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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/7
Addresses2^121
/64 networks2^57
Network
3600::/7
First address
3600::
Last address
37ff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
2,658,455,991,569,831,745,807,614,120,560,689,152 (2^121)
/64 networks (LANs)
144,115,188,075,855,872 (2^57)
Full form
3600:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
6.3.ip6.arpa
7.3.ip6.arpa
/7 is not on a 4-bit boundary, so it takes 2 /8 zones.
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/16 (512)/20 (8,192)

3600::/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetLast address
13600::/163600:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23601::/163601:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33602::/163602:ffff:ffff:ffff:ffff:ffff:ffff:ffff
43603::/163603:ffff:ffff:ffff:ffff:ffff:ffff:ffff
53604::/163604:ffff:ffff:ffff:ffff:ffff:ffff:ffff
63605::/163605:ffff:ffff:ffff:ffff:ffff:ffff:ffff
73606::/163606:ffff:ffff:ffff:ffff:ffff:ffff:ffff
83607::/163607:ffff:ffff:ffff:ffff:ffff:ffff:ffff
93608::/163608:ffff:ffff:ffff:ffff:ffff:ffff:ffff
103609::/163609:ffff:ffff:ffff:ffff:ffff:ffff:ffff
11360a::/16360a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
12360b::/16360b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
13360c::/16360c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
14360d::/16360d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
15360e::/16360e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16360f::/16360f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
173610::/163610:ffff:ffff:ffff:ffff:ffff:ffff:ffff
183611::/163611:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193612::/163612:ffff:ffff:ffff:ffff:ffff:ffff:ffff
203613::/163613:ffff:ffff:ffff:ffff:ffff:ffff:ffff
213614::/163614:ffff:ffff:ffff:ffff:ffff:ffff:ffff
223615::/163615:ffff:ffff:ffff:ffff:ffff:ffff:ffff
233616::/163616:ffff:ffff:ffff:ffff:ffff:ffff:ffff
243617::/163617:ffff:ffff:ffff:ffff:ffff:ffff:ffff
253618::/163618:ffff:ffff:ffff:ffff:ffff:ffff:ffff
263619::/163619:ffff:ffff:ffff:ffff:ffff:ffff:ffff
27361a::/16361a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
28361b::/16361b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
29361c::/16361c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
30361d::/16361d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
31361e::/16361e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
32361f::/16361f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
333620::/163620:ffff:ffff:ffff:ffff:ffff:ffff:ffff
343621::/163621:ffff:ffff:ffff:ffff:ffff:ffff:ffff
353622::/163622:ffff:ffff:ffff:ffff:ffff:ffff:ffff
363623::/163623:ffff:ffff:ffff:ffff:ffff:ffff:ffff
373624::/163624:ffff:ffff:ffff:ffff:ffff:ffff:ffff
383625::/163625:ffff:ffff:ffff:ffff:ffff:ffff:ffff
393626::/163626:ffff:ffff:ffff:ffff:ffff:ffff:ffff
403627::/163627:ffff:ffff:ffff:ffff:ffff:ffff:ffff
413628::/163628:ffff:ffff:ffff:ffff:ffff:ffff:ffff
423629::/163629:ffff:ffff:ffff:ffff:ffff:ffff:ffff
43362a::/16362a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
44362b::/16362b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
45362c::/16362c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
46362d::/16362d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
47362e::/16362e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
48362f::/16362f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
493630::/163630:ffff:ffff:ffff:ffff:ffff:ffff:ffff
503631::/163631:ffff:ffff:ffff:ffff:ffff:ffff:ffff
513632::/163632:ffff:ffff:ffff:ffff:ffff:ffff:ffff
523633::/163633:ffff:ffff:ffff:ffff:ffff:ffff:ffff
533634::/163634:ffff:ffff:ffff:ffff:ffff:ffff:ffff
543635::/163635:ffff:ffff:ffff:ffff:ffff:ffff:ffff
553636::/163636:ffff:ffff:ffff:ffff:ffff:ffff:ffff
563637::/163637:ffff:ffff:ffff:ffff:ffff:ffff:ffff
573638::/163638:ffff:ffff:ffff:ffff:ffff:ffff:ffff
583639::/163639:ffff:ffff:ffff:ffff:ffff:ffff:ffff
59363a::/16363a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
60363b::/16363b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
61363c::/16363c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
62363d::/16363d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
63363e::/16363e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
64363f::/16363f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
653640::/163640:ffff:ffff:ffff:ffff:ffff:ffff:ffff
663641::/163641:ffff:ffff:ffff:ffff:ffff:ffff:ffff
673642::/163642:ffff:ffff:ffff:ffff:ffff:ffff:ffff
683643::/163643:ffff:ffff:ffff:ffff:ffff:ffff:ffff
693644::/163644:ffff:ffff:ffff:ffff:ffff:ffff:ffff
703645::/163645:ffff:ffff:ffff:ffff:ffff:ffff:ffff
713646::/163646:ffff:ffff:ffff:ffff:ffff:ffff:ffff
723647::/163647:ffff:ffff:ffff:ffff:ffff:ffff:ffff
733648::/163648:ffff:ffff:ffff:ffff:ffff:ffff:ffff
743649::/163649:ffff:ffff:ffff:ffff:ffff:ffff:ffff
75364a::/16364a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
76364b::/16364b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
77364c::/16364c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
78364d::/16364d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
79364e::/16364e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
80364f::/16364f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
813650::/163650:ffff:ffff:ffff:ffff:ffff:ffff:ffff
823651::/163651:ffff:ffff:ffff:ffff:ffff:ffff:ffff
833652::/163652:ffff:ffff:ffff:ffff:ffff:ffff:ffff
843653::/163653:ffff:ffff:ffff:ffff:ffff:ffff:ffff
853654::/163654:ffff:ffff:ffff:ffff:ffff:ffff:ffff
863655::/163655:ffff:ffff:ffff:ffff:ffff:ffff:ffff
873656::/163656:ffff:ffff:ffff:ffff:ffff:ffff:ffff
883657::/163657:ffff:ffff:ffff:ffff:ffff:ffff:ffff
893658::/163658:ffff:ffff:ffff:ffff:ffff:ffff:ffff
903659::/163659:ffff:ffff:ffff:ffff:ffff:ffff:ffff
91365a::/16365a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
92365b::/16365b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
93365c::/16365c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
94365d::/16365d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
95365e::/16365e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
96365f::/16365f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
973660::/163660:ffff:ffff:ffff:ffff:ffff:ffff:ffff
983661::/163661:ffff:ffff:ffff:ffff:ffff:ffff:ffff
993662::/163662:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1003663::/163663:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1013664::/163664:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1023665::/163665:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1033666::/163666:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1043667::/163667:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1053668::/163668:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1063669::/163669:ffff:ffff:ffff:ffff:ffff:ffff:ffff
107366a::/16366a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
108366b::/16366b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
109366c::/16366c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
110366d::/16366d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
111366e::/16366e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
112366f::/16366f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1133670::/163670:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1143671::/163671:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1153672::/163672:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1163673::/163673:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1173674::/163674:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1183675::/163675:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1193676::/163676:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1203677::/163677:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1213678::/163678:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1223679::/163679:ffff:ffff:ffff:ffff:ffff:ffff:ffff
123367a::/16367a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
124367b::/16367b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
125367c::/16367c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
126367d::/16367d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
127367e::/16367e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
