hobby calculator

Dog Food Portion Calculator

Calculate your dog's daily food portion in cups and grams from body weight, life stage, and your food's calorie density.

Daily food amount comes from Resting Energy Requirement, RER = 70 × (weight in kg)^0.75, multiplied by a life-stage factor (about 1.6 for a neutered adult dog). A 30 lb neutered dog needs roughly 794 kcal per day, which is about 2.3 cups of a 350-kcal-per-cup food.

Quick actions: Save inputs, view saved runs, print, share, or export results

Saved Runs

Inputs

Dog's weightlb

Life stage / activity

Calories per cup (from food label)kcal

Grams per cup (approx.)g

Feedings per day

These life-stage factors are commonly cited starting points, not a prescription — your vet may recommend a different target based on body condition score, breed, and health history.

Results

Daily portion

2.27 cups (272 g)

Per feeding1.13 cups (136 g)

Daily calories (MER)794 kcal

Resting energy (RER)496 kcal

Bookmark this dog food calculator

Re-run this whenever your dog's weight, activity level, or food changes — a portion sized for one food doesn't carry over to a different calorie density.

Formula

Dog food portion formula

RER (kcal/day) = 70 × (weight in kg)^0.75. MER (kcal/day) = RER × life-stage factor. Portion = MER ÷ food's kcal per cup.

RER is a veterinary-standard resting energy formula. The life-stage factor (roughly 1.0 to 3.0 depending on neuter status, activity and age) scales it up to a maintenance energy requirement — these factors are commonly cited starting points, not a substitute for veterinary guidance.

Step by step

How the calculation works

1Enter your dog's body weight in pounds.
2Choose the life-stage category that best matches your dog.
3Enter the calories per cup from your specific food's label (check the guaranteed analysis or manufacturer feeding chart).
4Read the daily and per-feeding portion in both cups and grams.

Example

Worked example — 30 lb neutered adult dog, 350 kcal/cup food

30 lb = 13.61 kg. RER = 70 × 13.61^0.75 = 495.95 kcal. MER = 495.95 × 1.6 = 793.5 kcal. Portion = 793.5 ÷ 350 = 2.27 cups/day (272 g/day), or 1.13 cups per feeding across 2 feedings.

Related guides

Learn more about this calculation

Guide

How Much Should You Feed Your Dog or Cat? The RER/MER Science

The WSAVA-aligned veterinary formula behind daily feeding amounts for dogs and cats, why life stage changes the number so much, and why cats need extra caution with weight loss.

Site Guide

How to Use Do The Calculation Calculators: A Practical Step-by-Step Guide

Learn the fastest reliable workflow for using Do The Calculation calculators, reading results, checking formulas, and using save, print, share, and export actions correctly.

Cat Feeding

Cat Food Portion Calculator

The same RER-based portioning method, tuned for cats and their lower life-stage factors.

Age Conversion

Dog & Cat Age to Human Years Calculator

Convert your dog's age to human-equivalent years using AVMA-compliant, size-based formulas.

hobby calculator

Dog Food Portion Calculator

Calculate your dog's daily food portion in cups and grams from body weight, life stage, and your food's calorie density.

Quick actions: Save inputs, view saved runs, print, share, or export results

Saved Runs

Inputs

Dog's weightlb

Life stage / activity

Calories per cup (from food label)kcal

Grams per cup (approx.)g

Feedings per day

These life-stage factors are commonly cited starting points, not a prescription — your vet may recommend a different target based on body condition score, breed, and health history.

Results

Daily portion

2.27 cups (272 g)

Per feeding1.13 cups (136 g)

Daily calories (MER)794 kcal

Resting energy (RER)496 kcal

Bookmark this dog food calculator

Re-run this whenever your dog's weight, activity level, or food changes — a portion sized for one food doesn't carry over to a different calorie density.

Summary

Key output metrics

Daily portion

2.27 cups

272 g per day.

Per feeding

1.13 cups

136 g, split across 2 feedings.

Daily calories (MER)

794 kcal

RER 496 kcal × 1.6 life-stage factor.

