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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.

Network64.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
64.0.0.0
Broadcast address
67.255.255.255
First usable
64.0.0.1
Last usable
67.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 40000000 · Integer 1073741824 to 1140850687
Reverse DNS zones
64.in-addr.arpa
65.in-addr.arpa
66.in-addr.arpa
67.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000000.00000000.00000000.0000000064.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01000000.00000000.00000000.0000000064.0.0.0
Broadcast01000011.11111111.11111111.1111111167.255.255.255
Split into smaller subnets/18
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

64.0.0.0/6 makes 4,096 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
164.0.0.0/1864.0.0.1 to 64.0.63.25464.0.63.25516,382
264.0.64.0/1864.0.64.1 to 64.0.127.25464.0.127.25516,382
364.0.128.0/1864.0.128.1 to 64.0.191.25464.0.191.25516,382
464.0.192.0/1864.0.192.1 to 64.0.255.25464.0.255.25516,382
564.1.0.0/1864.1.0.1 to 64.1.63.25464.1.63.25516,382
664.1.64.0/1864.1.64.1 to 64.1.127.25464.1.127.25516,382
764.1.128.0/1864.1.128.1 to 64.1.191.25464.1.191.25516,382
864.1.192.0/1864.1.192.1 to 64.1.255.25464.1.255.25516,382
964.2.0.0/1864.2.0.1 to 64.2.63.25464.2.63.25516,382
1064.2.64.0/1864.2.64.1 to 64.2.127.25464.2.127.25516,382
1164.2.128.0/1864.2.128.1 to 64.2.191.25464.2.191.25516,382
1264.2.192.0/1864.2.192.1 to 64.2.255.25464.2.255.25516,382
1364.3.0.0/1864.3.0.1 to 64.3.63.25464.3.63.25516,382
1464.3.64.0/1864.3.64.1 to 64.3.127.25464.3.127.25516,382
1564.3.128.0/1864.3.128.1 to 64.3.191.25464.3.191.25516,382
1664.3.192.0/1864.3.192.1 to 64.3.255.25464.3.255.25516,382
1764.4.0.0/1864.4.0.1 to 64.4.63.25464.4.63.25516,382
1864.4.64.0/1864.4.64.1 to 64.4.127.25464.4.127.25516,382
1964.4.128.0/1864.4.128.1 to 64.4.191.25464.4.191.25516,382
2064.4.192.0/1864.4.192.1 to 64.4.255.25464.4.255.25516,382
2164.5.0.0/1864.5.0.1 to 64.5.63.25464.5.63.25516,382
2264.5.64.0/1864.5.64.1 to 64.5.127.25464.5.127.25516,382
2364.5.128.0/1864.5.128.1 to 64.5.191.25464.5.191.25516,382
2464.5.192.0/1864.5.192.1 to 64.5.255.25464.5.255.25516,382
2564.6.0.0/1864.6.0.1 to 64.6.63.25464.6.63.25516,382
2664.6.64.0/1864.6.64.1 to 64.6.127.25464.6.127.25516,382
2764.6.128.0/1864.6.128.1 to 64.6.191.25464.6.191.25516,382
2864.6.192.0/1864.6.192.1 to 64.6.255.25464.6.255.25516,382
2964.7.0.0/1864.7.0.1 to 64.7.63.25464.7.63.25516,382
3064.7.64.0/1864.7.64.1 to 64.7.127.25464.7.127.25516,382
3164.7.128.0/1864.7.128.1 to 64.7.191.25464.7.191.25516,382
3264.7.192.0/1864.7.192.1 to 64.7.255.25464.7.255.25516,382
3364.8.0.0/1864.8.0.1 to 64.8.63.25464.8.63.25516,382
3464.8.64.0/1864.8.64.1 to 64.8.127.25464.8.127.25516,382
