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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/20
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/16 (512)/20 (8,192)

3600::/7 makes 8,192 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
13600::/203600:fff:ffff:ffff:ffff:ffff:ffff:ffff
23600:1000::/203600:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33600:2000::/203600:2fff:ffff:ffff:ffff:ffff:ffff:ffff
43600:3000::/203600:3fff:ffff:ffff:ffff:ffff:ffff:ffff
53600:4000::/203600:4fff:ffff:ffff:ffff:ffff:ffff:ffff
63600:5000::/203600:5fff:ffff:ffff:ffff:ffff:ffff:ffff
73600:6000::/203600:6fff:ffff:ffff:ffff:ffff:ffff:ffff
83600:7000::/203600:7fff:ffff:ffff:ffff:ffff:ffff:ffff
93600:8000::/203600:8fff:ffff:ffff:ffff:ffff:ffff:ffff
103600:9000::/203600:9fff:ffff:ffff:ffff:ffff:ffff:ffff
113600:a000::/203600:afff:ffff:ffff:ffff:ffff:ffff:ffff
123600:b000::/203600:bfff:ffff:ffff:ffff:ffff:ffff:ffff
133600:c000::/203600:cfff:ffff:ffff:ffff:ffff:ffff:ffff
143600:d000::/203600:dfff:ffff:ffff:ffff:ffff:ffff:ffff
153600:e000::/203600:efff:ffff:ffff:ffff:ffff:ffff:ffff
163600:f000::/203600:ffff:ffff:ffff:ffff:ffff:ffff:ffff
173601::/203601:fff:ffff:ffff:ffff:ffff:ffff:ffff
183601:1000::/203601:1fff:ffff:ffff:ffff:ffff:ffff:ffff
193601:2000::/203601:2fff:ffff:ffff:ffff:ffff:ffff:ffff
203601:3000::/203601:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213601:4000::/203601:4fff:ffff:ffff:ffff:ffff:ffff:ffff
223601:5000::/203601:5fff:ffff:ffff:ffff:ffff:ffff:ffff
233601:6000::/203601:6fff:ffff:ffff:ffff:ffff:ffff:ffff
243601:7000::/203601:7fff:ffff:ffff:ffff:ffff:ffff:ffff
253601:8000::/203601:8fff:ffff:ffff:ffff:ffff:ffff:ffff
263601:9000::/203601:9fff:ffff:ffff:ffff:ffff:ffff:ffff
273601:a000::/203601:afff:ffff:ffff:ffff:ffff:ffff:ffff
283601:b000::/203601:bfff:ffff:ffff:ffff:ffff:ffff:ffff
293601:c000::/203601:cfff:ffff:ffff:ffff:ffff:ffff:ffff
303601:d000::/203601:dfff:ffff:ffff:ffff:ffff:ffff:ffff
313601:e000::/203601:efff:ffff:ffff:ffff:ffff:ffff:ffff
323601:f000::/203601:ffff:ffff:ffff:ffff:ffff:ffff:ffff
333602::/203602:fff:ffff:ffff:ffff:ffff:ffff:ffff
343602:1000::/203602:1fff:ffff:ffff:ffff:ffff:ffff:ffff
353602:2000::/203602:2fff:ffff:ffff:ffff:ffff:ffff:ffff
363602:3000::/203602:3fff:ffff:ffff:ffff:ffff:ffff:ffff
373602:4000::/203602:4fff:ffff:ffff:ffff:ffff:ffff:ffff
383602:5000::/203602:5fff:ffff:ffff:ffff:ffff:ffff:ffff
393602:6000::/203602:6fff:ffff:ffff:ffff:ffff:ffff:ffff
403602:7000::/203602:7fff:ffff:ffff:ffff:ffff:ffff:ffff
413602:8000::/203602:8fff:ffff:ffff:ffff:ffff:ffff:ffff
423602:9000::/203602:9fff:ffff:ffff:ffff:ffff:ffff:ffff
433602:a000::/203602:afff:ffff:ffff:ffff:ffff:ffff:ffff
443602:b000::/203602:bfff:ffff:ffff:ffff:ffff:ffff:ffff
453602:c000::/203602:cfff:ffff:ffff:ffff:ffff:ffff:ffff
463602:d000::/203602:dfff:ffff:ffff:ffff:ffff:ffff:ffff
473602:e000::/203602:efff:ffff:ffff:ffff:ffff:ffff:ffff
483602:f000::/203602:ffff:ffff:ffff:ffff:ffff:ffff:ffff
493603::/203603:fff:ffff:ffff:ffff:ffff:ffff:ffff
503603:1000::/203603:1fff:ffff:ffff:ffff:ffff:ffff:ffff
513603:2000::/203603:2fff:ffff:ffff:ffff:ffff:ffff:ffff
523603:3000::/203603:3fff:ffff:ffff:ffff:ffff:ffff:ffff
533603:4000::/203603:4fff:ffff:ffff:ffff:ffff:ffff:ffff
543603:5000::/203603:5fff:ffff:ffff:ffff:ffff:ffff:ffff
553603:6000::/203603:6fff:ffff:ffff:ffff:ffff:ffff:ffff
563603:7000::/203603:7fff:ffff:ffff:ffff:ffff:ffff:ffff
573603:8000::/203603:8fff:ffff:ffff:ffff:ffff:ffff:ffff
583603:9000::/203603:9fff:ffff:ffff:ffff:ffff:ffff:ffff
593603:a000::/203603:afff:ffff:ffff:ffff:ffff:ffff:ffff
603603:b000::/203603:bfff:ffff:ffff:ffff:ffff:ffff:ffff
613603:c000::/203603:cfff:ffff:ffff:ffff:ffff:ffff:ffff
623603:d000::/203603:dfff:ffff:ffff:ffff:ffff:ffff:ffff
633603:e000::/203603:efff:ffff:ffff:ffff:ffff:ffff:ffff
643603:f000::/203603:ffff:ffff:ffff:ffff:ffff:ffff:ffff
653604::/203604:fff:ffff:ffff:ffff:ffff:ffff:ffff
663604:1000::/203604:1fff:ffff:ffff:ffff:ffff:ffff:ffff
673604:2000::/203604:2fff:ffff:ffff:ffff:ffff:ffff:ffff
683604:3000::/203604:3fff:ffff:ffff:ffff:ffff:ffff:ffff
693604:4000::/203604:4fff:ffff:ffff:ffff:ffff:ffff:ffff
703604:5000::/203604:5fff:ffff:ffff:ffff:ffff:ffff:ffff
713604:6000::/203604:6fff:ffff:ffff:ffff:ffff:ffff:ffff
723604:7000::/203604:7fff:ffff:ffff:ffff:ffff:ffff:ffff
733604:8000::/203604:8fff:ffff:ffff:ffff:ffff:ffff:ffff
743604:9000::/203604:9fff:ffff:ffff:ffff:ffff:ffff:ffff
753604:a000::/203604:afff:ffff:ffff:ffff:ffff:ffff:ffff
763604:b000::/203604:bfff:ffff:ffff:ffff:ffff:ffff:ffff
773604:c000::/203604:cfff:ffff:ffff:ffff:ffff:ffff:ffff
783604:d000::/203604:dfff:ffff:ffff:ffff:ffff:ffff:ffff
793604:e000::/203604:efff:ffff:ffff:ffff:ffff:ffff:ffff
803604:f000::/203604:ffff:ffff:ffff:ffff:ffff:ffff:ffff
813605::/203605:fff:ffff:ffff:ffff:ffff:ffff:ffff
823605:1000::/203605:1fff:ffff:ffff:ffff:ffff:ffff:ffff
833605:2000::/203605:2fff:ffff:ffff:ffff:ffff:ffff:ffff
843605:3000::/203605:3fff:ffff:ffff:ffff:ffff:ffff:ffff
853605:4000::/203605:4fff:ffff:ffff:ffff:ffff:ffff:ffff
863605:5000::/203605:5fff:ffff:ffff:ffff:ffff:ffff:ffff
873605:6000::/203605:6fff:ffff:ffff:ffff:ffff:ffff:ffff
883605:7000::/203605:7fff:ffff:ffff:ffff:ffff:ffff:ffff
893605:8000::/203605:8fff:ffff:ffff:ffff:ffff:ffff:ffff
903605:9000::/203605:9fff:ffff:ffff:ffff:ffff:ffff:ffff
913605:a000::/203605:afff:ffff:ffff:ffff:ffff:ffff:ffff
923605:b000::/203605:bfff:ffff:ffff:ffff:ffff:ffff:ffff
933605:c000::/203605:cfff:ffff:ffff:ffff:ffff:ffff:ffff
943605:d000::/203605:dfff:ffff:ffff:ffff:ffff:ffff:ffff
953605:e000::/203605:efff:ffff:ffff:ffff:ffff:ffff:ffff
963605:f000::/203605:ffff:ffff:ffff:ffff:ffff:ffff:ffff
973606::/203606:fff:ffff:ffff:ffff:ffff:ffff:ffff
983606:1000::/203606:1fff:ffff:ffff:ffff:ffff:ffff:ffff
