65.95.2552,046
4574.65.96.0/2174.65.96.1 to 74.65.103.25474.65.103.2552,046
4674.65.104.0/2174.65.104.1 to 74.65.111.25474.65.111.2552,046
4774.65.112.0/2174.65.112.1 to 74.65.119.25474.65.119.2552,046
4874.65.120.0/2174.65.120.1 to 74.65.127.25474.65.127.2552,046
4974.65.128.0/2174.65.128.1 to 74.65.135.25474.65.135.2552,046
5074.65.136.0/2174.65.136.1 to 74.65.143.25474.65.143.2552,046
5174.65.144.0/2174.65.144.1 to 74.65.151.25474.65.151.2552,046
5274.65.152.0/2174.65.152.1 to 74.65.159.25474.65.159.2552,046
5374.65.160.0/2174.65.160.1 to 74.65.167.25474.65.167.2552,046
5474.65.168.0/2174.65.168.1 to 74.65.175.25474.65.175.2552,046
5574.65.176.0/2174.65.176.1 to 74.65.183.25474.65.183.2552,046
5674.65.184.0/2174.65.184.1 to 74.65.191.25474.65.191.2552,046
5774.65.192.0/2174.65.192.1 to 74.65.199.25474.65.199.2552,046
5874.65.200.0/2174.65.200.1 to 74.65.207.25474.65.207.2552,046
5974.65.208.0/2174.65.208.1 to 74.65.215.25474.65.215.2552,046
6074.65.216.0/2174.65.216.1 to 74.65.223.25474.65.223.2552,046
6174.65.224.0/2174.65.224.1 to 74.65.231.25474.65.231.2552,046
6274.65.232.0/2174.65.232.1 to 74.65.239.25474.65.239.2552,046
6374.65.240.0/2174.65.240.1 to 74.65.247.25474.65.247.2552,046
6474.65.248.0/2174.65.248.1 to 74.65.255.25474.65.255.2552,046
6574.66.0.0/2174.66.0.1 to 74.66.7.25474.66.7.2552,046
6674.66.8.0/2174.66.8.1 to 74.66.15.25474.66.15.2552,046
6774.66.16.0/2174.66.16.1 to 74.66.23.25474.66.23.2552,046
6874.66.24.0/2174.66.24.1 to 74.66.31.25474.66.31.2552,046
6974.66.32.0/2174.66.32.1 to 74.66.39.25474.66.39.2552,046
7074.66.40.0/2174.66.40.1 to 74.66.47.25474.66.47.2552,046
7174.66.48.0/2174.66.48.1 to 74.66.55.25474.66.55.2552,046
7274.66.56.0/2174.66.56.1 to 74.66.63.25474.66.63.2552,046
7374.66.64.0/2174.66.64.1 to 74.66.71.25474.66.71.2552,046
7474.66.72.0/2174.66.72.1 to 74.66.79.25474.66.79.2552,046
7574.66.80.0/2174.66.80.1 to 74.66.87.25474.66.87.2552,046
7674.66.88.0/2174.66.88.1 to 74.66.95.25474.66.95.2552,046
7774.66.96.0/2174.66.96.1 to 74.66.103.25474.66.103.2552,046
7874.66.104.0/2174.66.104.1 to 74.66.111.25474.66.111.2552,046
7974.66.112.0/2174.66.112.1 to 74.66.119.25474.66.119.2552,046
8074.66.120.0/2174.66.120.1 to 74.66.127.25474.66.127.2552,046
8174.66.128.0/2174.66.128.1 to 74.66.135.25474.66.135.2552,046
8274.66.136.0/2174.66.136.1 to 74.66.143.25474.66.143.2552,046
8374.66.144.0/2174.66.144.1 to 74.66.151.25474.66.151.2552,046
8474.66.152.0/2174.66.152.1 to 74.66.159.25474.66.159.2552,046
8574.66.160.0/2174.66.160.1 to 74.66.167.25474.66.167.2552,046
8674.66.168.0/2174.66.168.1 to 74.66.175.25474.66.175.2552,046
8774.66.176.0/2174.66.176.1 to 74.66.183.25474.66.183.2552,046