Resting energy (RER)

496 kcal

70 × (13.6 kg)^0.75.

D3 visualization

Portion across life-stage factors

How the daily portion would change if this dog fell into a different life-stage category, at the same weight and food.

D3 visualization

Per-feeding split

Equal split of the daily portion across each feeding.

Feeding 1136 g

Feeding 2136 g

Guide

How to understand and use this calculator

Quick Answer — How Much Should I Feed My Dog?

The core formula: Resting Energy Requirement (RER, kcal/day) = 70 × (body weight in kg)^0.75. Maintenance Energy Requirement (MER) = RER × a life-stage factor. Daily portion = MER ÷ your food's calories per cup.

Quick reference (350 kcal/cup food):

30 lb neutered adult dog (factor 1.6) → 2.27 cups/day (272 g/day)
65 lb active/working dog (factor 2.0), 380 kcal/cup food → 4.66 cups/day (559 g/day)
15 lb puppy under 4 months (factor 3.0), 400 kcal/cup food → 2.21 cups/day (265 g/day)

Worked example: a 30 lb neutered adult dog converts to 13.61 kg. RER = 70 × 13.61^0.75 = 495.95 kcal. Applying a neutered-adult factor of 1.6: MER = 495.95 × 1.6 = 793.5 kcal/day. On a 350-kcal-per-cup food, that's 793.5 ÷ 350 = 2.27 cups per day, or about 1.13 cups per feeding split across two meals.

This is a starting point for a healthy dog at a stable weight — your veterinarian may adjust it based on body condition score, breed, medical history, and how your dog actually responds over the following weeks.

How to Use This Calculator

Enter your dog's body weight in pounds.

Choose the life-stage / activity category that best matches your dog — neutered/spayed adult is the most common default for a typical companion dog.

Enter the calories per cup from your specific food's label or manufacturer's website — this number varies substantially between brands and formulas, so don't reuse a figure from a different food.

Set the feedings per day to see the per-meal amount, not just the daily total.

Example input: Weight = 65 lb • Life stage = Active/working • Food = 380 kcal/cup • Feedings = 2.

Output: RER = 885.7 kcal • MER = 885.7 × 2.0 = 1,771.4 kcal/day • Portion = 1,771.4 ÷ 380 = 4.66 cups/day (559 g/day), or 2.33 cups per feeding.

If you're also curious how your dog's age translates to human-equivalent years, the dog & cat age to human years calculator uses AVMA-compliant, size-adjusted formulas.

The Formula This Calculator Uses

Everything here is transparent, standard veterinary nutrition math — not a proprietary formula.

Step 1 — Convert weight to kilograms. Weight (kg) = Weight (lb) × 0.453592.

Step 2 — Resting Energy Requirement. RER (kcal/day) = 70 × Weight (kg)^0.75. This is the widely used allometric formula for resting energy needs across dog (and cat) sizes — the 0.75 exponent reflects that metabolic rate doesn't scale linearly with body mass.

Step 3 — Apply a life-stage factor. MER (kcal/day) = RER × Factor. Commonly cited factors: 1.6 for a neutered adult, 1.8 for an intact adult, 1.0 for weight loss, roughly 1.2-1.8 for weight gain, 2.0 or higher for active/working dogs, and around 3.0 for puppies under 4 months (whose growth demands significantly more energy per kilogram than an adult's maintenance needs).

Step 4 — Convert to a food-specific portion. Portion (cups/day) = MER ÷ Calories per cup. This is why the same dog needs a different cup measurement on two different foods — a calorie-dense food requires fewer cups for the same energy intake.

Why these factors are ranges, not fixed numbers: individual metabolism varies. These factors are commonly cited starting points from veterinary nutrition references — the right number for your specific dog is the one that maintains a healthy body condition over several weeks of monitoring, adjusted with your vet's input.

Step-by-Step Worked Derivation

Take the 30 lb neutered adult dog example and do it by hand.

Step 1. 30 lb × 0.453592 = 13.61 kg.

Step 2. 13.61^0.75 ≈ 7.085. RER = 70 × 7.085 = 495.95 kcal.

