The coefficient must match the species, radial or tangential direction and moisture range. The initial value is an illustrative coefficient, not a species lookup. The linear estimate applies below the assumed fiber-saturation threshold of 30% moisture; variation between boards and species remains. A negative change means shrinkage. This tool does not predict warping or strength.
Worked reference example
Illustrative inputs in metres and SI units; the price is an example entered by the user, not a market quotation. Numeric reference verified by the automated test suite.
- Width
- 3
- Movement coefficient per moisture percentage point
- 0.002
- Initial moisture
- 8
- Final moisture
- 12
- Result
- 0.024
- Cost (example currency units)
- 0
Calculation method
Δw ≈ w × k × (M₂ − M₁)Measure. Calculate. Build.
- Use actual dimensions and split complex rooms into rectangles.
- Allow for cuts, joints and package sizes. Compare stock formats.
- Combine your results in a shopping list you can save and print.
Sources & limits
Planning estimates; verify measurements and product data before purchasing.
USDA Wood Handbook — Use a species- and direction-specific coefficient below fiber saturation. The default coefficient is illustrative, not a certified species value.
Prices are supplied by you. Area estimates do not establish a feasible cutting arrangement. These tools do not assess structural loads or issue construction approvals.