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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
2800::/7
First address
2800::
Last address
29ff: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
2800:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
8.2.ip6.arpa
9.2.ip6.arpa
/7 is not on a 4-bit boundary, so it takes 2 /8 zones.
Split into smaller subnets/20
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/16 (512)/20 (8,192)

2800::/7 makes 8,192 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
12800::/202800:fff:ffff:ffff:ffff:ffff:ffff:ffff
22800:1000::/202800:1fff:ffff:ffff:ffff:ffff:ffff:ffff
32800:2000::/202800:2fff:ffff:ffff:ffff:ffff:ffff:ffff
42800:3000::/202800:3fff:ffff:ffff:ffff:ffff:ffff:ffff
52800:4000::/202800:4fff:ffff:ffff:ffff:ffff:ffff:ffff
62800:5000::/202800:5fff:ffff:ffff:ffff:ffff:ffff:ffff
72800:6000::/202800:6fff:ffff:ffff:ffff:ffff:ffff:ffff
82800:7000::/202800:7fff:ffff:ffff:ffff:ffff:ffff:ffff
92800:8000::/202800:8fff:ffff:ffff:ffff:ffff:ffff:ffff
102800:9000::/202800:9fff:ffff:ffff:ffff:ffff:ffff:ffff
112800:a000::/202800:afff:ffff:ffff:ffff:ffff:ffff:ffff
122800:b000::/202800:bfff:ffff:ffff:ffff:ffff:ffff:ffff
132800:c000::/202800:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142800:d000::/202800:dfff:ffff:ffff:ffff:ffff:ffff:ffff
152800:e000::/202800:efff:ffff:ffff:ffff:ffff:ffff:ffff
162800:f000::/202800:ffff:ffff:ffff:ffff:ffff:ffff:ffff
172801::/202801:fff:ffff:ffff:ffff:ffff:ffff:ffff
182801:1000::/202801:1fff:ffff:ffff:ffff:ffff:ffff:ffff
192801:2000::/202801:2fff:ffff:ffff:ffff:ffff:ffff:ffff
202801:3000::/202801:3fff:ffff:ffff:ffff:ffff:ffff:ffff
212801:4000::/202801:4fff:ffff:ffff:ffff:ffff:ffff:ffff
222801:5000::/202801:5fff:ffff:ffff:ffff:ffff:ffff:ffff
232801:6000::/202801:6fff:ffff:ffff:ffff:ffff:ffff:ffff
242801:7000::/202801:7fff:ffff:ffff:ffff:ffff:ffff:ffff
252801:8000::/202801:8fff:ffff:ffff:ffff:ffff:ffff:ffff
262801:9000::/202801:9fff:ffff:ffff:ffff:ffff:ffff:ffff
272801:a000::/202801:afff:ffff:ffff:ffff:ffff:ffff:ffff
282801:b000::/202801:bfff:ffff:ffff:ffff:ffff:ffff:ffff
292801:c000::/202801:cfff:ffff:ffff:ffff:ffff:ffff:ffff
302801:d000::/202801:dfff:ffff:ffff:ffff:ffff:ffff:ffff
312801:e000::/202801:efff:ffff:ffff:ffff:ffff:ffff:ffff
322801:f000::/202801:ffff:ffff:ffff:ffff:ffff:ffff:ffff
332802::/202802:fff:ffff:ffff:ffff:ffff:ffff:ffff
342802:1000::/202802:1fff:ffff:ffff:ffff:ffff:ffff:ffff
352802:2000::/202802:2fff:ffff:ffff:ffff:ffff:ffff:ffff
362802:3000::/202802:3fff:ffff:ffff:ffff:ffff:ffff:ffff
372802:4000::/202802:4fff:ffff:ffff:ffff:ffff:ffff:ffff
382802:5000::/202802:5fff:ffff:ffff:ffff:ffff:ffff:ffff
392802:6000::/202802:6fff:ffff:ffff:ffff:ffff:ffff:ffff
402802:7000::/202802:7fff:ffff:ffff:ffff:ffff:ffff:ffff
412802:8000::/202802:8fff:ffff:ffff:ffff:ffff:ffff:ffff
422802:9000::/202802:9fff:ffff:ffff:ffff:ffff:ffff:ffff
432802:a000::/202802:afff:ffff:ffff:ffff:ffff:ffff:ffff
442802:b000::/202802:bfff:ffff:ffff:ffff:ffff:ffff:ffff
452802:c000::/202802:cfff:ffff:ffff:ffff:ffff:ffff:ffff
462802:d000::/202802:dfff:ffff:ffff:ffff:ffff:ffff:ffff
472802:e000::/202802:efff:ffff:ffff:ffff:ffff:ffff:ffff
482802:f000::/202802:ffff:ffff:ffff:ffff:ffff:ffff:ffff
492803::/202803:fff:ffff:ffff:ffff:ffff:ffff:ffff
502803:1000::/202803:1fff:ffff:ffff:ffff:ffff:ffff:ffff
512803:2000::/202803:2fff:ffff:ffff:ffff:ffff:ffff:ffff
522803:3000::/202803:3fff:ffff:ffff:ffff:ffff:ffff:ffff
532803:4000::/202803:4fff:ffff:ffff:ffff:ffff:ffff:ffff
542803:5000::/202803:5fff:ffff:ffff:ffff:ffff:ffff:ffff
552803:6000::/202803:6fff:ffff:ffff:ffff:ffff:ffff:ffff
562803:7000::/202803:7fff:ffff:ffff:ffff:ffff:ffff:ffff
572803:8000::/202803:8fff:ffff:ffff:ffff:ffff:ffff:ffff
582803:9000::/202803:9fff:ffff:ffff:ffff:ffff:ffff:ffff
592803:a000::/202803:afff:ffff:ffff:ffff:ffff:ffff:ffff
602803:b000::/202803:bfff:ffff:ffff:ffff:ffff:ffff:ffff
612803:c000::/202803:cfff:ffff:ffff:ffff:ffff:ffff:ffff
622803:d000::/202803:dfff:ffff:ffff:ffff:ffff:ffff:ffff
632803:e000::/202803:efff:ffff:ffff:ffff:ffff:ffff:ffff
642803:f000::/202803:ffff:ffff:ffff:ffff:ffff:ffff:ffff
652804::/202804:fff:ffff:ffff:ffff:ffff:ffff:ffff
662804:1000::/202804:1fff:ffff:ffff:ffff:ffff:ffff:ffff
672804:2000::/202804:2fff:ffff:ffff:ffff:ffff:ffff:ffff
682804:3000::/202804:3fff:ffff:ffff:ffff:ffff:ffff:ffff
692804:4000::/202804:4fff:ffff:ffff:ffff:ffff:ffff:ffff
702804:5000::/202804:5fff:ffff:ffff:ffff:ffff:ffff:ffff
712804:6000::/202804:6fff:ffff:ffff:ffff:ffff:ffff:ffff
722804:7000::/202804:7fff:ffff:ffff:ffff:ffff:ffff:ffff
732804:8000::/202804:8fff:ffff:ffff:ffff:ffff:ffff:ffff
742804:9000::/202804:9fff:ffff:ffff:ffff:ffff:ffff:ffff
752804:a000::/202804:afff:ffff:ffff:ffff:ffff:ffff:ffff
762804:b000::/202804:bfff:ffff:ffff:ffff:ffff:ffff:ffff
772804:c000::/202804:cfff:ffff:ffff:ffff:ffff:ffff:ffff
782804:d000::/202804:dfff:ffff:ffff:ffff:ffff:ffff:ffff
792804:e000::/202804:efff:ffff:ffff:ffff:ffff:ffff:ffff
802804:f000::/202804:ffff:ffff:ffff:ffff:ffff:ffff:ffff
812805::/202805:fff:ffff:ffff:ffff:ffff:ffff:ffff
822805:1000::/202805:1fff:ffff:ffff:ffff:ffff:ffff:ffff
832805:2000::/202805:2fff:ffff:ffff:ffff:ffff:ffff:ffff
842805:3000::/202805:3fff:ffff:ffff:ffff:ffff:ffff:ffff
852805:4000::/202805:4fff:ffff:ffff:ffff:ffff:ffff:ffff
862805:5000::/202805:5fff:ffff:ffff:ffff:ffff:ffff:ffff
872805:6000::/202805:6fff:ffff:ffff:ffff:ffff:ffff:ffff
882805:7000::/202805:7fff:ffff:ffff:ffff:ffff:ffff:ffff
892805:8000::/202805:8fff:ffff:ffff:ffff:ffff:ffff:ffff
902805:9000::/202805:9fff:ffff:ffff:ffff:ffff:ffff:ffff
912805:a000::/202805:afff:ffff:ffff:ffff:ffff:ffff:ffff
922805:b000::/202805:bfff:ffff:ffff:ffff:ffff:ffff:ffff
932805:c000::/202805:cfff:ffff:ffff:ffff:ffff:ffff:ffff
942805:d000::/202805:dfff:ffff:ffff:ffff:ffff:ffff:ffff
952805:e000::/202805:efff:ffff:ffff:ffff:ffff:ffff:ffff
