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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.

Network64.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
64.0.0.0
Broadcast address
64.7.255.255
First usable
64.0.0.1
Last usable
64.7.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 40000000 · Integer 1073741824 to 1074266111
Reverse DNS zones
0.64.in-addr.arpa
1.64.in-addr.arpa
2.64.in-addr.arpa
3.64.in-addr.arpa
4.64.in-addr.arpa
5.64.in-addr.arpa
6.64.in-addr.arpa
7.64.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000000.00000000.00000000.0000000064.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network01000000.00000000.00000000.0000000064.0.0.0
Broadcast01000000.00000111.11111111.1111111164.7.255.255
Split into smaller subnets/21
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

64.0.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
164.0.0.0/2164.0.0.1 to 64.0.7.25464.0.7.2552,046
264.0.8.0/2164.0.8.1 to 64.0.15.25464.0.15.2552,046
364.0.16.0/2164.0.16.1 to 64.0.23.25464.0.23.2552,046
464.0.24.0/2164.0.24.1 to 64.0.31.25464.0.31.2552,046
564.0.32.0/2164.0.32.1 to 64.0.39.25464.0.39.2552,046
664.0.40.0/2164.0.40.1 to 64.0.47.25464.0.47.2552,046
764.0.48.0/2164.0.48.1 to 64.0.55.25464.0.55.2552,046
864.0.56.0/2164.0.56.1 to 64.0.63.25464.0.63.2552,046
964.0.64.0/2164.0.64.1 to 64.0.71.25464.0.71.2552,046
1064.0.72.0/2164.0.72.1 to 64.0.79.25464.0.79.2552,046
1164.0.80.0/2164.0.80.1 to 64.0.87.25464.0.87.2552,046
1264.0.88.0/2164.0.88.1 to 64.0.95.25464.0.95.2552,046
1364.0.96.0/2164.0.96.1 to 64.0.103.25464.0.103.2552,046
1464.0.104.0/2164.0.104.1 to 64.0.111.25464.0.111.2552,046
1564.0.112.0/2164.0.112.1 to 64.0.119.25464.0.119.2552,046
1664.0.120.0/2164.0.120.1 to 64.0.127.25464.0.127.2552,046
1764.0.128.0/2164.0.128.1 to 64.0.135.25464.0.135.2552,046
1864.0.136.0/2164.0.136.1 to 64.0.143.25464.0.143.2552,046
1964.0.144.0/2164.0.144.1 to 64.0.151.25464.0.151.2552,046
2064.0.152.0/2164.0.152.1 to 64.0.159.25464.0.159.2552,046
2164.0.160.0/2164.0.160.1 to 64.0.167.25464.0.167.2552,046
2264.0.168.0/2164.0.168.1 to 64.0.175.25464.0.175.2552,046
2364.0.176.0/2164.0.176.1 to 64.0.183.25464.0.183.2552,046
2464.0.184.0/2164.0.184.1 to 64.0.191.25464.0.191.2552,046
2564.0.192.0/2164.0.192.1 to 64.0.199.25464.0.199.2552,046
2664.0.200.0/2164.0.200.1 to 64.0.207.25464.0.207.2552,046
2764.0.208.0/2164.0.208.1 to 64.0.215.25464.0.215.2552,046
2864.0.216.0/2164.0.216.1 to 64.0.223.25464.0.223.2552,046
2964.0.224.0/2164.0.224.1 to 64.0.231.25464.0.231.2552,046
3064.0.232.0/2164.0.232.1 to 64.0.239.25464.0.239.2552,046
