Dog Food Calculator: How Much to Feed a Dog

This tool provides a general estimate and does not replace professional veterinary advice.

Updated October 13, 2026 · How we check our tools

What is the Dog Food Calculator?

A moderately active 50 lb dog needs about 1,090 calories a day, which is roughly 2¾ cups of a dry food with 400 calories per cup. Smaller dogs need far less: a 20 lb dog needs about 550 calories, or around 1⅓ cups of the same food.

The Dog Food Calculator calculates daily food portion in grams or cups for dogs based on weight, age and activity level. Overfeeding is one of the most common and most preventable health problems in pets, while underfeeding a growing or active animal can slow development or sap energy.

Dogs generally live 10-13 years when they are well looked after. As an omnivore, what a dog needs from its diet changes across its life stages. Dogs live indoors with their family, needing daily exercise, mental stimulation, and a securely fenced outdoor area for larger or high-energy breeds. Health problems that show up most often in dogs include dental disease, obesity, ear infections (in floppy-eared breeds), which is part of why tracking this over time pays off.

How much to feed a dog: calories and cups by weight

Daily calories from resting energy (70 × kg^0.75) times 1.2 (less active), 1.5 (moderate) or 1.8 (very active). Cups assume a dry food with 400 kcal per cup; check your bag.
Dog weight	Less active	Moderate	Very active	Cups a day (moderate)
10 lb (4.5 kg)	260 kcal	330 kcal	390 kcal	0.8
20 lb (9.1 kg)	440 kcal	550 kcal	660 kcal	1.4
30 lb (13.6 kg)	600 kcal	740 kcal	890 kcal	1.9
50 lb (22.7 kg)	870 kcal	1090 kcal	1310 kcal	2.7
70 lb (31.8 kg)	1120 kcal	1400 kcal	1690 kcal	3.5
90 lb (40.8 kg)	1360 kcal	1700 kcal	2030 kcal	4.2

How does the Dog Food Calculator work?

The estimate starts from a resting-energy formula based on body weight, then adjusts for activity level, life stage and, where relevant, the specific nutritional profile of dogs. Individual dogs vary more than averages suggest, so read the number as a reference point rather than a measurement.

What affects the result

Body weight: the single biggest driver of daily calorie needs
Activity level: a sedentary indoor animal needs meaningfully less than an active or working one
Life stage: since growing, pregnant or nursing animals need more energy per kilogram than a stable adult
Spay/neuter status: which typically lowers metabolic needs somewhat

How do you use the Dog Food Calculator?

Enter the body weight in whichever unit you use (lb, oz, kg)
Pick your activity level (Low, Moderate, High)
Enter the calories per cup of your food
Press Calculate, then read the result alongside the sources listed below

Bring the number to your next appointment. Vets can work with a figure and a date far more easily than with "he seems a bit off lately".

For related questions, see the other nutrition tools or browse every dog tool.

Before you rely on this

This calculation assumes a healthy adult dog with no complicating conditions. Pregnancy, recovery from illness, medication and significant age at either end of the scale all change what is appropriate. When in doubt, the safest move is to take the number to a vet and ask whether it fits your particular animal.

Sources and references

The formulas, reference ranges and species data behind the Dog Food Calculator come from these veterinary references, professional bodies and published research.

Built on veterinary referencesFormulas and ranges come from veterinary manuals, university research and welfare bodies, listed above for you to check.
Instant resultsNo page reload, no waiting and no account. Enter your details and the result appears straight away.
Private by designCalculations run in your browser. Nothing you enter is stored on our servers or shared with anyone.
Always freeEvery XpertsPet tool is free to use, with no premium tier and nothing to sign up for.

Frequently asked questions

How many cups of food should my dog eat a day?

Divide your dog's daily calories by the calories per cup printed on the bag. At 400 calories per cup, a 20 lb dog needs about 1⅓ cups, a 50 lb dog about 2¾ cups and an 80 lb dog about 4 cups a day at moderate activity.

How is daily calorie need worked out?

It starts from resting energy, 70 × body weight in kg to the power of 0.75 (the WSAVA formula), then multiplies by an activity factor: about 1.2 for a less active dog, 1.5 for moderate and 1.8 for a very active one.

Should I feed my dog by the bag's chart or a calculator?

Use either as a starting point, then adjust. Weigh your dog every two to four weeks, and if it is gaining or losing weight you did not intend, change the daily amount by about 10%.

Do neutered dogs need less food?

Usually yes. Neutered dogs often need around 20–30% fewer calories than intact dogs of the same weight, which is a common reason for weight gain after neutering.

What is the Dog Food Calculator based on?

It uses published reference data and formulas from sources including Cornell University College of Veterinary Medicine, WSAVA Global Nutrition Guidelines, NRC. The full list, with links, is in the sources section above.