Pet Ideal Weight Calculator
This pet ideal weight calculator uses the 9-point body condition score to estimate a target weight, a safe timeline, and daily calories for a dog or cat. Score the shape you see — waist from above, belly tuck from the side, and how easily you can feel the ribs — rather than guessing from breed charts alone.
Body condition worksheet
Ideal weight & slimming plan
Score your pet's shape on the 9-point body condition scale, and this works out a target weight, a safe rate to get there, and the daily calories to do it.
Target weight is estimated from the body condition score, where each point above 5 represents roughly 10% excess body weight. Safe loss is 0.5–1% of body weight per week for cats and 1–2% for dogs — faster than that risks serious liver disease in cats. Weigh every two weeks on the same scale and adjust. Have a vet confirm the target and rule out thyroid or hormonal causes before starting, especially if the weight changed without a change in feeding.
How the ideal weight estimate is made
On the 9-point scale, 4–5 is ideal. Each point above 5 is roughly 10% extra body weight, so a dog at BCS 7 is about 20% over the target. The calculator divides current weight by that surplus to get a goal weight, then sets calories from resting energy at the ideal weight: about 0.8 × RER for cats on a loss plan and 1.0 × RER for dogs.
Safe loss is 0.5–1% of body weight per week for cats and 1–2% for dogs. Faster loss in cats can trigger hepatic lipidosis. Never starve a cat, and call a vet if eating stops for more than 24 hours.
Frequently asked questions
How is ideal pet weight calculated?
Each point above 5 on the 9-point body condition scale is about 10% extra body weight. The calculator uses that to estimate a target weight and a safe calorie range.
How fast can a cat or dog lose weight safely?
Cats should lose about 0.5–1% of body weight per week. Dogs can usually lose 1–2%. Faster loss in cats can cause hepatic lipidosis.
Do I still need a vet?
Yes. A vet should confirm the target and rule out thyroid or hormonal causes, especially if weight changed without a diet change.