8874.66.184.0/2174.66.184.1 to 74.66.191.25474.66.191.2552,046
8974.66.192.0/2174.66.192.1 to 74.66.199.25474.66.199.2552,046
9074.66.200.0/2174.66.200.1 to 74.66.207.25474.66.207.2552,046
9174.66.208.0/2174.66.208.1 to 74.66.215.25474.66.215.2552,046
9274.66.216.0/2174.66.216.1 to 74.66.223.25474.66.223.2552,046
9374.66.224.0/2174.66.224.1 to 74.66.231.25474.66.231.2552,046
9474.66.232.0/2174.66.232.1 to 74.66.239.25474.66.239.2552,046
9574.66.240.0/2174.66.240.1 to 74.66.247.25474.66.247.2552,046
9674.66.248.0/2174.66.248.1 to 74.66.255.25474.66.255.2552,046
9774.67.0.0/2174.67.0.1 to 74.67.7.25474.67.7.2552,046
9874.67.8.0/2174.67.8.1 to 74.67.15.25474.67.15.2552,046
9974.67.16.0/2174.67.16.1 to 74.67.23.25474.67.23.2552,046
10074.67.24.0/2174.67.24.1 to 74.67.31.25474.67.31.2552,046
10174.67.32.0/2174.67.32.1 to 74.67.39.25474.67.39.2552,046
10274.67.40.0/2174.67.40.1 to 74.67.47.25474.67.47.2552,046
10374.67.48.0/2174.67.48.1 to 74.67.55.25474.67.55.2552,046
10474.67.56.0/2174.67.56.1 to 74.67.63.25474.67.63.2552,046
10574.67.64.0/2174.67.64.1 to 74.67.71.25474.67.71.2552,046
10674.67.72.0/2174.67.72.1 to 74.67.79.25474.67.79.2552,046
10774.67.80.0/2174.67.80.1 to 74.67.87.25474.67.87.2552,046
10874.67.88.0/2174.67.88.1 to 74.67.95.25474.67.95.2552,046
10974.67.96.0/2174.67.96.1 to 74.67.103.25474.67.103.2552,046
11074.67.104.0/2174.67.104.1 to 74.67.111.25474.67.111.2552,046
11174.67.112.0/2174.67.112.1 to 74.67.119.25474.67.119.2552,046
11274.67.120.0/2174.67.120.1 to 74.67.127.25474.67.127.2552,046
11374.67.128.0/2174.67.128.1 to 74.67.135.25474.67.135.2552,046
11474.67.136.0/2174.67.136.1 to 74.67.143.25474.67.143.2552,046
11574.67.144.0/2174.67.144.1 to 74.67.151.25474.67.151.2552,046
11674.67.152.0/2174.67.152.1 to 74.67.159.25474.67.159.2552,046
11774.67.160.0/2174.67.160.1 to 74.67.167.25474.67.167.2552,046
11874.67.168.0/2174.67.168.1 to 74.67.175.25474.67.175.2552,046
11974.67.176.0/2174.67.176.1 to 74.67.183.25474.67.183.2552,046
12074.67.184.0/2174.67.184.1 to 74.67.191.25474.67.191.2552,046
12174.67.192.0/2174.67.192.1 to 74.67.199.25474.67.199.2552,046
12274.67.200.0/2174.67.200.1 to 74.67.207.25474.67.207.2552,046
12374.67.208.0/2174.67.208.1 to 74.67.215.25474.67.215.2552,046
12474.67.216.0/2174.67.216.1 to 74.67.223.25474.67.223.2552,046
12574.67.224.0/2174.67.224.1 to 74.67.231.25474.67.231.2552,046
12674.67.232.0/2174.67.232.1 to 74.67.239.25474.67.239.2552,046
12774.67.240.0/2174.67.240.1 to 74.67.247.25474.67.247.2552,046
12874.67.248.0/2174.67.248.1 to 74.67.255.25474.67.255.2552,046
12974.68.0.0/2174.68.0.1 to 74.68.7.25474.68.7.2552,046
