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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/9
Addresses2^119
/64 networks2^55
Network
2500::/9
First address
2500::
Last address
257f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
664,613,997,892,457,936,451,903,530,140,172,288 (2^119)
/64 networks (LANs)
36,028,797,018,963,968 (2^55)
Full form
2500:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
0.5.2.ip6.arpa
1.5.2.ip6.arpa
2.5.2.ip6.arpa
3.5.2.ip6.arpa
4.5.2.ip6.arpa
5.5.2.ip6.arpa
6.5.2.ip6.arpa
7.5.2.ip6.arpa
/9 is not on a 4-bit boundary, so it takes 8 /12 zones.
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/16 (128)/20 (2,048)/24 (32,768)

2500::/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
12500::/202500:fff:ffff:ffff:ffff:ffff:ffff:ffff
22500:1000::/202500:1fff:ffff:ffff:ffff:ffff:ffff:ffff
32500:2000::/202500:2fff:ffff:ffff:ffff:ffff:ffff:ffff
42500:3000::/202500:3fff:ffff:ffff:ffff:ffff:ffff:ffff
52500:4000::/202500:4fff:ffff:ffff:ffff:ffff:ffff:ffff
62500:5000::/202500:5fff:ffff:ffff:ffff:ffff:ffff:ffff
72500:6000::/202500:6fff:ffff:ffff:ffff:ffff:ffff:ffff
82500:7000::/202500:7fff:ffff:ffff:ffff:ffff:ffff:ffff
92500:8000::/202500:8fff:ffff:ffff:ffff:ffff:ffff:ffff
102500:9000::/202500:9fff:ffff:ffff:ffff:ffff:ffff:ffff
112500:a000::/202500:afff:ffff:ffff:ffff:ffff:ffff:ffff
122500:b000::/202500:bfff:ffff:ffff:ffff:ffff:ffff:ffff
132500:c000::/202500:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142500:d000::/202500:dfff:ffff:ffff:ffff:ffff:ffff:ffff
152500:e000::/202500:efff:ffff:ffff:ffff:ffff:ffff:ffff
162500:f000::/202500:ffff:ffff:ffff:ffff:ffff:ffff:ffff
172501::/202501:fff:ffff:ffff:ffff:ffff:ffff:ffff
182501:1000::/202501:1fff:ffff:ffff:ffff:ffff:ffff:ffff
192501:2000::/202501:2fff:ffff:ffff:ffff:ffff:ffff:ffff
202501:3000::/202501:3fff:ffff:ffff:ffff:ffff:ffff:ffff
212501:4000::/202501:4fff:ffff:ffff:ffff:ffff:ffff:ffff
222501:5000::/202501:5fff:ffff:ffff:ffff:ffff:ffff:ffff
232501:6000::/202501:6fff:ffff:ffff:ffff:ffff:ffff:ffff
242501:7000::/202501:7fff:ffff:ffff:ffff:ffff:ffff:ffff
252501:8000::/202501:8fff:ffff:ffff:ffff:ffff:ffff:ffff
262501:9000::/202501:9fff:ffff:ffff:ffff:ffff:ffff:ffff
272501:a000::/202501:afff:ffff:ffff:ffff:ffff:ffff:ffff
282501:b000::/202501:bfff:ffff:ffff:ffff:ffff:ffff:ffff
292501:c000::/202501:cfff:ffff:ffff:ffff:ffff:ffff:ffff
302501:d000::/202501:dfff:ffff:ffff:ffff:ffff:ffff:ffff
312501:e000::/202501:efff:ffff:ffff:ffff:ffff:ffff:ffff
322501:f000::/202501:ffff:ffff:ffff:ffff:ffff:ffff:ffff
332502::/202502:fff:ffff:ffff:ffff:ffff:ffff:ffff
342502:1000::/202502:1fff:ffff:ffff:ffff:ffff:ffff:ffff
352502:2000::/202502:2fff:ffff:ffff:ffff:ffff:ffff:ffff
362502:3000::/202502:3fff:ffff:ffff:ffff:ffff:ffff:ffff
372502:4000::/202502:4fff:ffff:ffff:ffff:ffff:ffff:ffff
382502:5000::/202502:5fff:ffff:ffff:ffff:ffff:ffff:ffff
392502:6000::/202502:6fff:ffff:ffff:ffff:ffff:ffff:ffff
402502:7000::/202502:7fff:ffff:ffff:ffff:ffff:ffff:ffff
412502:8000::/202502:8fff:ffff:ffff:ffff:ffff:ffff:ffff
422502:9000::/202502:9fff:ffff:ffff:ffff:ffff:ffff:ffff
432502:a000::/202502:afff:ffff:ffff:ffff:ffff:ffff:ffff
442502:b000::/202502:bfff:ffff:ffff:ffff:ffff:ffff:ffff
452502:c000::/202502:cfff:ffff:ffff:ffff:ffff:ffff:ffff
462502:d000::/202502:dfff:ffff:ffff:ffff:ffff:ffff:ffff
472502:e000::/202502:efff:ffff:ffff:ffff:ffff:ffff:ffff
482502:f000::/202502:ffff:ffff:ffff:ffff:ffff:ffff:ffff
492503::/202503:fff:ffff:ffff:ffff:ffff:ffff:ffff
502503:1000::/202503:1fff:ffff:ffff:ffff:ffff:ffff:ffff
512503:2000::/202503:2fff:ffff:ffff:ffff:ffff:ffff:ffff
522503:3000::/202503:3fff:ffff:ffff:ffff:ffff:ffff:ffff
532503:4000::/202503:4fff:ffff:ffff:ffff:ffff:ffff:ffff
542503:5000::/202503:5fff:ffff:ffff:ffff:ffff:ffff:ffff
552503:6000::/202503:6fff:ffff:ffff:ffff:ffff:ffff:ffff
562503:7000::/202503:7fff:ffff:ffff:ffff:ffff:ffff:ffff
572503:8000::/202503:8fff:ffff:ffff:ffff:ffff:ffff:ffff
582503:9000::/202503:9fff:ffff:ffff:ffff:ffff:ffff:ffff
592503:a000::/202503:afff:ffff:ffff:ffff:ffff:ffff:ffff
602503:b000::/202503:bfff:ffff:ffff:ffff:ffff:ffff:ffff
612503:c000::/202503:cfff:ffff:ffff:ffff:ffff:ffff:ffff
622503:d000::/202503:dfff:ffff:ffff:ffff:ffff:ffff:ffff
632503:e000::/202503:efff:ffff:ffff:ffff:ffff:ffff:ffff
642503:f000::/202503:ffff:ffff:ffff:ffff:ffff:ffff:ffff
652504::/202504:fff:ffff:ffff:ffff:ffff:ffff:ffff
662504:1000::/202504:1fff:ffff:ffff:ffff:ffff:ffff:ffff
