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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
3800::/7
First address
3800::
Last address
39ff: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
3800:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
8.3.ip6.arpa
9.3.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)

3800::/7 makes 8,192 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
13800::/203800:fff:ffff:ffff:ffff:ffff:ffff:ffff
23800:1000::/203800:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33800:2000::/203800:2fff:ffff:ffff:ffff:ffff:ffff:ffff
43800:3000::/203800:3fff:ffff:ffff:ffff:ffff:ffff:ffff
53800:4000::/203800:4fff:ffff:ffff:ffff:ffff:ffff:ffff
63800:5000::/203800:5fff:ffff:ffff:ffff:ffff:ffff:ffff
73800:6000::/203800:6fff:ffff:ffff:ffff:ffff:ffff:ffff
83800:7000::/203800:7fff:ffff:ffff:ffff:ffff:ffff:ffff
93800:8000::/203800:8fff:ffff:ffff:ffff:ffff:ffff:ffff
103800:9000::/203800:9fff:ffff:ffff:ffff:ffff:ffff:ffff
113800:a000::/203800:afff:ffff:ffff:ffff:ffff:ffff:ffff
123800:b000::/203800:bfff:ffff:ffff:ffff:ffff:ffff:ffff
133800:c000::/203800:cfff:ffff:ffff:ffff:ffff:ffff:ffff
143800:d000::/203800:dfff:ffff:ffff:ffff:ffff:ffff:ffff
153800:e000::/203800:efff:ffff:ffff:ffff:ffff:ffff:ffff
163800:f000::/203800:ffff:ffff:ffff:ffff:ffff:ffff:ffff
173801::/203801:fff:ffff:ffff:ffff:ffff:ffff:ffff
183801:1000::/203801:1fff:ffff:ffff:ffff:ffff:ffff:ffff
193801:2000::/203801:2fff:ffff:ffff:ffff:ffff:ffff:ffff
203801:3000::/203801:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213801:4000::/203801:4fff:ffff:ffff:ffff:ffff:ffff:ffff
223801:5000::/203801:5fff:ffff:ffff:ffff:ffff:ffff:ffff
233801:6000::/203801:6fff:ffff:ffff:ffff:ffff:ffff:ffff
243801:7000::/203801:7fff:ffff:ffff:ffff:ffff:ffff:ffff
253801:8000::/203801:8fff:ffff:ffff:ffff:ffff:ffff:ffff
263801:9000::/203801:9fff:ffff:ffff:ffff:ffff:ffff:ffff
273801:a000::/203801:afff:ffff:ffff:ffff:ffff:ffff:ffff
283801:b000::/203801:bfff:ffff:ffff:ffff:ffff:ffff:ffff
293801:c000::/203801:cfff:ffff:ffff:ffff:ffff:ffff:ffff
303801:d000::/203801:dfff:ffff:ffff:ffff:ffff:ffff:ffff
313801:e000::/203801:efff:ffff:ffff:ffff:ffff:ffff:ffff
323801:f000::/203801:ffff:ffff:ffff:ffff:ffff:ffff:ffff
333802::/203802:fff:ffff:ffff:ffff:ffff:ffff:ffff
343802:1000::/203802:1fff:ffff:ffff:ffff:ffff:ffff:ffff
353802:2000::/203802:2fff:ffff:ffff:ffff:ffff:ffff:ffff
363802:3000::/203802:3fff:ffff:ffff:ffff:ffff:ffff:ffff
373802:4000::/203802:4fff:ffff:ffff:ffff:ffff:ffff:ffff
383802:5000::/203802:5fff:ffff:ffff:ffff:ffff:ffff:ffff
393802:6000::/203802:6fff:ffff:ffff:ffff:ffff:ffff:ffff
403802:7000::/203802:7fff:ffff:ffff:ffff:ffff:ffff:ffff
413802:8000::/203802:8fff:ffff:ffff:ffff:ffff:ffff:ffff
423802:9000::/203802:9fff:ffff:ffff:ffff:ffff:ffff:ffff
433802:a000::/203802:afff:ffff:ffff:ffff:ffff:ffff:ffff
443802:b000::/203802:bfff:ffff:ffff:ffff:ffff:ffff:ffff
453802:c000::/203802:cfff:ffff:ffff:ffff:ffff:ffff:ffff
463802:d000::/203802:dfff:ffff:ffff:ffff:ffff:ffff:ffff
473802:e000::/203802:efff:ffff:ffff:ffff:ffff:ffff:ffff
483802:f000::/203802:ffff:ffff:ffff:ffff:ffff:ffff:ffff
493803::/203803:fff:ffff:ffff:ffff:ffff:ffff:ffff
503803:1000::/203803:1fff:ffff:ffff:ffff:ffff:ffff:ffff
513803:2000::/203803:2fff:ffff:ffff:ffff:ffff:ffff:ffff
523803:3000::/203803:3fff:ffff:ffff:ffff:ffff:ffff:ffff
533803:4000::/203803:4fff:ffff:ffff:ffff:ffff:ffff:ffff
543803:5000::/203803:5fff:ffff:ffff:ffff:ffff:ffff:ffff
553803:6000::/203803:6fff:ffff:ffff:ffff:ffff:ffff:ffff
563803:7000::/203803:7fff:ffff:ffff:ffff:ffff:ffff:ffff
573803:8000::/203803:8fff:ffff:ffff:ffff:ffff:ffff:ffff
583803:9000::/203803:9fff:ffff:ffff:ffff:ffff:ffff:ffff
593803:a000::/203803:afff:ffff:ffff:ffff:ffff:ffff:ffff
603803:b000::/203803:bfff:ffff:ffff:ffff:ffff:ffff:ffff
613803:c000::/203803:cfff:ffff:ffff:ffff:ffff:ffff:ffff
623803:d000::/203803:dfff:ffff:ffff:ffff:ffff:ffff:ffff
633803:e000::/203803:efff:ffff:ffff:ffff:ffff:ffff:ffff
643803:f000::/203803:ffff:ffff:ffff:ffff:ffff:ffff:ffff
653804::/203804:fff:ffff:ffff:ffff:ffff:ffff:ffff
663804:1000::/203804:1fff:ffff:ffff:ffff:ffff:ffff:ffff
673804:2000::/203804:2fff:ffff:ffff:ffff:ffff:ffff:ffff
683804:3000::/203804:3fff:ffff:ffff:ffff:ffff:ffff:ffff
693804:4000::/203804:4fff:ffff:ffff:ffff:ffff:ffff:ffff
703804:5000::/203804:5fff:ffff:ffff:ffff:ffff:ffff:ffff
713804:6000::/203804:6fff:ffff:ffff:ffff:ffff:ffff:ffff
723804:7000::/203804:7fff:ffff:ffff:ffff:ffff:ffff:ffff
733804:8000::/203804:8fff:ffff:ffff:ffff:ffff:ffff:ffff
743804:9000::/203804:9fff:ffff:ffff:ffff:ffff:ffff:ffff
753804:a000::/203804:afff:ffff:ffff:ffff:ffff:ffff:ffff
763804:b000::/203804:bfff:ffff:ffff:ffff:ffff:ffff:ffff
773804:c000::/203804:cfff:ffff:ffff:ffff:ffff:ffff:ffff
783804:d000::/203804:dfff:ffff:ffff:ffff:ffff:ffff:ffff
793804:e000::/203804:efff:ffff:ffff:ffff:ffff:ffff:ffff
803804:f000::/203804:ffff:ffff:ffff:ffff:ffff:ffff:ffff
813805::/203805:fff:ffff:ffff:ffff:ffff:ffff:ffff
823805:1000::/203805:1fff:ffff:ffff:ffff:ffff:ffff:ffff
833805:2000::/203805:2fff:ffff:ffff:ffff:ffff:ffff:ffff
843805:3000::/203805:3fff:ffff:ffff:ffff:ffff:ffff:ffff
853805:4000::/203805:4fff:ffff:ffff:ffff:ffff:ffff:ffff
863805:5000::/203805:5fff:ffff:ffff:ffff:ffff:ffff:ffff
873805:6000::/203805:6fff:ffff:ffff:ffff:ffff:ffff:ffff
883805:7000::/203805:7fff:ffff:ffff:ffff:ffff:ffff:ffff
893805:8000::/203805:8fff:ffff:ffff:ffff:ffff:ffff:ffff
903805:9000::/203805:9fff:ffff:ffff:ffff:ffff:ffff:ffff
913805:a000::/203805:afff:ffff:ffff:ffff:ffff:ffff:ffff
923805:b000::/203805:bfff:ffff:ffff:ffff:ffff:ffff:ffff
933805:c000::/203805:cfff:ffff:ffff:ffff:ffff:ffff:ffff
943805:d000::/203805:dfff:ffff:ffff:ffff:ffff:ffff:ffff
953805:e000::/203805:efff:ffff:ffff:ffff:ffff:ffff:ffff
963805:f000::/203805:ffff:ffff:ffff:ffff:ffff:ffff:ffff
