Pet Food Portion Calculator
Metabolism scales to the 3/4 power, not per kilogram.
Work out Pet Food Portion. Metabolism scales to the 3/4 power, not per kilogram. Free, with no account and nothing to install.
Food per day
303 g
1,059 kcal · Neutered adult, typical activity
The resting energy requirement is 70 × (body weight in kg to the power 0.75). The three-quarter power is not a fudge factor — metabolic rate scales that way across essentially every mammal from a mouse to an elephant, which is why a 40 kg dog needs about 1.7 times the food of a 20 kg one rather than twice. That is where per-kilogram feeding guides go wrong. They overfeed large animals and underfeed small ones, and the error compounds across a lifetime. The cups figure assumes roughly 120 g of dry kibble per standard cup, which varies with kibble size and shape by 20% or more. Weighing food is worth the thirty seconds — it is the single most effective intervention against pet obesity, which affects a majority of dogs and cats in most surveyed countries.
How the Pet Food Portion Calculator works
Daily food from the veterinary resting energy requirement, 70 × (kg to the power 0.75), multiplied by a life-stage factor. Per-kilogram feeding guides overfeed large animals and underfeed small ones, because metabolic rate is not linear in body mass.
Also known as: how much should i feed my dog · how many cups of food for my dog · cat food portion per day · calories my dog needs
Frequently asked questions
How much should I feed my dog?
Start from resting energy — 70 times body weight in kilograms to the power 0.75 — and multiply by 1.6 for a typical neutered adult. Then adjust from body condition rather than from the number, which is a starting point rather than a prescription.
Why isn't food just proportional to weight?
Because metabolic rate scales with the three-quarter power of body mass across essentially all mammals. A 40 kg dog needs about 1.7 times the food of a 20 kg one, not twice — which is why per-kilogram guides get both ends wrong.
How do I know if my pet is the right weight?
Body condition scoring beats any calculator. You should feel the ribs easily under a thin layer of fat, see a waist from above and a tuck from the side. If you cannot feel ribs without pressing, the ration is too large whatever the arithmetic says.
How many cups of food is that?
Roughly, at about 120 g of dry kibble per standard cup — but that varies by 20% or more with kibble size and shape. Weighing food takes thirty seconds and is the single most effective thing anyone does about pet obesity.
Should I feed once or twice a day?
Twice suits most dogs and cats, and more frequent small meals suit cats particularly, which are adapted to many small kills rather than one large meal. For deep-chested breeds prone to bloat, split feeding is a specific veterinary recommendation.
Put this calculator on your own site
Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.
<iframe src="https://www.thecalclibrary.com/embed/pet-food-portion-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Pet Food Portion Calculator"></iframe>
<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/pet-food-portion-calculator" style="color:#64748b">Pet Food Portion Calculator</a> from The Calc Library</p>The only condition is that the credit line below the frame stays in place. That one line is what pays for the tool being free — it is how anyone else finds it.