How much should you feed your cat?
The right portion for their ideal weight and profile, plus a benchmark to tell if they're overweight. Based on the formula vets use, not guesswork.
Portion & healthy weight
Body shape (by touch and seen from above)
Profile
Food type
Estimated healthy weight
9.9 lb (4.5 kg)
at healthy weight
Daily portion
≈ 2.5 oz (70 g) a day
about 260 kcal a day
Estimate based on the RER formula vets use × an activity factor, plus the Body Condition Score. Always check your cat's body shape with your vet, who is the only one who can set an exact portion.
How the portion is calculated
We start from the resting energy requirement (RER), calculated from the ideal weight: 70 × (weight in kg, that is pounds divided by 2.2) to the power of 0.75. We then multiply it by a factor matching the cat's profile (about 1.2 for a fixed cat, 1.4 for an intact one, 1.6 for a very active cat). The result, in kilocalories per day, is finally converted to ounces and grams based on the food's energy density.
Telling whether your cat is overweight
The number on the scale doesn't say much on its own. Vets use the body condition score (BCS), a simple check you can do at home:
- The ribs: you should feel them easily under a thin layer of fat, without pressing, like the back of your hand.
- The waist: seen from above, your cat should show a tuck behind the ribs.
- The belly: in profile, the belly line should rise toward the back, not sag.
If the ribs are hard to feel and the waist has vanished, your cat is probably overweight. It's very common (especially in fixed indoor cats) and far from harmless: diabetes, arthritis and urinary problems are all linked to it.
A diet plan belongs in a vet's hands
In cats, losing weight too fast can cause hepatic lipidosis (the liver becomes overloaded with fat), a potentially fatal emergency. Any weight loss must be gradual and supervised. The calculator gives a benchmark, never a protocol: your vet has the final say.
Frequently asked questions
+How much kibble should I give my cat per day?
It depends on their ideal weight, their profile (fixed or not, active or a couch potato) and the energy density of their kibble. The calculator above gives a daily baseline in ounces and grams; then adjust as their body shape changes, and weigh the food rather than eyeballing it.
+My cat is overweight, how do I help them slim down?
Never abruptly. Losing weight too fast can trigger hepatic lipidosis in cats, a potentially fatal liver condition. A reasonable goal is around 0.5 to 1% of body weight per week, with a suitable diet and veterinary follow-up.
+The scale or the body shape: which should I trust?
The body shape. There is no universal "ideal weight": a Maine Coon and a Singapura have nothing in common. The body condition score (feeling the ribs, looking at the waist) is far more reliable than a number on the scale.
Also worth a look: our breed profiles (ideal weight and predispositions by breed).
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