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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.

Network64.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
64.0.0.0
Broadcast address
64.127.255.255
First usable
64.0.0.1
Last usable
64.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 40000000 · Integer 1073741824 to 1082130431
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
8.64.in-addr.arpa
9.64.in-addr.arpa
10.64.in-addr.arpa
11.64.in-addr.arpa
12.64.in-addr.arpa
13.64.in-addr.arpa
14.64.in-addr.arpa
15.64.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000000.00000000.00000000.0000000064.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01000000.00000000.00000000.0000000064.0.0.0
Broadcast01000000.01111111.11111111.1111111164.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

64.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
164.0.0.0/2064.0.0.1 to 64.0.15.25464.0.15.2554,094
264.0.16.0/2064.0.16.1 to 64.0.31.25464.0.31.2554,094
364.0.32.0/2064.0.32.1 to 64.0.47.25464.0.47.2554,094
464.0.48.0/2064.0.48.1 to 64.0.63.25464.0.63.2554,094
564.0.64.0/2064.0.64.1 to 64.0.79.25464.0.79.2554,094
664.0.80.0/2064.0.80.1 to 64.0.95.25464.0.95.2554,094
764.0.96.0/2064.0.96.1 to 64.0.111.25464.0.111.2554,094
864.0.112.0/2064.0.112.1 to 64.0.127.25464.0.127.2554,094
964.0.128.0/2064.0.128.1 to 64.0.143.25464.0.143.2554,094
1064.0.144.0/2064.0.144.1 to 64.0.159.25464.0.159.2554,094
1164.0.160.0/2064.0.160.1 to 64.0.175.25464.0.175.2554,094
1264.0.176.0/2064.0.176.1 to 64.0.191.25464.0.191.2554,094
1364.0.192.0/2064.0.192.1 to 64.0.207.25464.0.207.2554,094
1464.0.208.0/2064.0.208.1 to 64.0.223.25464.0.223.2554,094
1564.0.224.0/2064.0.224.1 to 64.0.239.25464.0.239.2554,094
1664.0.240.0/2064.0.240.1 to 64.0.255.25464.0.255.2554,094
1764.1.0.0/2064.1.0.1 to 64.1.15.25464.1.15.2554,094
1864.1.16.0/2064.1.16.1 to 64.1.31.25464.1.31.2554,094
1964.1.32.0/2064.1.32.1 to 64.1.47.25464.1.47.2554,094
2064.1.48.0/2064.1.48.1 to 64.1.63.25464.1.63.2554,094
2164.1.64.0/2064.1.64.1 to 64.1.79.25464.1.79.2554,094
2264.1.80.0/2064.1.80.1 to 64.1.95.25464.1.95.2554,094
2364.1.96.0/2064.1.96.1 to 64.1.111.25464.1.111.2554,094
2464.1.112.0/2064.1.112.1 to 64.1.127.25464.1.127.2554,094
2564.1.128.0/2064.1.128.1 to 64.1.143.25464.1.143.2554,094
2664.1.144.0/2064.1.144.1 to 64.1.159.25464.1.159.2554,094
2764.1.160.0/2064.1.160.1 to 64.1.175.25464.1.175.2554,094
2864.1.176.0/2064.1.176.1 to 64.1.191.25464.1.191.2554,094
2964.1.192.0/2064.1.192.1 to 64.1.207.25464.1.207.2554,094
3064.1.208.0/2064.1.208.1 to 64.1.223.25464.1.223.2554,094
3164.1.224.0/2064.1.224.1 to 64.1.239.25464.1.239.2554,094
3264.1.240.0/2064.1.240.1 to 64.1.255.25464.1.255.2554,094