Step 3. MER = 495.95 × 1.6 = 793.52 kcal.

Step 4. Portion = 793.52 ÷ 350 = 2.27 cups, or 2.27 × 120 g/cup ≈ 272 g.

Step 5 — per feeding. Split across 2 feedings: 2.27 ÷ 2 = 1.13 cups (136 g) per meal.

Answer: about 2.27 cups (272 g) per day, split into two 1.13-cup feedings.

Why the Life-Stage Factor Matters So Much

The life-stage factor is the single biggest lever in this calculation — it varies by up to 3x between categories for the identical body weight.

Neutered vs. intact: neutering typically reduces metabolic rate somewhat, which is why the neutered factor (1.6) sits below the intact factor (1.8) for an otherwise identical adult dog.

Puppies eat far more per kilogram than adults. A puppy's factor of around 3.0 — nearly double a neutered adult's 1.6 — reflects the substantial energy cost of tissue growth on top of ordinary maintenance.

Working and highly active dogs can need factors of 2.0 or considerably higher depending on the intensity and duration of their activity — a dog doing several hours of field work or sled-pulling has energy needs that can rival or exceed a human endurance athlete's, relative to body size.

Getting the category wrong in either direction has a real cost: using an intact-adult factor for a neutered dog will tend to overfeed and contribute to weight gain over time; using a weight-loss factor for an active dog will tend to underfeed and leave the dog without enough energy for its activity level.

Realistic Scenarios

Scenario 1 — A typical companion dog. 30 lb neutered adult, 350 kcal/cup food, 2 feedings: 2.27 cups/day (272 g/day), 1.13 cups per feeding.

Scenario 2 — An active working dog. 65 lb, active/working factor of 2.0, 380 kcal/cup food, 2 feedings: 4.66 cups/day (559 g/day) — more than double Scenario 1's cup volume, driven by both the larger body size and the higher activity factor.

Scenario 3 — A growing puppy. 15 lb puppy under 4 months, factor 3.0, 400 kcal/cup food, 3 feedings: 2.21 cups/day (265 g/day) — nearly matching the 30 lb adult's daily volume despite weighing half as much, because of the puppy growth factor.

A note on transitioning between scenarios: as a puppy grows into adulthood or a dog's activity level changes seasonally, re-run this calculator rather than keeping a fixed cup measurement — the energy needs behind each scenario are genuinely different, not just a rounding difference.

Common Feeding Mistakes

Using the bag's generic feeding chart instead of this dog's actual factor. Bag charts are typically built around a single 'average' activity assumption and don't distinguish neutered from intact, or sedentary from working dogs.
Reusing a cup measurement across different foods. Calorie density varies significantly between brands and formulas — the same 2 cups can represent very different total calories.
Not accounting for treats and table scraps in the daily total. Treats should count toward the day's calorie budget, not sit entirely outside it, especially for a dog on a weight-management plan.
Feeding a fixed portion through a dog's whole life. Puppy, adult, and senior needs differ substantially — and neutering status, if it changes, should trigger a recalculation.
Ignoring an actual weight trend. If a dog is steadily gaining or losing weight at the calculated portion, that's a signal to adjust the amount (or re-check the life-stage factor) rather than treat the formula's output as immovable.

What This Calculator Can and Cannot Do

It can:

Estimate a starting daily calorie need using a standard veterinary RER/MER formula
Convert that calorie need into cups and grams for a specific food's calorie density
Split the daily portion across multiple feedings
Show how the portion would change under a different life-stage category

It cannot:

Diagnose obesity, underweight, or any medical condition affecting nutritional needs
Account for medical conditions, medications, or breed-specific metabolic differences that a veterinarian would factor in
Replace a body condition score assessment or a veterinary weight-management plan
Know your specific food's exact calorie content without you entering it correctly from the label

The honest summary: this is a starting-point estimate built on standard formulas. Monitor your dog's actual body condition and weight trend over several weeks, and adjust the portion — or consult your veterinarian — based on real results rather than the formula alone.

