Dog & Cat Calorie Calculator
How much should you actually feed? Start with the standard veterinary formula below. It gives a daily calorie target from body weight and life stage — then you adjust by weighing your pet every couple of weeks instead of guessing.
The formula
RER (resting energy requirement) = 70 × body weight in kg0.75
DER (daily energy requirement) = RER × life-stage factor
Example: a 10 kg neutered dog. RER = 70 × 100.75 ≈ 394 kcal. DER = 394 × 1.6 ≈ 630 kcal per day.
Life-stage factors
| Life stage | Factor | When to use it |
|---|---|---|
| Neutered adult | 1.6 | The default for most household pets. |
| Intact adult | 1.8 | Unneutered adults usually need slightly more. |
| Inactive or obesity-prone | 1.2–1.4 | Couch potatoes and breeds that gain weight easily. |
| Weight loss | 0.8–1.0 | Only under a vet’s supervision — crash dieting is dangerous for cats. |
| Weight gain | 1.2–1.8 | Feed to the target weight, not the current weight. |
| Puppy or kitten (0–4 months) | 3.0 | Growing animals need far more energy per kilogram. |
| Puppy (4 months to adult) | 2.0 | Taper towards the adult factor as growth slows. |
| Light work or active pet | 2.0 | Daily walks, working dogs, very active cats. |
| Heavy work (sled, herding, police) | 3.0–8.0 | Depends heavily on workload and weather. |
Turning kcal into food
- Read the label. Food labels state kcal per cup or per can — divide your daily target by that number to get cups or cans per day.
- Treats count. Keep them under roughly 10% of the daily total, or the maths quietly stops working.
- Weigh, don’t scoop. A “cup” eyeballed into a mug can be 30% off either way.
- Adjust by 10%. If weight is drifting the wrong way after two weeks, change the portion by about a tenth and recheck.
Frequently asked questions
How is this calculated?
The calculator uses the standard veterinary formula: resting energy requirement (RER) = 70 × body weight in kilograms^0.75, multiplied by a life-stage factor. It is the same starting point most vets use before adjusting for body condition.
Why is the result a range?
Life-stage factors are published as ranges, and individual pets differ. Start in the middle, weigh your pet every two weeks, and adjust by about 10% at a time.
How do I convert this into food?
Divide the daily kcal by the kcal per cup or per can printed on your food’s label. Treats should stay under about 10% of the daily total.
My pet is on a prescription diet. Can I use this?
Use it only as a sanity check. Prescription diets and medical conditions (kidney disease, diabetes, pancreatitis) need a plan from your vet, not a calculator.
Does body condition matter more than weight?
Often, yes. Two dogs of the same weight can need different amounts depending on muscle and fat. Check ribs and waist every couple of weeks rather than trusting the scale alone.