993606:2000::/203606:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1003606:3000::/203606:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1013606:4000::/203606:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1023606:5000::/203606:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1033606:6000::/203606:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1043606:7000::/203606:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1053606:8000::/203606:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1063606:9000::/203606:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1073606:a000::/203606:afff:ffff:ffff:ffff:ffff:ffff:ffff
1083606:b000::/203606:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1093606:c000::/203606:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1103606:d000::/203606:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1113606:e000::/203606:efff:ffff:ffff:ffff:ffff:ffff:ffff
1123606:f000::/203606:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1133607::/203607:fff:ffff:ffff:ffff:ffff:ffff:ffff
1143607:1000::/203607:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1153607:2000::/203607:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1163607:3000::/203607:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1173607:4000::/203607:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1183607:5000::/203607:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1193607:6000::/203607:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1203607:7000::/203607:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1213607:8000::/203607:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1223607:9000::/203607:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1233607:a000::/203607:afff:ffff:ffff:ffff:ffff:ffff:ffff
1243607:b000::/203607:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1253607:c000::/203607:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1263607:d000::/203607:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1273607:e000::/203607:efff:ffff:ffff:ffff:ffff:ffff:ffff
1283607:f000::/203607:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1293608::/203608:fff:ffff:ffff:ffff:ffff:ffff:ffff
1303608:1000::/203608:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1313608:2000::/203608:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1323608:3000::/203608:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1333608:4000::/203608:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1343608:5000::/203608:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1353608:6000::/203608:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1363608:7000::/203608:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1373608:8000::/203608:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1383608:9000::/203608:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1393608:a000::/203608:afff:ffff:ffff:ffff:ffff:ffff:ffff
1403608:b000::/203608:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1413608:c000::/203608:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1423608:d000::/203608:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1433608:e000::/203608:efff:ffff:ffff:ffff:ffff:ffff:ffff
1443608:f000::/203608:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1453609::/203609:fff:ffff:ffff:ffff:ffff:ffff:ffff
1463609:1000::/203609:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1473609:2000::/203609:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1483609:3000::/203609:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1493609:4000::/203609:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1503609:5000::/203609:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1513609:6000::/203609:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1523609:7000::/203609:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1533609:8000::/203609:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1543609:9000::/203609:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1553609:a000::/203609:afff:ffff:ffff:ffff:ffff:ffff:ffff
1563609:b000::/203609:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1573609:c000::/203609:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1583609:d000::/203609:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1593609:e000::/203609:efff:ffff:ffff:ffff:ffff:ffff:ffff
1603609:f000::/203609:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161360a::/20360a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162360a:1000::/20360a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163360a:2000::/20360a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164360a:3000::/20360a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165360a:4000::/20360a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166360a:5000::/20360a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167360a:6000::/20360a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168360a:7000::/20360a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169360a:8000::/20360a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170360a:9000::/20360a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171360a:a000::/20360a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172360a:b000::/20360a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173360a:c000::/20360a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174360a:d000::/20360a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175360a:e000::/20360a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176360a:f000::/20360a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177360b::/20360b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178360b:1000::/20360b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179360b