Use this construction calculation for preliminary quantity, geometry, material, load, or coverage planning when dimensions and units have been measured consistently.

Defect Millimeters (mm)

Required number input.

Board Millimeters (mm)

Required number input.

Rejected portion of a lumber length from total measured defect length divided by the original board length. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Defect Percent (%)

The resulting defect percent returned as a number.

• Lumber calculations depend on actual dimensions, species, grade, moisture content, defects, treatment, orientation, and waste. Nominal size and average density are not substitutes for the specified product or structural grading.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Verify dimensions on site, use current product data and local code requirements, include an explicit waste or safety allowance where appropriate, and obtain qualified structural, electrical, plumbing, or geotechnical review when required.

• Board Feet

  Calculate lumber board feet from nominal or actual thickness and width in inches and length in feet: thickness×width×length/12.

• Concrete Yield

  Calculate fresh concrete batch yield as total batch mass divided by measured fresh density, both from the same batch.

• Drip Edge Length

  Total roof drip-edge material along measured eaves and rakes, including a waste allowance for cuts.