Dry Matter Calculator
Compare nutrient percentages in two pet foods after removing their moisture content.
On this page
CalculatorHow to useFormula & methodWorked exampleWhy removing moisture helpsRead label values carefullyFrequently asked questionsRelated calculatorsSourcesHow to use this calculator
- Copy moisture and the selected nutrient percentages from each food’s label.
- Keep entries on the as-fed basis shown by the label; do not enter an already converted dry-matter percentage.
- Compare the dry-basis results while also considering energy density and nutritional suitability.
Formula and method
For the assumptions behind these results, read the explanation below. You can also explore Crickets Chirping Thermometer and Horse Weight.
A worked example
Food A contains 22% dry matter, making its 10% as-fed protein about 45.45% on a dry basis. Food B contains 90% dry matter, making 30% as-fed protein about 33.33% on a dry basis.
Why removing moisture helps
A wet food can appear lower in protein simply because water contributes a large share of its weight. Dry-matter conversion asks what proportion of the remaining material is the nutrient being compared. It makes moisture-different products easier to compare without claiming that one label’s larger percentage automatically makes it better.
The percentages are mass proportions. If 100 grams of food contains 78 grams of water, 22 grams remains after moisture removal. Ten grams of protein within that remaining material represents 10 divided by 22, or about 45.45%. The protein amount has not increased; only the comparison basis has changed.
Read label values carefully
Guaranteed analyses often state minimum protein and fat and maximum fiber and moisture, not exact laboratory measurements of one batch. Combining those bounds creates an approximate comparison, not a precise nutrient analysis. Ask the manufacturer for typical analyses when a more exact comparison matters.
This tool checks whether the entered percentages can represent a single composition. A sum above 100% is rejected because those endpoints cannot be used together; it does not mean that the product or its guaranteed analysis is invalid. Ask for typical values in that case. It does not calculate digestibility, amino-acid quality, calories from each nutrient, or dietary completeness. A food with a higher dry-basis protein result may still be unsuitable for a particular animal’s life stage or medical needs.
Frequently asked questions
Can moisture be 100%?
No. That would leave no dry material, making the dry-basis division undefined.
Does dry-basis protein tell me grams per meal?
No. Multiply the meal’s as-fed weight by the original as-fed percentage to estimate grams of nutrient in that portion.
Why do the displayed nutrients not total 100%?
Water has been removed, but other components such as minerals and carbohydrate are not entered in this comparison.
Sources and further reading
- US Food and Drug Administration: comparing pet foods on a dry-matter basis ↗
Documents moisture removal and nutrient percentage ÷ dry-matter percentage × 100. Label guarantees are bounds rather than a complete measured composition.
Our explanations are written for BiologyCalc. Read how we build and check our tools. These calculations are educational estimates where the underlying model requires assumptions.