Stop guessing. Our free pet food calculator gives you a personalized daily calorie and portion guide for your dog or cat, powered by the same RER/MER formula veterinarians use worldwide.
Step 1
Select your pet type to get started. The calculator will adjust all values accordingly.
Trusted Science
Built on peer-reviewed veterinary nutrition science, not pet food marketing.
We use the RER/MER formula from the National Research Council's Nutrient Requirements of Dogs and Cats (2006), the gold standard for veterinary nutrition worldwide.
Your pet's caloric needs vary by life stage, spay/neuter status, and activity. We apply the correct WSAVA-aligned multiplier for each combination automatically.
We convert calories into cups or cans based on your food type. Enter your brand's caloric density from the bag for the most accurate result.
Input your pet's Body Condition Score and we'll estimate their ideal weight range and flag if their current diet needs adjustment.
Learn More
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Read guide →Common Questions
Daily food needs depend on your dog's weight, age, activity level, and whether they are spayed or neutered. The vet-standard formula is: RER = 70 × (body weight in kg)0.75, multiplied by a life-stage factor (1.6 for a neutered adult at moderate activity, 1.8 for intact). Use the free calculator above for a personalized result.
A typical 10 lb neutered adult indoor cat needs approximately 200–260 kcal/day. At 350 kcal/cup of dry kibble, that is roughly 0.6–0.75 cups per day. Exact amounts vary by activity level, food brand, and reproductive status; use the calculator for a personalized estimate.
RER (Resting Energy Requirement) = 70 × (body weight in kg)0.75 kcal/day. MER (Maintenance Energy Requirement) = RER × a life-stage multiplier. Multipliers range from 0.8 (weight-loss cat) to 4.0 (lactating dog). This formula is published by the National Research Council in Nutrient Requirements of Dogs and Cats (2006) and is the same method used by veterinarians worldwide.
Divide pounds by 2.205 to get kilograms. For example, a 22 lb dog weighs 22 ÷ 2.205 = 9.98 kg ≈ 10 kg. The calculator accepts either unit and converts automatically.
Yes, significantly. Spaying or neutering reduces a pet's metabolic rate. Neutered dogs typically need about 20% fewer calories than intact dogs of the same weight and activity level. For cats, the reduction can be 24–33%. The calculator applies the correct multiplier automatically based on your selection.
The best indicator is Body Condition Score (BCS), not scale weight. At an ideal BCS of 4–5 on the 9-point WSAVA scale, you should be able to feel your pet's ribs easily without pressing hard, see a visible waist from above, and notice an abdominal tuck from the side. If ribs are hard to feel, reduce daily portions by 10%. See our guide: How to Tell If Your Pet Is Overweight.
PetFeedCalculator.com uses the same RER/MER formula published by the National Research Council and used by veterinarians worldwide, rather than the generic per-bag chart calibrated for one average intact adult dog at moderate activity. Enter your dog's weight, age, spay/neuter status, and activity level above for a personalized daily calorie and portion estimate in under a minute, free, with no account or sign-up required.
It takes less than 60 seconds. No sign-up required.
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