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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.

Prefix/16
Addresses2^112
/64 networks2^48
Network
24cd::/16
First address
24cd::
Last address
24cd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
24cd:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
d.c.4.2.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

24cd::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
124cd::/3224cd:0:ffff:ffff:ffff:ffff:ffff:ffff
224cd:1::/3224cd:1:ffff:ffff:ffff:ffff:ffff:ffff
324cd:2::/3224cd:2:ffff:ffff:ffff:ffff:ffff:ffff
424cd:3::/3224cd:3:ffff:ffff:ffff:ffff:ffff:ffff
524cd:4::/3224cd:4:ffff:ffff:ffff:ffff:ffff:ffff
624cd:5::/3224cd:5:ffff:ffff:ffff:ffff:ffff:ffff
724cd:6::/3224cd:6:ffff:ffff:ffff:ffff:ffff:ffff
824cd:7::/3224cd:7:ffff:ffff:ffff:ffff:ffff:ffff
924cd:8::/3224cd:8:ffff:ffff:ffff:ffff:ffff:ffff
1024cd:9::/3224cd:9:ffff:ffff:ffff:ffff:ffff:ffff
1124cd:a::/3224cd:a:ffff:ffff:ffff:ffff:ffff:ffff
1224cd:b::/3224cd:b:ffff:ffff:ffff:ffff:ffff:ffff
1324cd:c::/3224cd:c:ffff:ffff:ffff:ffff:ffff:ffff
1424cd:d::/3224cd:d:ffff:ffff:ffff:ffff:ffff:ffff
1524cd:e::/3224cd:e:ffff:ffff:ffff:ffff:ffff:ffff
1624cd:f::/3224cd:f:ffff:ffff:ffff:ffff:ffff:ffff
1724cd:10::/3224cd:10:ffff:ffff:ffff:ffff:ffff:ffff
1824cd:11::/3224cd:11:ffff:ffff:ffff:ffff:ffff:ffff
1924cd:12::/3224cd:12:ffff:ffff:ffff:ffff:ffff:ffff
2024cd:13::/3224cd:13:ffff:ffff:ffff:ffff:ffff:ffff
2124cd:14::/3224cd:14:ffff:ffff:ffff:ffff:ffff:ffff
2224cd:15::/3224cd:15:ffff:ffff:ffff:ffff:ffff:ffff
2324cd:16::/3224cd:16:ffff:ffff:ffff:ffff:ffff:ffff
2424cd:17::/3224cd:17:ffff:ffff:ffff:ffff:ffff:ffff
2524cd:18::/3224cd:18:ffff:ffff:ffff:ffff:ffff:ffff
2624cd:19::/3224cd:19:ffff:ffff:ffff:ffff:ffff:ffff
2724cd:1a::/3224cd:1a:ffff:ffff:ffff:ffff:ffff:ffff
2824cd:1b::/3224cd:1b:ffff:ffff:ffff:ffff:ffff:ffff
2924cd:1c::/3224cd:1c:ffff:ffff:ffff:ffff:ffff:ffff
3024cd:1d::/3224cd:1d:ffff:ffff:ffff:ffff:ffff:ffff
3124cd:1e::/3224cd:1e:ffff:ffff:ffff:ffff:ffff:ffff
3224cd:1f::/3224cd:1f:ffff:ffff:ffff:ffff:ffff:ffff
3324cd:20::/3224cd:20:ffff:ffff:ffff:ffff:ffff:ffff
3424cd:21::/3224cd:21:ffff:ffff:ffff:ffff:ffff:ffff
3524cd:22::/3224cd:22:ffff:ffff:ffff:ffff:ffff:ffff
3624cd:23::/3224cd:23:ffff:ffff:ffff:ffff:ffff:ffff
3724cd:24::/3224cd:24:ffff:ffff:ffff:ffff:ffff:ffff