3364.2.0.0/2064.2.0.1 to 64.2.15.25464.2.15.2554,094
3464.2.16.0/2064.2.16.1 to 64.2.31.25464.2.31.2554,094
3564.2.32.0/2064.2.32.1 to 64.2.47.25464.2.47.2554,094
3664.2.48.0/2064.2.48.1 to 64.2.63.25464.2.63.2554,094
3764.2.64.0/2064.2.64.1 to 64.2.79.25464.2.79.2554,094
3864.2.80.0/2064.2.80.1 to 64.2.95.25464.2.95.2554,094
3964.2.96.0/2064.2.96.1 to 64.2.111.25464.2.111.2554,094
4064.2.112.0/2064.2.112.1 to 64.2.127.25464.2.127.2554,094
4164.2.128.0/2064.2.128.1 to 64.2.143.25464.2.143.2554,094
4264.2.144.0/2064.2.144.1 to 64.2.159.25464.2.159.2554,094
4364.2.160.0/2064.2.160.1 to 64.2.175.25464.2.175.2554,094
4464.2.176.0/2064.2.176.1 to 64.2.191.25464.2.191.2554,094
4564.2.192.0/2064.2.192.1 to 64.2.207.25464.2.207.2554,094
4664.2.208.0/2064.2.208.1 to 64.2.223.25464.2.223.2554,094
4764.2.224.0/2064.2.224.1 to 64.2.239.25464.2.239.2554,094
4864.2.240.0/2064.2.240.1 to 64.2.255.25464.2.255.2554,094
4964.3.0.0/2064.3.0.1 to 64.3.15.25464.3.15.2554,094
5064.3.16.0/2064.3.16.1 to 64.3.31.25464.3.31.2554,094
5164.3.32.0/2064.3.32.1 to 64.3.47.25464.3.47.2554,094
5264.3.48.0/2064.3.48.1 to 64.3.63.25464.3.63.2554,094
5364.3.64.0/2064.3.64.1 to 64.3.79.25464.3.79.2554,094
5464.3.80.0/2064.3.80.1 to 64.3.95.25464.3.95.2554,094
5564.3.96.0/2064.3.96.1 to 64.3.111.25464.3.111.2554,094
5664.3.112.0/2064.3.112.1 to 64.3.127.25464.3.127.2554,094
5764.3.128.0/2064.3.128.1 to 64.3.143.25464.3.143.2554,094
5864.3.144.0/2064.3.144.1 to 64.3.159.25464.3.159.2554,094
5964.3.160.0/2064.3.160.1 to 64.3.175.25464.3.175.2554,094
6064.3.176.0/2064.3.176.1 to 64.3.191.25464.3.191.2554,094
6164.3.192.0/2064.3.192.1 to 64.3.207.25464.3.207.2554,094
6264.3.208.0/2064.3.208.1 to 64.3.223.25464.3.223.2554,094
6364.3.224.0/2064.3.224.1 to 64.3.239.25464.3.239.2554,094
6464.3.240.0/2064.3.240.1 to 64.3.255.25464.3.255.2554,094
6564.4.0.0/2064.4.0.1 to 64.4.15.25464.4.15.2554,094
6664.4.16.0/2064.4.16.1 to 64.4.31.25464.4.31.2554,094
6764.4.32.0/2064.4.32.1 to 64.4.47.25464.4.47.2554,094
6864.4.48.0/2064.4.48.1 to 64.4.63.25464.4.63.2554,094
6964.4.64.0/2064.4.64.1 to 64.4.79.25464.4.79.2554,094
7064.4.80.0/2064.4.80.1 to 64.4.95.25464.4.95.2554,094
7164.4.96.0/2064.4.96.1 to 64.4.111.25464.4.111.2554,094
7264.4.112.0/2064.4.112.1 to 64.4.127.25464.4.127.2554,094
7364.4.128.0/2064.4.128.1 to 64.4.143.25464.4.143.2554,094
7464.4.144.0/2064.4.144.1 to 64.4.159.25464.4.159.2554,094
7564.4.160.0/2064.4.160.1 to 64.4.175.25464.4.175.2554,094
7664.4.176.0/2064.4.176.1 to 64.4.191.25464.4.191.2554,094
7764.4.192.0/2064.4.192.1 to 64.4.207.25464.4.207.2554,094
7864.4.208.0/2064.4.208.1 to 64.4.223.25464.4.223.2554,094
7964.4.224.0/2064.4.224.1 to 64.4.239.25464.4.239.2554,094
