Dog Food Calculator — Daily Portion by Weight & Life Stage

Calculate your dog's daily food portion in cups or grams using the veterinary RER/DER formula, weight, and life-stage activity level.

July 8, 2026

Dog's Weight

Life Stage / Activity Category

Food's Calorie Density (from the bag/label)

Calorie density varies a lot by brand and formula — use the exact number printed on your specific food's label, not a generic average.

Grams per Cup (optional — to see both cups and grams)

RER

615 kcal

DER (×1.6)

985 kcal

Estimated Daily Portion

2.81 cups/day

Enter grams per cup above to see this converted to grams too.

Split into 2–4 meals a day rather than fed all at once, especially for puppies.

RER = 70 × (weight in kg)^0.75. DER = RER × the life-stage/activity multiplier. Individual dogs can need up to ±50% more or less than this calculated amount depending on metabolism, breed, and environment — treat this as a starting point, then adjust up or down every 2–4 weeks based on your dog's body condition score (are ribs easily felt but not visible? is there a visible waist from above?), not the number alone. This tool doesn't replace a veterinarian's individualized dietary guidance, especially for dogs with a medical condition, on a prescription diet, or with unexplained weight changes.

93% found this helpful

Reference Values

Last verified: Jul 8, 2026

Category	Range	What It Means	Status
Resting Energy Requirement (RER) ★	70 × (weight in kg)^0.75	The calories a dog burns at complete rest — the baseline every daily portion is built from. All life-stage/activity multipliers below are applied on top of RER, not calculated separately.	★ Best
Weight loss (use IDEAL weight, not current weight)	×1.0 RER	Calculate RER from the dog's target/ideal weight, not its current weight, then apply this multiplier. Using current weight overstates the deficit needed.	Okay
Neutered adult (typical/low activity)	×1.6 RER	The most common multiplier for an average spayed/neutered adult dog at a healthy weight with normal daily activity.	Good
Intact adult	×1.8 RER	Intact (not spayed/neutered) adult dogs run a slightly higher metabolic rate than neutered dogs on average.	Good
Weight gain	×1.2–1.8 RER	Applied to current weight's RER when a dog needs to gain weight; the low end suits a modest gain goal, the high end a more aggressive one — monitor body condition score and adjust.	Okay
Senior (7+ years)	×1.2 RER	Older dogs typically have lower activity levels and slower metabolism than younger adults, though this varies a lot by individual health and breed.	Okay
Puppy, 0–4 months ★	×3.0 RER	Highest multiplier of any life stage — very young puppies have enormous energy needs relative to body size to fuel rapid growth.	★ Best
Puppy, 4–12 months	×2.0 RER	Growth continues but at a slower rate than the first four months, so the multiplier steps down accordingly.	Good
Active / working dog ★	×2.0–5.0 RER	Wide range because "active" covers everything from a daily jogging companion to a competitive sled or herding dog — start conservatively and adjust based on body condition and performance.	★ Best

Source: Today's Veterinary Nurse, "Nutrition Math 101" (RER/DER formula and standard multiplier ranges); Pet Nutrition Alliance MER/RER clinical reference for companion animal energy requirements.

Worked Examples

10 lb Neutered Adult Dog

Weight: 10 lb (4.54 kg)
Category: Neutered adult (×1.6)
Food: 350 kcal/cup dry food

≈218 kcal RER, 348 kcal DER, ≈1.0 cup/day

RER = 70 × 4.54^0.75 ≈ 218 kcal. DER = 218 × 1.6 ≈ 348 kcal. Portion = 348 ÷ 350 kcal/cup ≈ 0.99 cup/day.

50 lb Intact Adult Dog

Weight: 50 lb (22.68 kg)
Category: Intact adult (×1.8)
Food: 400 kcal/cup dry food

≈727 kcal RER, 1,309 kcal DER, ≈3.27 cups/day

RER = 70 × 22.68^0.75 ≈ 727 kcal. DER = 727 × 1.8 ≈ 1,309 kcal. Portion = 1,309 ÷ 400 kcal/cup ≈ 3.27 cups/day.

15 lb Puppy, 3 Months Old

Weight: 15 lb (6.80 kg)
Category: Puppy 0–4 months (×3.0)
Food: 450 kcal/cup puppy formula

≈295 kcal RER, 885 kcal DER, ≈1.97 cups/day

RER = 70 × 6.80^0.75 ≈ 295 kcal. DER = 295 × 3.0 ≈ 885 kcal. Portion = 885 ÷ 450 kcal/cup ≈ 1.97 cups/day, typically split into 3–4 meals at this age.

