Pet Weight Calculator
Check if your dog or cat is at a healthy weight and find their ideal range.
Written by Golam Rabbani, Founder & Lead Engineer — Last updated 2026-05-01
How to use this pet weight calculator
- Select your pet type — Dog or Cat.
- Enter your pet's current weight and toggle kg or lbs as needed.
- Select the breed size category that best matches your pet.
- Press Calculate to see the weight status and ideal range.
- Use Copy to save the result, or Reset to start over.
About this pet weight calculator
The pet weight calculator tells you whether your dog or cat is underweight, at a healthy weight, or overweight by comparing their current weight against a breed-size reference range.
The tool works by mapping your pet's weight in kilograms against a set of minimum and maximum thresholds for five size classes: Toy, Small, Medium, Large, and Giant. If you enter a weight in pounds, it converts to kilograms first (1 lb = 0.453592 kg) before comparing. A weight below the minimum for the selected size class returns Underweight; between minimum and maximum returns Healthy; above the maximum returns Overweight, along with a short note on next steps. This is an estimate for general information and is not a substitute for advice from a qualified veterinarian. Consult your veterinarian before changing your pet's diet.
For example, a medium-sized dog weighing 18 kg falls within the 11–25 kg range for the Medium size class, so the tool returns Healthy. A large cat — such as a Ragdoll — weighing 9 kg against the Large cat range of 5–8 kg would return Overweight. This tool is useful for pet owners who want a quick reference between vet visits to monitor whether their pet's weight is on track.
FAQ
- How does the pet weight calculator determine if my pet is a healthy weight?
- It compares your pet's weight in kilograms against a breed-size reference range. If the weight falls below the minimum it returns Underweight, within the range it returns Healthy, and above the maximum it returns Overweight.
- What weight ranges does the tool use?
- The tool uses five size classes for dogs (Toy 2–6 kg, Small 5–10 kg, Medium 11–25 kg, Large 26–44 kg, Giant 45–90 kg) and five for cats matched to common breed types. Select the class that best fits your pet's breed.
- How accurate is this pet weight calculator?
- The ranges are broad breed-size approximations, not breed-specific veterinary targets. Individual pets can be healthy outside these ranges depending on build and health history. Always confirm weight goals with your vet.
- What happens if I enter a weight of zero or leave the field empty?
- The tool shows an error message asking you to enter a valid weight. A weight must be a positive number greater than zero for the calculation to run.
- Does this tool store my pet's data?
- No. The pet weight calculator runs entirely in your browser. No weight or pet information is sent to a server or saved between visits.
- Is the pet weight calculator free?
- Yes, it is completely free to use with no account or signup required.