3824cd:25::/3224cd:25:ffff:ffff:ffff:ffff:ffff:ffff
3924cd:26::/3224cd:26:ffff:ffff:ffff:ffff:ffff:ffff
4024cd:27::/3224cd:27:ffff:ffff:ffff:ffff:ffff:ffff
4124cd:28::/3224cd:28:ffff:ffff:ffff:ffff:ffff:ffff
4224cd:29::/3224cd:29:ffff:ffff:ffff:ffff:ffff:ffff
4324cd:2a::/3224cd:2a:ffff:ffff:ffff:ffff:ffff:ffff
4424cd:2b::/3224cd:2b:ffff:ffff:ffff:ffff:ffff:ffff
4524cd:2c::/3224cd:2c:ffff:ffff:ffff:ffff:ffff:ffff
4624cd:2d::/3224cd:2d:ffff:ffff:ffff:ffff:ffff:ffff
4724cd:2e::/3224cd:2e:ffff:ffff:ffff:ffff:ffff:ffff
4824cd:2f::/3224cd:2f:ffff:ffff:ffff:ffff:ffff:ffff
4924cd:30::/3224cd:30:ffff:ffff:ffff:ffff:ffff:ffff
5024cd:31::/3224cd:31:ffff:ffff:ffff:ffff:ffff:ffff
5124cd:32::/3224cd:32:ffff:ffff:ffff:ffff:ffff:ffff
5224cd:33::/3224cd:33:ffff:ffff:ffff:ffff:ffff:ffff
5324cd:34::/3224cd:34:ffff:ffff:ffff:ffff:ffff:ffff
5424cd:35::/3224cd:35:ffff:ffff:ffff:ffff:ffff:ffff
5524cd:36::/3224cd:36:ffff:ffff:ffff:ffff:ffff:ffff
5624cd:37::/3224cd:37:ffff:ffff:ffff:ffff:ffff:ffff
5724cd:38::/3224cd:38:ffff:ffff:ffff:ffff:ffff:ffff
5824cd:39::/3224cd:39:ffff:ffff:ffff:ffff:ffff:ffff
5924cd:3a::/3224cd:3a:ffff:ffff:ffff:ffff:ffff:ffff
6024cd:3b::/3224cd:3b:ffff:ffff:ffff:ffff:ffff:ffff
6124cd:3c::/3224cd:3c:ffff:ffff:ffff:ffff:ffff:ffff
6224cd:3d::/3224cd:3d:ffff:ffff:ffff:ffff:ffff:ffff
6324cd:3e::/3224cd:3e:ffff:ffff:ffff:ffff:ffff:ffff
6424cd:3f::/3224cd:3f:ffff:ffff:ffff:ffff:ffff:ffff
6524cd:40::/3224cd:40:ffff:ffff:ffff:ffff:ffff:ffff
6624cd:41::/3224cd:41:ffff:ffff:ffff:ffff:ffff:ffff
6724cd:42::/3224cd:42:ffff:ffff:ffff:ffff:ffff:ffff
6824cd:43::/3224cd:43:ffff:ffff:ffff:ffff:ffff:ffff
6924cd:44::/3224cd:44:ffff:ffff:ffff:ffff:ffff:ffff
7024cd:45::/3224cd:45:ffff:ffff:ffff:ffff:ffff:ffff
7124cd:46::/3224cd:46:ffff:ffff:ffff:ffff:ffff:ffff
7224cd:47::/3224cd:47:ffff:ffff:ffff:ffff:ffff:ffff
7324cd:48::/3224cd:48:ffff:ffff:ffff:ffff:ffff:ffff
7424cd:49::/3224cd:49:ffff:ffff:ffff:ffff:ffff:ffff
7524cd:4a::/3224cd:4a:ffff:ffff:ffff:ffff:ffff:ffff
7624cd:4b::/3224cd:4b:ffff:ffff:ffff:ffff:ffff:ffff
7724cd:4c::/3224cd:4c:ffff:ffff:ffff:ffff:ffff:ffff
7824cd:4d::/3224cd:4d:ffff:ffff:ffff:ffff:ffff:ffff
7924cd:4e::/3224cd:4e:ffff:ffff:ffff:ffff:ffff:ffff
8024cd:4f::/3224cd:4f:ffff:ffff:ffff:ffff:ffff:ffff
8124cd:50::/3224cd:50:ffff:ffff:ffff:ffff:ffff:ffff
8224cd:51::/3224cd:51:ffff:ffff:ffff:ffff:ffff:ffff