8064.4.240.0/2064.4.240.1 to 64.4.255.25464.4.255.2554,094
8164.5.0.0/2064.5.0.1 to 64.5.15.25464.5.15.2554,094
8264.5.16.0/2064.5.16.1 to 64.5.31.25464.5.31.2554,094
8364.5.32.0/2064.5.32.1 to 64.5.47.25464.5.47.2554,094
8464.5.48.0/2064.5.48.1 to 64.5.63.25464.5.63.2554,094
8564.5.64.0/2064.5.64.1 to 64.5.79.25464.5.79.2554,094
8664.5.80.0/2064.5.80.1 to 64.5.95.25464.5.95.2554,094
8764.5.96.0/2064.5.96.1 to 64.5.111.25464.5.111.2554,094
8864.5.112.0/2064.5.112.1 to 64.5.127.25464.5.127.2554,094
8964.5.128.0/2064.5.128.1 to 64.5.143.25464.5.143.2554,094
9064.5.144.0/2064.5.144.1 to 64.5.159.25464.5.159.2554,094
9164.5.160.0/2064.5.160.1 to 64.5.175.25464.5.175.2554,094
9264.5.176.0/2064.5.176.1 to 64.5.191.25464.5.191.2554,094
9364.5.192.0/2064.5.192.1 to 64.5.207.25464.5.207.2554,094
9464.5.208.0/2064.5.208.1 to 64.5.223.25464.5.223.2554,094
9564.5.224.0/2064.5.224.1 to 64.5.239.25464.5.239.2554,094
9664.5.240.0/2064.5.240.1 to 64.5.255.25464.5.255.2554,094
9764.6.0.0/2064.6.0.1 to 64.6.15.25464.6.15.2554,094
9864.6.16.0/2064.6.16.1 to 64.6.31.25464.6.31.2554,094
9964.6.32.0/2064.6.32.1 to 64.6.47.25464.6.47.2554,094
10064.6.48.0/2064.6.48.1 to 64.6.63.25464.6.63.2554,094
10164.6.64.0/2064.6.64.1 to 64.6.79.25464.6.79.2554,094
10264.6.80.0/2064.6.80.1 to 64.6.95.25464.6.95.2554,094
10364.6.96.0/2064.6.96.1 to 64.6.111.25464.6.111.2554,094
10464.6.112.0/2064.6.112.1 to 64.6.127.25464.6.127.2554,094
10564.6.128.0/2064.6.128.1 to 64.6.143.25464.6.143.2554,094
10664.6.144.0/2064.6.144.1 to 64.6.159.25464.6.159.2554,094
10764.6.160.0/2064.6.160.1 to 64.6.175.25464.6.175.2554,094
10864.6.176.0/2064.6.176.1 to 64.6.191.25464.6.191.2554,094
10964.6.192.0/2064.6.192.1 to 64.6.207.25464.6.207.2554,094
11064.6.208.0/2064.6.208.1 to 64.6.223.25464.6.223.2554,094
11164.6.224.0/2064.6.224.1 to 64.6.239.25464.6.239.2554,094
11264.6.240.0/2064.6.240.1 to 64.6.255.25464.6.255.2554,094
11364.7.0.0/2064.7.0.1 to 64.7.15.25464.7.15.2554,094
11464.7.16.0/2064.7.16.1 to 64.7.31.25464.7.31.2554,094
11564.7.32.0/2064.7.32.1 to 64.7.47.25464.7.47.2554,094
11664.7.48.0/2064.7.48.1 to 64.7.63.25464.7.63.2554,094
11764.7.64.0/2064.7.64.1 to 64.7.79.25464.7.79.2554,094
11864.7.80.0/2064.7.80.1 to 64.7.95.25464.7.95.2554,094
11964.7.96.0/2064.7.96.1 to 64.7.111.25464.7.111.2554,094
12064.7.112.0/2064.7.112.1 to 64.7.127.25464.7.127.2554,094
12164.7.128.0/2064.7.128.1 to 64.7.143.25464.7.143.2554,094
12264.7.144.0/2064.7.144.1 to 64.7.159.25464.7.159.2554,094
12364.7.160.0/2064.7.160.1 to 64.7.175.25464.7.175.2554,094
12464.7.176.0/2064.7.176.1 to 64.7.191.25464.7.191.2554,094
12564.7.192.0/2064.7.192.1 to 64.7.207.25464.7.207.2554,094
