Pearson's Square rations balancer free online tool

Pearson's Square (also called the Pearson Square, the box method, the rectangle method) is a great tool to help you determine the proper mixture of two different feedstuffs to reach a particular nutritional percentage.  

This is a particularly useful tool when you're trying to combine feedstuff for winter feeding or to simply optimize your animals' intake for proper growth and health while not having any feed waste.

Normally you would have to do the math manually. We wanted to give you an easier way to get your mixed ration calculations done quickly, so we built a Pearson's Square calculator for you to use.

Follow the steps below to use the calculator.

Step 1: Choose your target nutrient and nutrient basis

  • Select the target nutrient you want to calculate: CP (crude protein), TDN (total digestible nutrient), Ca (Calcium) or P (phosphorus).
  • Select the feedstuff basis: as-fed or dry matter. 

Ingredients in a mixture must be calculated on the same basis. We have set the calculator up so that all nutrient percentages displayed are based on your chosen basis. 

Step 2: Enter the target percentage

The target percentage must be between the percentages of your feedstuffs for the calculation to work.  

Example: A protein mix of Bromegrass (10.0% CP) and Alfalafa (18.0% CP) must have a target CP percentage between 10.1% and 17.99%.

Step 3: Select your feedstuffs

Select the two feedstuffs you want to balance. We have an extensive list of options and their nutrient percentages, taken from the National Research Council's publication, Nutrient Requirements of Small Ruminants.  

If you have tested your feed and know their values, overwrite the default percentage to match your specific feedstuff by typing your number over the value in the percentage field for a more accurate calculation.  

If the feedstuff you're using is not in our list, type it over any value in the feedstuff name field, and its percentage over the value in the percentage field to get a result with your specific feedstuff.

Step 4: Click "Calculate"

Your results will be expressed both in the parts and percentages of each feedstuff required to meet your target nutrient percentage. If results are not displayed after completing steps 1 through 3 above, check that all fields have information in them and that your target percentage is between the two feedstuffs.

If you'd like to see an example of where a Pearson's Square could come in handy, check out our Fundamentals of goat nutrition article contributed by Dr. Frank Pinkerton.

Have a feedstuff you would like us to add?

If you use a feedstuff or nutrient you would like us to add to the calculator, please send an email to

The percentages included in this Pearson's Square are only generalizations or averages of nutrient composition provided by the "Nutrient Requirements of Small Ruminants", published by the National Research Council. Actual analyses should be used when formulating rations. EasyKeeper Herd Manager assumes no liability for rations developed using the information included in this nutrition calculator.

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