8324cd:52::/3224cd:52:ffff:ffff:ffff:ffff:ffff:ffff
8424cd:53::/3224cd:53:ffff:ffff:ffff:ffff:ffff:ffff
8524cd:54::/3224cd:54:ffff:ffff:ffff:ffff:ffff:ffff
8624cd:55::/3224cd:55:ffff:ffff:ffff:ffff:ffff:ffff
8724cd:56::/3224cd:56:ffff:ffff:ffff:ffff:ffff:ffff
8824cd:57::/3224cd:57:ffff:ffff:ffff:ffff:ffff:ffff
8924cd:58::/3224cd:58:ffff:ffff:ffff:ffff:ffff:ffff
9024cd:59::/3224cd:59:ffff:ffff:ffff:ffff:ffff:ffff
9124cd:5a::/3224cd:5a:ffff:ffff:ffff:ffff:ffff:ffff
9224cd:5b::/3224cd:5b:ffff:ffff:ffff:ffff:ffff:ffff
9324cd:5c::/3224cd:5c:ffff:ffff:ffff:ffff:ffff:ffff
9424cd:5d::/3224cd:5d:ffff:ffff:ffff:ffff:ffff:ffff
9524cd:5e::/3224cd:5e:ffff:ffff:ffff:ffff:ffff:ffff
9624cd:5f::/3224cd:5f:ffff:ffff:ffff:ffff:ffff:ffff
9724cd:60::/3224cd:60:ffff:ffff:ffff:ffff:ffff:ffff
9824cd:61::/3224cd:61:ffff:ffff:ffff:ffff:ffff:ffff
9924cd:62::/3224cd:62:ffff:ffff:ffff:ffff:ffff:ffff
10024cd:63::/3224cd:63:ffff:ffff:ffff:ffff:ffff:ffff
10124cd:64::/3224cd:64:ffff:ffff:ffff:ffff:ffff:ffff
10224cd:65::/3224cd:65:ffff:ffff:ffff:ffff:ffff:ffff
10324cd:66::/3224cd:66:ffff:ffff:ffff:ffff:ffff:ffff
10424cd:67::/3224cd:67:ffff:ffff:ffff:ffff:ffff:ffff
10524cd:68::/3224cd:68:ffff:ffff:ffff:ffff:ffff:ffff
10624cd:69::/3224cd:69:ffff:ffff:ffff:ffff:ffff:ffff
10724cd:6a::/3224cd:6a:ffff:ffff:ffff:ffff:ffff:ffff
10824cd:6b::/3224cd:6b:ffff:ffff:ffff:ffff:ffff:ffff
10924cd:6c::/3224cd:6c:ffff:ffff:ffff:ffff:ffff:ffff
11024cd:6d::/3224cd:6d:ffff:ffff:ffff:ffff:ffff:ffff
11124cd:6e::/3224cd:6e:ffff:ffff:ffff:ffff:ffff:ffff
11224cd:6f::/3224cd:6f:ffff:ffff:ffff:ffff:ffff:ffff
11324cd:70::/3224cd:70:ffff:ffff:ffff:ffff:ffff:ffff
11424cd:71::/3224cd:71:ffff:ffff:ffff:ffff:ffff:ffff
11524cd:72::/3224cd:72:ffff:ffff:ffff:ffff:ffff:ffff
11624cd:73::/3224cd:73:ffff:ffff:ffff:ffff:ffff:ffff
11724cd:74::/3224cd:74:ffff:ffff:ffff:ffff:ffff:ffff
11824cd:75::/3224cd:75:ffff:ffff:ffff:ffff:ffff:ffff
11924cd:76::/3224cd:76:ffff:ffff:ffff:ffff:ffff:ffff
12024cd:77::/3224cd:77:ffff:ffff:ffff:ffff:ffff:ffff
12124cd:78::/3224cd:78:ffff:ffff:ffff:ffff:ffff:ffff
12224cd:79::/3224cd:79:ffff:ffff:ffff:ffff:ffff:ffff
12324cd:7a::/3224cd:7a:ffff:ffff:ffff:ffff:ffff:ffff
12424cd:7b::/3224cd:7b:ffff:ffff:ffff:ffff:ffff:ffff
12524cd:7c::/3224cd:7c:ffff:ffff:ffff:ffff:ffff:ffff
12624cd:7d::/3224cd:7d:ffff:ffff:ffff:ffff:ffff:ffff