973806::/203806:fff:ffff:ffff:ffff:ffff:ffff:ffff
983806:1000::/203806:1fff:ffff:ffff:ffff:ffff:ffff:ffff
993806:2000::/203806:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1003806:3000::/203806:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1013806:4000::/203806:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1023806:5000::/203806:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1033806:6000::/203806:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1043806:7000::/203806:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1053806:8000::/203806:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1063806:9000::/203806:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1073806:a000::/203806:afff:ffff:ffff:ffff:ffff:ffff:ffff
1083806:b000::/203806:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1093806:c000::/203806:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1103806:d000::/203806:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1113806:e000::/203806:efff:ffff:ffff:ffff:ffff:ffff:ffff
1123806:f000::/203806:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1133807::/203807:fff:ffff:ffff:ffff:ffff:ffff:ffff
1143807:1000::/203807:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1153807:2000::/203807:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1163807:3000::/203807:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1173807:4000::/203807:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1183807:5000::/203807:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1193807:6000::/203807:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1203807:7000::/203807:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1213807:8000::/203807:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1223807:9000::/203807:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1233807:a000::/203807:afff:ffff:ffff:ffff:ffff:ffff:ffff
1243807:b000::/203807:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1253807:c000::/203807:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1263807:d000::/203807:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1273807:e000::/203807:efff:ffff:ffff:ffff:ffff:ffff:ffff
1283807:f000::/203807:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1293808::/203808:fff:ffff:ffff:ffff:ffff:ffff:ffff
1303808:1000::/203808:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1313808:2000::/203808:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1323808:3000::/203808:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1333808:4000::/203808:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1343808:5000::/203808:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1353808:6000::/203808:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1363808:7000::/203808:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1373808:8000::/203808:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1383808:9000::/203808:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1393808:a000::/203808:afff:ffff:ffff:ffff:ffff:ffff:ffff
1403808:b000::/203808:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1413808:c000::/203808:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1423808:d000::/203808:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1433808:e000::/203808:efff:ffff:ffff:ffff:ffff:ffff:ffff
1443808:f000::/203808:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1453809::/203809:fff:ffff:ffff:ffff:ffff:ffff:ffff
1463809:1000::/203809:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1473809:2000::/203809:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1483809:3000::/203809:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1493809:4000::/203809:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1503809:5000::/203809:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1513809:6000::/203809:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1523809:7000::/203809:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1533809:8000::/203809:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1543809:9000::/203809:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1553809:a000::/203809:afff:ffff:ffff:ffff:ffff:ffff:ffff
1563809:b000::/203809:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1573809:c000::/203809:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1583809:d000::/203809:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1593809:e000::/203809:efff:ffff:ffff:ffff:ffff:ffff:ffff
1603809:f000::/203809:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161380a::/20380a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162380a:1000::/20380a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163380a:2000::/20380a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164380a:3000::/20380a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165380a:4000::/20380a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166380a:5000::/20380a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167380a:6000::/20380a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168380a:7000::/20380a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169380a:8000::/20380a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170380a:9000::/20380a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171380a:a000::/20380a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172380a:b000::/20380a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173380a:c000::/20380a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174380a:d000::/20380a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175380a:e000::/20380a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176380a:f000::/20380a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177380b::/20380b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178380b:1000::/20380b