How much food should a dog eat per day?

Enough to hit a calorie target of RER (70 × kg^0.75) times a life-stage factor, which is about 1.6 for a typical neutered adult. In practice that means roughly 400 kcal a day for a 10 lb dog, 700 for 30 lb, and 1,200 for 70 lb. Convert to cups with the kcal/cup number on your food's bag.

Is it better to feed a dog once or twice a day?

Twice daily is the standard for adult dogs. It spreads calories, steadies energy, and reduces scavenging behavior; single large meals raise bloat concerns in deep-chested breeds. Puppies need 3–4 meals while growing.

How do I know if my dog is overweight?

Use the 9-point body condition score: at a healthy 4–5/9 you can feel ribs easily under a thin fat layer, see a waist behind the ribs from above, and see a belly tuck from the side. No waist, ribs hard to find, or fat pads at the tail base mean it’s time to cut portions about 10% and re-weigh in a month.

Why is my dog always hungry?

Appetite in dogs is a drive, not a fuel gauge. Most dogs will eat well past their needs, and persistent begging is usually habit or boredom, not hunger. But if a correctly portioned dog suddenly turns ravenous, call the vet. Diabetes, Cushing's, and some medications do exactly that.

Do I need to adjust food in winter or summer?

Only if activity actually changes. A dog hiking less in winter may need about 10% less. A dog living outdoors in the cold may need more. Track monthly weight. The trend is the truth.

How Much to Feed a Dog

The short answer: feed to a calorie target, not a scoop count. A typical spayed or neutered adult dog needs about 1.6 × RER calories per day, where RER = 70 × (weight in kg)^0.75. Then convert that into cups using the calorie density printed on your bag. The dog calorie calculator and dog food calculator do both steps for you; this guide explains what's behind them so you can adjust intelligently.

Step 1: Get the daily calorie target

Veterinary nutrition builds every feeding plan from the Resting Energy Requirement, the calories a dog burns doing nothing. The formula, from the WSAVA Global Nutrition Guidelines, is 70 × (kg)^0.75. A 30 lb (13.6 kg) dog has an RER of about 496 kcal.

Then multiply by a life-stage factor: 1.6 for neutered adults, 1.8 for intact adults, 2–3 for puppies, 1.4 for seniors, 2.5+ for genuinely working dogs, and 1.0 (calculated at ideal weight) for weight loss. Our 30 lb neutered example: 496 × 1.6 ≈ 794 kcal/day. Treats count inside that number, and the standard rule is to cap them at 10%.

Step 2: Read the bag like a vet, not like the marketing

Two numbers matter, and neither is on the front:

Calorie content, in the fine print near the guaranteed analysis, stated as kcal/kg and kcal/cup ("3,600 kcal/kg, 380 kcal/cup"). Dry foods range from about 300 to 450 kcal/cup, which is why "2 cups a day" means nothing without knowing which food.
AAFCO statement: "complete and balanced for adult maintenance" (or "growth" for puppies). This is the line that tells you the food can be the whole diet.

The feeding chart on the bag is written for intact, active dogs and typically overshoots a neutered house dog's needs by 20–30%. Treat it as an upper bound, not a prescription.

Step 3: Convert calories to cups, then weigh instead of scooping

Daily cups = calorie target ÷ kcal/cup. Our 794 kcal example on a 380 kcal/cup food is about 2.1 cups a day, or just over a cup per meal fed twice daily. Then improve on the cup: studies of owners pouring "one cup" found errors up to 80%. A $15 kitchen scale and the grams figure from the food calculator removes that error entirely.

Step 4: Let the body grade your math

Every formula is a starting point; your dog's body condition score is the feedback loop. On the 9-point scale, aim for 4–5: ribs easy to feel but not see, a visible waist from above, a belly tuck from the side. Weigh monthly. Trending up → cut 10%. Ribs getting prominent → add 10%. Re-check in four weeks. That simple control loop beats any chart, because it measures your dog. Metabolism varies around 20% between individuals of the same weight.

Special cases worth knowing

Puppies change portion needs every few weeks. Use the puppy feeding chart, and keep large breeds lean while growing.
Weight loss plans calculate 1.0 × RER at the dog's ideal weight, not current, and deserve vet supervision beyond ~20% overweight.
Raw diets use a percent-of-body-weight rule instead. The raw food calculator covers portions and the safety context.
Multiple food sources (kibble + wet + training treats) all draw from one calorie budget; subtract the extras before setting the kibble portion.

Sources

WSAVA Global Nutrition Committee: Nutritional Assessment Guidelines and feeding factors.
AAFCO: pet food labeling and nutritional adequacy statements.
AAHA: Canine Life Stage and Nutritional Assessment Guidelines (body condition scoring).
German A.J. et al.: portion-measurement error studies.