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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/120
Addresses256
/64 networksPart of one
Network
2c19:dd:c25:c25:dd:dd:dd:4200/120
First address
2c19:dd:c25:c25:dd:dd:dd:4200
Last address
2c19:dd:c25:c25:dd:dd:dd:42ff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:0c25:0c25:00dd:00dd:00dd:4200
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
2.4.d.d.0.0.d.d.0.0.d.d.0.0.5.2.c.0.5.2.c.0.d.d.0.0.9.1.c.2.ip6.arpa
Split into smaller subnets/128
/121 (2)/122 (4)/123 (8)/124 (16)/127 (128)/128 (256)

2c19:dd:c25:c25:dd:dd:dd:4200/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:c25:c25:dd:dd:dd:4200/1282c19:dd:c25:c25:dd:dd:dd:4200
22c19:dd:c25:c25:dd:dd:dd:4201/1282c19:dd:c25:c25:dd:dd:dd:4201
32c19:dd:c25:c25:dd:dd:dd:4202/1282c19:dd:c25:c25:dd:dd:dd:4202
42c19:dd:c25:c25:dd:dd:dd:4203/1282c19:dd:c25:c25:dd:dd:dd:4203
52c19:dd:c25:c25:dd:dd:dd:4204/1282c19:dd:c25:c25:dd:dd:dd:4204
62c19:dd:c25:c25:dd:dd:dd:4205/1282c19:dd:c25:c25:dd:dd:dd:4205
72c19:dd:c25:c25:dd:dd:dd:4206/1282c19:dd:c25:c25:dd:dd:dd:4206
82c19:dd:c25:c25:dd:dd:dd:4207/1282c19:dd:c25:c25:dd:dd:dd:4207
92c19:dd:c25:c25:dd:dd:dd:4208/1282c19:dd:c25:c25:dd:dd:dd:4208
102c19:dd:c25:c25:dd:dd:dd:4209/1282c19:dd:c25:c25:dd:dd:dd:4209
112c19:dd:c25:c25:dd:dd:dd:420a/1282c19:dd:c25:c25:dd:dd:dd:420a
122c19:dd:c25:c25:dd:dd:dd:420b/1282c19:dd:c25:c25:dd:dd:dd:420b
132c19:dd:c25:c25:dd:dd:dd:420c/1282c19:dd:c25:c25:dd:dd:dd:420c
142c19:dd:c25:c25:dd:dd:dd:420d/1282c19:dd:c25:c25:dd:dd:dd:420d
152c19:dd:c25:c25:dd:dd:dd:420e/1282c19:dd:c25:c25:dd:dd:dd:420e
162c19:dd:c25:c25:dd:dd:dd:420f/1282c19:dd:c25:c25:dd:dd:dd:420f
172c19:dd:c25:c25:dd:dd:dd:4210/1282c19:dd:c25:c25:dd:dd:dd:4210
182c19:dd:c25:c25:dd:dd:dd:4211/1282c19:dd:c25:c25:dd:dd:dd:4211
192c19:dd:c25:c25:dd:dd:dd:4212/1282c19:dd:c25:c25:dd:dd:dd:4212
202c19:dd:c25:c25:dd:dd:dd:4213/1282c19:dd:c25:c25:dd:dd:dd:4213
212c19:dd:c25:c25:dd:dd:dd:4214/1282c19:dd:c25:c25:dd:dd:dd:4214
222c19:dd:c25:c25:dd:dd:dd:4215/1282c19:dd:c25:c25:dd:dd:dd:4215
232c19:dd:c25:c25:dd:dd:dd:4216/1282c19:dd:c25:c25:dd:dd:dd:4216
