How to read the calorie information on your pet food bag

Written by Josh · Founder of petportioncalc.com · About the author

By Josh · Reviewed and updated: 2026-09-16

Weight-to-volume differs by species — cups in a pound of cat food shows the cat figures.

To convert: kcal/kg ÷ 10 = kcal per 100g. A food at 4,000 kcal/kg gives 400 kcal/100g. Cup-based labels need one extra step — divide by the cup weight in grams (typically 90-130g for dry food).

The feeding chart on the back of the bag is a rough population average. The calorie number is the one figure that lets you work out an amount for your pet and your food — and it is printed on almost every US pet food package. Here is where to find it and how to use it.

Where to look

Look for a section on the back or side panel headed “Calorie Content” (sometimes “Calorie Content (calculated)”). It usually sits near the Guaranteed Analysis. It is separate from the feeding chart, and it is the part you want.

A typical dry dog food prints two figures, like this:

Wet food usually prints kcal per can instead, and sometimes kcal/kg as well. Turning a per-can figure into a per-100 g one — which is what you need before you can compare it with dry food — is covered on the wet and dry food conversion page.

What “ME” means

ME stands for metabolizable energy: the portion of the food's total energy that the animal can actually absorb and use, rather than excrete. It is the only energy figure worth calculating with. If you see a figure labelled “gross energy”, that is a different measurement and will not match how your pet actually uses the food.

The two numbers are not alternatives — they are the same food

kcal/kg and kcal/cup both describe the same food, and they are linked by how much the kibble weighs per cup. That link gives you a genuinely useful trick.

To find grams per cup from a label:

Using the label above: (370 ÷ 3,364) × 1,000 = 110 g per cup.

That is where the 110 g figure used as the default in our calculator comes from — it is the typical relationship between the two label values for adult kibble. If your bag's own figures give you a different result, use yours. Compute it once and you have the number.

Which one should you use?

If you intend to weigh food instead of scooping it — which is more repeatable — use kcal/kg. It skips the cup conversion entirely, because the result comes out in grams.

The mistake that throws portions off by ten times

Pet food labels mix units, and the difference between them is a factor of ten. These all appear on real packaging:

• kcal per kg — typically 3,000 to 4,500
• kcal per 100 g — typically 300 to 450
• kcal per cup — typically 250 to 500
• kcal per can — typically 350 to 500

Entering 3,700 where the calculator expects a per-100 g figure, or entering 370 where it expects per-kg, changes the answer by tenfold. It is the single most common error in home portion calculation, because the two numbers look equally plausible. That trap has its own page: kcal/cup or kcal/kg — which one do you use? covers how to tell the two apart and how to convert between them.

The check: after you calculate, compare the result with the feeding chart on the bag. They will not match exactly, but they should be in the same ballpark. If your calculated portion is ten times the chart, or a quarter of it, you have almost certainly mismatched the unit.

A scale settles it: the fastest way to stop mismatching units is to stop converting and weigh the food instead — a kitchen scale that reads in 1 g increments gives you grams directly, whichever figure the label printed.

How the calorie statement connects to the feeding chart

The two numbers on the label work together in a way most bag descriptions skip. The feeding chart was calculated from the kcal/kg figure using that manufacturer's assumed cup weight — so if your dog's portions come from the chart, you are already using the energy data indirectly. Reading the calorie statement directly simply removes the cup-weight assumption from the middle. For dogs whose weight drifts on a chart-fed routine, switching to gram-based portions calculated from the energy density closes the loop: the chart becomes a starting point, the calorie line becomes the instrument.

One practical detail: the energy statement is expressed on an as-fed basis, which includes the water in the food. That is why dry food and wet food numbers cannot be compared directly against each other on the label — a wet food at 1,000 kcal/kg is far denser per gram of dry matter than a dry food at 4,000 kcal/kg. When comparing a wet topper against the kibble it replaces, convert both to a dry-matter or per-calorie basis first.

A worked example, both ways

Take a 30 lb (13.6 kg) neutered adult dog of typical activity, eating the food from the label above.

Step 1 — the calorie target. Resting energy requirement is 70 × 13.6^0.75 = 496 kcal/day. The life-stage factor for a neutered adult of typical activity is 1.6, giving a maintenance requirement of 794 kcal/day.

Step 2a — using kcal/cup. 794 ÷ 370 = 2.14 cups per day, or about 1.07 cups per meal across two meals.

Step 2b — using kcal/kg. 794 ÷ 3,364 × 1,000 = 236 g per day, or about 118 g per meal. That is the same amount of food as 2a, just measured on a scale instead of in a cup.

Both routes land in the same place. That is the point of the check: if your two methods disagree, one of your inputs is wrong.

Then check the pet, not the arithmetic

Any figure you derive this way is a starting estimate. Published reference data shows wide variation between individual animals of the same weight, so the label gives you a defensible starting point, not an answer. Set the amount, then look at body condition every two to four weeks — ribs easy to feel but not visible, a visible waist from above, a belly tuck from the side — and adjust by about 10% at a time. See our weight chart by size for the body condition check in more detail.

Frequently asked questions

Calculate your pet's exact portion →
kcal/cup or kcal/kg — the mix-up that costs tenfold →