1 pound = 0.45359237 kg exactly (NIST SP 811). Enter any weight in pounds, kilograms, or ounces and the converter updates the other two instantly.
Why pet weight in multiple units
Most veterinary dosing in the United States and internationally uses kilograms. Drug dosages, fluid rates, and nutritional calculations are expressed in mg/kg — so if your pet's medical record shows a weight in pounds, converting it to kilograms before a vet visit lets you cross-check instructions. This converter uses NIST-exact factors throughout.
Common pet weight reference
| Weight (lb) | Weight (kg) | Weight (oz) |
|---|---|---|
| 2 lb | 0.907 kg | 32 oz |
| 5 lb | 2.268 kg | 80 oz |
| 10 lb | 4.536 kg | 160 oz |
| 20 lb | 9.072 kg | 320 oz |
| 30 lb | 13.608 kg | 480 oz |
| 50 lb | 22.680 kg | 800 oz |
| 80 lb | 36.287 kg | 1280 oz |
| 100 lb | 45.359 kg | 1600 oz |
Weighing small pets
For small pets — kittens, hamsters, guinea pigs, small birds — ounces and grams are more practical units than pounds or kilograms. A kitchen scale that displays grams and ounces is accurate enough for most purposes. For very small animals (under 100 g), a postal or laboratory scale with 1-gram resolution gives better results.
To convert ounces to grams: multiply by 28.3495 (NIST SP 811). The converter above handles oz ↔ lb and oz ↔ kg directly.
Mixed units: pounds and ounces
Veterinary records and pet food labels sometimes use "X lb Y oz" format. To convert this to a decimal pound value, divide the ounces by 16 and add: for example, 6 lb 8 oz = 6 + (8 ÷ 16) = 6.5 lb = 2.948 kg.
For calculating your dog's age in human years, see the Dog Age Calculator →. For cat age conversions, see the Cat Age Calculator →.