242c19:dd:c25:c25:dd:dd:dd:4217/1282c19:dd:c25:c25:dd:dd:dd:4217
252c19:dd:c25:c25:dd:dd:dd:4218/1282c19:dd:c25:c25:dd:dd:dd:4218
262c19:dd:c25:c25:dd:dd:dd:4219/1282c19:dd:c25:c25:dd:dd:dd:4219
272c19:dd:c25:c25:dd:dd:dd:421a/1282c19:dd:c25:c25:dd:dd:dd:421a
282c19:dd:c25:c25:dd:dd:dd:421b/1282c19:dd:c25:c25:dd:dd:dd:421b
292c19:dd:c25:c25:dd:dd:dd:421c/1282c19:dd:c25:c25:dd:dd:dd:421c
302c19:dd:c25:c25:dd:dd:dd:421d/1282c19:dd:c25:c25:dd:dd:dd:421d
312c19:dd:c25:c25:dd:dd:dd:421e/1282c19:dd:c25:c25:dd:dd:dd:421e
322c19:dd:c25:c25:dd:dd:dd:421f/1282c19:dd:c25:c25:dd:dd:dd:421f
332c19:dd:c25:c25:dd:dd:dd:4220/1282c19:dd:c25:c25:dd:dd:dd:4220
342c19:dd:c25:c25:dd:dd:dd:4221/1282c19:dd:c25:c25:dd:dd:dd:4221
352c19:dd:c25:c25:dd:dd:dd:4222/1282c19:dd:c25:c25:dd:dd:dd:4222
362c19:dd:c25:c25:dd:dd:dd:4223/1282c19:dd:c25:c25:dd:dd:dd:4223
372c19:dd:c25:c25:dd:dd:dd:4224/1282c19:dd:c25:c25:dd:dd:dd:4224
382c19:dd:c25:c25:dd:dd:dd:4225/1282c19:dd:c25:c25:dd:dd:dd:4225
392c19:dd:c25:c25:dd:dd:dd:4226/1282c19:dd:c25:c25:dd:dd:dd:4226
402c19:dd:c25:c25:dd:dd:dd:4227/1282c19:dd:c25:c25:dd:dd:dd:4227
412c19:dd:c25:c25:dd:dd:dd:4228/1282c19:dd:c25:c25:dd:dd:dd:4228
422c19:dd:c25:c25:dd:dd:dd:4229/1282c19:dd:c25:c25:dd:dd:dd:4229
432c19:dd:c25:c25:dd:dd:dd:422a/1282c19:dd:c25:c25:dd:dd:dd:422a
442c19:dd:c25:c25:dd:dd:dd:422b/1282c19:dd:c25:c25:dd:dd:dd:422b
452c19:dd:c25:c25:dd:dd:dd:422c/1282c19:dd:c25:c25:dd:dd:dd:422c
462c19:dd:c25:c25:dd:dd:dd:422d/1282c19:dd:c25:c25:dd:dd:dd:422d
472c19:dd:c25:c25:dd:dd:dd:422e/1282c19:dd:c25:c25:dd:dd:dd:422e
482c19:dd:c25:c25:dd:dd:dd:422f/1282c19:dd:c25:c25:dd:dd:dd:422f
492c19:dd:c25:c25:dd:dd:dd:4230/1282c19:dd:c25:c25:dd:dd:dd:4230
502c19:dd:c25:c25:dd:dd:dd:4231/1282c19:dd:c25:c25:dd:dd:dd:4231
512c19:dd:c25:c25:dd:dd:dd:4232/1282c19:dd:c25:c25:dd:dd:dd:4232
522c19:dd:c25:c25:dd:dd:dd:4233/1282c19:dd:c25:c25:dd:dd:dd:4233
532c19:dd:c25:c25:dd:dd:dd:4234/1282c19:dd:c25:c25:dd:dd:dd:4234
542c19:dd:c25:c25:dd:dd:dd:4235/1282c19:dd:c25:c25:dd:dd:dd:4235
552c19:dd:c25:c25:dd:dd:dd:4236/1282c19:dd:c25:c25:dd:dd:dd:4236