3564.8.128.0/1864.8.128.1 to 64.8.191.25464.8.191.25516,382
3664.8.192.0/1864.8.192.1 to 64.8.255.25464.8.255.25516,382
3764.9.0.0/1864.9.0.1 to 64.9.63.25464.9.63.25516,382
3864.9.64.0/1864.9.64.1 to 64.9.127.25464.9.127.25516,382
3964.9.128.0/1864.9.128.1 to 64.9.191.25464.9.191.25516,382
4064.9.192.0/1864.9.192.1 to 64.9.255.25464.9.255.25516,382
4164.10.0.0/1864.10.0.1 to 64.10.63.25464.10.63.25516,382
4264.10.64.0/1864.10.64.1 to 64.10.127.25464.10.127.25516,382
4364.10.128.0/1864.10.128.1 to 64.10.191.25464.10.191.25516,382
4464.10.192.0/1864.10.192.1 to 64.10.255.25464.10.255.25516,382
4564.11.0.0/1864.11.0.1 to 64.11.63.25464.11.63.25516,382
4664.11.64.0/1864.11.64.1 to 64.11.127.25464.11.127.25516,382
4764.11.128.0/1864.11.128.1 to 64.11.191.25464.11.191.25516,382
4864.11.192.0/1864.11.192.1 to 64.11.255.25464.11.255.25516,382
4964.12.0.0/1864.12.0.1 to 64.12.63.25464.12.63.25516,382
5064.12.64.0/1864.12.64.1 to 64.12.127.25464.12.127.25516,382
5164.12.128.0/1864.12.128.1 to 64.12.191.25464.12.191.25516,382
5264.12.192.0/1864.12.192.1 to 64.12.255.25464.12.255.25516,382
5364.13.0.0/1864.13.0.1 to 64.13.63.25464.13.63.25516,382
5464.13.64.0/1864.13.64.1 to 64.13.127.25464.13.127.25516,382
5564.13.128.0/1864.13.128.1 to 64.13.191.25464.13.191.25516,382
5664.13.192.0/1864.13.192.1 to 64.13.255.25464.13.255.25516,382
5764.14.0.0/1864.14.0.1 to 64.14.63.25464.14.63.25516,382
5864.14.64.0/1864.14.64.1 to 64.14.127.25464.14.127.25516,382
5964.14.128.0/1864.14.128.1 to 64.14.191.25464.14.191.25516,382
6064.14.192.0/1864.14.192.1 to 64.14.255.25464.14.255.25516,382
6164.15.0.0/1864.15.0.1 to 64.15.63.25464.15.63.25516,382
6264.15.64.0/1864.15.64.1 to 64.15.127.25464.15.127.25516,382
6364.15.128.0/1864.15.128.1 to 64.15.191.25464.15.191.25516,382
6464.15.192.0/1864.15.192.1 to 64.15.255.25464.15.255.25516,382
6564.16.0.0/1864.16.0.1 to 64.16.63.25464.16.63.25516,382
6664.16.64.0/1864.16.64.1 to 64.16.127.25464.16.127.25516,382
6764.16.128.0/1864.16.128.1 to 64.16.191.25464.16.191.25516,382
6864.16.192.0/1864.16.192.1 to 64.16.255.25464.16.255.25516,382
6964.17.0.0/1864.17.0.1 to 64.17.63.25464.17.63.25516,382
7064.17.64.0/1864.17.64.1 to 64.17.127.25464.17.127.25516,382
7164.17.128.0/1864.17.128.1 to 64.17.191.25464.17.191.25516,382
7264.17.192.0/1864.17.192.1 to 64.17.255.25464.17.255.25516,382
7364.18.0.0/1864.18.0.1 to 64.18.63.25464.18.63.25516,382
7464.18.64.0/1864.18.64.1 to 64.18.127.25464.18.127.25516,382
7564.18.128.0/1864.18.128.1 to 64.18.191.25464.18.191.25516,382
7664.18.192.0/1864.18.192.1 to 64.18.255.25464.18.255.25516,382
7764.19.0.0/1864.19.0.1 to 64.19.63.25464.19.63.25516,382
7864.19.64.0/1864.19.64.1 to 64.19.127.25464.19.127.25516,382
7964.19.128.0/1864.19.128.1 to 64.19.191.25464.19.191.25516,382