3164.0.240.0/2164.0.240.1 to 64.0.247.25464.0.247.2552,046
3264.0.248.0/2164.0.248.1 to 64.0.255.25464.0.255.2552,046
3364.1.0.0/2164.1.0.1 to 64.1.7.25464.1.7.2552,046
3464.1.8.0/2164.1.8.1 to 64.1.15.25464.1.15.2552,046
3564.1.16.0/2164.1.16.1 to 64.1.23.25464.1.23.2552,046
3664.1.24.0/2164.1.24.1 to 64.1.31.25464.1.31.2552,046
3764.1.32.0/2164.1.32.1 to 64.1.39.25464.1.39.2552,046
3864.1.40.0/2164.1.40.1 to 64.1.47.25464.1.47.2552,046
3964.1.48.0/2164.1.48.1 to 64.1.55.25464.1.55.2552,046
4064.1.56.0/2164.1.56.1 to 64.1.63.25464.1.63.2552,046
4164.1.64.0/2164.1.64.1 to 64.1.71.25464.1.71.2552,046
4264.1.72.0/2164.1.72.1 to 64.1.79.25464.1.79.2552,046
4364.1.80.0/2164.1.80.1 to 64.1.87.25464.1.87.2552,046
4464.1.88.0/2164.1.88.1 to 64.1.95.25464.1.95.2552,046
4564.1.96.0/2164.1.96.1 to 64.1.103.25464.1.103.2552,046
4664.1.104.0/2164.1.104.1 to 64.1.111.25464.1.111.2552,046
4764.1.112.0/2164.1.112.1 to 64.1.119.25464.1.119.2552,046
4864.1.120.0/2164.1.120.1 to 64.1.127.25464.1.127.2552,046
4964.1.128.0/2164.1.128.1 to 64.1.135.25464.1.135.2552,046
5064.1.136.0/2164.1.136.1 to 64.1.143.25464.1.143.2552,046
5164.1.144.0/2164.1.144.1 to 64.1.151.25464.1.151.2552,046
5264.1.152.0/2164.1.152.1 to 64.1.159.25464.1.159.2552,046
5364.1.160.0/2164.1.160.1 to 64.1.167.25464.1.167.2552,046
5464.1.168.0/2164.1.168.1 to 64.1.175.25464.1.175.2552,046
5564.1.176.0/2164.1.176.1 to 64.1.183.25464.1.183.2552,046
5664.1.184.0/2164.1.184.1 to 64.1.191.25464.1.191.2552,046
5764.1.192.0/2164.1.192.1 to 64.1.199.25464.1.199.2552,046
5864.1.200.0/2164.1.200.1 to 64.1.207.25464.1.207.2552,046
5964.1.208.0/2164.1.208.1 to 64.1.215.25464.1.215.2552,046
6064.1.216.0/2164.1.216.1 to 64.1.223.25464.1.223.2552,046
6164.1.224.0/2164.1.224.1 to 64.1.231.25464.1.231.2552,046
6264.1.232.0/2164.1.232.1 to 64.1.239.25464.1.239.2552,046
6364.1.240.0/2164.1.240.1 to 64.1.247.25464.1.247.2552,046
6464.1.248.0/2164.1.248.1 to 64.1.255.25464.1.255.2552,046
6564.2.0.0/2164.2.0.1 to 64.2.7.25464.2.7.2552,046
6664.2.8.0/2164.2.8.1 to 64.2.15.25464.2.15.2552,046
6764.2.16.0/2164.2.16.1 to 64.2.23.25464.2.23.2552,046
6864.2.24.0/2164.2.24.1 to 64.2.31.25464.2.31.2552,046
6964.2.32.0/2164.2.32.1 to 64.2.39.25464.2.39.2552,046
7064.2.40.0/2164.2.40.1 to 64.2.47.25464.2.47.2552,046
7164.2.48.0/2164.2.48.1 to 64.2.55.25464.2.55.2552,046
7264.2.56.0/2164.2.56.1 to 64.2.63.25464.2.63.2552,046
7364.2.64.0/2164.2.64.1 to 64.2.71.25464.2.71.2552,046
7464.2.72.0/2164.2.72.1 to 64.2.79.25464.2.79.2552,046
7564.2.80.0/2164.2.80.1 to 64.2.87.25464.2.87.2552,046
7664.2.88.0/2164.2.88.1 to 64.2.95.25464.2.95.2552,046
7764.2.96.0/2164.2.96.1 to 64.2.103.25464.2.103.2552,046
