Accurate material quantities for every roofing project. From concrete and clay tiles to natural slates, breathable felt, flat roof joists, guttering, and lead flashing - calculate what you need before you order and keep your project on budget.
The roof is one of the most expensive elements of any building project, and getting the quantities wrong is a costly mistake. Over-ordering tiles adds unnecessary transport and waste costs, while running short can delay a job significantly if materials are out of stock or from a different batch.
Our roofing calculators are built around real UK roofing practice. They account for roof pitch, headlap and side lap requirements, ridge and valley tile quantities, batten spacing, and typical waste factors - so your material lists are accurate before work begins.
Whether you are a roofer pricing a new build, a builder replacing a tired old roof, or a homeowner planning a reroof, these tools help you order with confidence.
Select a calculator below to get instant material quantities for your roofing project.
Calculate the number of concrete or clay roof tiles required for any pitched roof. Enter the roof dimensions and pitch, select your tile type and gauge, and the calculator returns total tiles needed plus ridge, hip, and valley tile quantities. Includes waste allowance and optional batten length estimates.
Use CalculatorCalculate rafter length, roof pitch angle in degrees, ridge height, and true roof area from your span and rise dimensions. Enter the building width and desired pitch, and get all the measurements you need for ordering timber and calculating roof areas. Useful for planning both traditional cut roofs and trussed rafter systems.
Use CalculatorEstimate natural Welsh or Spanish slate quantities, or fibre cement slate counts, for pitched roofs. Specify slate size, headlap, and roof dimensions to get the total number of slates, tonnes of natural slate, or packs of fibre cement product needed. Also calculates nails, rivets, and batten lengths.
Use CalculatorCalculate the area of roofing felt or breathable membrane needed for pitched roofs, including the required side lap and end lap overlaps. Select your membrane roll width, enter the roof area, and get the total roll length and number of rolls required. Supports both traditional roofing felt and modern vapour-permeable underlays.
Use CalculatorCalculate joist quantities, noggins, wall plates and optional firring pieces for flat roof construction. Enter the joist span, roof length, joist size, grade, and centres to get a complete timber schedule. Covers cold and warm roof construction with BS 6229 minimum fall guidance and Approved Document A span checks.
Use CalculatorEstimate gutter lengths, downpipes, and fittings for roof drainage. Enter the total eaves length, number of corners, outlets, and downpipe runs. Returns gutter lengths per side, the number of sections, brackets, unions, stop ends, outlets, downpipe lengths, and clips. Covers standard half-round, ogee, and square guttering profiles.
Use CalculatorCalculate lead or aluminium flashing quantities for valleys, abutments, chimney stacks, and other roof penetrations. Enter flashing type, dimensions, and the number of locations to get total lead weight in kg, roll lengths, and optional code 4 or code 5 lead sheet areas. Covers stepped, cover, and soaker flashing configurations.
Use CalculatorBefore you build, make sure your project has the right consents in place.
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