Weight Chart :
This chart below was taken from The Complete Chihuahua Encyclopedia by Hilary Harmer. This chart may be used to provide an estimate for the weight of your puppy full grown. Please keep in mind that this method is not always accurate. It is simply meant to be used as a guideline. Other things for estimating a puppy's adult weight should be taken into consideration as well, such as knowing your puppies lineage, and your puppies diet. No puppy's adult weight can be guaranteed, only an estimate can ever be given. Beware of Breeders that try to sell you on your dogs weight.
| Birth | 2½ 0z. | 2¾ oz. | 3 oz. | 3½ oz. | 4 oz. | 4¼ oz | 4½ oz. | 5 oz. | 5½ oz. |
| 1 week | 3¾ | 4 | 5 | 5½ | 6½ | 7 | 8 | 9 | 9½ |
| 2 weeks | 5 | 5½ | 6½ | 7 | 9 | 10 | 11 | 12½ | 13½ |
| 3 weeks | 6 | 7 | 8 | 9 | 11 | 13 | 14 | 16 | 17½ |
| 4 weeks | 7 | 8 | 9½ | 11 | 13 | 15 | 17 | 19½ | 21 |
| 5 weeks | 8 | 9 | 11 | 13 | 15 | 17 | 19½ | 22 | 24 |
| 6 weeks | 9 | 11 | 12½ | 15 | 17½ | 20 | 22 | 24 | 27 |
| 7 weeks | 10 | 12 | 14½ | 17 | 19½ | 22 | 24½ | 27 | 30 |
| 8 weeks | 11 | 13 | 16 | 19 | 21½ | 24 | 27 | 29 | 33 |
| 9 weeks | 12 | 15 | 17½ | 20 | 23 | 26 | 29 | 32 | 35 |
| 10 weeks | 13 | 16 | 19 | 22 | 25 | 28 | 31 | 34 | 38 |
| 11 weeks | 14 | 17 | 21 | 24 | 27 | 31 | 34 | 37 | 42 |
| 12 weeks | 15 | 19 | 22 | 26 | 30 | 33 | 37 | 41 | 45 |
| 13 weeks | 16 | 20 | 24 | 28 | 32 | 36 | 40 | 44 | 49 |
| 14 weeks | 17 | 22 | 26 | 30 | 34 | 39 | 43 | 47 | 52 |
| 15 weeks | 19 | 23 | 28 | 32 | 37 | 41 | 46 | 51 | 56 |
| 16 weeks | 20 | 25 | 30 | 34 | 39 | 44 | 49 | 54 | 59 |
| 17 weeks | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 57 | 62 |
| 18 weeks | 22 | 28 | 33 | 37 | 43 | 48 | 54 | 60 | 65 |
| 19 weeks | 23 | 29 | 34 | 39 | 44 | 50 | 56 | 62 | 67 |
| 20 weeks | 24 | 30 | 35 | 41 | 46 | 52 | 58 | 64 | 70 |
| 21 weeks | 25 | 31 | 36 | 42 | 48 | 54 | 60 | 66 | 72 |
| 22 weeks | 25 | 32 | 37 | 43 | 49 | 56 | 62 | 68 | 74 |
| 23 weeks | 26 | 33 | 38 | 44 | 50 | 57 | 64 | 70 | 76 |
| 24 weeks | 26 | 33 | 39 | 45 | 51 | 58 | 65 | 71 | 78 |
| 25 weeks | 27 | 34 | 40 | 46 | 52 | 59 | 66 | 72 | 79 |
| 26 weeks | 27 | 34 | 40 | 47 | 53 | 60 | 67 | 73 | 80 |
| 18 months-full grown | 2 lb. | 2½ lb. | 3 lb. | 3½ lb. | 4 lb. | 4½ lb. | 5 lb. | 5 ½ lb. | 6 lb. |

