Reviewed, sourced guidance

Roofing calculator: area, tiles and battens

Published 24 Sept 2026Reviewed 25 Sept 20262 min read

Direct answer

This calculator supports two measurement modes and an optional material step. Enter a whole rectangular footprint with one uniform pitch, or enter each of up to four planes with its eaves length, horizontal run and pitch. Optionally add an exact product rate or a supported Marley preset to turn the area into field quantities.

Choose whole-footprint mode for one rectangular roof at a uniform pitch, or enter up to four measured planes, each with its eaves length, horizontal run and pitch. Add exact product rates or a supported Marley preset in plane mode; the manual formula and worked example are on the roof area guide.

Roof area and covering estimate

Use a uniform-pitch footprint estimate for a simple roof or enter each plane separately. Product rates must come from the exact manufacturer's data for your pitch and exposure.

Measurement method

Measure each plane Whole footprint, one pitch

Whole rectangular roof footprint

This quick method assumes one uniform pitch across the whole roof. Measure the plan outline to the outer roof covering edges, including eaves and verge overhangs. Use plane measurements for dormers, valleys, roof openings, mixed pitches or irregular outlines.

Plan length (m)Plan width (m)Uniform pitch (degrees)

Area = plan length × plan width ÷ cos(pitch). The selected Marley checks need individual plane lengths, so its preset is unavailable in this mode.

Add product-specific material quantities (optional)

Product dataProduct data presetOnly the four sourced Marley configurations are included. A preset applies its published tile and batten rates and checks each entered pitch against its listed minimum. Use plane measurements for this check; the preset is unavailable in whole-footprint mode.

Marley Duo Modern product data (observed 2026-09-25). The preset is not a product recommendation or a roof specification.

Tiles per m²Use the figure for the selected product, headlap, pitch and exposure.Waste allowance (%)Leave blank to see the net tile count only; choose an allowance for your roof and cuts.Tiles per packOptional. Requires tile coverage above.Battens (linear m per m²)Use the exact system's stated batten rate; the output excludes detailing and extra cuts.Usable membrane coverage per roll (m²)Enter the manufacturer's coverage after laps and overlaps.Combined hip length for Marley Universal HipFast (m)Enter the measured total for the hips you want to check. This estimates boxes by the included 6 m hip roll only.

Marley Universal HipFast box contents (observed 2026-09-25). Confirm compatibility, junctions, cuts, waste and final kit quantity with Marley or your installer.

Combined ridge length for Marley Universal RidgeFast (m)Enter the measured total for the ridges you want to check. The result counts boxes from the included 6 m roll only.

Marley Universal RidgeFast box contents (observed 2026-09-25). Check ridge-tile profile and pitch limits; this is not a compatibility check or full kit quantity.

Plane mode calculates each slope separately; footprint mode uses one rectangular plan outline and uniform pitch.

Method and limits

Model version: 2026-09-25-v9

Plane mode sums each plane's eaves length × horizontal run ÷ cos(pitch). Whole-footprint mode uses plan length × plan width ÷ cos(uniform pitch) and only applies to a rectangular roof with one pitch.
Plane mode accepts one to four planes. Footprint mode assumes a rectangular outline and one uniform pitch; neither detects overlaps, dormers, valleys or roof openings.
Custom tile and batten quantities use the exact rates you enter. The optional Marley preset applies only to its four listed finish/headlap configurations and requires plane mode for its length checks.
A preset flags pitches below the manufacturer's listed minimum. A quantity calculation is not a roof design or compatibility approval.
Marley says special circumstances can affect minimum pitch and recommends technical advice for slopes over 6 m or severe exposure.
Pack output includes the number of tiles in whole packs and the surplus over the entered order quantity.
Membrane rolls use the usable coverage per roll that you enter after overlaps.
The optional HipFast result divides combined measured hip length by the published 6 m roll per box and rounds up. It is a length-only minimum, not a sufficient kit order or a compatibility check; junctions, cuts, waste and product details can change the quantity.
The optional RidgeFast result separately divides measured ridge length by the published 6 m roll per box and rounds up. It is a roll-length minimum, not a full accessory schedule; check tile profile, pitch limits, junctions, cuts and waste with Marley.
Other fittings, fixings, structural checks and a fixing specification are excluded.