7864.2.104.0/2164.2.104.1 to 64.2.111.25464.2.111.2552,046
7964.2.112.0/2164.2.112.1 to 64.2.119.25464.2.119.2552,046
8064.2.120.0/2164.2.120.1 to 64.2.127.25464.2.127.2552,046
8164.2.128.0/2164.2.128.1 to 64.2.135.25464.2.135.2552,046
8264.2.136.0/2164.2.136.1 to 64.2.143.25464.2.143.2552,046
8364.2.144.0/2164.2.144.1 to 64.2.151.25464.2.151.2552,046
8464.2.152.0/2164.2.152.1 to 64.2.159.25464.2.159.2552,046
8564.2.160.0/2164.2.160.1 to 64.2.167.25464.2.167.2552,046
8664.2.168.0/2164.2.168.1 to 64.2.175.25464.2.175.2552,046
8764.2.176.0/2164.2.176.1 to 64.2.183.25464.2.183.2552,046
8864.2.184.0/2164.2.184.1 to 64.2.191.25464.2.191.2552,046
8964.2.192.0/2164.2.192.1 to 64.2.199.25464.2.199.2552,046
9064.2.200.0/2164.2.200.1 to 64.2.207.25464.2.207.2552,046
9164.2.208.0/2164.2.208.1 to 64.2.215.25464.2.215.2552,046
9264.2.216.0/2164.2.216.1 to 64.2.223.25464.2.223.2552,046
9364.2.224.0/2164.2.224.1 to 64.2.231.25464.2.231.2552,046
9464.2.232.0/2164.2.232.1 to 64.2.239.25464.2.239.2552,046
9564.2.240.0/2164.2.240.1 to 64.2.247.25464.2.247.2552,046
9664.2.248.0/2164.2.248.1 to 64.2.255.25464.2.255.2552,046
9764.3.0.0/2164.3.0.1 to 64.3.7.25464.3.7.2552,046
9864.3.8.0/2164.3.8.1 to 64.3.15.25464.3.15.2552,046
9964.3.16.0/2164.3.16.1 to 64.3.23.25464.3.23.2552,046
10064.3.24.0/2164.3.24.1 to 64.3.31.25464.3.31.2552,046
10164.3.32.0/2164.3.32.1 to 64.3.39.25464.3.39.2552,046
10264.3.40.0/2164.3.40.1 to 64.3.47.25464.3.47.2552,046
10364.3.48.0/2164.3.48.1 to 64.3.55.25464.3.55.2552,046
10464.3.56.0/2164.3.56.1 to 64.3.63.25464.3.63.2552,046
10564.3.64.0/2164.3.64.1 to 64.3.71.25464.3.71.2552,046
10664.3.72.0/2164.3.72.1 to 64.3.79.25464.3.79.2552,046
10764.3.80.0/2164.3.80.1 to 64.3.87.25464.3.87.2552,046
10864.3.88.0/2164.3.88.1 to 64.3.95.25464.3.95.2552,046
10964.3.96.0/2164.3.96.1 to 64.3.103.25464.3.103.2552,046
11064.3.104.0/2164.3.104.1 to 64.3.111.25464.3.111.2552,046
11164.3.112.0/2164.3.112.1 to 64.3.119.25464.3.119.2552,046
11264.3.120.0/2164.3.120.1 to 64.3.127.25464.3.127.2552,046
11364.3.128.0/2164.3.128.1 to 64.3.135.25464.3.135.2552,046
11464.3.136.0/2164.3.136.1 to 64.3.143.25464.3.143.2552,046
11564.3.144.0/2164.3.144.1 to 64.3.151.25464.3.151.2552,046
11664.3.152.0/2164.3.152.1 to 64.3.159.25464.3.159.2552,046
11764.3.160.0/2164.3.160.1 to 64.3.167.25464.3.167.2552,046
11864.3.168.0/2164.3.168.1 to 64.3.175.25464.3.175.2552,046
11964.3.176.0/2164.3.176.1 to 64.3.183.25464.3.183.2552,046
12064.3.184.0/2164.3.184.1 to 64.3.191.25464.3.191.2552,046
12164.3.192.0/2164.3.192.1 to 64.3.199.25464.3.199.2552,046
12264.3.200.0/2164.3.200.1 to 64.3.207.25464.3.207.2552,046