562c19:dd:c25:c25:dd:dd:dd:4237/1282c19:dd:c25:c25:dd:dd:dd:4237
572c19:dd:c25:c25:dd:dd:dd:4238/1282c19:dd:c25:c25:dd:dd:dd:4238
582c19:dd:c25:c25:dd:dd:dd:4239/1282c19:dd:c25:c25:dd:dd:dd:4239
592c19:dd:c25:c25:dd:dd:dd:423a/1282c19:dd:c25:c25:dd:dd:dd:423a
602c19:dd:c25:c25:dd:dd:dd:423b/1282c19:dd:c25:c25:dd:dd:dd:423b
612c19:dd:c25:c25:dd:dd:dd:423c/1282c19:dd:c25:c25:dd:dd:dd:423c
622c19:dd:c25:c25:dd:dd:dd:423d/1282c19:dd:c25:c25:dd:dd:dd:423d
632c19:dd:c25:c25:dd:dd:dd:423e/1282c19:dd:c25:c25:dd:dd:dd:423e
642c19:dd:c25:c25:dd:dd:dd:423f/1282c19:dd:c25:c25:dd:dd:dd:423f
652c19:dd:c25:c25:dd:dd:dd:4240/1282c19:dd:c25:c25:dd:dd:dd:4240
662c19:dd:c25:c25:dd:dd:dd:4241/1282c19:dd:c25:c25:dd:dd:dd:4241
672c19:dd:c25:c25:dd:dd:dd:4242/1282c19:dd:c25:c25:dd:dd:dd:4242
682c19:dd:c25:c25:dd:dd:dd:4243/1282c19:dd:c25:c25:dd:dd:dd:4243
692c19:dd:c25:c25:dd:dd:dd:4244/1282c19:dd:c25:c25:dd:dd:dd:4244
702c19:dd:c25:c25:dd:dd:dd:4245/1282c19:dd:c25:c25:dd:dd:dd:4245
712c19:dd:c25:c25:dd:dd:dd:4246/1282c19:dd:c25:c25:dd:dd:dd:4246
722c19:dd:c25:c25:dd:dd:dd:4247/1282c19:dd:c25:c25:dd:dd:dd:4247
732c19:dd:c25:c25:dd:dd:dd:4248/1282c19:dd:c25:c25:dd:dd:dd:4248
742c19:dd:c25:c25:dd:dd:dd:4249/1282c19:dd:c25:c25:dd:dd:dd:4249
752c19:dd:c25:c25:dd:dd:dd:424a/1282c19:dd:c25:c25:dd:dd:dd:424a
762c19:dd:c25:c25:dd:dd:dd:424b/1282c19:dd:c25:c25:dd:dd:dd:424b
772c19:dd:c25:c25:dd:dd:dd:424c/1282c19:dd:c25:c25:dd:dd:dd:424c
782c19:dd:c25:c25:dd:dd:dd:424d/1282c19:dd:c25:c25:dd:dd:dd:424d
792c19:dd:c25:c25:dd:dd:dd:424e/1282c19:dd:c25:c25:dd:dd:dd:424e
802c19:dd:c25:c25:dd:dd:dd:424f/1282c19:dd:c25:c25:dd:dd:dd:424f
812c19:dd:c25:c25:dd:dd:dd:4250/1282c19:dd:c25:c25:dd:dd:dd:4250
822c19:dd:c25:c25:dd:dd:dd:4251/1282c19:dd:c25:c25:dd:dd:dd:4251
832c19:dd:c25:c25:dd:dd:dd:4252/1282c19:dd:c25:c25:dd:dd:dd:4252
842c19:dd:c25:c25:dd:dd:dd:4253/1282c19:dd:c25:c25:dd:dd:dd:4253
852c19:dd:c25:c25:dd:dd:dd:4254/1282c19:dd:c25:c25:dd:dd:dd:4254
862c19:dd:c25:c25:dd:dd:dd:4255/1282c19:dd:c25:c25:dd:dd:dd:4255
872c19:dd:c25:c25:dd:dd:dd:4256/1282c19:dd:c25:c25:dd:dd:dd:4256
882c19:dd:c25:c25:dd:dd:dd:4257/1282c19:dd:c25:c25:dd:dd:dd:4257
