Architect Tools

Roofing · Calculator

Roof Pitch Calculator

Convert roof rise and run into pitch ratio, angle and slope percentage.

Project inputs

Enter your project values, then press Calculate.

How this calculator works

Convert roof rise and run into pitch ratio, angle and slope percentage.

angle = atan(rise ÷ run); slope% = rise ÷ run × 100

How to use the Roof Pitch Calculator

1. Enter project inputs

  • Rise (mm)
  • Run (mm)

2. Review the results

  • Pitch (rise:run)
  • Roof angle
  • Slope
  • Slope factor

3. Check the calculation

The calculator uses the following core relationship:

angle = atan(rise ÷ run); slope% = rise ÷ run × 100

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

Roof Pitch Calculator FAQ

What does the Roof Pitch Calculator calculate?

Convert roof rise and run into pitch ratio, angle and slope percentage.

What information do I need to use the Roof Pitch Calculator?

The calculator uses inputs such as Rise (mm), and Run (mm). Use values from your drawings, measurements, product data, or project specifications.

How should I use the results from the Roof Pitch Calculator?

Use outputs such as Pitch (rise:run), Roof angle, Slope, and Slope factor for estimating and cross-checking. Before purchasing or construction, confirm the dimensions, units, waste factors, supplier packaging, and project specifications.