Project notes
Understand this estimate
Dry-basis wood moisture content compares the water lost during drying with the sample’s oven-dry mass. Both weights must refer to the same sample.
How to use the calculator
Weigh the sample before drying
Record the wet mass before oven drying.
Inputs Wet sample mass
Weigh the same sample after drying
Use the oven-dry mass after the sample reaches constant mass. Enter both masses in the same unit.
Inputs Oven-dry sample mass
Formula and variables
Water mass = wet mass − oven-dry mass. Wood moisture content (%) = water mass ÷ oven-dry mass × 100.
- mᵥWet sample mass
- Mass before oven drying.US oz
- m₀Oven-dry mass
- Dry-basis denominator.US oz
- mᵥ − m₀Water mass
- Mass lost during drying.US oz
What the result means
Result interpretation
Moisture content is expressed as water mass divided by oven-dry mass. Water mass is also shown in ounces and grams. This result does not establish finish readiness.
Limits and assumptions
Wet mass must be at least the oven-dry mass, and the dry mass must be positive. Metric water-mass equivalent is also shown. This measurement does not establish whether a surface is ready for staining or finishing.
Worked example
A sample loses 20 ounces during drying
Assumptions
- Both measurements use the same unit and same wood sample.
- The dry mass is positive and lower than the wet mass.
Calculation
- Water mass = 120 − 100 = 20 oz.
- 20 ÷ 100 × 100 = 20% dry-basis moisture content.
- 20 oz × 28.3495 = 567.0 g water.
| Wood moisture content | 20 % |
|---|---|
| Water mass | 20 US oz |
| Water mass metric equivalent | 567 g |
Common questions
- Is the denominator wet mass?
- No. This calculator uses oven-dry mass as the denominator.
- Does this say whether wood is ready for staining?
- No. Finish-readiness depends on the selected product and substrate conditions.