12724cd:7e::/3224cd:7e:ffff:ffff:ffff:ffff:ffff:ffff
12824cd:7f::/3224cd:7f:ffff:ffff:ffff:ffff:ffff:ffff
12924cd:80::/3224cd:80:ffff:ffff:ffff:ffff:ffff:ffff
13024cd:81::/3224cd:81:ffff:ffff:ffff:ffff:ffff:ffff
13124cd:82::/3224cd:82:ffff:ffff:ffff:ffff:ffff:ffff
13224cd:83::/3224cd:83:ffff:ffff:ffff:ffff:ffff:ffff
13324cd:84::/3224cd:84:ffff:ffff:ffff:ffff:ffff:ffff
13424cd:85::/3224cd:85:ffff:ffff:ffff:ffff:ffff:ffff
13524cd:86::/3224cd:86:ffff:ffff:ffff:ffff:ffff:ffff
13624cd:87::/3224cd:87:ffff:ffff:ffff:ffff:ffff:ffff
13724cd:88::/3224cd:88:ffff:ffff:ffff:ffff:ffff:ffff
13824cd:89::/3224cd:89:ffff:ffff:ffff:ffff:ffff:ffff
13924cd:8a::/3224cd:8a:ffff:ffff:ffff:ffff:ffff:ffff
14024cd:8b::/3224cd:8b:ffff:ffff:ffff:ffff:ffff:ffff
14124cd:8c::/3224cd:8c:ffff:ffff:ffff:ffff:ffff:ffff
14224cd:8d::/3224cd:8d:ffff:ffff:ffff:ffff:ffff:ffff
14324cd:8e::/3224cd:8e:ffff:ffff:ffff:ffff:ffff:ffff
14424cd:8f::/3224cd:8f:ffff:ffff:ffff:ffff:ffff:ffff
14524cd:90::/3224cd:90:ffff:ffff:ffff:ffff:ffff:ffff
14624cd:91::/3224cd:91:ffff:ffff:ffff:ffff:ffff:ffff
14724cd:92::/3224cd:92:ffff:ffff:ffff:ffff:ffff:ffff
14824cd:93::/3224cd:93:ffff:ffff:ffff:ffff:ffff:ffff
14924cd:94::/3224cd:94:ffff:ffff:ffff:ffff:ffff:ffff
15024cd:95::/3224cd:95:ffff:ffff:ffff:ffff:ffff:ffff
15124cd:96::/3224cd:96:ffff:ffff:ffff:ffff:ffff:ffff
15224cd:97::/3224cd:97:ffff:ffff:ffff:ffff:ffff:ffff
15324cd:98::/3224cd:98:ffff:ffff:ffff:ffff:ffff:ffff
15424cd:99::/3224cd:99:ffff:ffff:ffff:ffff:ffff:ffff
15524cd:9a::/3224cd:9a:ffff:ffff:ffff:ffff:ffff:ffff
15624cd:9b::/3224cd:9b:ffff:ffff:ffff:ffff:ffff:ffff
15724cd:9c::/3224cd:9c:ffff:ffff:ffff:ffff:ffff:ffff
15824cd:9d::/3224cd:9d:ffff:ffff:ffff:ffff:ffff:ffff
15924cd:9e::/3224cd:9e:ffff:ffff:ffff:ffff:ffff:ffff
16024cd:9f::/3224cd:9f:ffff:ffff:ffff:ffff:ffff:ffff
16124cd:a0::/3224cd:a0:ffff:ffff:ffff:ffff:ffff:ffff
16224cd:a1::/3224cd:a1:ffff:ffff:ffff:ffff:ffff:ffff
16324cd:a2::/3224cd:a2:ffff:ffff:ffff:ffff:ffff:ffff
16424cd:a3::/3224cd:a3:ffff:ffff:ffff:ffff:ffff:ffff
16524cd:a4::/3224cd:a4:ffff:ffff:ffff:ffff:ffff:ffff
16624cd:a5::/3224cd:a5:ffff:ffff:ffff:ffff:ffff:ffff
16724cd:a6::/3224cd:a6:ffff:ffff:ffff:ffff:ffff:ffff
16824cd:a7::/3224cd:a7:ffff:ffff:ffff:ffff:ffff:ffff
16924cd:a8::/3224cd:a8:ffff:ffff:ffff:ffff:ffff:ffff