12664.7.208.0/2064.7.208.1 to 64.7.223.25464.7.223.2554,094
12764.7.224.0/2064.7.224.1 to 64.7.239.25464.7.239.2554,094
12864.7.240.0/2064.7.240.1 to 64.7.255.25464.7.255.2554,094
12964.8.0.0/2064.8.0.1 to 64.8.15.25464.8.15.2554,094
13064.8.16.0/2064.8.16.1 to 64.8.31.25464.8.31.2554,094
13164.8.32.0/2064.8.32.1 to 64.8.47.25464.8.47.2554,094
13264.8.48.0/2064.8.48.1 to 64.8.63.25464.8.63.2554,094
13364.8.64.0/2064.8.64.1 to 64.8.79.25464.8.79.2554,094
13464.8.80.0/2064.8.80.1 to 64.8.95.25464.8.95.2554,094
13564.8.96.0/2064.8.96.1 to 64.8.111.25464.8.111.2554,094
13664.8.112.0/2064.8.112.1 to 64.8.127.25464.8.127.2554,094
13764.8.128.0/2064.8.128.1 to 64.8.143.25464.8.143.2554,094
13864.8.144.0/2064.8.144.1 to 64.8.159.25464.8.159.2554,094
13964.8.160.0/2064.8.160.1 to 64.8.175.25464.8.175.2554,094
14064.8.176.0/2064.8.176.1 to 64.8.191.25464.8.191.2554,094
14164.8.192.0/2064.8.192.1 to 64.8.207.25464.8.207.2554,094
14264.8.208.0/2064.8.208.1 to 64.8.223.25464.8.223.2554,094
14364.8.224.0/2064.8.224.1 to 64.8.239.25464.8.239.2554,094
14464.8.240.0/2064.8.240.1 to 64.8.255.25464.8.255.2554,094
14564.9.0.0/2064.9.0.1 to 64.9.15.25464.9.15.2554,094
14664.9.16.0/2064.9.16.1 to 64.9.31.25464.9.31.2554,094
14764.9.32.0/2064.9.32.1 to 64.9.47.25464.9.47.2554,094
14864.9.48.0/2064.9.48.1 to 64.9.63.25464.9.63.2554,094
14964.9.64.0/2064.9.64.1 to 64.9.79.25464.9.79.2554,094
15064.9.80.0/2064.9.80.1 to 64.9.95.25464.9.95.2554,094
15164.9.96.0/2064.9.96.1 to 64.9.111.25464.9.111.2554,094
15264.9.112.0/2064.9.112.1 to 64.9.127.25464.9.127.2554,094
15364.9.128.0/2064.9.128.1 to 64.9.143.25464.9.143.2554,094
15464.9.144.0/2064.9.144.1 to 64.9.159.25464.9.159.2554,094
15564.9.160.0/2064.9.160.1 to 64.9.175.25464.9.175.2554,094
15664.9.176.0/2064.9.176.1 to 64.9.191.25464.9.191.2554,094
15764.9.192.0/2064.9.192.1 to 64.9.207.25464.9.207.2554,094
15864.9.208.0/2064.9.208.1 to 64.9.223.25464.9.223.2554,094
15964.9.224.0/2064.9.224.1 to 64.9.239.25464.9.239.2554,094
16064.9.240.0/2064.9.240.1 to 64.9.255.25464.9.255.2554,094
16164.10.0.0/2064.10.0.1 to 64.10.15.25464.10.15.2554,094
16264.10.16.0/2064.10.16.1 to 64.10.31.25464.10.31.2554,094
16364.10.32.0/2064.10.32.1 to 64.10.47.25464.10.47.2554,094
16464.10.48.0/2064.10.48.1 to 64.10.63.25464.10.63.2554,094
16564.10.64.0/2064.10.64.1 to 64.10.79.25464.10.79.2554,094
16664.10.80.0/2064.10.80.1 to 64.10.95.25464.10.95.2554,094
16764.10.96.0/2064.10.96.1 to 64.10.111.25464.10.111.2554,094
16864.10.112.0/2064.10.112.1 to 64.10.127.25464.10.127.2554,094
16964.10.128.0/2064.10.128.1 to 64.10.143.25464.10.143.2554,094
17064.10.144.0/2064.10.144.1 to 64.10.159.25464.10.159.2554,094
17164.10.160.0/2064.10.160.1 to 64.10.175.25464.10.175.2554,094
