Calculate wood moisture content on both dry and wet bases from a weighed oven-dry sample.
Moisture content — dry basis
Dry basis uses oven-dry wood as the denominator; wet basis uses original total weight. They are not interchangeable.
Two different denominators
Dry-basis MC = (wet weight − oven-dry weight) ÷ oven-dry weight × 100. Wet-basis MC = (wet weight − oven-dry weight) ÷ wet weight × 100. Dry-basis values can exceed 100%; wet-basis values cannot.
Oven-dry measurement
Use the sample’s original weight and its constant weight after oven drying. Keep both measurements in the same unit; grams are shown for convenience.
Source and limitation
The definitions follow the USDA Forest Products Laboratory drying manual. Sampling location, extractives and incomplete drying can affect the measured result. This calculator does not predict drying time.
Log weight calculator · Firewood BTU calculator
