Pet Food Math – Calculating Portions

Pet Food Math?

All you ever wanted to know about your pet food label in numbers

Calculating Portions – How Much To Feed
Part 6

I’m sure you have seen many calculators or guides online or on pet food packages that tell you how much you should feed your dog. I can assure you that 99% of them will tell you to feed too much food. I’m allowing 1% because I know there are some good companies out there trying their best and have truly put a lot of effort into getting this right. Why would they tell you to feed too much? I’m sure you have already figured out the more you feed, the more often you purchase, the more money they make. More sales, more profits! 

You’ve gathered a lot of information.  Now you know:

  • The carbohydrate content of the food you purchased
  • The number of calories in one ounce of the food you purchased
  • How ounces there are in 1 cup of that food, and

Most importantly for the final steps:

  • How many cups are in a package, and
  • How many calories you should be feeding your pet each day

In order to figure out how long a package will last you and whether or not the product fits into your monthly budget you’ll need to figure out exactly how much of the food you purchased you’re going to be feeding each day. You already know how many calories to feed but how much food is that?

Revisiting our example Guaranteed Analysis, we again see the number of calories in 1 cup of food.  Again, in this case there are 451 calories in 1 cup of food.

Crude Protein (min)24%
Crude Fat (min)7%
Crude Fiber (max)4%
Moisture (max)10%

3,973kcals/kg, 451kcals/cup

In Part 5, we used an example of a dog named “Harley.”

We calculated that Harley needs 396kcals/day. Let’s use Harley as an example, and also (from random selection) use 1,052kcals/day and 732kcals/day just so we can see the math a few times.

In order to figure out how much to feed each day, divide the number of calories in 1 cup of food (listed on the package) by the number of calories you need to feed each day. Here are our examples:

Example #1:

396 (kcals/day) / 451 (kcals/cup) = 0.878 cups per day… or 0.9 cups per day for Harley

Example #2:

1,052 (kcals/day) / 451 (kcals/cup) = 2.3 cups per day

Example #3:

732 (kcals/day) / 451 (kcals/cup) = 1.6 cups per day

Now you know how many cups you’re going to be using every day and you’re one step closer to being able to figure out if this product fits in your monthly budget.

For most people, the above listed “cups per day” feeding is sufficient.  However, I know that some of you want to be able to measure with a little more precision.  Here are tips for those of you that love to calculate as much as I do:

Calculating for using a FOOD SCALE:

Food scales measure mass, not volume.  As we previously learned, just because you’re using an 8oz measuring cup doesn’t mean it contains 8oz.  In the case of the product we’re using, an 8oz cup has a mass of only 4oz.  So you need to be able to convert the number of cups that you’re using to the number of ounces you’re going to be weighing out.

Multiply the number of cups that you are supposed to feed by the calculated number of ounces in the product you purchased. We’ll use the 3 examples from above.

0.9 (cups/day for Harley) x 4 (oz calculated in one cup of this particular food) = 3.6 oz/day MASS

2.3 (cups/day) x 4 (oz calculated in one cup of this particular food) = 9.2 oz/day MASS

1.6 (cups/day x 4 (oz calculated in one cup of this particular food) = 6.4 oz/day MASS


The original results were for a standard 8oz measuring cup. I do understand, however, that most people aren’t great with measurements so here is a guide that may help you know exactly what line to go to for fractions of a cup.

Click “Next Post” for Part 7
How long will this package of food last?

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