672504:2000::/202504:2fff:ffff:ffff:ffff:ffff:ffff:ffff
682504:3000::/202504:3fff:ffff:ffff:ffff:ffff:ffff:ffff
692504:4000::/202504:4fff:ffff:ffff:ffff:ffff:ffff:ffff
702504:5000::/202504:5fff:ffff:ffff:ffff:ffff:ffff:ffff
712504:6000::/202504:6fff:ffff:ffff:ffff:ffff:ffff:ffff
722504:7000::/202504:7fff:ffff:ffff:ffff:ffff:ffff:ffff
732504:8000::/202504:8fff:ffff:ffff:ffff:ffff:ffff:ffff
742504:9000::/202504:9fff:ffff:ffff:ffff:ffff:ffff:ffff
752504:a000::/202504:afff:ffff:ffff:ffff:ffff:ffff:ffff
762504:b000::/202504:bfff:ffff:ffff:ffff:ffff:ffff:ffff
772504:c000::/202504:cfff:ffff:ffff:ffff:ffff:ffff:ffff
782504:d000::/202504:dfff:ffff:ffff:ffff:ffff:ffff:ffff
792504:e000::/202504:efff:ffff:ffff:ffff:ffff:ffff:ffff
802504:f000::/202504:ffff:ffff:ffff:ffff:ffff:ffff:ffff
812505::/202505:fff:ffff:ffff:ffff:ffff:ffff:ffff
822505:1000::/202505:1fff:ffff:ffff:ffff:ffff:ffff:ffff
832505:2000::/202505:2fff:ffff:ffff:ffff:ffff:ffff:ffff
842505:3000::/202505:3fff:ffff:ffff:ffff:ffff:ffff:ffff
852505:4000::/202505:4fff:ffff:ffff:ffff:ffff:ffff:ffff
862505:5000::/202505:5fff:ffff:ffff:ffff:ffff:ffff:ffff
872505:6000::/202505:6fff:ffff:ffff:ffff:ffff:ffff:ffff
882505:7000::/202505:7fff:ffff:ffff:ffff:ffff:ffff:ffff
892505:8000::/202505:8fff:ffff:ffff:ffff:ffff:ffff:ffff
902505:9000::/202505:9fff:ffff:ffff:ffff:ffff:ffff:ffff
912505:a000::/202505:afff:ffff:ffff:ffff:ffff:ffff:ffff
922505:b000::/202505:bfff:ffff:ffff:ffff:ffff:ffff:ffff
932505:c000::/202505:cfff:ffff:ffff:ffff:ffff:ffff:ffff
942505:d000::/202505:dfff:ffff:ffff:ffff:ffff:ffff:ffff
952505:e000::/202505:efff:ffff:ffff:ffff:ffff:ffff:ffff
962505:f000::/202505:ffff:ffff:ffff:ffff:ffff:ffff:ffff
972506::/202506:fff:ffff:ffff:ffff:ffff:ffff:ffff
982506:1000::/202506:1fff:ffff:ffff:ffff:ffff:ffff:ffff
992506:2000::/202506:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1002506:3000::/202506:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1012506:4000::/202506:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1022506:5000::/202506:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1032506:6000::/202506:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1042506:7000::/202506:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1052506:8000::/202506:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1062506:9000::/202506:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1072506:a000::/202506:afff:ffff:ffff:ffff:ffff:ffff:ffff
1082506:b000::/202506:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1092506:c000::/202506:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1102506:d000::/202506:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1112506:e000::/202506:efff:ffff:ffff:ffff:ffff:ffff:ffff
1122506:f000::/202506:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1132507::/202507:fff:ffff:ffff:ffff:ffff:ffff:ffff
1142507:1000::/202507:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1152507:2000::/202507:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1162507:3000::/202507:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1172507:4000::/202507:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1182507:5000::/202507:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1192507:6000::/202507:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1202507:7000::/202507:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1212507:8000::/202507:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1222507:9000::/202507:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1232507:a000::/202507:afff:ffff:ffff:ffff:ffff:ffff:ffff
1242507:b000::/202507:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1252507:c000::/202507:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1262507:d000::/202507:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1272507:e000::/202507:efff:ffff:ffff:ffff:ffff:ffff:ffff
1282507:f000::/202507:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1292508::/202508:fff:ffff:ffff:ffff:ffff:ffff:ffff
1302508:1000::/202508:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1312508:2000::/202508:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1322508:3000::/202508:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1332508:4000::/202508:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1342508:5000::/202508:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1352508:6000::/202508:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1362508:7000::/202508:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1372508:8000::/202508:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1382508:9000::/202508:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1392508:a000::/202508:afff:ffff:ffff:ffff:ffff:ffff:ffff