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179380b:2000::/20380b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180380b:3000::/20380b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181380b:4000::/20380b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182380b:5000::/20380b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183380b:6000::/20380b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184380b:7000::/20380b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185380b:8000::/20380b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186380b:9000::/20380b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187380b:a000::/20380b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188380b:b000::/20380b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189380b:c000::/20380b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190380b:d000::/20380b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191380b:e000::/20380b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192380b:f000::/20380b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193380c::/20380c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194380c:1000::/20380c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195380c:2000::/20380c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196380c:3000::/20380c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197380c:4000::/20380c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198380c:5000::/20380c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199380c:6000::/20380c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200380c:7000::/20380c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201380c:8000::/20380c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202380c:9000::/20380c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203380c:a000::/20380c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204380c:b000::/20380c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205380c:c000::/20380c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206380c:d000::/20380c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207380c:e000::/20380c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208380c:f000::/20380c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209380d::/20380d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210380d:1000::/20380d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211380d:2000::/20380d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212380d:3000::/20380d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213380d:4000::/20380d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214380d:5000::/20380d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215380d:6000::/20380d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216380d:7000::/20380d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217380d:8000::/20380d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218380d:9000::/20380d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219380d:a000::/20380d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220380d:b000::/20380d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221380d:c000::/20380d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222380d:d000::/20380d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223380d:e000::/20380d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224380d:f000::/20380d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225380e::/20380e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226380e:1000::/20380e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227380e:2000::/20380e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228380e:3000::/20380e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229380e:4000::/20380e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230380e:5000::/20380e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231380e:6000::/20380e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232380e:7000::/20380e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233380e:8000::/20380e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234380e:9000::/20380e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235380e:a000::/20380e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236380e:b000::/20380e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237380e:c000::/20380e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238380e:d000::/20380e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239380e:e000::/20380e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240380e:f000::/20380e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241380f::/20380f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242380f:1000::/20380f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243380f:2000::/20380f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244380f:3000::/20380f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245380f:4000::/20380f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246380f:5000::/20380f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247380f:6000::/20380f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248380f:7000::/20380f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249380f:8000::/20380f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250380f:9000::/20380f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251380f:a000::/20380f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252380f:b000::/20380f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253380f:c000::/20380f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254380f:d000::/20380f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255380f:e000::/20380f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256380f:f000::/20380f: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.