8064.19.192.0/1864.19.192.1 to 64.19.255.25464.19.255.25516,382
8164.20.0.0/1864.20.0.1 to 64.20.63.25464.20.63.25516,382
8264.20.64.0/1864.20.64.1 to 64.20.127.25464.20.127.25516,382
8364.20.128.0/1864.20.128.1 to 64.20.191.25464.20.191.25516,382
8464.20.192.0/1864.20.192.1 to 64.20.255.25464.20.255.25516,382
8564.21.0.0/1864.21.0.1 to 64.21.63.25464.21.63.25516,382
8664.21.64.0/1864.21.64.1 to 64.21.127.25464.21.127.25516,382
8764.21.128.0/1864.21.128.1 to 64.21.191.25464.21.191.25516,382
8864.21.192.0/1864.21.192.1 to 64.21.255.25464.21.255.25516,382
8964.22.0.0/1864.22.0.1 to 64.22.63.25464.22.63.25516,382
9064.22.64.0/1864.22.64.1 to 64.22.127.25464.22.127.25516,382
9164.22.128.0/1864.22.128.1 to 64.22.191.25464.22.191.25516,382
9264.22.192.0/1864.22.192.1 to 64.22.255.25464.22.255.25516,382
9364.23.0.0/1864.23.0.1 to 64.23.63.25464.23.63.25516,382
9464.23.64.0/1864.23.64.1 to 64.23.127.25464.23.127.25516,382
9564.23.128.0/1864.23.128.1 to 64.23.191.25464.23.191.25516,382
9664.23.192.0/1864.23.192.1 to 64.23.255.25464.23.255.25516,382
9764.24.0.0/1864.24.0.1 to 64.24.63.25464.24.63.25516,382
9864.24.64.0/1864.24.64.1 to 64.24.127.25464.24.127.25516,382
9964.24.128.0/1864.24.128.1 to 64.24.191.25464.24.191.25516,382
10064.24.192.0/1864.24.192.1 to 64.24.255.25464.24.255.25516,382
10164.25.0.0/1864.25.0.1 to 64.25.63.25464.25.63.25516,382
10264.25.64.0/1864.25.64.1 to 64.25.127.25464.25.127.25516,382
10364.25.128.0/1864.25.128.1 to 64.25.191.25464.25.191.25516,382
10464.25.192.0/1864.25.192.1 to 64.25.255.25464.25.255.25516,382
10564.26.0.0/1864.26.0.1 to 64.26.63.25464.26.63.25516,382
10664.26.64.0/1864.26.64.1 to 64.26.127.25464.26.127.25516,382
10764.26.128.0/1864.26.128.1 to 64.26.191.25464.26.191.25516,382
10864.26.192.0/1864.26.192.1 to 64.26.255.25464.26.255.25516,382
10964.27.0.0/1864.27.0.1 to 64.27.63.25464.27.63.25516,382
11064.27.64.0/1864.27.64.1 to 64.27.127.25464.27.127.25516,382
11164.27.128.0/1864.27.128.1 to 64.27.191.25464.27.191.25516,382
11264.27.192.0/1864.27.192.1 to 64.27.255.25464.27.255.25516,382
11364.28.0.0/1864.28.0.1 to 64.28.63.25464.28.63.25516,382
11464.28.64.0/1864.28.64.1 to 64.28.127.25464.28.127.25516,382
11564.28.128.0/1864.28.128.1 to 64.28.191.25464.28.191.25516,382
11664.28.192.0/1864.28.192.1 to 64.28.255.25464.28.255.25516,382
11764.29.0.0/1864.29.0.1 to 64.29.63.25464.29.63.25516,382
11864.29.64.0/1864.29.64.1 to 64.29.127.25464.29.127.25516,382
11964.29.128.0/1864.29.128.1 to 64.29.191.25464.29.191.25516,382
12064.29.192.0/1864.29.192.1 to 64.29.255.25464.29.255.25516,382
12164.30.0.0/1864.30.0.1 to 64.30.63.25464.30.63.25516,382
12264.30.64.0/1864.30.64.1 to 64.30.127.25464.30.127.25516,382
12364.30.128.0/1864.30.128.1 to 64.30.191.25464.30.191.25516,382
12464.30.192.0/1864.30.192.1 to 64.30.255.25464.30.255.25516,382
