Home, DIY & Construction Calculators

Calculate ceiling area from length and width for paint, plasterboard, insulation or finish planning.

Estimate how much ceiling paint is needed from ceiling area, number of coats and the coverage stated on the tin.

Plan deck-stain quantity from decking surface area, number of coats and the product's coverage rate.

Estimate whole plasterboard or drywall sheets from surface area, sheet size and a cutting-waste allowance.

Plan exterior paint quantity from measured outside wall area, coat count, product coverage and a weathering/porosity allowance.

Calculate the square area of a feature wall from its measured width and height.

Calculate fence-paint quantity from the area of panels or boards, coat count and the paint's coverage rate.

Estimate masonry paint for brick, block, render or concrete using measured area, coats and the product's stated coverage.

Work out paint litres or gallons from surface area, coat count and the exact product coverage rate, with an optional extra allowance.

Estimate plaster quantity from measured area, product coverage and an extra allowance.

Work out primer or sealer quantity from surface area, planned coats and the exact product coverage figure.

Calculate paintable wall area and paint quantity from room dimensions, measured doors and windows, coat count and the paint's stated coverage.

Work out skirting or baseboard run and whole stock lengths from the measured perimeter, piece length and cutting allowance.

Calculate wall area in square metres or square feet from measured wall length and height.

Turn measured wall area into a wall-paint quantity using coat count, product coverage and an optional extra allowance.

Calculate wallpaper drops and whole rolls from total wall width, drop height, roll dimensions and pattern repeat.

Work out whole wallpaper rolls from wall width, wall height, roll size and pattern repeat, with each drop matched to the usable roll length.

Estimate wood-stain quantity for timber surfaces from measured area, coat count and the stain's stated coverage.

Calculate backsplash tiles around cabinets, edges and outlets from surface area, tile size, box quantity and a cutting-waste allowance.

Calculate bathroom tiles across measured floor and wall zones from surface area, tile size, box quantity and a cutting-waste allowance.

Estimate carpet area and indicative roll length from room dimensions, fixed carpet roll width and a cutting allowance.

Calculate floor area from room length and width in metric or imperial units.

Calculate screed volume from floor area and average installed thickness, with allowance for real floor variation before converting to product quantity.

Calculate floor-tile count and box quantity from floor area, tile size and a cutting allowance suited to the floor layout.

Estimate flooring packs from room dimensions, pack coverage and a waste allowance suited to the laying pattern.

Estimate hardwood flooring packs or cartons from room area, pack coverage and a pattern-appropriate waste allowance.

Calculate herringbone tile quantity with additional cutting waste from surface area, tile size, box quantity and a cutting-waste allowance.

Calculate laminate flooring packs from room area, pack coverage and cutting waste.

Calculate self-levelling compound volume from length, width and average installed thickness, with an optional extra allowance.

Estimate thinset mortar quantity from tile area and product coverage, with trowel notch and tile format taken into account.

Estimate tile adhesive quantity from tiled area and product coverage, with trowel size and back-buttering considered separately.

Calculate general tile quantity and optional box count from surface area, tile size, box quantity and a cutting-waste allowance.

Estimate tile grout quantity from tiled area and product coverage, with joint geometry checked against the manufacturer's table.

Estimate underlay packs or rolls from room dimensions, coverage per pack and an allowance for joins and trimming.

Calculate vinyl plank packs from room dimensions, pack coverage and layout waste.

Work out wall-tile quantity from the tiled wall area, tile dimensions, openings and a waste allowance for cuts around edges and fittings.

Estimate concrete or masonry block count from wall area, block face size, joint thickness and waste.

Estimate block-laying mortar quantity from wall area, product coverage and an extra allowance.

Estimate whole brick count from net wall area, installed brick-and-joint module and a breakage allowance.

Calculate bricks for a specific wall from net area, brick size, mortar joint and cutting/breakage allowance.

Calculate the cement share of a target mix volume from the specified ratio parts.