13074.68.8.0/2174.68.8.1 to 74.68.15.25474.68.15.2552,046
13174.68.16.0/2174.68.16.1 to 74.68.23.25474.68.23.2552,046
13274.68.24.0/2174.68.24.1 to 74.68.31.25474.68.31.2552,046
13374.68.32.0/2174.68.32.1 to 74.68.39.25474.68.39.2552,046
13474.68.40.0/2174.68.40.1 to 74.68.47.25474.68.47.2552,046
13574.68.48.0/2174.68.48.1 to 74.68.55.25474.68.55.2552,046
13674.68.56.0/2174.68.56.1 to 74.68.63.25474.68.63.2552,046
13774.68.64.0/2174.68.64.1 to 74.68.71.25474.68.71.2552,046
13874.68.72.0/2174.68.72.1 to 74.68.79.25474.68.79.2552,046
13974.68.80.0/2174.68.80.1 to 74.68.87.25474.68.87.2552,046
14074.68.88.0/2174.68.88.1 to 74.68.95.25474.68.95.2552,046
14174.68.96.0/2174.68.96.1 to 74.68.103.25474.68.103.2552,046
14274.68.104.0/2174.68.104.1 to 74.68.111.25474.68.111.2552,046
14374.68.112.0/2174.68.112.1 to 74.68.119.25474.68.119.2552,046
14474.68.120.0/2174.68.120.1 to 74.68.127.25474.68.127.2552,046
14574.68.128.0/2174.68.128.1 to 74.68.135.25474.68.135.2552,046
14674.68.136.0/2174.68.136.1 to 74.68.143.25474.68.143.2552,046
14774.68.144.0/2174.68.144.1 to 74.68.151.25474.68.151.2552,046
14874.68.152.0/2174.68.152.1 to 74.68.159.25474.68.159.2552,046
14974.68.160.0/2174.68.160.1 to 74.68.167.25474.68.167.2552,046
15074.68.168.0/2174.68.168.1 to 74.68.175.25474.68.175.2552,046
15174.68.176.0/2174.68.176.1 to 74.68.183.25474.68.183.2552,046
15274.68.184.0/2174.68.184.1 to 74.68.191.25474.68.191.2552,046
15374.68.192.0/2174.68.192.1 to 74.68.199.25474.68.199.2552,046
15474.68.200.0/2174.68.200.1 to 74.68.207.25474.68.207.2552,046
15574.68.208.0/2174.68.208.1 to 74.68.215.25474.68.215.2552,046
15674.68.216.0/2174.68.216.1 to 74.68.223.25474.68.223.2552,046
15774.68.224.0/2174.68.224.1 to 74.68.231.25474.68.231.2552,046
15874.68.232.0/2174.68.232.1 to 74.68.239.25474.68.239.2552,046
15974.68.240.0/2174.68.240.1 to 74.68.247.25474.68.247.2552,046
16074.68.248.0/2174.68.248.1 to 74.68.255.25474.68.255.2552,046
16174.69.0.0/2174.69.0.1 to 74.69.7.25474.69.7.2552,046
16274.69.8.0/2174.69.8.1 to 74.69.15.25474.69.15.2552,046
16374.69.16.0/2174.69.16.1 to 74.69.23.25474.69.23.2552,046
16474.69.24.0/2174.69.24.1 to 74.69.31.25474.69.31.2552,046
16574.69.32.0/2174.69.32.1 to 74.69.39.25474.69.39.2552,046
16674.69.40.0/2174.69.40.1 to 74.69.47.25474.69.47.2552,046
16774.69.48.0/2174.69.48.1 to 74.69.55.25474.69.55.2552,046
16874.69.56.0/2174.69.56.1 to 74.69.63.25474.69.63.2552,046
16974.69.64.0/2174.69.64.1 to 74.69.71.25474.69.71.2552,046
17074.69.72.0/2174.69.72.1 to 74.69.79.25474.69.79.2552,046
17174.69.80.0/2174.69.80.1 to 74.69.87.25474.69.87.2552,046
17274.69.88.0/2174.69.88.1 to 74.69.95.25474.69.95.2552,046
