ORM Calculator

Open Roof Measurement Calculator

Calculate roof area, pitch, and material requirements quickly.

How to Use the Open Roof Measurement (ORM) Calculator

The ORM Calculator is designed to help contractors, architects, DIY homeowners, and builders quickly estimate roof area, slope, and material requirements. Follow these simple steps to get accurate results.

Step 1: Select Roof Type

  • Choose the type of roof from the dropdown menu:
    • Flat Roof – simple horizontal roof.
    • Gable Roof – two sloping sides forming a ridge.
    • Hip Roof – all sides slope downwards to the walls.

Tip: Selecting the correct roof type ensures the area and pitch calculations are accurate.

Step 2: Enter Roof Dimensions

  • Length (m): Enter the length of your roof.
  • Width (m): Enter the width of your roof.
  • Height (m) (optional): For sloped roofs (gable or hip), enter the height from the base to the ridge.

Note: For flat roofs, the height field can be left blank.

Step 3: Enter Material Coverage

  • Enter the number of tiles, sheets, or units per square meter in the coverage field.
  • Example: If one roofing tile covers 1 m², enter 1.
  • This helps the calculator estimate the total material required accurately.

Step 4: Calculate

  • Click the “Calculate” button.
  • The calculator will display:
    • Roof Area (m²) – total surface area of the roof.
    • Pitch/Slope – for gable and hip roofs, this is the ratio of height to half-width.
    • Material Required – total number of tiles, sheets, or units needed.

Step 5: Adjust and Recalculate

  • You can adjust length, width, height, or coverage and recalculate anytime.
  • This helps you quickly test different roof sizes or materials without starting over.

Tips for Accurate Results

  1. Measure carefully: Accurate roof measurements lead to precise area calculations.
  2. Include slope height: For sloped roofs, entering the height ensures correct pitch and area estimates.
  3. Use correct coverage: Make sure the coverage per unit matches the material you plan to use.
  4. Check units: Ensure all inputs are in meters for consistency.

Example Usage

  1. Select Gable Roof.
  2. Enter Length = 10 m, Width = 8 m, Height = 3 m.
  3. Set Coverage = 1 tile/m².
  4. Click Calculate.

Result:

  • Roof Area = 51.96 m²
  • Pitch = 0.75
  • Material Required = 52 tiles

Why Use the ORM Calculator

  • Save Time: Quickly calculate roof area without manual geometry.
  • Save Money: Purchase exactly the number of tiles or sheets needed.
  • Plan Accurately: Ensure your project estimates for materials and labor are precise.
  • Easy to Use: Works in any browser and can be embedded in WordPress pages or posts.