892c19:dd:c25:c25:dd:dd:dd:4258/1282c19:dd:c25:c25:dd:dd:dd:4258
902c19:dd:c25:c25:dd:dd:dd:4259/1282c19:dd:c25:c25:dd:dd:dd:4259
912c19:dd:c25:c25:dd:dd:dd:425a/1282c19:dd:c25:c25:dd:dd:dd:425a
922c19:dd:c25:c25:dd:dd:dd:425b/1282c19:dd:c25:c25:dd:dd:dd:425b
932c19:dd:c25:c25:dd:dd:dd:425c/1282c19:dd:c25:c25:dd:dd:dd:425c
942c19:dd:c25:c25:dd:dd:dd:425d/1282c19:dd:c25:c25:dd:dd:dd:425d
952c19:dd:c25:c25:dd:dd:dd:425e/1282c19:dd:c25:c25:dd:dd:dd:425e
962c19:dd:c25:c25:dd:dd:dd:425f/1282c19:dd:c25:c25:dd:dd:dd:425f
972c19:dd:c25:c25:dd:dd:dd:4260/1282c19:dd:c25:c25:dd:dd:dd:4260
982c19:dd:c25:c25:dd:dd:dd:4261/1282c19:dd:c25:c25:dd:dd:dd:4261
992c19:dd:c25:c25:dd:dd:dd:4262/1282c19:dd:c25:c25:dd:dd:dd:4262
1002c19:dd:c25:c25:dd:dd:dd:4263/1282c19:dd:c25:c25:dd:dd:dd:4263
1012c19:dd:c25:c25:dd:dd:dd:4264/1282c19:dd:c25:c25:dd:dd:dd:4264
1022c19:dd:c25:c25:dd:dd:dd:4265/1282c19:dd:c25:c25:dd:dd:dd:4265
1032c19:dd:c25:c25:dd:dd:dd:4266/1282c19:dd:c25:c25:dd:dd:dd:4266
1042c19:dd:c25:c25:dd:dd:dd:4267/1282c19:dd:c25:c25:dd:dd:dd:4267
1052c19:dd:c25:c25:dd:dd:dd:4268/1282c19:dd:c25:c25:dd:dd:dd:4268
1062c19:dd:c25:c25:dd:dd:dd:4269/1282c19:dd:c25:c25:dd:dd:dd:4269
1072c19:dd:c25:c25:dd:dd:dd:426a/1282c19:dd:c25:c25:dd:dd:dd:426a
1082c19:dd:c25:c25:dd:dd:dd:426b/1282c19:dd:c25:c25:dd:dd:dd:426b
1092c19:dd:c25:c25:dd:dd:dd:426c/1282c19:dd:c25:c25:dd:dd:dd:426c
1102c19:dd:c25:c25:dd:dd:dd:426d/1282c19:dd:c25:c25:dd:dd:dd:426d
1112c19:dd:c25:c25:dd:dd:dd:426e/1282c19:dd:c25:c25:dd:dd:dd:426e
1122c19:dd:c25:c25:dd:dd:dd:426f/1282c19:dd:c25:c25:dd:dd:dd:426f
1132c19:dd:c25:c25:dd:dd:dd:4270/1282c19:dd:c25:c25:dd:dd:dd:4270
1142c19:dd:c25:c25:dd:dd:dd:4271/1282c19:dd:c25:c25:dd:dd:dd:4271
1152c19:dd:c25:c25:dd:dd:dd:4272/1282c19:dd:c25:c25:dd:dd:dd:4272
1162c19:dd:c25:c25:dd:dd:dd:4273/1282c19:dd:c25:c25:dd:dd:dd:4273
1172c19:dd:c25:c25:dd:dd:dd:4274/1282c19:dd:c25:c25:dd:dd:dd:4274
1182c19:dd:c25:c25:dd:dd:dd:4275/1282c19:dd:c25:c25:dd:dd:dd:4275
1192c19:dd:c25:c25:dd:dd:dd:4276/1282c19:dd:c25:c25:dd:dd:dd:4276
1202c19:dd:c25:c25:dd:dd:dd:4277/1282c19:dd:c25:c25:dd:dd:dd:4277
