Tools for Woodworkers

Seasonal allowance

Wood movement calculator

Estimate how much a solid-wood panel may change across its width as moisture content changes below fiber saturation. Use the result to plan gaps, fasteners, and joinery that allow movement.

Bench calculator

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Verify critical dimensions and machine setups independently before cutting project material.

01 / METHOD

How to use this calculator

  1. Choose a species and grain orientation.
  2. Enter board width and expected low and high moisture content.
  3. Treat the range as an estimate and design for movement in both directions.

02 / APPLICATION

Useful in the workshop

  • Size a floating panel gap
  • Plan tabletop fastener travel
  • Compare flat-sawn and quarter-sawn movement

03 / MODEL

Assumptions

  • Fiber saturation is approximated as 30% moisture content.
  • Published total radial and tangential shrinkage values are linearly scaled below fiber saturation.
  • Rift-sawn movement is approximated midway between radial and tangential values.

04 / CHECKS

Limitations and safety

  • Actual boards vary by tree, cut, environment, and measurement.
  • The linear model is an estimate, not an engineering guarantee; moisture above fiber saturation is capped.

Before cutting: independently verify important dimensions, angles, clearances, material behavior, and machine settings. Use safe procedures appropriate to your tools and material.

05 / QUESTIONS

Frequently asked questions

Does wood move along its length?

Longitudinal movement is usually much smaller; this calculator estimates the more significant across-grain movement.

Why does flat-sawn wood move more?

Flat-sawn width follows the tangential direction, whose shrinkage is generally greater than radial shrinkage.