1402508:b000::/202508:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1412508:c000::/202508:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1422508:d000::/202508:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1432508:e000::/202508:efff:ffff:ffff:ffff:ffff:ffff:ffff
1442508:f000::/202508:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1452509::/202509:fff:ffff:ffff:ffff:ffff:ffff:ffff
1462509:1000::/202509:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1472509:2000::/202509:2fff:ffff:ffff:ffff:ffff:ffff:ffff
1482509:3000::/202509:3fff:ffff:ffff:ffff:ffff:ffff:ffff
1492509:4000::/202509:4fff:ffff:ffff:ffff:ffff:ffff:ffff
1502509:5000::/202509:5fff:ffff:ffff:ffff:ffff:ffff:ffff
1512509:6000::/202509:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1522509:7000::/202509:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1532509:8000::/202509:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1542509:9000::/202509:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1552509:a000::/202509:afff:ffff:ffff:ffff:ffff:ffff:ffff
1562509:b000::/202509:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1572509:c000::/202509:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1582509:d000::/202509:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1592509:e000::/202509:efff:ffff:ffff:ffff:ffff:ffff:ffff
1602509:f000::/202509:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161250a::/20250a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162250a:1000::/20250a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163250a:2000::/20250a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164250a:3000::/20250a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165250a:4000::/20250a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166250a:5000::/20250a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167250a:6000::/20250a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168250a:7000::/20250a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169250a:8000::/20250a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170250a:9000::/20250a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171250a:a000::/20250a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172250a:b000::/20250a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173250a:c000::/20250a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174250a:d000::/20250a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175250a:e000::/20250a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176250a:f000::/20250a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177250b::/20250b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178250b:1000::/20250b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179250b:2000::/20250b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180250b:3000::/20250b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181250b:4000::/20250b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182250b:5000::/20250b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183250b:6000::/20250b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184250b:7000::/20250b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185250b:8000::/20250b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186250b:9000::/20250b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187250b:a000::/20250b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188250b:b000::/20250b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189250b:c000::/20250b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190250b:d000::/20250b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191250b:e000::/20250b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192250b:f000::/20250b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193250c::/20250c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194250c:1000::/20250c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195250c:2000::/20250c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196250c:3000::/20250c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197250c:4000::/20