Cream Butterfat Blending Calculator
Standardizing dairy to a target butterfat is a classic application of the Pearson square: blend a high-fat component and a low-fat component so the mixture lands on the fat percentage you want. This calculator takes the fat content of each component, your target fat percentage, and the total batch weight, then returns how much of each component to use along with the verified blended fat. The math balances fat by weight, so the weighted average of the two parts equals your target exactly. All inputs are user-editable.
Pearson square formula
parts high = target - low
parts low = high - target
total parts = parts high + parts low
high grams = batch * parts high / total parts
low grams = batch * parts low / total parts
The differences across the square give the proportions. The blended fat check is (high grams times high fat + low grams times low fat) divided by total weight, which equals the target when the inputs bracket it.
Butterfat blending context
- The target fat must lie between the low-fat and high-fat percentages.
- Heavy cream commonly sits near 36 percent fat; whole milk near 3.25 to 3.5 percent.
- The Pearson square balances fat by weight, not by volume.
- Label fat content can vary from actual; verify with a fat test for regulated products.
- The weighted average of the two parts equals the target exactly.
Butterfat blending: frequently asked questions
What is the Pearson square?
The Pearson square (also called the Pearson square method or box method) is a standard dairy technique for blending two ingredients of known fat content to hit a target fat content. It works by taking differences across the diagonals of a square: the parts of each ingredient are proportional to the difference between the other ingredient and the target.
How do I standardize cream to a target fat?
Pick a high-fat component (such as heavy cream) and a low-fat component (such as skim milk or whole milk) that straddle your target. Parts of high-fat equal the target minus the low-fat percentage; parts of low-fat equal the high-fat percentage minus the target. Scale those parts to your desired batch weight.
What if my target is outside the two fat levels?
The target must lie between the low-fat and high-fat percentages for a valid blend. If your target is higher than your high-fat ingredient or lower than your low-fat ingredient, no mixture of the two can reach it, and the calculator shows n/a. Choose components that bracket the target.
Does this account for non-fat solids or volume?
This calculator works on a mass basis using fat percentage by weight, which is the convention in dairy standardization. It does not separately track non-fat solids or convert between weight and volume. Weigh your components for accurate results.
Is the result exact?
The blend math is exact for the fat balance: the weighted average of the two components equals your target. Real cream fat content can vary from its label, so verify with a measured fat test if precision matters, for example when meeting a legal standard for a labeled product.
Official sources
- U.S. FDA Code of Federal Regulations: 21 CFR Part 131, Milk and Cream.
- USDA Agricultural Marketing Service: Dairy Grades and Standards.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.