12364.3.208.0/2164.3.208.1 to 64.3.215.25464.3.215.2552,046
12464.3.216.0/2164.3.216.1 to 64.3.223.25464.3.223.2552,046
12564.3.224.0/2164.3.224.1 to 64.3.231.25464.3.231.2552,046
12664.3.232.0/2164.3.232.1 to 64.3.239.25464.3.239.2552,046
12764.3.240.0/2164.3.240.1 to 64.3.247.25464.3.247.2552,046
12864.3.248.0/2164.3.248.1 to 64.3.255.25464.3.255.2552,046
12964.4.0.0/2164.4.0.1 to 64.4.7.25464.4.7.2552,046
13064.4.8.0/2164.4.8.1 to 64.4.15.25464.4.15.2552,046
13164.4.16.0/2164.4.16.1 to 64.4.23.25464.4.23.2552,046
13264.4.24.0/2164.4.24.1 to 64.4.31.25464.4.31.2552,046
13364.4.32.0/2164.4.32.1 to 64.4.39.25464.4.39.2552,046
13464.4.40.0/2164.4.40.1 to 64.4.47.25464.4.47.2552,046
13564.4.48.0/2164.4.48.1 to 64.4.55.25464.4.55.2552,046
13664.4.56.0/2164.4.56.1 to 64.4.63.25464.4.63.2552,046
13764.4.64.0/2164.4.64.1 to 64.4.71.25464.4.71.2552,046
13864.4.72.0/2164.4.72.1 to 64.4.79.25464.4.79.2552,046
13964.4.80.0/2164.4.80.1 to 64.4.87.25464.4.87.2552,046
14064.4.88.0/2164.4.88.1 to 64.4.95.25464.4.95.2552,046
14164.4.96.0/2164.4.96.1 to 64.4.103.25464.4.103.2552,046
14264.4.104.0/2164.4.104.1 to 64.4.111.25464.4.111.2552,046
14364.4.112.0/2164.4.112.1 to 64.4.119.25464.4.119.2552,046
14464.4.120.0/2164.4.120.1 to 64.4.127.25464.4.127.2552,046
14564.4.128.0/2164.4.128.1 to 64.4.135.25464.4.135.2552,046
14664.4.136.0/2164.4.136.1 to 64.4.143.25464.4.143.2552,046
14764.4.144.0/2164.4.144.1 to 64.4.151.25464.4.151.2552,046
14864.4.152.0/2164.4.152.1 to 64.4.159.25464.4.159.2552,046
14964.4.160.0/2164.4.160.1 to 64.4.167.25464.4.167.2552,046
15064.4.168.0/2164.4.168.1 to 64.4.175.25464.4.175.2552,046
15164.4.176.0/2164.4.176.1 to 64.4.183.25464.4.183.2552,046
15264.4.184.0/2164.4.184.1 to 64.4.191.25464.4.191.2552,046
15364.4.192.0/2164.4.192.1 to 64.4.199.25464.4.199.2552,046
15464.4.200.0/2164.4.200.1 to 64.4.207.25464.4.207.2552,046
15564.4.208.0/2164.4.208.1 to 64.4.215.25464.4.215.2552,046
15664.4.216.0/2164.4.216.1 to 64.4.223.25464.4.223.2552,046
15764.4.224.0/2164.4.224.1 to 64.4.231.25464.4.231.2552,046
15864.4.232.0/2164.4.232.1 to 64.4.239.25464.4.239.2552,046
15964.4.240.0/2164.4.240.1 to 64.4.247.25464.4.247.2552,046
16064.4.248.0/2164.4.248.1 to 64.4.255.25464.4.255.2552,046
16164.5.0.0/2164.5.0.1 to 64.5.7.25464.5.7.2552,046
16264.5.8.0/2164.5.8.1 to 64.5.15.25464.5.15.2552,046
16364.5.16.0/2164.5.16.1 to 64.5.23.25464.5.23.2552,046
16464.5.24.0/2164.5.24.1 to 64.5.31.25464.5.31.2552,046
16564.5.32.0/2164.5.32.1 to 64.5.39.25464.5.39.2552,046
16664.5.40.0/2164.5.40.1 to 64.5.47.25464.5.47.2552,046
16764.5.48.0/2164.5.48.1 to 64.5.55.25464.5.55.2552,046
