Free Woodworking Tool

Free Wood Movement Calculator

The Wood Movement Calculator estimates how much a board may expand or shrink across its width when shop or home humidity changes. Choose the species, board width, grain orientation, and starting and ending relative humidity to plan panels, cutting boards, drawer fronts, tabletops, and frame-and-panel parts with safer clearance.

Seasonal movementExpansion and shrinkageBuild clearance

Calculate seasonal board movement

Wood species

Board width, inGrain orientation

Starting humidity, %Ending humidity, %

Movement estimate

Hard maple is expected to expand by about 0.18 in across 12.0 in of width as moisture content changes from 6.7% to 10.9%.

Start EMC

6.7%

End EMC

10.9%

Moisture change

4.2%

Build allowance

0.22 in

Planning notes

Flat-sawn stock moves the most. Use floating panels, elongated screw holes, or quarter-sawn stock when tight tolerances matter.

Build recommendations

Leave movement room across the grain with floating panels, buttons, clips, figure-eight fasteners, or elongated screw holes.
Finish both faces similarly to slow uneven moisture exchange and reduce cupping risk.
Use this estimate for planning, then favor extra clearance on doors, drawers, table tops, and cutting boards that will see water.

How to use this wood movement estimate

1

Choose a wood species

Pick the closest species profile. Each profile uses typical radial and tangential shrinkage values from green to oven-dry wood.

2

Enter the board width

Measure the board width across the grain. Wood movement is largest across width, not along board length.

3

Select the grain orientation

Use flat-sawn for mostly tangential movement, quarter-sawn for mostly radial movement, or mixed grain when the board has a blended growth-ring pattern.

4

Add starting and ending humidity

Enter the relative humidity where the board starts and the expected humidity where it will live. Seasonal indoor swings often matter more than one-day weather.

5

Build with allowance

Use the movement estimate and conservative allowance to leave room in panels, breadboard ends, drawer fronts, cabinet doors, and cutting-board glue-ups.

Wood movement FAQ

How much does wood move with humidity?

Wood movement depends on species, grain orientation, board width, and moisture change. A 12-inch flat-sawn hardwood board can easily move around 1/8 inch or more across seasonal indoor humidity swings.

Does wood move more across width or length?

Wood moves far more across width than along length. Longitudinal movement is usually small enough to ignore in normal furniture and cutting-board planning, while radial and tangential width movement must be allowed for.

Do quarter-sawn boards move less than flat-sawn boards?

Yes. Quarter-sawn boards follow radial shrinkage values, which are usually lower than tangential values. That is why quarter-sawn stock is more dimensionally stable for panels, doors, and wide parts.

Should cutting boards allow for wood movement?

Yes. Cutting boards still expand and contract with moisture, washing, and seasonal humidity. Use stable species, balanced construction, and avoid trapping a board so tightly that it cannot move.

Is this wood movement estimate exact?

No calculator can predict exact movement for every board. Growth conditions, grain runout, finish, moisture content, and environment all matter. Use the result as a planning estimate and leave extra room for important parts.

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