Dry Matter Calculator

Compare feeds fairly by removing the effect of water content.

How the Math Works

The Dry Matter Calculator uses the formula DM basis = as-fed % ÷ (1 − moisture/100) to convert nutrient concentrations from as-fed to dry-matter basis. This works because as-fed values include water content, which dilutes the actual nutrient concentration. By dividing the as-fed percentage by the dry matter fraction (1 minus moisture percentage), we remove the water's influence and reveal the true nutrient concentration in the solid material alone. For example, if a feed has 10% moisture and 14% protein on as-fed basis, the calculation becomes 14 ÷ (1 - 0.10) = 14 ÷ 0.90 = 15.6% protein on dry-matter basis.

Practical Applications

To use this calculator, simply enter the as-fed nutrient percentage and the moisture percentage of your feed or sample. The calculator will automatically apply the formula and return the dry-matter value. This is particularly useful when comparing different feeds with varying moisture contents, such as fresh grass hay versus dried hay, or comparing supplements that may be processed with different moisture levels. Always ensure your moisture percentage is entered as a whole number (e.g., 10 for 10%) rather than a decimal.

Day-to-Day Use

This calculation helps you make more accurate nutritional decisions in everyday situations like feeding livestock, meal planning, or assessing food quality. When you know the true dry-matter nutrient content, you can better evaluate if you're getting the nutrients you need without being fooled by water weight. For instance, two bags of feed might show different protein percentages on the label, but after calculating dry-matter basis, you might discover they actually provide the same nutritional value. This prevents overfeeding expensive supplements or underfeeding animals when moisture content varies between batches or seasons.

Worked example

10% protein at 75% moisture → 40% on a DM basis.

FAQ