17024cd:a9::/3224cd:a9:ffff:ffff:ffff:ffff:ffff:ffff
17124cd:aa::/3224cd:aa:ffff:ffff:ffff:ffff:ffff:ffff
17224cd:ab::/3224cd:ab:ffff:ffff:ffff:ffff:ffff:ffff
17324cd:ac::/3224cd:ac:ffff:ffff:ffff:ffff:ffff:ffff
17424cd:ad::/3224cd:ad:ffff:ffff:ffff:ffff:ffff:ffff
17524cd:ae::/3224cd:ae:ffff:ffff:ffff:ffff:ffff:ffff
17624cd:af::/3224cd:af:ffff:ffff:ffff:ffff:ffff:ffff
17724cd:b0::/3224cd:b0:ffff:ffff:ffff:ffff:ffff:ffff
17824cd:b1::/3224cd:b1:ffff:ffff:ffff:ffff:ffff:ffff
17924cd:b2::/3224cd:b2:ffff:ffff:ffff:ffff:ffff:ffff
18024cd:b3::/3224cd:b3:ffff:ffff:ffff:ffff:ffff:ffff
18124cd:b4::/3224cd:b4:ffff:ffff:ffff:ffff:ffff:ffff
18224cd:b5::/3224cd:b5:ffff:ffff:ffff:ffff:ffff:ffff
18324cd:b6::/3224cd:b6:ffff:ffff:ffff:ffff:ffff:ffff
18424cd:b7::/3224cd:b7:ffff:ffff:ffff:ffff:ffff:ffff
18524cd:b8::/3224cd:b8:ffff:ffff:ffff:ffff:ffff:ffff
18624cd:b9::/3224cd:b9:ffff:ffff:ffff:ffff:ffff:ffff
18724cd:ba::/3224cd:ba:ffff:ffff:ffff:ffff:ffff:ffff
18824cd:bb::/3224cd:bb:ffff:ffff:ffff:ffff:ffff:ffff
18924cd:bc::/3224cd:bc:ffff:ffff:ffff:ffff:ffff:ffff
19024cd:bd::/3224cd:bd:ffff:ffff:ffff:ffff:ffff:ffff
19124cd:be::/3224cd:be:ffff:ffff:ffff:ffff:ffff:ffff
19224cd:bf::/3224cd:bf:ffff:ffff:ffff:ffff:ffff:ffff
19324cd:c0::/3224cd:c0:ffff:ffff:ffff:ffff:ffff:ffff
19424cd:c1::/3224cd:c1:ffff:ffff:ffff:ffff:ffff:ffff
19524cd:c2::/3224cd:c2:ffff:ffff:ffff:ffff:ffff:ffff
19624cd:c3::/3224cd:c3:ffff:ffff:ffff:ffff:ffff:ffff
19724cd:c4::/3224cd:c4:ffff:ffff:ffff:ffff:ffff:ffff
19824cd:c5::/3224cd:c5:ffff:ffff:ffff:ffff:ffff:ffff
19924cd:c6::/3224cd:c6:ffff:ffff:ffff:ffff:ffff:ffff
20024cd:c7::/3224cd:c7:ffff:ffff:ffff:ffff:ffff:ffff
20124cd:c8::/3224cd:c8:ffff:ffff:ffff:ffff:ffff:ffff
20224cd:c9::/3224cd:c9:ffff:ffff:ffff:ffff:ffff:ffff
20324cd:ca::/3224cd:ca:ffff:ffff:ffff:ffff:ffff:ffff
20424cd:cb::/3224cd:cb:ffff:ffff:ffff:ffff:ffff:ffff
20524cd:cc::/3224cd:cc:ffff:ffff:ffff:ffff:ffff:ffff
20624cd:cd::/3224cd:cd:ffff:ffff:ffff:ffff:ffff:ffff
20724cd:ce::/3224cd:ce:ffff:ffff:ffff:ffff:ffff:ffff
20824cd:cf::/3224cd:cf:ffff:ffff:ffff:ffff:ffff:ffff
20924cd:d0::/3224cd:d0:ffff:ffff:ffff:ffff:ffff:ffff
21024cd:d1::/3224cd:d1:ffff:ffff:ffff:ffff:ffff:ffff
21124cd:d2::/3224cd:d2:ffff:ffff:ffff:ffff:ffff:ffff
21224cd:d3::/3224cd:d3:ffff:ffff:ffff:ffff:ffff:ffff
21324cd:d4::/3224cd:d4:ffff:ffff:ffff:ffff:ffff:ffff