17374.69.96.0/2174.69.96.1 to 74.69.103.25474.69.103.2552,046
17474.69.104.0/2174.69.104.1 to 74.69.111.25474.69.111.2552,046
17574.69.112.0/2174.69.112.1 to 74.69.119.25474.69.119.2552,046
17674.69.120.0/2174.69.120.1 to 74.69.127.25474.69.127.2552,046
17774.69.128.0/2174.69.128.1 to 74.69.135.25474.69.135.2552,046
17874.69.136.0/2174.69.136.1 to 74.69.143.25474.69.143.2552,046
17974.69.144.0/2174.69.144.1 to 74.69.151.25474.69.151.2552,046
18074.69.152.0/2174.69.152.1 to 74.69.159.25474.69.159.2552,046
18174.69.160.0/2174.69.160.1 to 74.69.167.25474.69.167.2552,046
18274.69.168.0/2174.69.168.1 to 74.69.175.25474.69.175.2552,046
18374.69.176.0/2174.69.176.1 to 74.69.183.25474.69.183.2552,046
18474.69.184.0/2174.69.184.1 to 74.69.191.25474.69.191.2552,046
18574.69.192.0/2174.69.192.1 to 74.69.199.25474.69.199.2552,046
18674.69.200.0/2174.69.200.1 to 74.69.207.25474.69.207.2552,046
18774.69.208.0/2174.69.208.1 to 74.69.215.25474.69.215.2552,046
18874.69.216.0/2174.69.216.1 to 74.69.223.25474.69.223.2552,046
18974.69.224.0/2174.69.224.1 to 74.69.231.25474.69.231.2552,046
19074.69.232.0/2174.69.232.1 to 74.69.239.25474.69.239.2552,046
19174.69.240.0/2174.69.240.1 to 74.69.247.25474.69.247.2552,046
19274.69.248.0/2174.69.248.1 to 74.69.255.25474.69.255.2552,046
19374.70.0.0/2174.70.0.1 to 74.70.7.25474.70.7.2552,046
19474.70.8.0/2174.70.8.1 to 74.70.15.25474.70.15.2552,046
19574.70.16.0/2174.70.16.1 to 74.70.23.25474.70.23.2552,046
19674.70.24.0/2174.70.24.1 to 74.70.31.25474.70.31.2552,046
19774.70.32.0/2174.70.32.1 to 74.70.39.25474.70.39.2552,046
19874.70.40.0/2174.70.40.1 to 74.70.47.25474.70.47.2552,046
19974.70.48.0/2174.70.48.1 to 74.70.55.25474.70.55.2552,046
20074.70.56.0/2174.70.56.1 to 74.70.63.25474.70.63.2552,046
20174.70.64.0/2174.70.64.1 to 74.70.71.25474.70.71.2552,046
20274.70.72.0/2174.70.72.1 to 74.70.79.25474.70.79.2552,046
20374.70.80.0/2174.70.80.1 to 74.70.87.25474.70.87.2552,046
20474.70.88.0/2174.70.88.1 to 74.70.95.25474.70.95.2552,046
20574.70.96.0/2174.70.96.1 to 74.70.103.25474.70.103.2552,046
20674.70.104.0/2174.70.104.1 to 74.70.111.25474.70.111.2552,046
20774.70.112.0/2174.70.112.1 to 74.70.119.25474.70.119.2552,046
20874.70.120.0/2174.70.120.1 to 74.70.127.25474.70.127.2552,046
20974.70.128.0/2174.70.128.1 to 74.70.135.25474.70.135.2552,046
21074.70.136.0/2174.70.136.1 to 74.70.143.25474.70.143.2552,046
21174.70.144.0/2174.70.144.1 to 74.70.151.25474.70.151.2552,046
21274.70.152.0/2174.70.152.1 to 74.70.159.25474.70.159.2552,046
21374.70.160.0/2174.70.160.1 to 74.70.167.25474.70.167.2552,046
21474.70.168.0/2174.70.168.1 to 74.70.175.25474.70.175.2552,046
21574.70.176.0/2174.70.176.1 to 74.70.183.25474.70.183.2552,046