Convert required concrete volume into whole premix bags using the finished-volume yield printed for the exact bag.

Calculate block core-fill volume from block count, the manufacturer's fill volume per block and a placement allowance.

Calculate concrete volume for rectangular pours from length, width, depth and a practical ordering allowance.

Calculate concrete volume for round columns from diameter, height, quantity and an extra allowance.

Calculate concrete volume for strip or rectangular footings from measured length, width, depth and allowance.

Split a target mixed volume into component quantities for a specified concrete ratio.

Calculate concrete volume for a rectangular slab from slab length, width, thickness and an extra allowance.

Calculate solid-step concrete volume from step width, tread depth, riser height, number of steps and an extra allowance.

Estimate concrete mass from known concrete volume and density.

Calculate flowable grout volume for a defined void, baseplate gap or cavity from its dimensions and an appropriate placement allowance.

Split a target mortar volume into component quantities using the specified mix ratio.

Estimate compacted base-course volume beneath paving from the paved area, planned sub-base depth and an allowance for site variation.

Estimate whole pavers from project area, paver size and a cutting/breakage allowance.

Estimate polymeric jointing sand from paved area and product coverage, then check joint width and depth against the bag coverage table.

Estimate concrete volume for cylindrical post holes from hole diameter, depth, quantity and allowance.

Estimate rebar grid count and total bar length from slab dimensions, specified bar spacing and lap/waste allowance.

Calculate theoretical rebar mass from bar diameter, length per bar, quantity and steel density.

Estimate whole reinforcing-mesh sheets from slab size, sheet dimensions and the required overlap.

Calculate cylindrical volume for round columns or piers from diameter, height/depth and quantity.

Calculate sand and cement quantities for a chosen mix ratio and total mixed volume.

Estimate bark mulch volume for landscaping from length, width, layer depth, bulk density and an extra allowance.

Estimate compost volume for beds and planters from length, width, layer depth, bulk density and an extra allowance.

Estimate crushed-stone volume and tonnage from length, width, layer depth, bulk density and an extra allowance.

Calculate soil or amendment volume for a rectangular flower bed from length, width and fill depth.

Calculate French-drain trench volume and aggregate fill from trench length, width, depth, pipe diameter and allowance.

Calculate grass-seed quantity from lawn area, the manufacturer's sowing rate and an extra allowance.

Estimate loose gravel volume and approximate weight for a measured area at a chosen finished depth, using the bulk density of the actual aggregate.

Estimate driveway aggregate volume and tonnage from length, width, layer depth, bulk density and an extra allowance.

Estimate landscape-rock volume and estimated tonnage from length, width, layer depth, bulk density and an extra allowance.

Calculate lawn area from measured length and width before planning turf, seed, feed or treatments.

Estimate lawn mowing time from lawn area and a realistic coverage or work rate per hour.

Estimate mulch volume for beds and borders from length, width, layer depth, bulk density and an extra allowance.

Estimate patio sub-base aggregate volume and weight from length, width, layer depth, bulk density and an extra allowance.

Estimate patio slab count from patio area, slab dimensions and a cutting/breakage allowance.

Work out rounded pea-gravel quantity for paths, play areas or decorative beds from coverage area, layer depth and pea-gravel density.

Calculate plant count and spacing along a measured run from the usable run and desired centre-to-centre spacing.

Estimate rectangular pond water volume from length, width and average depth.

Estimate pool water volume from length, width and average depth.

Work out the soil volume needed to fill raised beds, with an optional settling allowance and density-based weight estimate for delivery planning.

Estimate retaining-wall facing units from visible wall area, installed block module and waste; structural design is separate.

Calculate decorative river-rock volume and approximate mass from bed dimensions, stone depth and the density of the selected rock.

Estimate bulk sand volume and weight from length, width, layer depth, bulk density and an extra allowance.

Estimate general planting-soil volume and mass for borders, infill or landscaping from area, fill depth and bulk density.