21424cd:d5::/3224cd:d5:ffff:ffff:ffff:ffff:ffff:ffff
21524cd:d6::/3224cd:d6:ffff:ffff:ffff:ffff:ffff:ffff
21624cd:d7::/3224cd:d7:ffff:ffff:ffff:ffff:ffff:ffff
21724cd:d8::/3224cd:d8:ffff:ffff:ffff:ffff:ffff:ffff
21824cd:d9::/3224cd:d9:ffff:ffff:ffff:ffff:ffff:ffff
21924cd:da::/3224cd:da:ffff:ffff:ffff:ffff:ffff:ffff
22024cd:db::/3224cd:db:ffff:ffff:ffff:ffff:ffff:ffff
22124cd:dc::/3224cd:dc:ffff:ffff:ffff:ffff:ffff:ffff
22224cd:dd::/3224cd:dd:ffff:ffff:ffff:ffff:ffff:ffff
22324cd:de::/3224cd:de:ffff:ffff:ffff:ffff:ffff:ffff
22424cd:df::/3224cd:df:ffff:ffff:ffff:ffff:ffff:ffff
22524cd:e0::/3224cd:e0:ffff:ffff:ffff:ffff:ffff:ffff
22624cd:e1::/3224cd:e1:ffff:ffff:ffff:ffff:ffff:ffff
22724cd:e2::/3224cd:e2:ffff:ffff:ffff:ffff:ffff:ffff
22824cd:e3::/3224cd:e3:ffff:ffff:ffff:ffff:ffff:ffff
22924cd:e4::/3224cd:e4:ffff:ffff:ffff:ffff:ffff:ffff
23024cd:e5::/3224cd:e5:ffff:ffff:ffff:ffff:ffff:ffff
23124cd:e6::/3224cd:e6:ffff:ffff:ffff:ffff:ffff:ffff
23224cd:e7::/3224cd:e7:ffff:ffff:ffff:ffff:ffff:ffff
23324cd:e8::/3224cd:e8:ffff:ffff:ffff:ffff:ffff:ffff
23424cd:e9::/3224cd:e9:ffff:ffff:ffff:ffff:ffff:ffff
23524cd:ea::/3224cd:ea:ffff:ffff:ffff:ffff:ffff:ffff
23624cd:eb::/3224cd:eb:ffff:ffff:ffff:ffff:ffff:ffff
23724cd:ec::/3224cd:ec:ffff:ffff:ffff:ffff:ffff:ffff
23824cd:ed::/3224cd:ed:ffff:ffff:ffff:ffff:ffff:ffff
23924cd:ee::/3224cd:ee:ffff:ffff:ffff:ffff:ffff:ffff
24024cd:ef::/3224cd:ef:ffff:ffff:ffff:ffff:ffff:ffff
24124cd:f0::/3224cd:f0:ffff:ffff:ffff:ffff:ffff:ffff
24224cd:f1::/3224cd:f1:ffff:ffff:ffff:ffff:ffff:ffff
24324cd:f2::/3224cd:f2:ffff:ffff:ffff:ffff:ffff:ffff
24424cd:f3::/3224cd:f3:ffff:ffff:ffff:ffff:ffff:ffff
24524cd:f4::/3224cd:f4:ffff:ffff:ffff:ffff:ffff:ffff
24624cd:f5::/3224cd:f5:ffff:ffff:ffff:ffff:ffff:ffff
24724cd:f6::/3224cd:f6:ffff:ffff:ffff:ffff:ffff:ffff
24824cd:f7::/3224cd:f7:ffff:ffff:ffff:ffff:ffff:ffff
24924cd:f8::/3224cd:f8:ffff:ffff:ffff:ffff:ffff:ffff
25024cd:f9::/3224cd:f9:ffff:ffff:ffff:ffff:ffff:ffff
25124cd:fa::/3224cd:fa:ffff:ffff:ffff:ffff:ffff:ffff
25224cd:fb::/3224cd:fb:ffff:ffff:ffff:ffff:ffff:ffff
25324cd:fc::/3224cd:fc:ffff:ffff:ffff:ffff:ffff:ffff
25424cd:fd::/3224cd:fd:ffff:ffff:ffff:ffff:ffff:ffff
25524cd:fe::/3224cd:fe:ffff:ffff:ffff:ffff:ffff:ffff
25624cd:ff::/3224cd:ff:ffff:ffff:ffff:ffff:ffff:ffff

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.