How much dry food should you feed your dog or cat?
Enter your pet's weight, life stage and activity level. You'll get a daily portion in cups, grams and pounds — plus the full calculation behind it, so you can check the math yourself.
Feeding calculator
How this calculator works
Every credible pet feeding calculator runs the same two-stage sequence. The numbers come from the National Research Council's Nutrient Requirements of Dogs and Cats (2006), the reference document behind the WSAVA Global Nutrition Guidelines.
Step 1 — Resting Energy Requirement (RER). The energy your pet burns at complete rest:
The 0.75 exponent is Kleiber's Law. Metabolic rate scales to roughly the three-quarter power of body mass, not to mass itself — which is why a 40 kg dog does not need four times the calories of a 10 kg dog. We deliberately avoid the linear shortcut (30 × kg + 70): it only holds between about 2 kg and 45 kg and drifts badly outside that band.
Step 2 — Maintenance Energy Requirement (MER). RER multiplied by a life-stage and activity factor, matched top-down from the tables below (life stage takes precedence over activity).
Step 3 — Convert calories into food. Divide MER by the calorie density printed on your bag.
If your bag lists kcal/kg instead, we convert to grams by dividing MER by the kcal/kg figure and multiplying by 1,000.
Factor tables used
These are the standard NRC / WSAVA maintenance factors. Life stage takes precedence: a puppy's row overrides the adult rows.
Dogs
| Condition | Factor |
|---|---|
| Puppy, under 4 months | 3.0 |
| Puppy, 4–12 months | 2.0 |
| Senior, 7 years and over | 1.4 |
| Adult, neutered, working | 2.5 |
| Adult, neutered, active | 2.0 |
| Adult, neutered, typical | 1.6 |
| Adult, neutered, low activity | 1.4 |
| Adult, intact, working | 2.5 |
| Adult, intact, active | 2.0 |
| Adult, intact, typical | 1.8 |
| Adult, intact, low activity | 1.6 |
| Weight-loss plan (uses target weight) | 1.0 |
Cats
Cats are not small dogs. Their maintenance factors are markedly lower, and the weight-loss factor is different for a specific physiological reason (see the safety note below).
| Condition | Factor |
|---|---|
| Kitten, under 4 months | 2.5 |
| Kitten, 4–12 months | 2.0 |
| Senior, 11 years and over | 1.1 |
| Adult, neutered, active or outdoor | 1.4 |
| Adult, neutered, typical indoor | 1.2 |
| Adult, neutered, sedentary | 1.0 |
| Adult, intact, active | 1.6 |
| Adult, intact, typical | 1.4 |
| Adult, intact, sedentary | 1.2 |
| Weight-loss plan (uses target weight) | 0.8 |
A note on accuracy: a meta-analysis by German and colleagues found mean maintenance energy requirements of 142.8 ± 55.3 kcal per kg0.75 across 70 treatment groups. That standard deviation is large. Two pets that look identical on paper can differ by hundreds of calories a day. Use the result as a number to test, not a number to trust blindly.
Frequently asked questions
How many cups of dry food should I feed my dog per day?
It depends on your dog's weight, life stage, activity level, and the calorie density of the specific food. A worked reference: a 30 lb (13.6 kg) neutered adult dog of typical activity has a resting energy requirement of 496 kcal/day, which becomes 794 kcal/day once the 1.6 life-stage factor is applied — about 2.14 cups of a 370 kcal/cup kibble, or 2.27 cups of a 350 kcal/cup kibble. Enter your own numbers above for an exact figure, or see the full weight chart by size.
Why doesn't this match the feeding chart on my bag?
Bag charts are broad starting points written for large groups of pets at once. They are built from the same RER × MER math, but manufacturers tend to round upward and assume generous activity levels. A calorie calculator works from your pet's metabolic body weight and your food's actual energy density, so the two frequently disagree. Use body condition and weight trend over the next few weeks to judge which starting point is right for your pet.
Which number on the bag do I use, kcal/cup or kcal/kg?
Either — the calculator handles both. US bags print both figures, for example 3,700 kcal/kg, 370 kcal/cup. Cups are the more convenient unit for dry food because you can scoop them. If your bag only lists kcal/kg and grams per cup, enter kcal/kg and our default 110 g per cup, or enter your bag's stated grams-per-cup value for a more precise gram figure.
Do treats and table scraps count?
Yes. Treats, dental chews, training rewards and table scraps all come out of the same daily calorie budget. A common starting point is treats at 10% or less of daily calories. On a weight-loss plan, uncounted extras are one of the most common reasons progress stalls.
How often should I change the amount I feed?
Treat the result as a starting estimate and reassess after about 2 to 4 weeks. If body weight is drifting, the waist is disappearing, the ribs are becoming too hard or too easy to feel, or stool quality worsens, adjust gradually. Small corrections backed by repeated observations work better than large jumps.
Is this calculator suitable for puppies, kittens, or pets with medical conditions?
It gives a useful starting estimate for healthy growing pets, but puppies, pregnant or nursing animals, very large breeds, working dogs, and pets with conditions such as pancreatitis, kidney disease or recovery from illness need a more individualised plan. In those cases confirm the result with your veterinarian rather than relying on the calculator alone.
Is this veterinary advice?
No. This is an estimation tool. It is not veterinary medical advice, and it does not diagnose or treat anything. Always consult your local veterinarian for your pet's specific dietary needs.
Feeding guides
Longer explanations of the numbers behind the calculator.
- How much should I feed my dog? A weight chart by size — adult dog chart from 5 lb to 120 lb, and how to adjust it for your food's calorie density.
- How to read the calorie information on your pet food bag — where the number is printed, kcal/kg versus kcal/cup, and the unit mistake that throws portions off tenfold.
- Body condition score: is your pet the right weight? — the three hands-on checks, what each of the nine score bands means, and how to change the amount safely.