How to Use the Wood Moisture Deformation Calculator
Wood behaves like a living material, absorbing or releasing moisture with the surrounding humidity and changing size as a result. Wide boards especially can shrink or expand by several millimeters as humidity shifts, so predicting deformation ahead of time matters for furniture and door building. Choose a species, enter the current board width, current moisture content, and target moisture content, and the calculator estimates the deformation and resulting width automatically.
Flat-Grain Movement Rate by Species (per 1% moisture change)
| Species | Movement Rate (%) | Notes |
|---|---|---|
| Oak | 0.36 | Higher movement, durable |
| Maple | 0.27 | Popular for furniture, cutting boards |
| Birch | 0.26 | Common in plywood, glued-up boards |
| Pine | 0.20 | Relatively lower movement |
| Walnut | 0.19 | Stable, used in fine furniture |
| Cherry | 0.16 | Among the most stable |
Frequently Asked Questions
Wood fiber absorbs or releases bound water below the fiber saturation point (about 28-30% MC), changing volume. Above that point, only free water changes, so dimensions stay the same.
Wood moves most along the tangential (flat-grain) direction, about half as much along the radial (quarter-grain) direction, and almost nothing along the length. This calculator uses average flat-grain values.