1212c19:dd:c25:c25:dd:dd:dd:4278/1282c19:dd:c25:c25:dd:dd:dd:4278
1222c19:dd:c25:c25:dd:dd:dd:4279/1282c19:dd:c25:c25:dd:dd:dd:4279
1232c19:dd:c25:c25:dd:dd:dd:427a/1282c19:dd:c25:c25:dd:dd:dd:427a
1242c19:dd:c25:c25:dd:dd:dd:427b/1282c19:dd:c25:c25:dd:dd:dd:427b
1252c19:dd:c25:c25:dd:dd:dd:427c/1282c19:dd:c25:c25:dd:dd:dd:427c
1262c19:dd:c25:c25:dd:dd:dd:427d/1282c19:dd:c25:c25:dd:dd:dd:427d
1272c19:dd:c25:c25:dd:dd:dd:427e/1282c19:dd:c25:c25:dd:dd:dd:427e
1282c19:dd:c25:c25:dd:dd:dd:427f/1282c19:dd:c25:c25:dd:dd:dd:427f
1292c19:dd:c25:c25:dd:dd:dd:4280/1282c19:dd:c25:c25:dd:dd:dd:4280
1302c19:dd:c25:c25:dd:dd:dd:4281/1282c19:dd:c25:c25:dd:dd:dd:4281
1312c19:dd:c25:c25:dd:dd:dd:4282/1282c19:dd:c25:c25:dd:dd:dd:4282
1322c19:dd:c25:c25:dd:dd:dd:4283/1282c19:dd:c25:c25:dd:dd:dd:4283
1332c19:dd:c25:c25:dd:dd:dd:4284/1282c19:dd:c25:c25:dd:dd:dd:4284
1342c19:dd:c25:c25:dd:dd:dd:4285/1282c19:dd:c25:c25:dd:dd:dd:4285
1352c19:dd:c25:c25:dd:dd:dd:4286/1282c19:dd:c25:c25:dd:dd:dd:4286
1362c19:dd:c25:c25:dd:dd:dd:4287/1282c19:dd:c25:c25:dd:dd:dd:4287
1372c19:dd:c25:c25:dd:dd:dd:4288/1282c19:dd:c25:c25:dd:dd:dd:4288
1382c19:dd:c25:c25:dd:dd:dd:4289/1282c19:dd:c25:c25:dd:dd:dd:4289
1392c19:dd:c25:c25:dd:dd:dd:428a/1282c19:dd:c25:c25:dd:dd:dd:428a
1402c19:dd:c25:c25:dd:dd:dd:428b/1282c19:dd:c25:c25:dd:dd:dd:428b
1412c19:dd:c25:c25:dd:dd:dd:428c/1282c19:dd:c25:c25:dd:dd:dd:428c
1422c19:dd:c25:c25:dd:dd:dd:428d/1282c19:dd:c25:c25:dd:dd:dd:428d
1432c19:dd:c25:c25:dd:dd:dd:428e/1282c19:dd:c25:c25:dd:dd:dd:428e
1442c19:dd:c25:c25:dd:dd:dd:428f/1282c19:dd:c25:c25:dd:dd:dd:428f
1452c19:dd:c25:c25:dd:dd:dd:4290/1282c19:dd:c25:c25:dd:dd:dd:4290
1462c19:dd:c25:c25:dd:dd:dd:4291/1282c19:dd:c25:c25:dd:dd:dd:4291
1472c19:dd:c25:c25:dd:dd:dd:4292/1282c19:dd:c25:c25:dd:dd:dd:4292
1482c19:dd:c25:c25:dd:dd:dd:4293/1282c19:dd:c25:c25:dd:dd:dd:4293
1492c19:dd:c25:c25:dd:dd:dd:4294/1282c19:dd:c25:c25:dd:dd:dd:4294
1502c19:dd:c25:c25:dd:dd:dd:4295/1282c19:dd:c25:c25:dd:dd:dd:4295
1512c19:dd:c25:c25:dd:dd:dd:4296/1282c19:dd:c25:c25:dd:dd:dd:4296
1522c19:dd:c25:c25:dd:dd:dd:4297/1282c19:dd:c25:c25:dd:dd:dd:4297