16864.5.56.0/2164.5.56.1 to 64.5.63.25464.5.63.2552,046
16964.5.64.0/2164.5.64.1 to 64.5.71.25464.5.71.2552,046
17064.5.72.0/2164.5.72.1 to 64.5.79.25464.5.79.2552,046
17164.5.80.0/2164.5.80.1 to 64.5.87.25464.5.87.2552,046
17264.5.88.0/2164.5.88.1 to 64.5.95.25464.5.95.2552,046
17364.5.96.0/2164.5.96.1 to 64.5.103.25464.5.103.2552,046
17464.5.104.0/2164.5.104.1 to 64.5.111.25464.5.111.2552,046
17564.5.112.0/2164.5.112.1 to 64.5.119.25464.5.119.2552,046
17664.5.120.0/2164.5.120.1 to 64.5.127.25464.5.127.2552,046
17764.5.128.0/2164.5.128.1 to 64.5.135.25464.5.135.2552,046
17864.5.136.0/2164.5.136.1 to 64.5.143.25464.5.143.2552,046
17964.5.144.0/2164.5.144.1 to 64.5.151.25464.5.151.2552,046
18064.5.152.0/2164.5.152.1 to 64.5.159.25464.5.159.2552,046
18164.5.160.0/2164.5.160.1 to 64.5.167.25464.5.167.2552,046
18264.5.168.0/2164.5.168.1 to 64.5.175.25464.5.175.2552,046
18364.5.176.0/2164.5.176.1 to 64.5.183.25464.5.183.2552,046
18464.5.184.0/2164.5.184.1 to 64.5.191.25464.5.191.2552,046
18564.5.192.0/2164.5.192.1 to 64.5.199.25464.5.199.2552,046
18664.5.200.0/2164.5.200.1 to 64.5.207.25464.5.207.2552,046
18764.5.208.0/2164.5.208.1 to 64.5.215.25464.5.215.2552,046
18864.5.216.0/2164.5.216.1 to 64.5.223.25464.5.223.2552,046
18964.5.224.0/2164.5.224.1 to 64.5.231.25464.5.231.2552,046
19064.5.232.0/2164.5.232.1 to 64.5.239.25464.5.239.2552,046
19164.5.240.0/2164.5.240.1 to 64.5.247.25464.5.247.2552,046
19264.5.248.0/2164.5.248.1 to 64.5.255.25464.5.255.2552,046
19364.6.0.0/2164.6.0.1 to 64.6.7.25464.6.7.2552,046
19464.6.8.0/2164.6.8.1 to 64.6.15.25464.6.15.2552,046
19564.6.16.0/2164.6.16.1 to 64.6.23.25464.6.23.2552,046
19664.6.24.0/2164.6.24.1 to 64.6.31.25464.6.31.2552,046
19764.6.32.0/2164.6.32.1 to 64.6.39.25464.6.39.2552,046
19864.6.40.0/2164.6.40.1 to 64.6.47.25464.6.47.2552,046
19964.6.48.0/2164.6.48.1 to 64.6.55.25464.6.55.2552,046
20064.6.56.0/2164.6.56.1 to 64.6.63.25464.6.63.2552,046
20164.6.64.0/2164.6.64.1 to 64.6.71.25464.6.71.2552,046
20264.6.72.0/2164.6.72.1 to 64.6.79.25464.6.79.2552,046
20364.6.80.0/2164.6.80.1 to 64.6.87.25464.6.87.2552,046
20464.6.88.0/2164.6.88.1 to 64.6.95.25464.6.95.2552,046
20564.6.96.0/2164.6.96.1 to 64.6.103.25464.6.103.2552,046
20664.6.104.0/2164.6.104.1 to 64.6.111.25464.6.111.2552,046
20764.6.112.0/2164.6.112.1 to 64.6.119.25464.6.119.2552,046
20864.6.120.0/2164.6.120.1 to 64.6.127.25464.6.127.2552,046
20964.6.128.0/2164.6.128.1 to 64.6.135.25464.6.135.2552,046
21064.6.136.0/2164.6.136.1 to 64.6.143.25464.6.143.2552,046
21164.6.144.0/2164.6.144.1 to 64.6.151.25464.6.151.2552,046
21264.6.152.0/2164.6.152.1 to 64.6.159.25464.6.159.2552,046
