How much should I feed my dog?
The number on the back of the bag is a broad range, and "however much they'll eat" is a recipe for an overweight dog. A better starting point comes from a little math — but it really is just a starting point, and your vet has the final word.
The math behind a daily amount
Feeding guidelines start from resting energy requirement (RER) — the calories a
dog burns just existing, including basic organ function and temperature regulation. RER scales with
body weight by the formula RER = 70 × (body weight in kg)0.75. The
exponent means a dog twice as heavy does not need twice the calories — a larger dog needs
proportionally less per pound of body weight. That resting number is then multiplied by a
life-stage and activity factor to get daily energy needs (sometimes called MER,
maintenance energy requirement):
| Life stage / activity level | Typical multiplier on RER |
|---|---|
| Puppy (weaning to ½ adult weight) | 3.0 |
| Puppy (½ adult weight to adult) | 2.0 |
| Intact adult (typical activity) | 1.8 |
| Spayed / neutered adult | 1.6 |
| Lightly active adult | 1.4–1.6 |
| Working / very active adult | 2.0–5.0 |
| Weight loss | 1.0–1.2 |
| Senior (low activity) | 1.2–1.4 |
These multipliers are general guidelines used in veterinary nutrition; your vet may apply different values based on your dog's individual health and body condition. Divide the daily calorie target by the calories per cup printed on your food label (it varies a lot between brands — commonly 300–500 kcal/cup for dry kibble) and you get cups per day. The Dog Food Calculator does all of this for you.
Worked example
Take a spayed female Labrador, 27 kg (about 60 lb), typical indoor activity:
- RER = 70 × 270.75 ≈ 70 × 12.0 ≈ 840 kcal/day
- Multiply by the spayed-adult factor (1.6): 840 × 1.6 = ~1,344 kcal/day
- If the kibble provides 380 kcal/cup: 1344 ÷ 380 ≈ 3.5 cups/day
Split across two meals, that's about 1¾ cups per feeding. Check this against the bag's feeding chart — if they wildly disagree, the gap is usually because the chart uses a different body weight assumption or a slightly different formula. Use the calculation as a cross-check, then monitor body condition over 3–4 weeks and adjust. If you're also wondering how much water your dog should drink, the Dog Water Intake Calculator can give you a daily target alongside calories.
How calorie needs change across life stages
Puppies
Growing dogs need significantly more energy per pound than adults — they're building muscle, bone, and organ tissue simultaneously. Most quality puppy foods are calorie-dense enough to support this, but the key is matching portions to the current weight, not the projected adult weight. Overfeeding a large-breed puppy to grow faster can stress developing joints; consult your vet on target growth rates for giant and large breeds specifically.
Seniors
Older dogs typically move less and have lower lean-muscle mass, which drops their metabolic rate. Many senior dogs do well on slightly reduced portions or a senior formula, but some seniors actually need more protein to maintain muscle. Your vet is the right person to assess this — don't assume a switch to senior food is always right just because the dog hit a certain age.
Feeding cats
The RER-based approach applies to cats too, with different multipliers. If you have a cat, the Cat Food Calculator handles the feline-specific math, including the higher protein requirements cats have as obligate carnivores.
Practical tips
- Measure, don't eyeball. Use an actual measuring cup or a kitchen scale; "a scoop" drifts bigger over time and can mean 20–30% more calories than intended.
- Count treats. Treats should stay under about 10% of daily calories — they add up fast, especially high-value training treats given in volume.
- Split into meals (usually two for adults) rather than free-feeding, which makes it harder to track intake and is a common driver of creeping weight gain.
- Re-check portions after a weight change. If your dog gains or loses 10% of body weight, recalculate — the math changes because RER scales with current weight.
- Switch foods gradually. If you change brands, the calories per cup often change too. Recalculate the target cups, and transition over 7–10 days to avoid GI upset.
Common mistakes
- Trusting the bag chart alone. Bag feeding guidelines are deliberately broad — they're designed to be correct for the high end of the weight range (and the activity level of an active dog). Most house pets need less than the bag says.
- Feeding to "finish the bowl." Dogs often eat past satiety, especially food-motivated breeds like Labs and Beagles. An empty bowl isn't a signal they needed more — it's often just a signal that there was food available.
- Ignoring calorie-dense extras. Toppers, wet food mixed in, dental chews, and peanut butter in Kongs all carry calories. A single filled Kong can represent 10–15% of a small dog's daily budget.
- Using adult portions for a growing puppy. Puppy calorie needs per pound are substantially higher than adult needs. Under-feeding a puppy stunts development; the reverse is also a problem in large breeds. When in doubt, ask your vet.