Moisture content is the amount of water present in a material, usually expressed as a percentage of that material’s total or dry weight.

Quick Scoop

Simple definition

  • In science and engineering, moisture content (also called water content) is how much water is contained in something like soil, wood, paper, food, or crops.
  • It is typically written as a percentage, for example “20% moisture content” means 20% of the sample’s weight or volume is water.

How it’s expressed

  • Gravimetric basis: water mass divided by dry mass, then multiplied by 100 (often used in soil and materials testing).
  • Volumetric basis: volume of water divided by total volume of the material (common in soil and environmental science).

Why moisture content matters

  • It affects strength and stability (e.g., wood warping, soil bearing capacity, paper strength).
  • It changes how materials behave in processing and storage, like drying time, spoilage risk in foods, and product quality.
  • Too high or too low moisture content can cause problems such as mold, cracking, poor printability of paper, or food safety issues.

One quick example

If you dry a 100 g soil sample in an oven and it weighs 80 g afterward, then 20 g was water. On a dry-mass basis, moisture content is (20÷80)×100=25%(20÷80)×100=25%(20÷80)×100=25%.