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Dog food calculator: how much should I feed my dog?
Calories a day from the veterinary energy formula, turned into cups of your own food, for puppies and adults.
Merck Veterinary Manual energy factors · checked
A neutered 50 lb adult dog needs about 1,164 kcal a day to start with: its resting energy requirement of 727 kcal multiplied by 1.6. That is the method set out in the Merck Veterinary Manual and taught in veterinary nutrition: first the resting energy requirement, seventy times the body weight in kilograms raised to the power 0.75, then a factor for the life stage, from 1.4 for an adult that gains weight easily to 3.0 for a puppy under four months. Enter the calories per cup printed on your bag and the calculator turns the daily figure into cups. Merck warns that individual dogs can need as much as 30 percent more or less than the formula, so the card shows that band too. Treat the result as day one of a feeding plan: weigh the dog every two weeks, feel the ribs, and move the portion up or down by small steps until the weight holds where it should. The feeding guide on the bag is usually written for an active, unneutered dog.
Runs in your browser: nothing you type is sent or stored. The result is a starting ration to adjust, not a prescription. How the figures are built.
The formula, step by step
Convert the weight to kilograms (pounds × 0.4536). Raise it to the power 0.75 and multiply by 70: that is the resting energy requirement, what the dog burns lying quietly in a comfortable room. A 22 lb (10 kg) dog has a RER of about 394 kcal.
Then multiply by the life-stage factor: 1.6 for a spayed or neutered adult, 1.8 for an intact adult, 1.4 for one prone to obesity, 2.0 for a puppy from four months to adult size and 3.0 below four months. The power of 0.75 is why a dog twice as heavy does not need twice the food.
Turning calories into cups
Dry foods differ widely in energy density, so a cup is not a fixed amount of food. Most American pet food labels state the calories, usually as kcal per kilogram and kcal per cup; enter the per-cup figure. The default value in the form is only an example to show a result.
Measure with a real measuring cup or, better, a kitchen scale, since a heaped cup can carry a fifth more than a level one. If you feed wet and dry together, work out the calories of the wet portion first and give the rest as kibble. Treats count too: keep them a small share of the day so the diet stays balanced.
How much to feed a puppy
Puppies need far more energy per pound than adults: 3.0 times their resting requirement before four months and 2.0 times after, until they reach adult size. Enter the puppy's current weight, not its expected adult weight, and recalculate every couple of weeks as it grows.
Split the day into three or four meals for young puppies and two or three later. Large and giant breed puppies should eat a food formulated for large-breed growth, which controls calcium and energy so the skeleton does not grow faster than it should. Check the puppy weight calculator for the adult range to aim at.
Adjusting for weight loss and activity
For a dog that needs to lose weight, vets compute the ration from the target weight rather than the current one, and set the pace of loss with a weigh-in plan. That calculation belongs with your vet, who can rule out a thyroid problem and set a safe rate.
Working dogs, sled dogs and dogs in hard training can need two to several times their resting requirement, beyond the range of this calculator. For them, feed to body condition and keep a log of weight and work.
Starting calories a day for a spayed or neutered adult dog
| Body weight | Resting need (RER) | × 1.6 (kcal/day) | × 1.8 intact |
|---|---|---|---|
| 5 lb | 129 | 207 | 233 |
| 10 lb | 218 | 348 | 392 |
| 20 lb | 366 | 585 | 659 |
| 30 lb | 496 | 794 | 893 |
| 40 lb | 615 | 985 | 1,108 |
| 50 lb | 727 | 1,164 | 1,309 |
| 60 lb | 834 | 1,335 | 1,501 |
| 70 lb | 936 | 1,498 | 1,685 |
| 80 lb | 1,035 | 1,656 | 1,863 |
| 100 lb | 1,223 | 1,958 | 2,202 |
| 120 lb | 1,403 | 2,244 | 2,525 |
| 150 lb | 1,658 | 2,653 | 2,985 |
Computed with the Merck formulas. Individual needs can be 30% higher or lower.
Not a substitute for a veterinarian
Dogs with kidney, liver, heart or digestive disease, pregnant or nursing dogs and dogs on a weight-loss plan need a ration set by a veterinarian. Sudden changes in appetite are worth a call to your clinic.
Sources
- Merck Veterinary Manual, resting and maintenance energy formulas with life-stage factors (read October 11, 2026)
- WSAVA Global Nutrition Committee, nutritional assessment guidelines and body condition tools (read October 11, 2026)
- AAFCO, how calorie content appears on US pet food labels (read October 11, 2026)