Key takeaways

Whole-footprint mode assumes a rectangular roof with one uniform pitch.
Use separate planes for mixed pitches or irregular roof sections.
Field quantities use a selected Marley tile preset or rates you enter from exact product data.
The result is a planning estimate, not a specification or a quote.

Evidence note

Source-led homeowner information with its scope, limits and commercial status recorded.

View the full evidence note

Produced by: My Roofing Calculator
Jurisdiction: UK-focused measurement information; permissions and building-control requirements are not assessed.
Page scope: A uniform-pitch rectangular roof footprint or one to four measured planes, plus optional product-specific material rates.
Default subject: Pitched roof area, product-based quantity estimates, roof pitch and comparable quote scope.
Excludes: Roof inspection, survey or access planning; Structural, engineering or installation advice; Product selection or manufacturer endorsement; Contractor recommendation, ranking, referral or lead collection; Roofing work, quotations or guaranteed material quantities
Published: 2026-09-24
Reviewed: 2026-09-25
Commercial status: Information preview only. No roofing contractor is active, no lead capture runs, no enquiries are collected and no affiliate links are present.

Footprint mode assumes a rectangular outline and one pitch. The tool does not detect overlaps, openings or roof shape, specify complete accessory quantities, select compatible products or assess structural capacity.

How this guidance is produced · Correction submission status

Choose a mode and enter measurements

Whole-footprint mode asks for one plan length, one plan width and a single pitch. Plan dimensions go to the outer roof covering edges, including overhangs once.

Plane mode asks for an eaves length, a horizontal run and a pitch for each plane, up to four. Use it for mixed pitches or a roof you can divide into measurable sections; the manual method is on the roof area guide.

Footprint mode does not infer roof shape or set a waste allowance.
Do not enter the full building span as the run for each side of a symmetrical gable in plane mode.
Keep units in metres and use the same measurement basis for every plane.
Leave unused plane inputs blank when the roof has fewer than four.

Sources for this section: Cushty, Roof Area Calculator UK (observed 2026-09-25)

Add product rates only when known

Tile coverage depends on the selected product and laying details. Battens and membrane also depend on the system specification.

Four source-linked presets cover the listed Marley Duo Modern finish and headlap combinations only. For other products, copy each rate from the exact current product data.

Tiles per square metre can change with headlap and product.
Batten length uses the stated linear metres per square metre.
Membrane roll count uses usable coverage after overlaps.

Sources for this section: Marley, Duo Modern product data (observed 2026-09-25)Russell Roof Tiles, Tile Estimator (observed 2026-09-25)

Read the estimate as a starting point

Tile counts include field tiles only. RidgeFast and HipFast results are separate length-only box minimums from their published 6 m rolls; neither counts the full compatible accessory schedule, junctions, cuts or waste.

The tool does not assess structure, exposure, installation details, system compatibility or the roof condition. Confirm tile profile, pitch limits and final quantities with the manufacturer and installer.

Use the waste field only for a quantity allowance you have decided to apply.
Pack count rounds up to whole packs when both coverage and pack size are entered.
Keep the specification and its version with the estimate.

Sources for this section: Marley, Duo Modern product data (observed 2026-09-25)Marley, Universal HipFast system and box contents (observed 2026-09-25)Marley, Universal RidgeFast system and box contents (observed 2026-09-25)Health and Safety Executive, Roof work (page updated 2026-06-05; observed 2026-09-25)

Next steps

Check the footprint assumptions or each plane pitch and run.
Confirm exact coverage and fittings before ordering.

Sources

Use the measuring checklist