1. Select Your Wood Species: Different species move at different rates.
2. Enter Board Width: Input the total width of your solid wood panel (e.g., a tabletop or cabinet side).
3. Calculate: The tool estimates the total change in width your board will experience between typical summer and winter indoor conditions (assuming a 4% moisture content swing).

• Seasonal Movement: The collective expansion and contraction of wood that occurs due to changes in relative humidity throughout the year.
• Frame and Panel: A construction method for doors and panels where a solid wood panel floats in a groove within a stable frame, allowing the panel to expand and contract without breaking the frame.
• Breadboard Ends: A classic technique where a board is attached to the end of a tabletop perpendicular to the main boards. The joinery is designed to keep the tabletop flat while allowing it to expand and contract.
• Cross-Grain Construction: Any construction where two pieces of wood are fixed together with their grains running perpendicular to each other. This is extremely risky and often leads to failure unless movement is accounted for.

"I can look at an antique piece of furniture and tell you if the maker understood wood movement. If the tabletop has a massive crack down the middle, they didn't. If it's still flat and perfect after 100 years, they did. They used breadboard ends, or they attached the top to the base with clips or slotted screw holes. They didn't fight the wood; they worked with it. That's the craft." - Furniture Restorer

Example 1: A 36-inch Wide Oak Tabletop
You build a beautiful, 36" wide dining table from flatsawn Red Oak boards.
The calculator estimates a total seasonal movement of approximately 0.41 inches, or nearly 7/16 of an inch! The top must be attached to its base in a way that allows for this much change in width.

Example 2: A Quartersawn Panel
If you build the same 36" tabletop from stable, quartersawn Red Oak, the movement is dramatically less.
The calculator estimates a total movement of only 0.19 inches—less than half that of the flatsawn panel. This is why quartersawn wood is prized for its stability.

• Rigidly Fixing a Wide Panel: The most common error. Gluing or screwing a wide solid wood panel (like a tabletop) directly to a perpendicular support structure (like an apron) is a guarantee of future failure.
• Using a Mitered Frame for a Solid Wood Panel: Miter joints have very poor cross-grain strength. A mitered frame around a solid wood panel will be forced apart at the corners as the panel expands.
• Believing a Finish Will Stop Movement: No finish is completely impermeable to water vapor. A finish can slow down seasonal moisture change, but it cannot stop it.

• Tabletop Construction: Designing an appropriate method (Z-clips, figure-8s, buttons) for attaching a top to its base.
• Door Making: Understanding why frame-and-panel construction is the only reliable method for making solid wood doors.
• Flooring: Leaving an appropriate expansion gap around the perimeter of a hardwood floor to prevent buckling in the summer.
• Material Choice: Justifying the extra expense of quartersawn lumber for applications that demand maximum stability.