About Shiplap Calculator
Building the web's definitive, free, contractor-grade millwork estimation tool without paywalls or AI filler.
Why We Built Shiplap Calculator
When reviewing popular calculator websites, our woodworking team discovered a persistent and costly flaw: nearly every top-ranking calculator on the internet calculates wall coverage by taking simple wall area divided by nominal or actual board dimensions, completely ignoring the ½-inch rabbet overlap joint.
This single error causes homeowners and contractors to underestimate their lumber orders by 10% to 15%, requiring frustrating mid-job emergency trips back to the lumber yard where matching dye lots and milling runs is often impossible.
Our Core Standards
- 1. Zero Paywalls: Unlimited instant calculations with full Bill of Materials (BOM) exports for every user.
- 2. True Joint Branching: Differentiated mathematical engines for Rabbet-Overlap Shiplap vs. Nickel-Gap Reveal vs. Tongue-and-Groove.
- 3. Visual Layout Confirmation: A live 2D SVG canvas preview showing real course counts, stud lines, and cutout positioning.
Audited by Master Carpenters
All formulas and reference tables are audited by Thomas Clark, a licensed finish carpenter and architectural millworker with over 18 years of field installation experience.