Architect Tools

Roofing · Calculator

Roofing Calculator

Estimate sloped roof area from plan dimensions, roof pitch, overhang and waste.

Project inputs

Enter your project values, then press Calculate.

How this calculator works

Estimate sloped roof area from plan dimensions, roof pitch, overhang and waste.

sloped area = plan area × √(1 + (rise/run)²)

How to use the Roofing Calculator

1. Enter project inputs

  • Building length (m)
  • Building width (m)
  • Overhang each side (m)
  • Pitch rise
  • Pitch run
  • Waste allowance (%)

2. Review the results

  • Roof plan area
  • Sloped roof area
  • Order area
  • Roof angle

3. Check the calculation

The calculator uses the following core relationship:

sloped area = plan area × √(1 + (rise/run)²)

Estimating note: Actual material quantities can vary with site conditions, detailing, product dimensions, installation method, and waste.

Roofing Calculator FAQ

What does the Roofing Calculator calculate?

Estimate sloped roof area from plan dimensions, roof pitch, overhang and waste.

What information do I need to use the Roofing Calculator?

The calculator uses inputs such as Building length (m), Building width (m), Overhang each side (m), Pitch rise, and Pitch run. Use values from your drawings, measurements, product data, or project specifications.

How should I use the results from the Roofing Calculator?

Use outputs such as Roof plan area, Sloped roof area, Order area, and Roof angle for estimating and cross-checking. Before purchasing or construction, confirm the dimensions, units, waste factors, supplier packaging, and project specifications.