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

Horizontal plan area (m²)

Required number input.

Pitch angle (°)

Required number input.

Convert horizontal roof plan area to sloped area for a uniform roof pitch; excludes overhangs and openings. 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]

Sloped roof area (m²)

The resulting sloped roof area returned as a number.

• A quantity estimate or simplified engineering formula is not a building-code check, stamped design, manufacturer approval, or site inspection. Material properties, tolerances, waste, moisture, workmanship, loads, local conditions, and code requirements can change the result.
• 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.

• Valley Flashing Length

  Estimate straight flashing length along a roof valley from its horizontal plan projection and vertical rise.

• Roof Pitch Angle

  Calculate a roof slope angle from vertical rise and horizontal run, not the rafter length.

• Shingles Bundles

  Round up shingle bundles required from sloped roof area, waste allowance, and coverage per bundle.