12564.31.0.0/1864.31.0.1 to 64.31.63.25464.31.63.25516,382
12664.31.64.0/1864.31.64.1 to 64.31.127.25464.31.127.25516,382
12764.31.128.0/1864.31.128.1 to 64.31.191.25464.31.191.25516,382
12864.31.192.0/1864.31.192.1 to 64.31.255.25464.31.255.25516,382
12964.32.0.0/1864.32.0.1 to 64.32.63.25464.32.63.25516,382
13064.32.64.0/1864.32.64.1 to 64.32.127.25464.32.127.25516,382
13164.32.128.0/1864.32.128.1 to 64.32.191.25464.32.191.25516,382
13264.32.192.0/1864.32.192.1 to 64.32.255.25464.32.255.25516,382
13364.33.0.0/1864.33.0.1 to 64.33.63.25464.33.63.25516,382
13464.33.64.0/1864.33.64.1 to 64.33.127.25464.33.127.25516,382
13564.33.128.0/1864.33.128.1 to 64.33.191.25464.33.191.25516,382
13664.33.192.0/1864.33.192.1 to 64.33.255.25464.33.255.25516,382
13764.34.0.0/1864.34.0.1 to 64.34.63.25464.34.63.25516,382
13864.34.64.0/1864.34.64.1 to 64.34.127.25464.34.127.25516,382
13964.34.128.0/1864.34.128.1 to 64.34.191.25464.34.191.25516,382
14064.34.192.0/1864.34.192.1 to 64.34.255.25464.34.255.25516,382
14164.35.0.0/1864.35.0.1 to 64.35.63.25464.35.63.25516,382
14264.35.64.0/1864.35.64.1 to 64.35.127.25464.35.127.25516,382
14364.35.128.0/1864.35.128.1 to 64.35.191.25464.35.191.25516,382
14464.35.192.0/1864.35.192.1 to 64.35.255.25464.35.255.25516,382
14564.36.0.0/1864.36.0.1 to 64.36.63.25464.36.63.25516,382
14664.36.64.0/1864.36.64.1 to 64.36.127.25464.36.127.25516,382
14764.36.128.0/1864.36.128.1 to 64.36.191.25464.36.191.25516,382
14864.36.192.0/1864.36.192.1 to 64.36.255.25464.36.255.25516,382
14964.37.0.0/1864.37.0.1 to 64.37.63.25464.37.63.25516,382
15064.37.64.0/1864.37.64.1 to 64.37.127.25464.37.127.25516,382
15164.37.128.0/1864.37.128.1 to 64.37.191.25464.37.191.25516,382
15264.37.192.0/1864.37.192.1 to 64.37.255.25464.37.255.25516,382
15364.38.0.0/1864.38.0.1 to 64.38.63.25464.38.63.25516,382
15464.38.64.0/1864.38.64.1 to 64.38.127.25464.38.127.25516,382
15564.38.128.0/1864.38.128.1 to 64.38.191.25464.38.191.25516,382
15664.38.192.0/1864.38.192.1 to 64.38.255.25464.38.255.25516,382
15764.39.0.0/1864.39.0.1 to 64.39.63.25464.39.63.25516,382
15864.39.64.0/1864.39.64.1 to 64.39.127.25464.39.127.25516,382
15964.39.128.0/1864.39.128.1 to 64.39.191.25464.39.191.25516,382
16064.39.192.0/1864.39.192.1 to 64.39.255.25464.39.255.25516,382
16164.40.0.0/1864.40.0.1 to 64.40.63.25464.40.63.25516,382
16264.40.64.0/1864.40.64.1 to 64.40.127.25464.40.127.25516,382
16364.40.128.0/1864.40.128.1 to 64.40.191.25464.40.191.25516,382
16464.40.192.0/1864.40.192.1 to 64.40.255.25464.40.255.25516,382
16564.41.0.0/1864.41.0.1 to 64.41.63.25464.41.63.25516,382
16664.41.64.0/1864.41.64.1 to 64.41.127.25464.41.127.25516,382
16764.41.128.0/1864.41.128.1 to 64.41.191.25464.41.191.25516,382
16864.41.192.0/1864.41.192.1 to 64.41.255.25464.41.255.25516,382
