Woodworking & Construction Calculators

Fine woodworking & cabinetry

Wood Movement Calculator (Shrinkage and Expansion)

Change ≈ width × coefficient × ΔMC. Flatsawn uses the tangential coefficient; quartersawn uses radial. Coefficients are typical FPL-style values per 1% moisture content.

Inputs

Units
in
%
%

Results

Width change
-0.178in

Negative means the board shrinks.

Final width
11.822in

Recommended gear

Calculation method

Across the grain, wood moves with moisture. Tangential (flatsawn) movement is larger than radial (quartersawn). Lengthwise movement is ignored here because it is tiny for furniture.

Exact formula

finalWidth = width + width × coeff × (endMC − startMC). Negative change is shrinkage.

Metric widths

A 300 mm flatsawn oak panel uses the same coefficients; only the width unit changes.

Frequently asked questions

How do I pick start and end MC?

Start is the board in the shop. End is the indoor winter or summer EMC you expect, often 6–11% in heated houses.

Why is quartersawn calmer?

Radial coefficients are smaller. That is why quartersawn panels cup and move less across their width.

Should tabletops be glued tight to the apron?

No. Leave the calculated change as button-slot travel.

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