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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
2600::/7
First address
2600::
Last address
27ff: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
2600:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
6.2.ip6.arpa
7.2.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)

2600::/7 makes 8,192 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
12600::/202600:fff:ffff:ffff:ffff:ffff:ffff:ffff
22600:1000::/202600:1fff:ffff:ffff:ffff:ffff:ffff:ffff
32600:2000::/202600:2fff:ffff:ffff:ffff:ffff:ffff:ffff
42600:3000::/202600:3fff:ffff:ffff:ffff:ffff:ffff:ffff
52600:4000::/202600:4fff:ffff:ffff:ffff:ffff:ffff:ffff
62600:5000::/202600:5fff:ffff:ffff:ffff:ffff:ffff:ffff
72600:6000::/202600:6fff:ffff:ffff:ffff:ffff:ffff:ffff
82600:7000::/202600:7fff:ffff:ffff:ffff:ffff:ffff:ffff
92600:8000::/202600:8fff:ffff:ffff:ffff:ffff:ffff:ffff
102600:9000::/202600:9fff:ffff:ffff:ffff:ffff:ffff:ffff
112600:a000::/202600:afff:ffff:ffff:ffff:ffff:ffff:ffff
122600:b000::/202600:bfff:ffff:ffff:ffff:ffff:ffff:ffff
132600:c000::/202600:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142600:d000::/202600:dfff:ffff:ffff:ffff:ffff:ffff:ffff
152600:e000::/202600:efff:ffff:ffff:ffff:ffff:ffff:ffff
162600:f000::/202600:ffff:ffff:ffff:ffff:ffff:ffff:ffff
172601::/202601:fff:ffff:ffff:ffff:ffff:ffff:ffff
182601:1000::/202601:1fff:ffff:ffff:ffff:ffff:ffff:ffff
192601:2000::/202601:2fff:ffff:ffff:ffff:ffff:ffff:ffff
202601:3000::/202601:3fff:ffff:ffff:ffff:ffff:ffff:ffff
212601:4000::/202601:4fff:ffff:ffff:ffff:ffff:ffff:ffff
222601:5000::/202601:5fff:ffff:ffff:ffff:ffff:ffff:ffff
232601:6000::/202601:6fff:ffff:ffff:ffff:ffff:ffff:ffff
242601:7000::/202601:7fff:ffff:ffff:ffff:ffff:ffff:ffff
252601:8000::/202601:8fff:ffff:ffff:ffff:ffff:ffff:ffff
262601:9000::/202601:9fff:ffff:ffff:ffff:ffff:ffff:ffff
272601:a000::/202601:afff:ffff:ffff:ffff:ffff:ffff:ffff
282601:b000::/202601:bfff:ffff:ffff:ffff:ffff:ffff:ffff
292601:c000::/202601:cfff:ffff:ffff:ffff:ffff:ffff:ffff
302601:d000::/202601:dfff:ffff:ffff:ffff:ffff:ffff:ffff
312601:e000::/202601:efff:ffff:ffff:ffff:ffff:ffff:ffff
322601:f000::/202601:ffff:ffff:ffff:ffff:ffff:ffff:ffff
332602::/202602:fff:ffff:ffff:ffff:ffff:ffff:ffff
342602:1000::/202602:1fff:ffff:ffff:ffff:ffff:ffff:ffff
352602:2000::/202602:2fff:ffff:ffff:ffff:ffff:ffff:ffff
362602:3000::/202602:3fff:ffff:ffff:ffff:ffff:ffff:ffff
372602:4000::/202602:4fff:ffff:ffff:ffff:ffff:ffff:ffff
382602:5000::/202602:5fff:ffff:ffff:ffff:ffff:ffff:ffff
392602:6000::/202602:6fff:ffff:ffff:ffff:ffff:ffff:ffff
402602:7000::/202602:7fff:ffff:ffff:ffff:ffff:ffff:ffff
412602:8000::/202602:8fff:ffff:ffff:ffff:ffff:ffff:ffff
422602:9000::/202602:9fff:ffff:ffff:ffff:ffff:ffff:ffff
432602:a000::/202602:afff:ffff:ffff:ffff:ffff:ffff:ffff
442602:b000::/202602:bfff:ffff:ffff:ffff:ffff:ffff:ffff
452602:c000::/202602:cfff:ffff:ffff:ffff:ffff:ffff:ffff
462602:d000::/202602:dfff:ffff:ffff:ffff:ffff:ffff:ffff
472602:e000::/202602:efff:ffff:ffff:ffff:ffff:ffff:ffff
482602:f000::/202602:ffff:ffff:ffff:ffff:ffff:ffff:ffff
492603::/202603:fff:ffff:ffff:ffff:ffff:ffff:ffff
502603:1000::/202603:1fff:ffff:ffff:ffff:ffff:ffff:ffff
512603:2000::/202603:2fff:ffff:ffff:ffff:ffff:ffff:ffff
522603:3000::/202603:3fff:ffff:ffff:ffff:ffff:ffff:ffff
532603:4000::/202603:4fff:ffff:ffff:ffff:ffff:ffff:ffff
542603:5000::/202603:5fff:ffff:ffff:ffff:ffff:ffff:ffff
552603:6000::/202603:6fff:ffff:ffff:ffff:ffff:ffff:ffff
562603:7000::/202603:7fff:ffff:ffff:ffff:ffff:ffff:ffff
572603:8000::/202603:8fff:ffff:ffff:ffff:ffff:ffff:ffff
582603:9000::/202603:9fff:ffff:ffff:ffff:ffff:ffff:ffff
592603:a000::/202603:afff:ffff:ffff:ffff:ffff:ffff:ffff
602603:b000::/202603:bfff:ffff:ffff:ffff:ffff:ffff:ffff
612603:c000::/202603:cfff:ffff:ffff:ffff:ffff:ffff:ffff
622603:d000::/202603:dfff:ffff:ffff:ffff:ffff:ffff:ffff
632603:e000::/202603:efff:ffff:ffff:ffff:ffff:ffff:ffff
642603:f000::/202603:ffff:ffff:ffff:ffff:ffff:ffff:ffff
652604::/202604:fff:ffff:ffff:ffff:ffff:ffff:ffff
662604:1000::/202604:1fff:ffff:ffff:ffff:ffff:ffff:ffff
672604:2000::/202604:2fff:ffff:ffff:ffff:ffff:ffff:ffff
682604:3000::/202604:3fff:ffff:ffff:ffff:ffff:ffff:ffff
692604:4000::/202604:4fff:ffff:ffff:ffff:ffff:ffff:ffff
702604:5000::/202604:5fff:ffff:ffff:ffff:ffff:ffff:ffff
712604:6000::/202604:6fff:ffff:ffff:ffff:ffff:ffff:ffff
722604:7000::/202604:7fff:ffff:ffff:ffff:ffff:ffff:ffff
732604:8000::/202604:8fff:ffff:ffff:ffff:ffff:ffff:ffff
742604:9000::/202604:9fff:ffff:ffff:ffff:ffff:ffff:ffff
752604:a000::/202604:afff:ffff:ffff:ffff:ffff:ffff:ffff
762604:b000::/202604:bfff:ffff:ffff:ffff:ffff:ffff:ffff
772604:c000::/202604:cfff:ffff:ffff:ffff:ffff:ffff:ffff
782604:d000::/202604:dfff:ffff:ffff:ffff:ffff:ffff:ffff
792604:e000::/202604:efff:ffff:ffff:ffff:ffff:ffff:ffff
802604:f000::/202604:ffff:ffff:ffff:ffff:ffff:ffff:ffff
812605::/202605:fff:ffff:ffff:ffff:ffff:ffff:ffff
822605:1000::/202605:1fff:ffff:ffff:ffff:ffff:ffff:ffff
832605:2000::/202605:2fff:ffff:ffff:ffff:ffff:ffff:ffff
842605:3000::/202605:3fff:ffff:ffff:ffff:ffff:ffff:ffff
852605:4000::/202605:4fff:ffff:ffff:ffff:ffff:ffff:ffff
862605:5000::/202605:5fff:ffff:ffff:ffff:ffff:ffff:ffff
872605:6000::/202605:6fff:ffff:ffff:ffff:ffff:ffff:ffff
882605:7000::/202605:7fff:ffff:ffff:ffff:ffff:ffff:ffff
892605:8000::/202605:8fff:ffff:ffff:ffff:ffff:ffff:ffff
902605:9000::/202605:9fff:ffff:ffff:ffff:ffff:ffff:ffff
912605:a000::/202605:afff:ffff:ffff:ffff:ffff:ffff:ffff
922605:b000::/202605:bfff:ffff:ffff:ffff:ffff:ffff:ffff
932605:c000::/202605:cfff:ffff:ffff:ffff:ffff:ffff:ffff
942605:d000::/202605:dfff:ffff:ffff:ffff:ffff:ffff:ffff
952605:e000::/202605:efff:ffff:ffff:ffff:ffff:ffff:ffff
962605:f000::/202605:ffff:ffff:ffff:ffff:ffff:ffff:ffff
972606::/202606:fff:ffff:ffff:ffff:ffff:ffff:ffff