:2000::/20360b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180360b:3000::/20360b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181360b:4000::/20360b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182360b:5000::/20360b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183360b:6000::/20360b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184360b:7000::/20360b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185360b:8000::/20360b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186360b:9000::/20360b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187360b:a000::/20360b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188360b:b000::/20360b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189360b:c000::/20360b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190360b:d000::/20360b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191360b:e000::/20360b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192360b:f000::/20360b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193360c::/20360c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194360c:1000::/20360c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195360c:2000::/20360c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196360c:3000::/20360c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197360c:4000::/20360c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198360c:5000::/20360c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199360c:6000::/20360c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200360c:7000::/20360c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201360c:8000::/20360c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202360c:9000::/20360c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203360c:a000::/20360c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204360c:b000::/20360c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205360c:c000::/20360c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206360c:d000::/20360c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207360c:e000::/20360c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208360c:f000::/20360c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209360d::/20360d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210360d:1000::/20360d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211360d:2000::/20360d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212360d:3000::/20360d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213360d:4000::/20360d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214360d:5000::/20360d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215360d:6000::/20360d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216360d:7000::/20360d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217360d:8000::/20360d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218360d:9000::/20360d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219360d:a000::/20360d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220360d:b000::/20360d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221360d:c000::/20360d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222360d:d000::/20360d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223360d:e000::/20360d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224360d:f000::/20360d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225360e::/20360e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226360e:1000::/20360e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227360e:2000::/20360e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228360e:3000::/20360e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229360e:4000::/20360e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230360e:5000::/20360e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231360e:6000::/20360e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232360e:7000::/20360e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233360e:8000::/20360e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234360e:9000::/20360e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235360e:a000::/20360e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236360e:b000::/20360e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237360e:c000::/20360e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238360e:d000::/20360e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239360e:e000::/20360e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240360e:f000::/20360e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241360f::/20360f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242360f:1000::/20360f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243360f:2000::/20360f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244360f:3000::/20360f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245360f:4000::/20360f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246360f:5000::/20360f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247360f:6000::/20360f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248360f:7000::/20360f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249360f:8000::/20360f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250360f:9000::/20360f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251360f:a000::/20360f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252360f:b000::/20360f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253360f:c000::/20360f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254360f:d000::/20360f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255360f:e000::/20360f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256360f:f000::/20360f: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.