17264.10.176.0/2064.10.176.1 to 64.10.191.25464.10.191.2554,094
17364.10.192.0/2064.10.192.1 to 64.10.207.25464.10.207.2554,094
17464.10.208.0/2064.10.208.1 to 64.10.223.25464.10.223.2554,094
17564.10.224.0/2064.10.224.1 to 64.10.239.25464.10.239.2554,094
17664.10.240.0/2064.10.240.1 to 64.10.255.25464.10.255.2554,094
17764.11.0.0/2064.11.0.1 to 64.11.15.25464.11.15.2554,094
17864.11.16.0/2064.11.16.1 to 64.11.31.25464.11.31.2554,094
17964.11.32.0/2064.11.32.1 to 64.11.47.25464.11.47.2554,094
18064.11.48.0/2064.11.48.1 to 64.11.63.25464.11.63.2554,094
18164.11.64.0/2064.11.64.1 to 64.11.79.25464.11.79.2554,094
18264.11.80.0/2064.11.80.1 to 64.11.95.25464.11.95.2554,094
18364.11.96.0/2064.11.96.1 to 64.11.111.25464.11.111.2554,094
18464.11.112.0/2064.11.112.1 to 64.11.127.25464.11.127.2554,094
18564.11.128.0/2064.11.128.1 to 64.11.143.25464.11.143.2554,094
18664.11.144.0/2064.11.144.1 to 64.11.159.25464.11.159.2554,094
18764.11.160.0/2064.11.160.1 to 64.11.175.25464.11.175.2554,094
18864.11.176.0/2064.11.176.1 to 64.11.191.25464.11.191.2554,094
18964.11.192.0/2064.11.192.1 to 64.11.207.25464.11.207.2554,094
19064.11.208.0/2064.11.208.1 to 64.11.223.25464.11.223.2554,094
19164.11.224.0/2064.11.224.1 to 64.11.239.25464.11.239.2554,094
19264.11.240.0/2064.11.240.1 to 64.11.255.25464.11.255.2554,094
19364.12.0.0/2064.12.0.1 to 64.12.15.25464.12.15.2554,094
19464.12.16.0/2064.12.16.1 to 64.12.31.25464.12.31.2554,094
19564.12.32.0/2064.12.32.1 to 64.12.47.25464.12.47.2554,094
19664.12.48.0/2064.12.48.1 to 64.12.63.25464.12.63.2554,094
19764.12.64.0/2064.12.64.1 to 64.12.79.25464.12.79.2554,094
19864.12.80.0/2064.12.80.1 to 64.12.95.25464.12.95.2554,094
19964.12.96.0/2064.12.96.1 to 64.12.111.25464.12.111.2554,094
20064.12.112.0/2064.12.112.1 to 64.12.127.25464.12.127.2554,094
20164.12.128.0/2064.12.128.1 to 64.12.143.25464.12.143.2554,094
20264.12.144.0/2064.12.144.1 to 64.12.159.25464.12.159.2554,094
20364.12.160.0/2064.12.160.1 to 64.12.175.25464.12.175.2554,094
20464.12.176.0/2064.12.176.1 to 64.12.191.25464.12.191.2554,094
20564.12.192.0/2064.12.192.1 to 64.12.207.25464.12.207.2554,094
20664.12.208.0/2064.12.208.1 to 64.12.223.25464.12.223.2554,094
20764.12.224.0/2064.12.224.1 to 64.12.239.25464.12.239.2554,094
20864.12.240.0/2064.12.240.1 to 64.12.255.25464.12.255.2554,094
20964.13.0.0/2064.13.0.1 to 64.13.15.25464.13.15.2554,094
21064.13.16.0/2064.13.16.1 to 64.13.31.25464.13.31.2554,094
21164.13.32.0/2064.13.32.1 to 64.13.47.25464.13.47.2554,094
21264.13.48.0/2064.13.48.1 to 64.13.63.25464.13.63.2554,094
21364.13.64.0/2064.13.64.1 to 64.13.79.25464.13.79.2554,094
21464.13.80.0/2064.13.80.1 to 64.13.95.25464.13.95.2554,094