962805:f000::/202805:ffff:ffff:ffff:ffff:ffff:ffff:ffff
972806::/202806:fff:ffff:ffff:ffff:ffff:ffff:ffff
982806:1000::/202806:1fff:ffff:ffff:ffff:ffff:ffff:ffff
992806:2000::/202806:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1002806:3000::/202806:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1012806:4000::/202806:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1022806:5000::/202806:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1032806:6000::/202806:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1042806:7000::/202806:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1052806:8000::/202806:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1062806:9000::/202806:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1072806:a000::/202806:afff:ffff:ffff:ffff:ffff:ffff:ffff
1082806:b000::/202806:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1092806:c000::/202806:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1102806:d000::/202806:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1112806:e000::/202806:efff:ffff:ffff:ffff:ffff:ffff:ffff
1122806:f000::/202806:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1132807::/202807:fff:ffff:ffff:ffff:ffff:ffff:ffff
1142807:1000::/202807:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1152807:2000::/202807:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1162807:3000::/202807:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1172807:4000::/202807:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1182807:5000::/202807:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1192807:6000::/202807:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1202807:7000::/202807:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1212807:8000::/202807:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1222807:9000::/202807:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1232807:a000::/202807:afff:ffff:ffff:ffff:ffff:ffff:ffff
1242807:b000::/202807:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1252807:c000::/202807:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1262807:d000::/202807:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1272807:e000::/202807:efff:ffff:ffff:ffff:ffff:ffff:ffff
1282807:f000::/202807:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1292808::/202808:fff:ffff:ffff:ffff:ffff:ffff:ffff
1302808:1000::/202808:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1312808:2000::/202808:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1322808:3000::/202808:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1332808:4000::/202808:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1342808:5000::/202808:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1352808:6000::/202808:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1362808:7000::/202808:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1372808:8000::/202808:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1382808:9000::/202808:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1392808:a000::/202808:afff:ffff:ffff:ffff:ffff:ffff:ffff
1402808:b000::/202808:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1412808:c000::/202808:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1422808:d000::/202808:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1432808:e000::/202808:efff:ffff:ffff:ffff:ffff:ffff:ffff
1442808:f000::/202808:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1452809::/202809:fff:ffff:ffff:ffff:ffff:ffff:ffff
1462809:1000::/202809:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1472809:2000::/202809:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1482809:3000::/202809:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1492809:4000::/202809:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1502809:5000::/202809:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1512809:6000::/202809:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1522809:7000::/202809:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1532809:8000::/202809:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1542809:9000::/202809:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1552809:a000::/202809:afff:ffff:ffff:ffff:ffff:ffff:ffff
1562809:b000::/202809:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1572809:c000::/202809:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1582809:d000::/202809:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1592809:e000::/202809:efff:ffff:ffff:ffff:ffff:ffff:ffff
1602809:f000::/202809:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161280a::/20280a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162280a:1000::/20280a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163280a:2000::/20280a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164280a:3000::/20280a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165280a:4000::/20280a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166280a:5000::/20280a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167280a:6000::/20280a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168280a:7000::/20280a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169280a:8000::/20280a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170280a:9000::/20280a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171280a:a000::/20280a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172280a:b000::/20280a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173280a:c000::/20280a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174280a:d000::/20280a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175280a:e000::/20280a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176280a:f000::/20280a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177280b::/20280b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