Free trade tool

Roof & Tile Calculator

Work out the roof tiles, slates and accessories you'll need for your project. Enter your dimensions and we'll do the maths.

1 Choose your covering

Tile

Slate

Tile type

Profiled

Plain

Which covering should I choose?

Concrete & clay roof tiles come in a range of colours and finishes, in textured or traditional styles.
Slates are available in their natural form or constructed from fibre-cement.

Things to consider

Location: coastal or windy sites benefit from steeper pitches and tighter laps, making slates a reliable choice.
Weight & structure: concrete tiles are heavier; natural slate is lighter but needs a precise batten gauge.
Maintenance: plain tiles and slates are easier to replace individually. Profiled tiles shed water better on lower pitches.
Fixings: roof pitch determines fixing placement. Always follow the manufacturer's batten and head lap guidance and nail or screw specifications.

Tile types explained

Profiled tiles are contoured with a typical coverage of 15-18 tiles/m². They suit 25-90° pitches, making them ideal for lower-pitched roofs.
Plain tiles are flat and overlap slightly, with a typical coverage of 60-66 tiles/m². They're usually installed at 35-90° and best suit steeper roofs.
Coverage tip: the actual count varies with batten gauge and head lap. Always check the manufacturer's data sheet for your chosen product.

Slates explained

Coverage typically ranges from 11-21 slates/m² depending on slate size, with larger slates needing fewer per m².
Pitch: most slates are designed for steep pitches over 35°, with natural slate able to handle the steepest roofs.
Common sizes: 500x250mm, 500x300mm, 600x300mm. Larger sizes give faster coverage and a more traditional look.
Fixings: usually nailed twice. Coastal or exposed sites may need additional clips. Follow manufacturer guidance for head lap and side joint.

2 Enter your dimensions

All measurements in metres. Optional fields can be left blank if not applicable.

Roof Area Required

The total surface area where tiles or slates will be laid.

Area (m²)

Roof Pitch Required

Used to filter the products suitable for your roof's slope.

Pitch range

Ridge Length Optional

Total length of the peak where opposing roof areas meet.

Length (m)

Verge Length Optional

Length from ridge to gutter at gable ends.

Length (m)

Please note: hip and valley tiles are not currently part of our stocked range.

3 Your estimate

Enter your dimensions above to see your material estimate.

Important - please read before ordering

This is a guide only. The figures shown are based on the following assumptions:

Profiled tiles: coverage of ~15.7 tiles/m² at a minimum head lap of 75mm.
Plain tiles: coverage of ~60 tiles/m² at a minimum head lap of 65mm, with a typical batten gauge of ~100mm.
Slates: coverage varies by size; we use a minimum head lap of 75mm and a side joint of 5mm.
Waste allowance: 10% added to the tile / slate total to cover cutting and breakages.
Ridge tiles: calculated at 0.45m per tile (manufacturer dependent).
Verge tiles: calculated at 0.267m per unit (plain tile only).

Always confirm batten spacing, head lap, and fixing requirements with the manufacturer's guidance for your chosen product. Site exposure, pitch, and local building regulations may affect what you need on the day. For a precise quotation, please contact our trade team.

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