21674.70.184.0/2174.70.184.1 to 74.70.191.25474.70.191.2552,046
21774.70.192.0/2174.70.192.1 to 74.70.199.25474.70.199.2552,046
21874.70.200.0/2174.70.200.1 to 74.70.207.25474.70.207.2552,046
21974.70.208.0/2174.70.208.1 to 74.70.215.25474.70.215.2552,046
22074.70.216.0/2174.70.216.1 to 74.70.223.25474.70.223.2552,046
22174.70.224.0/2174.70.224.1 to 74.70.231.25474.70.231.2552,046
22274.70.232.0/2174.70.232.1 to 74.70.239.25474.70.239.2552,046
22374.70.240.0/2174.70.240.1 to 74.70.247.25474.70.247.2552,046
22474.70.248.0/2174.70.248.1 to 74.70.255.25474.70.255.2552,046
22574.71.0.0/2174.71.0.1 to 74.71.7.25474.71.7.2552,046
22674.71.8.0/2174.71.8.1 to 74.71.15.25474.71.15.2552,046
22774.71.16.0/2174.71.16.1 to 74.71.23.25474.71.23.2552,046
22874.71.24.0/2174.71.24.1 to 74.71.31.25474.71.31.2552,046
22974.71.32.0/2174.71.32.1 to 74.71.39.25474.71.39.2552,046
23074.71.40.0/2174.71.40.1 to 74.71.47.25474.71.47.2552,046
23174.71.48.0/2174.71.48.1 to 74.71.55.25474.71.55.2552,046
23274.71.56.0/2174.71.56.1 to 74.71.63.25474.71.63.2552,046
23374.71.64.0/2174.71.64.1 to 74.71.71.25474.71.71.2552,046
23474.71.72.0/2174.71.72.1 to 74.71.79.25474.71.79.2552,046
23574.71.80.0/2174.71.80.1 to 74.71.87.25474.71.87.2552,046
23674.71.88.0/2174.71.88.1 to 74.71.95.25474.71.95.2552,046
23774.71.96.0/2174.71.96.1 to 74.71.103.25474.71.103.2552,046
23874.71.104.0/2174.71.104.1 to 74.71.111.25474.71.111.2552,046
23974.71.112.0/2174.71.112.1 to 74.71.119.25474.71.119.2552,046
24074.71.120.0/2174.71.120.1 to 74.71.127.25474.71.127.2552,046
24174.71.128.0/2174.71.128.1 to 74.71.135.25474.71.135.2552,046
24274.71.136.0/2174.71.136.1 to 74.71.143.25474.71.143.2552,046
24374.71.144.0/2174.71.144.1 to 74.71.151.25474.71.151.2552,046
24474.71.152.0/2174.71.152.1 to 74.71.159.25474.71.159.2552,046
24574.71.160.0/2174.71.160.1 to 74.71.167.25474.71.167.2552,046
24674.71.168.0/2174.71.168.1 to 74.71.175.25474.71.175.2552,046
24774.71.176.0/2174.71.176.1 to 74.71.183.25474.71.183.2552,046
24874.71.184.0/2174.71.184.1 to 74.71.191.25474.71.191.2552,046
24974.71.192.0/2174.71.192.1 to 74.71.199.25474.71.199.2552,046
25074.71.200.0/2174.71.200.1 to 74.71.207.25474.71.207.2552,046
25174.71.208.0/2174.71.208.1 to 74.71.215.25474.71.215.2552,046
25274.71.216.0/2174.71.216.1 to 74.71.223.25474.71.223.2552,046
25374.71.224.0/2174.71.224.1 to 74.71.231.25474.71.231.2552,046
25474.71.232.0/2174.71.232.1 to 74.71.239.25474.71.239.2552,046
25574.71.240.0/2174.71.240.1 to 74.71.247.25474.71.247.2552,046
25674.71.248.0/2174.71.248.1 to 74.71.255.25474.71.255.2552,046

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.