PawPortion is a free, ad-light pet nutrition calculator built on standard veterinary formulas — designed for pet parents who want to feed their dog or cat the right amount without a degree in animal nutrition.
Walk into any veterinary clinic and the most common preventable health problem on the schedule is the same: overweight pets. Roughly 56% of US dogs and 60% of US cats are overweight or obese, and the leading driver is almost always the same — well-meaning owners following pet-food bag charts that overshoot real calorie needs by 20-40%.
The math to fix it isn't complicated. It's the same RER and MER formulas taught in every veterinary school: 70 × (body weight in kg)0.75, multiplied by a life-stage factor. But that's not a number most owners will calculate by hand at the kitchen counter — so we built a calculator that does it in seconds, with the body-condition adjustments and portion-size conversions built in.
Every formula in PawPortion is sourced from NRC 2006 (National Research Council) or WSAVA nutritional guidelines — the same references your vet uses.
No paywalls. No "premium tier." No upsells. The calculators are free and will stay free.
The calculator runs entirely in your browser. We don't collect, store, or sell information from calculator users.
A calculator can give you a strong starting point — but your veterinarian sees your specific pet. We're a complement to professional care, not a substitute.
PawPortion uses the following calculations, applied transparently:
All multipliers are documented in our blog posts (see the dog calorie guide for the full table).
Every article on PawPortion is written by our editorial team, cross-referenced against multiple veterinary sources (NRC, WSAVA, AAHA, AAFCO regulations, and peer-reviewed research), and reviewed before publication. We update content when new evidence or guidelines emerge.
If you spot something that looks wrong or outdated, let us know. We'd rather be corrected than be confidently incorrect.