21364.6.160.0/2164.6.160.1 to 64.6.167.25464.6.167.2552,046
21464.6.168.0/2164.6.168.1 to 64.6.175.25464.6.175.2552,046
21564.6.176.0/2164.6.176.1 to 64.6.183.25464.6.183.2552,046
21664.6.184.0/2164.6.184.1 to 64.6.191.25464.6.191.2552,046
21764.6.192.0/2164.6.192.1 to 64.6.199.25464.6.199.2552,046
21864.6.200.0/2164.6.200.1 to 64.6.207.25464.6.207.2552,046
21964.6.208.0/2164.6.208.1 to 64.6.215.25464.6.215.2552,046
22064.6.216.0/2164.6.216.1 to 64.6.223.25464.6.223.2552,046
22164.6.224.0/2164.6.224.1 to 64.6.231.25464.6.231.2552,046
22264.6.232.0/2164.6.232.1 to 64.6.239.25464.6.239.2552,046
22364.6.240.0/2164.6.240.1 to 64.6.247.25464.6.247.2552,046
22464.6.248.0/2164.6.248.1 to 64.6.255.25464.6.255.2552,046
22564.7.0.0/2164.7.0.1 to 64.7.7.25464.7.7.2552,046
22664.7.8.0/2164.7.8.1 to 64.7.15.25464.7.15.2552,046
22764.7.16.0/2164.7.16.1 to 64.7.23.25464.7.23.2552,046
22864.7.24.0/2164.7.24.1 to 64.7.31.25464.7.31.2552,046
22964.7.32.0/2164.7.32.1 to 64.7.39.25464.7.39.2552,046
23064.7.40.0/2164.7.40.1 to 64.7.47.25464.7.47.2552,046
23164.7.48.0/2164.7.48.1 to 64.7.55.25464.7.55.2552,046
23264.7.56.0/2164.7.56.1 to 64.7.63.25464.7.63.2552,046
23364.7.64.0/2164.7.64.1 to 64.7.71.25464.7.71.2552,046
23464.7.72.0/2164.7.72.1 to 64.7.79.25464.7.79.2552,046
23564.7.80.0/2164.7.80.1 to 64.7.87.25464.7.87.2552,046
23664.7.88.0/2164.7.88.1 to 64.7.95.25464.7.95.2552,046
23764.7.96.0/2164.7.96.1 to 64.7.103.25464.7.103.2552,046
23864.7.104.0/2164.7.104.1 to 64.7.111.25464.7.111.2552,046
23964.7.112.0/2164.7.112.1 to 64.7.119.25464.7.119.2552,046
24064.7.120.0/2164.7.120.1 to 64.7.127.25464.7.127.2552,046
24164.7.128.0/2164.7.128.1 to 64.7.135.25464.7.135.2552,046
24264.7.136.0/2164.7.136.1 to 64.7.143.25464.7.143.2552,046
24364.7.144.0/2164.7.144.1 to 64.7.151.25464.7.151.2552,046
24464.7.152.0/2164.7.152.1 to 64.7.159.25464.7.159.2552,046
24564.7.160.0/2164.7.160.1 to 64.7.167.25464.7.167.2552,046
24664.7.168.0/2164.7.168.1 to 64.7.175.25464.7.175.2552,046
24764.7.176.0/2164.7.176.1 to 64.7.183.25464.7.183.2552,046
24864.7.184.0/2164.7.184.1 to 64.7.191.25464.7.191.2552,046
24964.7.192.0/2164.7.192.1 to 64.7.199.25464.7.199.2552,046
25064.7.200.0/2164.7.200.1 to 64.7.207.25464.7.207.2552,046
25164.7.208.0/2164.7.208.1 to 64.7.215.25464.7.215.2552,046
25264.7.216.0/2164.7.216.1 to 64.7.223.25464.7.223.2552,046
25364.7.224.0/2164.7.224.1 to 64.7.231.25464.7.231.2552,046
25464.7.232.0/2164.7.232.1 to 64.7.239.25464.7.239.2552,046
25564.7.240.0/2164.7.240.1 to 64.7.247.25464.7.247.2552,046
25664.7.248.0/2164.7.248.1 to 64.7.255.25464.7.255.2552,046

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.