16964.42.0.0/1864.42.0.1 to 64.42.63.25464.42.63.25516,382
17064.42.64.0/1864.42.64.1 to 64.42.127.25464.42.127.25516,382
17164.42.128.0/1864.42.128.1 to 64.42.191.25464.42.191.25516,382
17264.42.192.0/1864.42.192.1 to 64.42.255.25464.42.255.25516,382
17364.43.0.0/1864.43.0.1 to 64.43.63.25464.43.63.25516,382
17464.43.64.0/1864.43.64.1 to 64.43.127.25464.43.127.25516,382
17564.43.128.0/1864.43.128.1 to 64.43.191.25464.43.191.25516,382
17664.43.192.0/1864.43.192.1 to 64.43.255.25464.43.255.25516,382
17764.44.0.0/1864.44.0.1 to 64.44.63.25464.44.63.25516,382
17864.44.64.0/1864.44.64.1 to 64.44.127.25464.44.127.25516,382
17964.44.128.0/1864.44.128.1 to 64.44.191.25464.44.191.25516,382
18064.44.192.0/1864.44.192.1 to 64.44.255.25464.44.255.25516,382
18164.45.0.0/1864.45.0.1 to 64.45.63.25464.45.63.25516,382
18264.45.64.0/1864.45.64.1 to 64.45.127.25464.45.127.25516,382
18364.45.128.0/1864.45.128.1 to 64.45.191.25464.45.191.25516,382
18464.45.192.0/1864.45.192.1 to 64.45.255.25464.45.255.25516,382
18564.46.0.0/1864.46.0.1 to 64.46.63.25464.46.63.25516,382
18664.46.64.0/1864.46.64.1 to 64.46.127.25464.46.127.25516,382
18764.46.128.0/1864.46.128.1 to 64.46.191.25464.46.191.25516,382
18864.46.192.0/1864.46.192.1 to 64.46.255.25464.46.255.25516,382
18964.47.0.0/1864.47.0.1 to 64.47.63.25464.47.63.25516,382
19064.47.64.0/1864.47.64.1 to 64.47.127.25464.47.127.25516,382
19164.47.128.0/1864.47.128.1 to 64.47.191.25464.47.191.25516,382
19264.47.192.0/1864.47.192.1 to 64.47.255.25464.47.255.25516,382
19364.48.0.0/1864.48.0.1 to 64.48.63.25464.48.63.25516,382
19464.48.64.0/1864.48.64.1 to 64.48.127.25464.48.127.25516,382
19564.48.128.0/1864.48.128.1 to 64.48.191.25464.48.191.25516,382
19664.48.192.0/1864.48.192.1 to 64.48.255.25464.48.255.25516,382
19764.49.0.0/1864.49.0.1 to 64.49.63.25464.49.63.25516,382
19864.49.64.0/1864.49.64.1 to 64.49.127.25464.49.127.25516,382
19964.49.128.0/1864.49.128.1 to 64.49.191.25464.49.191.25516,382
20064.49.192.0/1864.49.192.1 to 64.49.255.25464.49.255.25516,382
20164.50.0.0/1864.50.0.1 to 64.50.63.25464.50.63.25516,382
20264.50.64.0/1864.50.64.1 to 64.50.127.25464.50.127.25516,382
20364.50.128.0/1864.50.128.1 to 64.50.191.25464.50.191.25516,382
20464.50.192.0/1864.50.192.1 to 64.50.255.25464.50.255.25516,382
20564.51.0.0/1864.51.0.1 to 64.51.63.25464.51.63.25516,382
20664.51.64.0/1864.51.64.1 to 64.51.127.25464.51.127.25516,382
20764.51.128.0/1864.51.128.1 to 64.51.191.25464.51.191.25516,382
20864.51.192.0/1864.51.192.1 to 64.51.255.25464.51.255.25516,382
20964.52.0.0/1864.52.0.1 to 64.52.63.25464.52.63.25516,382
21064.52.64.0/1864.52.64.1 to 64.52.127.25464.52.127.25516,382
21164.52.128.0/1864.52.128.1 to 64.52.191.25464.52.191.25516,382
21264.52.192.0/1864.52.192.1 to 64.52.255.25464.52.255.25516,382
21364.53.0.0/1864.53.0.1 to 64.53.63.25464.53.63.25516,382