128367f::/16367f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1293680::/163680:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1303681::/163681:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1313682::/163682:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1323683::/163683:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1333684::/163684:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1343685::/163685:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1353686::/163686:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1363687::/163687:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1373688::/163688:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1383689::/163689:ffff:ffff:ffff:ffff:ffff:ffff:ffff
139368a::/16368a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
140368b::/16368b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
141368c::/16368c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
142368d::/16368d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
143368e::/16368e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
144368f::/16368f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1453690::/163690:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1463691::/163691:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1473692::/163692:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1483693::/163693:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1493694::/163694:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1503695::/163695:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1513696::/163696:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1523697::/163697:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1533698::/163698:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1543699::/163699:ffff:ffff:ffff:ffff:ffff:ffff:ffff
155369a::/16369a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
156369b::/16369b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
157369c::/16369c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
158369d::/16369d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
159369e::/16369e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
160369f::/16369f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16136a0::/1636a0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16236a1::/1636a1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16336a2::/1636a2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16436a3::/1636a3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16536a4::/1636a4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16636a5::/1636a5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16736a6::/1636a6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16836a7::/1636a7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16936a8::/1636a8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17036a9::/1636a9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17136aa::/1636aa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17236ab::/1636ab:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17336ac::/1636ac:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17436ad::/1636ad:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17536ae::/1636ae:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17636af::/1636af:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17736b0::/1636b0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17836b1::/1636b1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17936b2::/1636b2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18036b3::/1636b3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18136b4::/1636b4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18236b5::/1636b5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18336b6::/1636b6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18436b7::/1636b7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18536b8::/1636b8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18636b9::/1636b9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18736ba::/1636ba:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18836bb::/1636bb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18936bc::/1636bc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19036bd::/1636bd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19136be::/1636be:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19236bf::/1636bf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19336c0::/1636c0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19436c1::/1636c1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19536c2::/1636c2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19636c3::/1636c3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19736c4::/1636c4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19836c5::/1636c5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19936c6::/1636c6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20036c7::/1636c7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20136c8::/1636c8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20236c9::/1636c9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20336ca::/1636ca:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20436cb::/1636cb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20536cc::/1636cc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20636cd::/1636cd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20736ce::/1636ce:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20836cf::/1636cf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20936d0::/1636d0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21036d1::/1636d1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21136d2::/1636d2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21236d3::/1636d3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21336d4::/1636d4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21436d5::/1636d5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21536d6::/1636d6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21636d7::/1636d7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21736d8::/1636d8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21836d9::/1636d9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21936da::/1636da:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22036db::/1636db:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22136dc::/1636dc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22236dd::/1636dd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22336de::/1636de:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22436df::/1636df:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22536e0::/1636e0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22636e1::/1636e1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22736e2::/1636e2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22836e3::/1636e3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22936e4::/1636e4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23036e5::/1636e5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23136e6::/1636e6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23236e7::/1636e7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23336e8::/1636e8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23436e9::/1636e9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23536ea::/1636ea:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23636eb::/1636eb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23736ec::/1636ec:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23836ed::/1636ed:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23936ee::/1636ee:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24036ef::/1636ef:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24136f0::/1636f0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24236f1::/1636f1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24336f2::/1636f2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24436f3::/1636f3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24536f4::/1636f4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24636f5::/1636f5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24736f6::/1636f6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24836f7::/1636f7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24936f8::/1636f8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25036f9::/1636f9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25136fa::/1636fa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25236fb::/1636fb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25336fc::/1636fc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25436fd::/1636fd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25536fe::/1636fe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25636ff::/1636ff:ffff: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.