1532c19:dd:c25:c25:dd:dd:dd:4298/1282c19:dd:c25:c25:dd:dd:dd:4298
1542c19:dd:c25:c25:dd:dd:dd:4299/1282c19:dd:c25:c25:dd:dd:dd:4299
1552c19:dd:c25:c25:dd:dd:dd:429a/1282c19:dd:c25:c25:dd:dd:dd:429a
1562c19:dd:c25:c25:dd:dd:dd:429b/1282c19:dd:c25:c25:dd:dd:dd:429b
1572c19:dd:c25:c25:dd:dd:dd:429c/1282c19:dd:c25:c25:dd:dd:dd:429c
1582c19:dd:c25:c25:dd:dd:dd:429d/1282c19:dd:c25:c25:dd:dd:dd:429d
1592c19:dd:c25:c25:dd:dd:dd:429e/1282c19:dd:c25:c25:dd:dd:dd:429e
1602c19:dd:c25:c25:dd:dd:dd:429f/1282c19:dd:c25:c25:dd:dd:dd:429f
1612c19:dd:c25:c25:dd:dd:dd:42a0/1282c19:dd:c25:c25:dd:dd:dd:42a0
1622c19:dd:c25:c25:dd:dd:dd:42a1/1282c19:dd:c25:c25:dd:dd:dd:42a1
1632c19:dd:c25:c25:dd:dd:dd:42a2/1282c19:dd:c25:c25:dd:dd:dd:42a2
1642c19:dd:c25:c25:dd:dd:dd:42a3/1282c19:dd:c25:c25:dd:dd:dd:42a3
1652c19:dd:c25:c25:dd:dd:dd:42a4/1282c19:dd:c25:c25:dd:dd:dd:42a4
1662c19:dd:c25:c25:dd:dd:dd:42a5/1282c19:dd:c25:c25:dd:dd:dd:42a5
1672c19:dd:c25:c25:dd:dd:dd:42a6/1282c19:dd:c25:c25:dd:dd:dd:42a6
1682c19:dd:c25:c25:dd:dd:dd:42a7/1282c19:dd:c25:c25:dd:dd:dd:42a7
1692c19:dd:c25:c25:dd:dd:dd:42a8/1282c19:dd:c25:c25:dd:dd:dd:42a8
1702c19:dd:c25:c25:dd:dd:dd:42a9/1282c19:dd:c25:c25:dd:dd:dd:42a9
1712c19:dd:c25:c25:dd:dd:dd:42aa/1282c19:dd:c25:c25:dd:dd:dd:42aa
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1762c19:dd:c25:c25:dd:dd:dd:42af/1282c19:dd:c25:c25:dd:dd:dd:42af
1772c19:dd:c25:c25:dd:dd:dd:42b0/1282c19:dd:c25:c25:dd:dd:dd:42b0
1782c19:dd:c25:c25:dd:dd:dd:42b1/1282c19:dd:c25:c25:dd:dd:dd:42b1
1792c19:dd:c25:c25:dd:dd:dd:42b2/1282c19:dd:c25:c25:dd:dd:dd:42b2
1802c19:dd:c25:c25:dd:dd:dd:42b3/1282c19:dd:c25:c25:dd:dd:dd:42b3
1812c19:dd:c25:c25:dd:dd:dd:42b4/1282c19:dd:c25:c25:dd:dd:dd:42b4
1822c19:dd:c25:c25:dd:dd:dd:42b5/1282c19:dd:c25:c25:dd:dd:dd:42b5
1832c19:dd:c25:c25:dd:dd:dd:42b6/1282c19:dd:c25:c25:dd:dd:dd:42b6
1842c19:dd:c25:c25:dd:dd:dd:42b7/1282c19:dd:c25:c25:dd:dd:dd:42b7
1852c19:dd:c25:c25:dd:dd:dd:42b8/1282c19:dd:c25:c25:dd:dd:dd:42b8
1862c19:dd:c25:c25:dd:dd:dd:42b9/1282c19:dd:c25:c25:dd:dd:dd:42b9
1872c19:dd:c25:c25:dd:dd:dd:42ba/1282c19:dd:c25:c25:dd:dd:dd:42ba
1882c19:dd:c25:c25:dd:dd:dd:42bb/1282c19:dd:c25:c25:dd:dd:dd:42bb
