Wood Movement Calculator

Wood is hygroscopic—it absorbs and releases moisture depending on the humidity of its environment. This causes wood to expand and contract across the grain, which can lead to gaps, cracks, or warped joints if not accounted for in your designs.

Use this calculator to predict how much your wood will move based on species, grain orientation, and expected moisture content changes. This is essential for:

Designing table tops and wide panels
Planning seasonal gap allowances in flooring
Sizing breadboard ends and frame-and-panel construction

How It Works

The calculator uses published shrinkage coefficients for different wood species. Tangential shrinkage (flat sawn) is typically about twice radial shrinkage (quarter sawn). Rift sawn lumber falls between the two.

The formula accounts for the percentage of moisture content change and the initial width of your board to give you an accurate prediction of dimensional change.