21464.53.64.0/1864.53.64.1 to 64.53.127.25464.53.127.25516,382
21564.53.128.0/1864.53.128.1 to 64.53.191.25464.53.191.25516,382
21664.53.192.0/1864.53.192.1 to 64.53.255.25464.53.255.25516,382
21764.54.0.0/1864.54.0.1 to 64.54.63.25464.54.63.25516,382
21864.54.64.0/1864.54.64.1 to 64.54.127.25464.54.127.25516,382
21964.54.128.0/1864.54.128.1 to 64.54.191.25464.54.191.25516,382
22064.54.192.0/1864.54.192.1 to 64.54.255.25464.54.255.25516,382
22164.55.0.0/1864.55.0.1 to 64.55.63.25464.55.63.25516,382
22264.55.64.0/1864.55.64.1 to 64.55.127.25464.55.127.25516,382
22364.55.128.0/1864.55.128.1 to 64.55.191.25464.55.191.25516,382
22464.55.192.0/1864.55.192.1 to 64.55.255.25464.55.255.25516,382
22564.56.0.0/1864.56.0.1 to 64.56.63.25464.56.63.25516,382
22664.56.64.0/1864.56.64.1 to 64.56.127.25464.56.127.25516,382
22764.56.128.0/1864.56.128.1 to 64.56.191.25464.56.191.25516,382
22864.56.192.0/1864.56.192.1 to 64.56.255.25464.56.255.25516,382
22964.57.0.0/1864.57.0.1 to 64.57.63.25464.57.63.25516,382
23064.57.64.0/1864.57.64.1 to 64.57.127.25464.57.127.25516,382
23164.57.128.0/1864.57.128.1 to 64.57.191.25464.57.191.25516,382
23264.57.192.0/1864.57.192.1 to 64.57.255.25464.57.255.25516,382
23364.58.0.0/1864.58.0.1 to 64.58.63.25464.58.63.25516,382
23464.58.64.0/1864.58.64.1 to 64.58.127.25464.58.127.25516,382
23564.58.128.0/1864.58.128.1 to 64.58.191.25464.58.191.25516,382
23664.58.192.0/1864.58.192.1 to 64.58.255.25464.58.255.25516,382
23764.59.0.0/1864.59.0.1 to 64.59.63.25464.59.63.25516,382
23864.59.64.0/1864.59.64.1 to 64.59.127.25464.59.127.25516,382
23964.59.128.0/1864.59.128.1 to 64.59.191.25464.59.191.25516,382
24064.59.192.0/1864.59.192.1 to 64.59.255.25464.59.255.25516,382
24164.60.0.0/1864.60.0.1 to 64.60.63.25464.60.63.25516,382
24264.60.64.0/1864.60.64.1 to 64.60.127.25464.60.127.25516,382
24364.60.128.0/1864.60.128.1 to 64.60.191.25464.60.191.25516,382
24464.60.192.0/1864.60.192.1 to 64.60.255.25464.60.255.25516,382
24564.61.0.0/1864.61.0.1 to 64.61.63.25464.61.63.25516,382
24664.61.64.0/1864.61.64.1 to 64.61.127.25464.61.127.25516,382
24764.61.128.0/1864.61.128.1 to 64.61.191.25464.61.191.25516,382
24864.61.192.0/1864.61.192.1 to 64.61.255.25464.61.255.25516,382
24964.62.0.0/1864.62.0.1 to 64.62.63.25464.62.63.25516,382
25064.62.64.0/1864.62.64.1 to 64.62.127.25464.62.127.25516,382
25164.62.128.0/1864.62.128.1 to 64.62.191.25464.62.191.25516,382
25264.62.192.0/1864.62.192.1 to 64.62.255.25464.62.255.25516,382
25364.63.0.0/1864.63.0.1 to 64.63.63.25464.63.63.25516,382
25464.63.64.0/1864.63.64.1 to 64.63.127.25464.63.127.25516,382
25564.63.128.0/1864.63.128.1 to 64.63.191.25464.63.191.25516,382
25664.63.192.0/1864.63.192.1 to 64.63.255.25464.63.255.25516,382

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.