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🐾 Pets & Animals

Dog Food Portion Calculator (Calories & Cups)

Calculate daily kcal and cup / gram portion for your dog from weight, age (puppy / adult / senior), activity level and food calorie density. Includes brand presets.

Built and maintained by Paul Clark, Redmoon Software · Checked against what this tool computes on

Kibble size changes this — weigh one cup to be sure.
Daily intake
— kcal/day
— cups · — g per day
Meals / daykcal / mealCups / mealGrams / meal
Quick reference

RER (resting energy) = 70 × (body weight in kg)^0.75. MER (daily need) = RER × life-stage multiplier: puppy 2–4 mo ×3, puppy 4–12 mo ×2, adult neutered ×1.6, senior ×1.4. Intact dogs run higher at every stage (×1.8 as an adult, about 10% more otherwise). Activity scales that from ×0.9 sedentary to ×1.4 very active. Weight loss targets ×1.0 of RER for adults and seniors; weight gain uses at least ×1.6, or ×1.2 of the maintenance figure when that is higher.

1 standard cup of dry kibble is about 100 g, but it varies roughly 90–120 g by kibble size — that figure is an editable field above, so set it from your own bag. Always weigh the food on a kitchen scale for accuracy. Adjust portion by ±10% every 2 weeks based on body condition score (you should feel ribs without seeing them).

How it works

Daily calories start from Resting Energy Requirement, RER = 70 × (body weight in kg) raised to the 0.75 power. That is multiplied by a life-stage factor — Puppy 2–4 months ×3.0, Puppy 4–12 months ×2.0, Adult ×1.6, Senior ×1.4 — and then by an activity factor: Sedentary 0.9, Normal 1.0, Active 1.2, Very active / working 1.4. An intact adult uses 1.8 rather than 1.6. Cups are simply the resulting calories divided by the kcal-per-cup figure, and grams follow from cups.

The kcal per cup value matters more than most owners expect. At 20 kg on the defaults, moving from the generic store brand at 350 to Purina Pro Plan at 410 changes the portion by about 15 percent for exactly the same calories, so set Food to Custom and enter the number printed on your own bag. Weight goal is the other big lever: Lose weight drops intake to RER alone, while Gain weight raises the multiplier.

Grams come from a fixed assumption that one cup of dry kibble weighs 100 g, and real kibble runs roughly 90 to 120 g per cup depending on piece size — weigh one level cup on a kitchen scale and trust grams from then on. The intact adjustment applies only to the Adult stage, and Lose weight discards age and activity entirely. None of this substitutes for a body condition score or veterinary advice.

Frequently asked questions

How many calories does a 20 kg dog need per day?

Resting energy is 70 times 20 to the 0.75 power, about 662 kcal. A neutered adult at normal activity multiplies that by 1.6 for roughly 1059 kcal a day, which at 370 kcal per cup works out to about 2.86 cups of food.

Why does my portion change when I switch food brands?

Because the cup figure is calories divided by calorie density. The presets run from 350 kcal per cup for a generic store brand up to 410 for Purina Pro Plan, so the same dog needs noticeably fewer cups of the denser food.

How do I feed a dog that needs to lose weight?

Selecting Lose weight sets intake to resting energy exactly, discarding the age and activity multipliers altogether. That is an aggressive target, so use it under a vet-supervised plan with regular reweighing rather than running it indefinitely on your own judgement.

Should I split the daily amount into two meals or three?

The table under the result shows two, three and four meals with kcal, cups and grams for each. Splitting does not change the daily total; it mainly affects hunger between meals, and matters most for puppies, who carry the highest multipliers here.

Is one cup of dog food really 100 grams?

That is the fixed conversion this tool uses, and it is only an average. Real kibble runs roughly 90 to 120 g per cup depending on piece size and shape, so weigh one level cup of your own food once and use the gram figure instead.

Package guidance describes an average dog

Feeding charts on a bag are calculated for an intact adult at maintenance, and most dogs are not that. Neutered dogs need meaningfully less; puppies, working dogs and lactating bitches considerably more, which is why the life-stage selector changes the figure so much.

Age bands matter within puppyhood too: a two-to-four-month puppy is growing far faster relative to its size than a four-to-twelve-month one, and the requirement per kilogram falls steadily as growth slows.

Body condition beats arithmetic

Whatever the calculation says, the check that matters is physical: ribs easily felt but not seen, a visible waist from above, and an abdominal tuck from the side. If ribs are hard to find, the portion is too large regardless of what any chart says.

Adjust by roughly 10% and reassess after two to three weeks rather than making large changes — weight moves slowly and over-correcting in either direction is easy.

Treats are the uncounted calories in most overweight dogs, and they should sit inside the daily total rather than on top of it. Food energy density also varies substantially between products, so the same weight of two different foods is not the same meal.

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