21564.13.96.0/2064.13.96.1 to 64.13.111.25464.13.111.2554,094
21664.13.112.0/2064.13.112.1 to 64.13.127.25464.13.127.2554,094
21764.13.128.0/2064.13.128.1 to 64.13.143.25464.13.143.2554,094
21864.13.144.0/2064.13.144.1 to 64.13.159.25464.13.159.2554,094
21964.13.160.0/2064.13.160.1 to 64.13.175.25464.13.175.2554,094
22064.13.176.0/2064.13.176.1 to 64.13.191.25464.13.191.2554,094
22164.13.192.0/2064.13.192.1 to 64.13.207.25464.13.207.2554,094
22264.13.208.0/2064.13.208.1 to 64.13.223.25464.13.223.2554,094
22364.13.224.0/2064.13.224.1 to 64.13.239.25464.13.239.2554,094
22464.13.240.0/2064.13.240.1 to 64.13.255.25464.13.255.2554,094
22564.14.0.0/2064.14.0.1 to 64.14.15.25464.14.15.2554,094
22664.14.16.0/2064.14.16.1 to 64.14.31.25464.14.31.2554,094
22764.14.32.0/2064.14.32.1 to 64.14.47.25464.14.47.2554,094
22864.14.48.0/2064.14.48.1 to 64.14.63.25464.14.63.2554,094
22964.14.64.0/2064.14.64.1 to 64.14.79.25464.14.79.2554,094
23064.14.80.0/2064.14.80.1 to 64.14.95.25464.14.95.2554,094
23164.14.96.0/2064.14.96.1 to 64.14.111.25464.14.111.2554,094
23264.14.112.0/2064.14.112.1 to 64.14.127.25464.14.127.2554,094
23364.14.128.0/2064.14.128.1 to 64.14.143.25464.14.143.2554,094
23464.14.144.0/2064.14.144.1 to 64.14.159.25464.14.159.2554,094
23564.14.160.0/2064.14.160.1 to 64.14.175.25464.14.175.2554,094
23664.14.176.0/2064.14.176.1 to 64.14.191.25464.14.191.2554,094
23764.14.192.0/2064.14.192.1 to 64.14.207.25464.14.207.2554,094
23864.14.208.0/2064.14.208.1 to 64.14.223.25464.14.223.2554,094
23964.14.224.0/2064.14.224.1 to 64.14.239.25464.14.239.2554,094
24064.14.240.0/2064.14.240.1 to 64.14.255.25464.14.255.2554,094
24164.15.0.0/2064.15.0.1 to 64.15.15.25464.15.15.2554,094
24264.15.16.0/2064.15.16.1 to 64.15.31.25464.15.31.2554,094
24364.15.32.0/2064.15.32.1 to 64.15.47.25464.15.47.2554,094
24464.15.48.0/2064.15.48.1 to 64.15.63.25464.15.63.2554,094
24564.15.64.0/2064.15.64.1 to 64.15.79.25464.15.79.2554,094
24664.15.80.0/2064.15.80.1 to 64.15.95.25464.15.95.2554,094
24764.15.96.0/2064.15.96.1 to 64.15.111.25464.15.111.2554,094
24864.15.112.0/2064.15.112.1 to 64.15.127.25464.15.127.2554,094
24964.15.128.0/2064.15.128.1 to 64.15.143.25464.15.143.2554,094
25064.15.144.0/2064.15.144.1 to 64.15.159.25464.15.159.2554,094
25164.15.160.0/2064.15.160.1 to 64.15.175.25464.15.175.2554,094
25264.15.176.0/2064.15.176.1 to 64.15.191.25464.15.191.2554,094
25364.15.192.0/2064.15.192.1 to 64.15.207.25464.15.207.2554,094
25464.15.208.0/2064.15.208.1 to 64.15.223.25464.15.223.2554,094
25564.15.224.0/2064.15.224.1 to 64.15.239.25464.15.239.2554,094
25664.15.240.0/2064.15.240.1 to 64.15.255.25464.15.255.2554,094

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.