250c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198250c:5000::/20250c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199250c:6000::/20250c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200250c:7000::/20250c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201250c:8000::/20250c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202250c:9000::/20250c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203250c:a000::/20250c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204250c:b000::/20250c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205250c:c000::/20250c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206250c:d000::/20250c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207250c:e000::/20250c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208250c:f000::/20250c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209250d::/20250d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210250d:1000::/20250d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211250d:2000::/20250d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212250d:3000::/20250d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213250d:4000::/20250d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214250d:5000::/20250d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215250d:6000::/20250d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216250d:7000::/20250d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217250d:8000::/20250d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218250d:9000::/20250d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219250d:a000::/20250d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220250d:b000::/20250d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221250d:c000::/20250d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222250d:d000::/20250d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223250d:e000::/20250d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224250d:f000::/20250d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225250e::/20250e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226250e:1000::/20250e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227250e:2000::/20250e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228250e:3000::/20250e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229250e:4000::/20250e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230250e:5000::/20250e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231250e:6000::/20250e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232250e:7000::/20250e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233250e:8000::/20250e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234250e:9000::/20250e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235250e:a000::/20250e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236250e:b000::/20250e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237250e:c000::/20250e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238250e:d000::/20250e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239250e:e000::/20250e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240250e:f000::/20250e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241250f::/20250f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242250f:1000::/20250f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243250f:2000::/20250f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244250f:3000::/20250f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245250f:4000::/20250f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246250f:5000::/20250f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247250f:6000::/20250f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248250f:7000::/20250f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249250f:8000::/20250f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250250f:9000::/20250f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251250f:a000::/20250f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252250f:b000::/20250f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253250f:c000::/20250f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254250f:d000::/20250f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255250f:e000::/20250f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256250f:f000::/20250f: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.