There's no universal chart that tells you exactly how much to feed your dog, and any resource that gives you a single fixed number without asking about your dog's weight, age, activity level, spay/neuter status, body condition, and the specific food you're feeding is oversimplifying. What follows is the general framework veterinary nutrition sources use to estimate calorie needs, plus how to turn that estimate into an actual daily amount of food — and where the limits of a general guide like this one are, versus what only your veterinarian and the feeding directions on your specific product can tell you.
The Science Behind Portion Sizes: Resting and Maintenance Energy
According to the Merck Veterinary Manual, a standard reference used in veterinary medicine, a dog's resting energy requirement (RER) — the calories needed just to maintain basic body function at rest — can be estimated with the formula:
RER = 70 × (body weight in kg) ^0.75
From there, maintenance energy requirement (MER) is estimated by multiplying RER by a factor that reflects life stage and activity, because an animal that's active, growing, or intact needs more than one that's resting. The Merck Veterinary Manual gives examples including:
- Neutered adult dog: RER × 1.6
- Intact adult dog: RER × 1.8
- Puppy under 4 months old: RER × 3.0
Critically, the same source is explicit that these are estimates, not exact prescriptions — an individual dog's real energy needs can run up to 30% higher or lower than the formula suggests, and the right way to fine-tune it is by monitoring your dog's actual body weight and body condition over time, not by treating the formula as a fixed target.
Estimated Daily Calories by Weight (Healthy Adult Dog)
Using the RER formula above, here's what that looks like translated into approximate daily calorie ranges for a healthy adult dog at maintenance (using the neutered-to-intact multiplier range of 1.6–1.8× RER). These are starting-point estimates, not individualized recommendations — see the caveats above and below.
| Dog's weight | Estimated RER (kcal/day) | Estimated daily maintenance calories (kcal/day) |
|---|---|---|
| 10 lbs | ~220 | ~350–400 |
| 20 lbs | ~365 | ~585–660 |
| 30 lbs | ~495 | ~790–890 |
| 40 lbs | ~615 | ~985–1,105 |
| 50 lbs | ~725 | ~1,160–1,305 |
| 60 lbs | ~835 | ~1,335–1,505 |
| 70 lbs | ~935 | ~1,495–1,685 |
| 80 lbs | ~1,035 | ~1,655–1,865 |
| 90 lbs | ~1,130 | ~1,810–2,035 |
| 100 lbs | ~1,225 | ~1,960–2,205 |
These figures are calculated from the published RER formula above for a healthy, resting-to-lightly-active adult dog. They do not account for growth, pregnancy/nursing, significant activity level, medical conditions, or individual metabolic variation — all of which can meaningfully change actual needs, sometimes by 30% or more in either direction.
From Calories to Cups: Why You Have to Check the Bag
A calorie target only becomes a useful portion once you know how many calories are in the specific food you're feeding — and that varies a lot between products. As an illustration, PetMD's own feeding-chart example uses a dry food with 382 calories per cup, which produces cup ranges like these for that specific product:
| Dog's weight | Example daily amount (for a food at 382 kcal/cup) |
|---|---|
| 3–12 lbs | ½–1¼ cups |
| 13–20 lbs | 1¼–1⅔ cups |
| 21–35 lbs | 1⅔–2⅓ cups |
| 36–50 lbs | 2⅓–3 cups |
| 51–75 lbs | 3–3¾ cups |
| 76–100 lbs | 3¾–4⅔ cups |
A denser food (more calories per cup) means fewer cups for the same calorie target; a less calorie-dense food means more cups. This is exactly why "one cup, twice a day" isn't a portion that transfers reliably between brands, or even between two different formulas from the same brand. The feeding chart printed on your specific bag, or the calorie-per-cup/per-can figure on the label combined with your dog's calorie target, is more accurate for your dog's actual food than any general chart — including this one.
Puppies, Seniors, and Other Situations That Change the Math
- Puppies need substantially more calories relative to their body weight than adults to fuel growth — the Merck Veterinary Manual's example multiplier for puppies under 4 months is roughly double that of an adult dog — and should generally be fed a growth-formula food (see our guide on choosing the right dog food) with feeding amounts following that product's own puppy chart, adjusted as they grow.
- Spayed/neutered dogs tend to need somewhat fewer calories than intact dogs at the same weight and activity level, which is reflected in the lower multiplier used above.
- Senior and less active dogs commonly need fewer calories than a younger, more active dog of the same weight, though "senior" isn't a fixed multiplier — it depends on the individual dog's actual activity and metabolism.
- Dogs that are already overweight or underweight shouldn't be fed to their current weight's calorie estimate — portion should be based on a target healthy weight your veterinarian helps you identify, not the number on the scale today. If you're not sure which category your dog falls into, our guide on telling if your dog is overweight walks through how to assess body condition.
Signs You May Be Over- or Under-Feeding
Rather than treating any calculated number as final, watch your dog directly: you should generally be able to feel (though not necessarily see) your dog's ribs with light pressure, and see a visible waist from above and an abdominal tuck from the side. Gradual weight gain or loss over several weeks, even with a "correct" calculated portion, is a signal to reassess — with your vet, if the trend continues.
A Word on Treats
Treats and extras count toward your dog's daily calorie total. The Pet Food Institute, a U.S. pet food industry association, advises keeping treats to no more than about 10% of a dog's daily calories, with the rest coming from a complete and balanced food — a useful rule of thumb if you're trying to figure out why a "correct" food portion still isn't maintaining a healthy weight.
The Bottom Line
The RER/MER formula above gives you a defensible starting point for how many calories your dog needs, and your food's own label tells you how to turn that into an actual amount of food or cups — but both are estimates that need to be checked against your individual dog's real body condition over time, not treated as a fixed answer. If your dog's weight is trending in the wrong direction despite following label or formula guidance, or you're feeding a puppy, a pregnant/nursing dog, or a dog with a medical condition, bring the specific numbers to your veterinarian rather than adjusting by guesswork.
Sources
Sources verified during editorial review, September 2026.