982606:1000::/202606:1fff:ffff:ffff:ffff:ffff:ffff:ffff
992606:2000::/202606:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1002606:3000::/202606:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1012606:4000::/202606:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1022606:5000::/202606:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1032606:6000::/202606:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1042606:7000::/202606:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1052606:8000::/202606:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1062606:9000::/202606:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1072606:a000::/202606:afff:ffff:ffff:ffff:ffff:ffff:ffff
1082606:b000::/202606:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1092606:c000::/202606:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1102606:d000::/202606:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1112606:e000::/202606:efff:ffff:ffff:ffff:ffff:ffff:ffff
1122606:f000::/202606:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1132607::/202607:fff:ffff:ffff:ffff:ffff:ffff:ffff
1142607:1000::/202607:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1152607:2000::/202607:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1162607:3000::/202607:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1172607:4000::/202607:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1182607:5000::/202607:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1192607:6000::/202607:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1202607:7000::/202607:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1212607:8000::/202607:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1222607:9000::/202607:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1232607:a000::/202607:afff:ffff:ffff:ffff:ffff:ffff:ffff
1242607:b000::/202607:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1252607:c000::/202607:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1262607:d000::/202607:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1272607:e000::/202607:efff:ffff:ffff:ffff:ffff:ffff:ffff
1282607:f000::/202607:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1292608::/202608:fff:ffff:ffff:ffff:ffff:ffff:ffff
1302608:1000::/202608:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1312608:2000::/202608:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1322608:3000::/202608:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1332608:4000::/202608:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1342608:5000::/202608:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1352608:6000::/202608:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1362608:7000::/202608:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1372608:8000::/202608:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1382608:9000::/202608:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1392608:a000::/202608:afff:ffff:ffff:ffff:ffff:ffff:ffff
1402608:b000::/202608:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1412608:c000::/202608:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1422608:d000::/202608:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1432608:e000::/202608:efff:ffff:ffff:ffff:ffff:ffff:ffff
1442608:f000::/202608:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1452609::/202609:fff:ffff:ffff:ffff:ffff:ffff:ffff
1462609:1000::/202609:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1472609:2000::/202609:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1482609:3000::/202609:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1492609:4000::/202609:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1502609:5000::/202609:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1512609:6000::/202609:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1522609:7000::/202609:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1532609:8000::/202609:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1542609:9000::/202609:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1552609:a000::/202609:afff:ffff:ffff:ffff:ffff:ffff:ffff
1562609:b000::/202609:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1572609:c000::/202609:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1582609:d000::/202609:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1592609:e000::/202609:efff:ffff:ffff:ffff:ffff:ffff:ffff
1602609:f000::/202609:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161260a::/20260a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162260a:1000::/20260a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163260a:2000::/20260a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164260a:3000::/20260a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165260a:4000::/20260a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166260a:5000::/20260a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167260a:6000::/20260a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168260a:7000::/20260a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169260a:8000::/20260a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170260a:9000::/20260a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171260a:a000::/20260a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172260a:b000::/20260a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173260a:c000::/20260a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174260a:d000::/20260a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175260a:e000::/20260a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176260a:f000::/20260a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177260b::/20260b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178260b:1000::/20260b