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Dog Food Calorie

Estimate the calories in a dog or cat food from the guaranteed analysis on the label.

✔ Reviewed by a licensed veterinarianContent updated 18 Oct 2026Reviewed 18 Oct 2026Sources: NRC · AAFCO Dog & Cat Food Nutrient Profiles / label guidance
Dog Food CalorieFree · instant
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Quick answer. A kibble with 26% protein, 16% fat, 4% fibre, 10% moisture and 7% ash contains about 3,565 kcal/kg by the modified Atwater method. If the bag prints kcal, use the manufacturer's figure instead; this is an estimate for when only the guaranteed analysis is available.

How to use the dog food calorie

  1. Enter protein, fat, fibre and moisture % from the label.
  2. Add ash % if listed.
  3. Press Calculate.

Worked example

A kibble with 26% protein, 16% fat, 4% fibre, 10% moisture and 7% ash.

Crude protein %
26
Crude fat %
16
Crude fibre %
4
Moisture %
10
Ash % (optional)
7
3,565 kcal/kg
Per 100 g
357 kcal
Carbohydrate (NFE, as fed)
37.0%

Estimate by the modified Atwater method. If the bag states kcal, use the manufacturer's figure.

Example values are illustrative; this result is produced by the same calculator above.

How we calculate it

Modified Atwater: kcal/100 g = 3.5×protein + 8.5×fat + 3.5×NFE; NFE = 100 − (protein+fat+fibre+moisture+ash); ×10 → kcal/kg

Sources: NRC · AAFCO Dog & Cat Food Nutrient Profiles / label guidance

Understanding your result

Many pet foods do not print their calories. You can estimate kcal per kg from the guaranteed analysis using the modified Atwater factors: 3.5 kcal per gram of protein, 8.5 per gram of fat and 3.5 per gram of carbohydrate (nitrogen-free extract).

Carbohydrate is not on the label, so it is calculated as what is left after protein, fat, fibre, moisture and ash. If ash is unknown, a typical default is used.

The result is an estimate. If the manufacturer states calories, use their number.

Common mistakes

  • Entering minimum percentages as if they were exact values.
  • Leaving out moisture or fibre, which makes carbohydrate wrong.
  • Using the figure to compare against a food that states calories on a different basis.

Good to know

  • The estimate can be off by a noticeable margin compared with the manufacturer's measured value.
  • Use the result with the dog food calculator to get portions.
  • Ash defaults are 8% for dry food and 2.5% for wet food if you do not know it.

Frequently asked questions

How many calories are in my dog food?

Use the kcal/kg on the bag if printed; otherwise this modified Atwater estimate is the standard method.

What are modified Atwater factors?

3.5 kcal/g for protein and carbohydrate and 8.5 kcal/g for fat (NRC 2006).

How do I find carbohydrates?

Pet food labels don't list carbs; they are estimated as 100 minus protein, fat, fibre, moisture and ash.

How accurate is the Atwater estimate?

It is an estimate. If the manufacturer prints kcal on the bag, use that figure instead, because digestibility differs between foods and the calculated value can be off.

What is NFE?

Nitrogen-free extract is the estimate of carbohydrate: 100 minus protein, fat, fibre, moisture and ash, all as fed.

What do I do with the result?

Enter the kcal per kg into the Dog Food Calculator to turn your dog's daily calories into grams of this food. Ash is optional here, but entering the value from the bag gives a better estimate.

Reviewed by a licensed veterinarian
Last reviewed 18 Oct 2026 · How we review

Sources

  1. NRC (2006) Nutrient Requirements of Dogs and Cats, National Academies Press
  2. AAFCO Dog & Cat Food Nutrient Profiles / label guidance
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Estimates only. Every pet is different — confirm with your veterinarian.