65 lb Senior Dog (8 years old)

Weight: 65 lb (29.48 kg)
Category: Senior 7+ years (×1.2)
Food: 320 kcal/cup senior formula

≈886 kcal RER, 1,063 kcal DER, ≈3.32 cups/day

RER = 70 × 29.48^0.75 ≈ 886 kcal. DER = 886 × 1.2 ≈ 1,063 kcal. Portion = 1,063 ÷ 320 kcal/cup ≈ 3.32 cups/day — lower multiplier than a typical adult reflects the generally reduced activity of senior dogs.

Weight-Loss Plan: 70 lb Dog With a 55 lb Ideal Weight

Current weight: 70 lb
Ideal weight used for RER: 55 lb (24.95 kg)
Category: Weight loss (×1.0)
Food: 300 kcal/cup weight-management formula

≈781 kcal RER/DER (from ideal weight), ≈2.60 cups/day

RER is calculated from the 55 lb ideal weight, not the current 70 lb: 70 × 24.95^0.75 ≈ 781 kcal. DER = 781 × 1.0 ≈ 781 kcal. Portion = 781 ÷ 300 kcal/cup ≈ 2.60 cups/day. Using current weight instead of ideal weight here would overstate the ration and stall weight loss.

How to Use This Calculator

1

Enter your dog's weight

Choose pounds or kilograms. If your dog needs to lose weight, select the weight-loss category first — a separate ideal-weight field will appear.
2

Select the life-stage / activity category

Choose the option that best matches your dog: puppy, neutered/intact adult, senior, weight loss, weight gain, or active/working. Weight-gain and active/working use an adjustable slider since their multiplier ranges are wide.
3

Enter your food's calorie density

Find kcal per cup or kcal per 100g on your specific food's label or the manufacturer's site — this number varies significantly by brand and formula, so don't rely on a generic average.
4

Optionally enter grams per cup

If you know how many grams your food's cup measure holds, enter it to see the portion in both cups and grams at once.
5

Read the daily portion

RER, DER, and the estimated daily amount update instantly. Split this total across 2–4 meals a day.

What Each Value Means

RER (Resting Energy Requirement) (kcal/day): The calories a dog burns at complete rest with no digestion or activity — the metabolic baseline every daily portion is calculated from. Formula: 70 × (weight in kg)^0.75.
DER (Daily Energy Requirement) (kcal/day): RER multiplied by a life-stage/activity factor that accounts for growth, reproductive status, and how active the dog actually is day to day. This is the number the daily food portion is based on.
Calorie Density (kcal per cup or kcal per 100g): How many calories a specific food packs per cup or per 100 grams, printed on the food's label or available from the manufacturer. This varies substantially between brands and formulas, which is why portions can't be estimated from weight alone.

Frequently Asked Questions

How accurate is this dog food calculator?

It gives you a scientifically grounded starting point using the same RER/DER formula veterinary nutritionists use, not a guaranteed exact number. Individual dogs can burn up to 50% more or less energy than the calculated DER depending on metabolism, breed, coat, climate, and true activity level. Use the result as a starting portion, then adjust every 2–4 weeks based on your dog's actual body condition rather than sticking rigidly to the number.

Why does my dog's food bag recommendation differ from this calculator?

Bag charts are built around a single generic 'average' dog and often round to wide weight brackets, so they tend to overestimate portions for the typical neutered, moderately active pet. This calculator uses your dog's actual weight and a life-stage/activity multiplier that better reflects real-world energy needs, which is why the two numbers frequently don't match — the bag chart is usually the less precise of the two.

Should I use my dog's current weight or ideal weight to calculate portions?

For a healthy dog at a good weight, use current weight. For a dog that needs to lose weight, calculate RER from the dog's ideal or target weight instead of its current weight, then apply the weight-loss multiplier (×1.0) — using current weight for an overweight dog overstates the calories needed and stalls weight loss. This calculator has a dedicated ideal-weight field that appears automatically when you select the weight-loss category.

How do I know if I'm feeding too much or too little?

The calculator's number is a starting point — your dog's body condition score (BCS) is the real feedback loop. Feel along the ribs: they should be easily felt under a thin layer of fat, not visible and not hard to find. Looking down from above, there should be a visible waist tuck behind the ribs. If ribs are hard to feel or the waist has disappeared, reduce the portion; if ribs are very prominent or there's no fat cover at all, increase it. Reassess every 2–4 weeks rather than daily, since weight changes take time to show.

Does this calculator work for puppies?

Yes — select the 0–4 month or 4–12 month puppy category, which use much higher multipliers (×3.0 and ×2.0 respectively) than an adult dog's ×1.6–1.8, reflecting the enormous energy cost of rapid growth. Puppy portions should also be split into 3–4 smaller meals a day instead of one or two large ones. For breed-specific growth context alongside feeding, pair this with the puppy weight calculator to predict adult size.