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179260b:2000::/20260b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180260b:3000::/20260b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181260b:4000::/20260b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182260b:5000::/20260b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183260b:6000::/20260b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184260b:7000::/20260b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185260b:8000::/20260b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186260b:9000::/20260b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187260b:a000::/20260b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188260b:b000::/20260b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189260b:c000::/20260b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190260b:d000::/20260b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191260b:e000::/20260b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192260b:f000::/20260b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193260c::/20260c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194260c:1000::/20260c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195260c:2000::/20260c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196260c:3000::/20260c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197260c:4000::/20260c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198260c:5000::/20260c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199260c:6000::/20260c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200260c:7000::/20260c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201260c:8000::/20260c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202260c:9000::/20260c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203260c:a000::/20260c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204260c:b000::/20260c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205260c:c000::/20260c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206260c:d000::/20260c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207260c:e000::/20260c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208260c:f000::/20260c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209260d::/20260d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210260d:1000::/20260d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211260d:2000::/20260d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212260d:3000::/20260d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213260d:4000::/20260d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214260d:5000::/20260d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215260d:6000::/20260d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216260d:7000::/20260d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217260d:8000::/20260d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218260d:9000::/20260d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219260d:a000::/20260d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220260d:b000::/20260d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221260d:c000::/20260d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222260d:d000::/20260d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223260d:e000::/20260d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224260d:f000::/20260d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225260e::/20260e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226260e:1000::/20260e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227260e:2000::/20260e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228260e:3000::/20260e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229260e:4000::/20260e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230260e:5000::/20260e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231260e:6000::/20260e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232260e:7000::/20260e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233260e:8000::/20260e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234260e:9000::/20260e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235260e:a000::/20260e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236260e:b000::/20260e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237260e:c000::/20260e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238260e:d000::/20260e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239260e:e000::/20260e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240260e:f000::/20260e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241260f::/20260f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242260f:1000::/20260f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243260f:2000::/20260f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244260f:3000::/20260f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245260f:4000::/20260f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246260f:5000::/20260f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247260f:6000::/20260f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248260f:7000::/20260f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249260f:8000::/20260f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250260f:9000::/20260f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251260f:a000::/20260f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252260f:b000::/20260f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253260f:c000::/20260f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254260f:d000::/20260f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255260f:e000::/20260f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256260f:f000::/20260f: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.