Wood Movement Calculator
Calculate wood expansion and contraction based on species and humidity changes
About this calculator
The Wood Movement Calculator helps woodworkers and carpenters predict how much wood will expand or contract based on species characteristics and humidity changes. Wood is a hygroscopic material that constantly absorbs and releases moisture from the environment, causing dimensional changes that can affect project fit and finish. This calculator uses scientific data about different wood species' movement coefficients to provide accurate predictions, helping you plan for seasonal changes and prevent costly mistakes in furniture making, cabinetry, and construction projects.
How to use
Select your wood species from the dropdown menu, then enter the starting and ending relative humidity percentages for your environment. Input the current dimensions of your wood piece. The calculator will display the expected expansion or contraction in both inches and millimeters, helping you plan appropriate gaps and allowances for your project.
Frequently asked questions
Which wood species move the most?
Hardwoods like oak, maple, and cherry typically have higher movement rates than softwoods like pine or cedar due to their denser cellular structure.
Does wood move more in length or width?
Wood moves significantly more across the grain (width/thickness) than along the grain (length), often by a factor of 10 to 20 times.
What humidity change causes noticeable movement?
Most wood species show measurable movement with humidity changes of 10-15%, with significant movement occurring during seasonal transitions of 20% or more.