Daily dog food portion from weight, life stage and food calorie density.
RER = 70 × weight_kg^0.75 (NRC 2006). MER = RER × life-stage multiplier. Cups → grams uses 120 g/cup as a typical dry-kibble density (varies 90–135 g/cup; check the bag).
Pet obesity is the single most common chronic-disease driver in dogs in developed countries — over 50 % of US and EU dogs are overweight or obese, and the leading cause is consistent over-feeding. Most owners feed by the cup-size suggested on the bag, which is calibrated for an average dog and doesn't account for individual weight, life stage, neuter status, activity level, or food calorie density. The result: Labradors at 35 kg targeted weight that creep to 42 kg over 5 years. A daily-portion calculator based on the Resting Energy Requirement (RER) plus a Maintenance Energy Requirement (MER) activity multiplier from the National Research Council's Nutrient Requirements of Dogs and Cats (2006) gives a starting point that's much closer to actual need. This calculator turns weight, life stage, food kcal density, and meals per day into a per-meal portion in cups and grams, with a per-meal bar visualization.
RER (Resting Energy Requirement, kcal/day) = 70 × weight_kg^0.75. The exponent 0.75 (Kleiber's law) reflects that metabolism scales with body surface area, not body mass directly. A 30 kg dog needs ~900 kcal/day at rest, not 1.5× that of a 20 kg dog.
MER (Maintenance, kcal/day) = RER × life_stage_multiplier:
Multipliers from NRC 2006 / WSAVA Global Nutrition Guidelines.
Cups per day = MER / kcal_per_cup. Most dry kibble is 350–420 kcal/cup; the calc default is 380.
Grams per day = cups × 120 (typical dry kibble bulk density 100–135 g/cup; the calc uses 120 as the centerpoint).
Per-meal portion = cups_per_day / meals_per_day.
Enter the dog's target weight (not current weight if obese — feed for the goal, not the current state) in kg or lb. Pick the life stage / activity that best matches your dog. Enter the food's kcal per cup (printed on the bag label, usually as "kcal/cup" or "kcal ME/kg"). Set the meals per day (puppies often 3–4; adults 1–2). The result panel shows daily ration in cups and grams as the headline, then MER, RER, the activity multiplier, and per-meal portions broken out as a bar chart per meal.
Adult Labrador, 30 kg, neutered, food at 380 kcal/cup, 2 meals/day.
Puppy 12 kg, 6 months old, food at 400 kcal/cup, 3 meals/day.
Senior small dog, 8 kg, 12 yr, food at 350 kcal/cup, 2 meals/day.
Feed for target weight, not current weight. An obese 40 kg Labrador whose target is 32 kg should be fed at 32 kg's MER, not 40 kg. The calc uses whatever weight you enter — enter target.
Multiplier ranges are population averages. Active border collies and working dogs may need ×2.0–2.5 even as adults; lazy bulldogs may need ×1.2 even when intact. Adjust ±20 % based on body condition score (BCS) over 4–6 weeks.
Body Condition Score (BCS) trumps weight. The 9-point BCS (5 = ideal) is the gold standard for "is this dog the right weight?". Visual ribs palpable but not visible; waist visible from above; abdominal tuck from the side. Adjust portion ±10 % per 1 BCS point above or below 5.
Treats matter. The MER is the total daily intake. If you give 100 kcal of treats (one large chew = 50–80 kcal; a piece of cheese = 100 kcal), subtract from the kibble portion.
Wet food has different math. Canned/wet food is ~25 % the kcal density of dry by volume but more by weight (~80 kcal / 100 g vs ~380 kcal / 100 g). The calc assumes dry kibble; for wet food, divide the daily kcal target by the wet food's kcal/100g and multiply by 100 to get grams.
Kcal per cup varies. Bag labels are required to show kcal/kg ME (metabolizable energy); kcal/cup is sometimes shown, sometimes not. If unknown, use the bag's kcal/kg and a standard 100 g/cup conversion: kcal/cup ≈ kcal/kg × 0.1.
Pregnancy and lactation. Lactating dogs need 2–4× MER. Pregnancy: ×1.6 in the last 3 weeks. Specialized formulas; this calc doesn't model.
Working dogs. Sled, search-and-rescue, hunting dogs in active season need ×3–8× RER. Out-of-band of the calc's multiplier set.
Breed-specific metabolism. Some breeds (Siberian Husky, Greyhound) have unusually efficient metabolism and need less than the multiplier suggests; some (Newfoundland, Saint Bernard) have higher needs. The NRC values are population averages.
Switching foods. New foods should be transitioned over 7–10 days (25 % new + 75 % old, then 50/50, etc.) to avoid GI upset.
Hydration. Dry kibble means dogs need free water ad libitum (60–80 mL/kg/day). The calc handles food only.