Lap Joint Calculator — Overlap Joint Dimensions
Calculate lap joint dimensions and material removal for half-lap, full-lap, and dovetail-lap joints.
Material thickness
Shortest dimension of the area
Material thickness
Shortest dimension of the area
Select the lap type for your calculation
How We Calculate This
This calculator determines the notch dimensions for lap joints.
Half lap
Each piece is notched to half its thickness. The notch width equals the width of the mating piece.
Full lap
One piece is notched to the full thickness of the other, which sits in the notch uncut.
Frequently Asked Questions
Related Calculators
Dovetail Calculator
Calculate dovetail pin and tail spacing for hand-cut or machine joints.
Mortise and Tenon Calculator
Work out mortise and tenon dimensions based on timber size.
Box Joint Calculator
Calculate finger joint spacing and dimensions for box construction.
Dowel Spacing Calculator
Determine optimal dowel positions and spacing for edge joints.
Biscuit Joint Calculator
Calculate biscuit size and spacing for panel and edge joints.
Last updated: February 2026
All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.