Final Summary

The formula worth remembering: RER = 70 × (kg)^0.75. MER = RER × life-stage factor (roughly 1.0 to 3.0). Portion = MER ÷ food's kcal per cup.

Quick reference: a 30 lb neutered adult dog on an average-calorie food needs roughly 2.25-2.5 cups per day; a puppy or active working dog needs meaningfully more per pound of body weight.

The one thing to actually do: re-check your dog's body condition and weight every few weeks after starting a new portion, and adjust — the formula gives you a starting point, not a fixed lifetime number.

Related tools worth a look: the cat food portion calculator for the same method applied to cats, and the dog & cat age to human years calculator for age-stage context. For the WSAVA-aligned RER/MER science and worked examples for both species, see our pet food portion guide.

Related concepts

Resting Energy Requirement (RER)

The calories an animal burns at complete rest, calculated as 70 × (body weight in kg)^0.75 — a standard starting point in veterinary nutrition for both dogs and cats.

Life-stage / activity factor

A multiplier applied to RER to estimate Maintenance Energy Requirement, varying by neuter status, activity level, and life stage — from about 1.0 for weight loss to 3.0 or more for puppies.

Body condition score

A veterinary assessment of a pet's fat coverage and body shape, used alongside (or instead of) a calculated calorie target to judge whether a feeding amount is appropriate.

Frequently Asked Questions

How much food should I feed my dog?+

Start with RER = 70 × (weight in kg)^0.75, then multiply by a life-stage factor — about 1.6 for a neutered adult dog. A 30 lb neutered dog needs roughly 794 kcal per day, which is about 2.27 cups of a 350-kcal-per-cup food.

What is RER in dog nutrition?+

Resting Energy Requirement — the calories a dog burns at rest, calculated as 70 × (body weight in kg) raised to the 0.75 power. It's the standard starting point veterinary nutrition guidance uses before applying a life-stage multiplier.

How much more should I feed a puppy compared to an adult dog?+

Puppies under about 4 months typically use a life-stage factor around 3.0, compared to roughly 1.6 for a neutered adult — nearly double, per unit of body weight, reflecting the extra energy growth requires.

Does neutering change how much a dog should eat?+

Yes, generally. Neutered/spayed dogs commonly use a lower life-stage factor (around 1.6) than intact dogs (around 1.8) at the same body weight, reflecting a typically lower metabolic rate after neutering.

Why does the same cup amount vary between dog foods?+

Because calorie density (kcal per cup) varies significantly between brands and formulas. A calculated portion is calorie-based first, then converted into cups using your specific food's label — reusing a cup measurement across different foods can under- or overfeed your dog.

How do I know if my dog's portion is right?+

Monitor body condition and weight trend over several weeks. If your dog is steadily gaining or losing weight at the calculated portion, adjust the amount, and consult your veterinarian, especially for significant or unexplained changes.

Should treats count toward my dog's daily food portion?+

Yes. Treats and table scraps contribute calories just like regular food, and ignoring them in the daily total is a common way an accurately calculated portion still results in weight gain.

Is this dog food calculator free?+

Yes — completely free, no registration, and no data leaves your browser. Every figure recalculates instantly as you change an input.

Formula

Dog food portion formula

RER (kcal/day) = 70 × (weight in kg)^0.75. MER (kcal/day) = RER × life-stage factor. Portion = MER ÷ food's kcal per cup.

Step by step

How the calculation works

1Enter your dog's body weight in pounds.
2Choose the life-stage category that best matches your dog.
3Enter the calories per cup from your specific food's label (check the guaranteed analysis or manufacturer feeding chart).
4Read the daily and per-feeding portion in both cups and grams.

Example

Worked example — 30 lb neutered adult dog, 350 kcal/cup food

30 lb = 13.61 kg. RER = 70 × 13.61^0.75 = 495.95 kcal. MER = 495.95 × 1.6 = 793.5 kcal. Portion = 793.5 ÷ 350 = 2.27 cups/day (272 g/day), or 1.13 cups per feeding across 2 feedings.

Related guides

Learn more about this calculation

Guide