178280b:1000::/20280b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179280b:2000::/20280b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180280b:3000::/20280b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181280b:4000::/20280b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182280b:5000::/20280b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183280b:6000::/20280b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184280b:7000::/20280b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185280b:8000::/20280b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186280b:9000::/20280b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187280b:a000::/20280b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188280b:b000::/20280b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189280b:c000::/20280b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190280b:d000::/20280b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191280b:e000::/20280b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192280b:f000::/20280b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193280c::/20280c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194280c:1000::/20280c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195280c:2000::/20280c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196280c:3000::/20280c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197280c:4000::/20280c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198280c:5000::/20280c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199280c:6000::/20280c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200280c:7000::/20280c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201280c:8000::/20280c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202280c:9000::/20280c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203280c:a000::/20280c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204280c:b000::/20280c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205280c:c000::/20280c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206280c:d000::/20280c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207280c:e000::/20280c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208280c:f000::/20280c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209280d::/20280d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210280d:1000::/20280d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211280d:2000::/20280d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212280d:3000::/20280d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213280d:4000::/20280d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214280d:5000::/20280d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215280d:6000::/20280d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216280d:7000::/20280d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217280d:8000::/20280d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218280d:9000::/20280d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219280d:a000::/20280d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220280d:b000::/20280d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221280d:c000::/20280d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222280d:d000::/20280d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223280d:e000::/20280d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224280d:f000::/20280d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225280e::/20280e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226280e:1000::/20280e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227280e:2000::/20280e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228280e:3000::/20280e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229280e:4000::/20280e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230280e:5000::/20280e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231280e:6000::/20280e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232280e:7000::/20280e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233280e:8000::/20280e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234280e:9000::/20280e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235280e:a000::/20280e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236280e:b000::/20280e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237280e:c000::/20280e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238280e:d000::/20280e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239280e:e000::/20280e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240280e:f000::/20280e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241280f::/20280f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242280f:1000::/20280f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243280f:2000::/20280f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244280f:3000::/20280f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245280f:4000::/20280f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246280f:5000::/20280f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247280f:6000::/20280f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248280f:7000::/20280f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249280f:8000::/20280f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250280f:9000::/20280f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251280f:a000::/20280f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252280f:b000::/20280f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253280f:c000::/20280f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254280f:d000::/20280f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255280f:e000::/20280f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256280f:f000::/20280f: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.