1892c19:dd:c25:c25:dd:dd:dd:42bc/1282c19:dd:c25:c25:dd:dd:dd:42bc
1902c19:dd:c25:c25:dd:dd:dd:42bd/1282c19:dd:c25:c25:dd:dd:dd:42bd
1912c19:dd:c25:c25:dd:dd:dd:42be/1282c19:dd:c25:c25:dd:dd:dd:42be
1922c19:dd:c25:c25:dd:dd:dd:42bf/1282c19:dd:c25:c25:dd:dd:dd:42bf
1932c19:dd:c25:c25:dd:dd:dd:42c0/1282c19:dd:c25:c25:dd:dd:dd:42c0
1942c19:dd:c25:c25:dd:dd:dd:42c1/1282c19:dd:c25:c25:dd:dd:dd:42c1
1952c19:dd:c25:c25:dd:dd:dd:42c2/1282c19:dd:c25:c25:dd:dd:dd:42c2
1962c19:dd:c25:c25:dd:dd:dd:42c3/1282c19:dd:c25:c25:dd:dd:dd:42c3
1972c19:dd:c25:c25:dd:dd:dd:42c4/1282c19:dd:c25:c25:dd:dd:dd:42c4
1982c19:dd:c25:c25:dd:dd:dd:42c5/1282c19:dd:c25:c25:dd:dd:dd:42c5
1992c19:dd:c25:c25:dd:dd:dd:42c6/1282c19:dd:c25:c25:dd:dd:dd:42c6
2002c19:dd:c25:c25:dd:dd:dd:42c7/1282c19:dd:c25:c25:dd:dd:dd:42c7
2012c19:dd:c25:c25:dd:dd:dd:42c8/1282c19:dd:c25:c25:dd:dd:dd:42c8
2022c19:dd:c25:c25:dd:dd:dd:42c9/1282c19:dd:c25:c25:dd:dd:dd:42c9
2032c19:dd:c25:c25:dd:dd:dd:42ca/1282c19:dd:c25:c25:dd:dd:dd:42ca
2042c19:dd:c25:c25:dd:dd:dd:42cb/1282c19:dd:c25:c25:dd:dd:dd:42cb
2052c19:dd:c25:c25:dd:dd:dd:42cc/1282c19:dd:c25:c25:dd:dd:dd:42cc
2062c19:dd:c25:c25:dd:dd:dd:42cd/1282c19:dd:c25:c25:dd:dd:dd:42cd
2072c19:dd:c25:c25:dd:dd:dd:42ce/1282c19:dd:c25:c25:dd:dd:dd:42ce
2082c19:dd:c25:c25:dd:dd:dd:42cf/1282c19:dd:c25:c25:dd:dd:dd:42cf
2092c19:dd:c25:c25:dd:dd:dd:42d0/1282c19:dd:c25:c25:dd:dd:dd:42d0
2102c19:dd:c25:c25:dd:dd:dd:42d1/1282c19:dd:c25:c25:dd:dd:dd:42d1
2112c19:dd:c25:c25:dd:dd:dd:42d2/1282c19:dd:c25:c25:dd:dd:dd:42d2
2122c19:dd:c25:c25:dd:dd:dd:42d3/1282c19:dd:c25:c25:dd:dd:dd:42d3
2132c19:dd:c25:c25:dd:dd:dd:42d4/1282c19:dd:c25:c25:dd:dd:dd:42d4
2142c19:dd:c25:c25:dd:dd:dd:42d5/1282c19:dd:c25:c25:dd:dd:dd:42d5
2152c19:dd:c25:c25:dd:dd:dd:42d6/1282c19:dd:c25:c25:dd:dd:dd:42d6
2162c19:dd:c25:c25:dd:dd:dd:42d7/1282c19:dd:c25:c25:dd:dd:dd:42d7
2172c19:dd:c25:c25:dd:dd:dd:42d8/1282c19:dd:c25:c25:dd:dd:dd:42d8
2182c19:dd:c25:c25:dd:dd:dd:42d9/1282c19:dd:c25:c25:dd:dd:dd:42d9
2192c19:dd:c25:c25:dd:dd:dd:42da/1282c19:dd:c25:c25:dd:dd:dd:42da
2202c19:dd:c25:c25:dd:dd:dd:42db/1282c19:dd:c25:c25:dd:dd:dd:42db
