Pearson Square Feed Mixing Calculator

How it works

Parts of A = |target − B%|; parts of B = |A% − target|; fraction of A = parts A ÷ (parts A + parts B); with fixed non-nutrient additions f, use target ÷ (1 − f) in the square

The Pearson square is the farm classic for hitting a nutrient target with two ingredients: write the target in the middle, the two ingredient values at the left corners, subtract diagonally and ignore signs, and the numbers on the right are the parts of each ingredient. It works for crude protein, calcium, energy, fat, milk solids — any single nutrient expressed as a percentage — as long as the target lies between the two sources. Real rations also carry a few percent of premix, salt and minerals that add no protein; the calculator reserves that share and raises the target for the remaining ingredients accordingly. For more than two ingredients, blend pairs into intermediate mixes (a protein concentrate and a grain mix) and square those, or move to least-cost formulation software.

Worked example

A 16% protein grower from 44% soybean meal and 9% maize with 3% premix: the two ingredients must supply 16.5% between them, giving 7.5 parts soy to 27.5 parts maize — 21.4% soy, 78.6% maize of the grain portion. A 500 kg batch needs 104 kg soybean meal, 381 kg maize and 15 kg premix at about 34¢ per kg.

Frequently asked questions