MetandumFREE TOOLS. NO SUBSCRIPTION.Find a calculator ⌕My projects
MEASURE ONCE. PLAN YOUR PURCHASE.

Roof Covering Units calculator.

Count effective roof-covering rectangles per plane and separately specified ridge-cap units.

ROOFING

Your inputs

Use measurements from your plan and properties from your chosen product. Any prefilled values are illustrative.

Where to get this value

Measure this dimension in your plan or on site and use the displayed unit. For irregular shapes, divide the geometry into the supported sections.

Where to get this value

Measure this dimension in your plan or on site and use the displayed unit. For irregular shapes, divide the geometry into the supported sections.

Shortcuts only; choose your own allowance above.
Where to get this value

Enter your own allowance. Presets are input shortcuts, not a construction recommendation.

Roof plane 1
Where to get this value

Measure this dimension in your plan or on site and use the displayed unit. For irregular shapes, divide the geometry into the supported sections.

Where to get this value

Measure this dimension in your plan or on site and use the displayed unit. For irregular shapes, divide the geometry into the supported sections.

Quantity and planning estimate
YOUR ESTIMATE
∑

A clear estimate starts here.

Enter your dimensions and product details to see the quantity and purchase breakdown.

CONTINUE YOUR PLAN

Find the next material.

Keep the quantity, then use another tool for the remaining parts of your purchase.

Explore all calculators
Formula and assumptions
BEHIND THE NUMBERS

How this calculation works.

Effective dimensions must already include your product’s specified overlaps. The tool rounds each plane’s rows and columns before adding allowance. Caps form a separate purchase line.

Cover units = Σceil(plane width / cover width) × ceil(slope length / cover length)Calculated with normalised units

A worked example

Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.

Effective installed unit width
1,000 mm
Effective installed unit length
2 m
Specified cap run length
6 m
Effective cap length per unit
1.5 m
Waste allowance
10 %
Roof plane 1
Slope length
5 m
Plane width
6 m

Roof covering units to purchase: 20 units

Fastener design, underlay requirements, wind resistance and roof suitability are not determined here.

Before you purchase

Use dimensions from your plan and properties from your chosen product. Any design spacing, section or fixing pattern must already be specified.

Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-04. Calculation and review policy.

Check your purchase assumptions

Keep a hip roof’s plan dimensions separate from sloped plane dimensionsKeep nominal roofing dimensions separate from effective coverage

Keep the project moving.

Explore roofing
RoofingRoof Plane Area Calculator

Sum the geometric area of specified roof planes from horizontal run, rise and ridge length.

Connected work guides and comparisons

Explore roof planes and finishing quantities

Browse all work types

Prepare your material measurements and product data

Roof covering units

Find material sheets for this calculator

Compare supplied alternatives and quantity changes

Browse all quantity scenarios