2212c19:dd:c25:c25:dd:dd:dd:42dc/1282c19:dd:c25:c25:dd:dd:dd:42dc
2222c19:dd:c25:c25:dd:dd:dd:42dd/1282c19:dd:c25:c25:dd:dd:dd:42dd
2232c19:dd:c25:c25:dd:dd:dd:42de/1282c19:dd:c25:c25:dd:dd:dd:42de
2242c19:dd:c25:c25:dd:dd:dd:42df/1282c19:dd:c25:c25:dd:dd:dd:42df
2252c19:dd:c25:c25:dd:dd:dd:42e0/1282c19:dd:c25:c25:dd:dd:dd:42e0
2262c19:dd:c25:c25:dd:dd:dd:42e1/1282c19:dd:c25:c25:dd:dd:dd:42e1
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2282c19:dd:c25:c25:dd:dd:dd:42e3/1282c19:dd:c25:c25:dd:dd:dd:42e3
2292c19:dd:c25:c25:dd:dd:dd:42e4/1282c19:dd:c25:c25:dd:dd:dd:42e4
2302c19:dd:c25:c25:dd:dd:dd:42e5/1282c19:dd:c25:c25:dd:dd:dd:42e5
2312c19:dd:c25:c25:dd:dd:dd:42e6/1282c19:dd:c25:c25:dd:dd:dd:42e6
2322c19:dd:c25:c25:dd:dd:dd:42e7/1282c19:dd:c25:c25:dd:dd:dd:42e7
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2362c19:dd:c25:c25:dd:dd:dd:42eb/1282c19:dd:c25:c25:dd:dd:dd:42eb
2372c19:dd:c25:c25:dd:dd:dd:42ec/1282c19:dd:c25:c25:dd:dd:dd:42ec
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2392c19:dd:c25:c25:dd:dd:dd:42ee/1282c19:dd:c25:c25:dd:dd:dd:42ee
2402c19:dd:c25:c25:dd:dd:dd:42ef/1282c19:dd:c25:c25:dd:dd:dd:42ef
2412c19:dd:c25:c25:dd:dd:dd:42f0/1282c19:dd:c25:c25:dd:dd:dd:42f0
2422c19:dd:c25:c25:dd:dd:dd:42f1/1282c19:dd:c25:c25:dd:dd:dd:42f1
2432c19:dd:c25:c25:dd:dd:dd:42f2/1282c19:dd:c25:c25:dd:dd:dd:42f2
2442c19:dd:c25:c25:dd:dd:dd:42f3/1282c19:dd:c25:c25:dd:dd:dd:42f3
2452c19:dd:c25:c25:dd:dd:dd:42f4/1282c19:dd:c25:c25:dd:dd:dd:42f4
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2492c19:dd:c25:c25:dd:dd:dd:42f8/1282c19:dd:c25:c25:dd:dd:dd:42f8
2502c19:dd:c25:c25:dd:dd:dd:42f9/1282c19:dd:c25:c25:dd:dd:dd:42f9
2512c19:dd:c25:c25:dd:dd:dd:42fa/1282c19:dd:c25:c25:dd:dd:dd:42fa
2522c19:dd:c25:c25:dd:dd:dd:42fb/1282c19:dd:c25:c25:dd:dd:dd:42fb
2532c19:dd:c25:c25:dd:dd:dd:42fc/1282c19:dd:c25:c25:dd:dd:dd:42fc
2542c19:dd:c25:c25:dd:dd:dd:42fd/1282c19:dd:c25:c25:dd:dd:dd:42fd
2552c19:dd:c25:c25:dd:dd:dd:42fe/1282c19:dd:c25:c25:dd:dd:dd:42fe
2562c19:dd:c25:c25:dd:dd:dd:42ff/1282c19:dd:c25:c25:dd:dd:dd:42ff

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.