Calculate topsoil volume and approximate tonnes for lawn preparation, grading or planting areas at a specified soil depth.

Calculate whole turf or sod rolls from measured lawn area, coverage per roll or slab and a trimming allowance.

Calculate the minimum baluster count and equal clear gap from opening length, baluster width and maximum allowed gap.

Calculate batten count, balanced clear spacing and total batten length from wall width/height, batten width and target gap.

Calculate board feet from timber thickness, width, length and quantity.

Calculate deck-board rows and total linear board requirement from deck dimensions, board width, gap and waste.

Estimate deck joist count and total joist length from frame run, joist centres and member length.

Estimate a simple deck support-post grid from deck length, deck width and planned maximum post spacing in both directions.

Estimate deck-board rows and total board length from deck size, installed board width, gaps and cutting waste.

Estimate decking fastener count from board rows, joist lines, fixings per board-to-joist intersection and a waste allowance.

Estimate fence panels or bays and basic post count from total run, standard bay width and gate openings.

Calculate whole fence panels or bays for a measured boundary, allowing for gate openings.

Estimate basic fence post count from fence run, panel/bay width and gate openings.

Estimate fence-post embedment depth and total post length from above-ground height, embedment ratio and optional minimum depth.

Estimate fence-stain quantity from timber fence area, coat count and the chosen stain's coverage rate.

Estimate whole plywood sheets from project area, sheet dimensions and cutting waste.

Calculate common rafter length from horizontal run, roof pitch and overhang; structural sizing remains separate.

Calculate spindle count and equal clear spacing from opening length, spindle width and maximum permitted gap.

Estimate regular stud count and total framing length from wall run, stud centres and member length.

Calculate timber volume or board feet from stock thickness, width, length and quantity.

Estimate brick slips or thin-brick units from net facade area, installed face module, joint width and waste.

Estimate preliminary cavity-wall insulation coverage from wall area and product coverage; final suitability and fill quantity depend on the cavity system.

Estimate roof-drainage flow demand and whole downspout count from catchment, rainfall and rated downspout capacity.

Estimate roof-runoff flow demand from catchment area and local design rainfall for preliminary gutter sizing.

Estimate insulation packs or rolls for a measured surface using the exact pack coverage, target area and a practical cutting allowance.

Estimate loft or attic insulation packs from floor area, product coverage and the planned layer thickness or build-up.

Estimate metal roofing panel coverage from horizontal footprint area, pitch, waste and effective product coverage.

Estimate true sloping roof area from horizontal footprint area, pitch, waste and effective product coverage.

Calculate roof pitch from rise and horizontal run, returning angle, percentage and rise-to-run ratio.

Estimate roof sheathing sheets from measured roof area, sheet size and cutting waste.

Estimate roof shingle or bundle coverage from horizontal footprint area, pitch, waste and effective product coverage.

Estimate roof tile coverage and quantity from horizontal footprint area, pitch, waste and effective product coverage.

Estimate roof underlayment roll coverage from horizontal footprint area, pitch, waste and effective product coverage.

Estimate general sloping roof area and material coverage from horizontal footprint area, pitch, waste and effective product coverage.

Calculate sealant volume and whole cartridge count from joint length, width, depth and cartridge volume.

Estimate siding or cladding panels/cartons from net wall area, effective installed coverage and cutting waste.

Estimate vinyl siding cartons or panels from net wall area, installed coverage per unit and cutting waste.

Calculate insulation quantity for wall areas after allowing for openings, pack coverage and installation waste.

Estimate room cooling load and express it in BTU/h, kW and refrigeration tons.

Calculate air changes per hour from room volume and measured or specified delivered airflow.

Estimate room air-conditioning capacity in BTU/h and kW from room size, insulation, glazing and climate.

Estimate an early whole-home boiler output from heated volume, insulation, design temperature difference and hot-water allowance.

Estimate an indicative room heating or cooling load in BTU/h and kW from dimensions, insulation, glazing and climate.

Calculate required airflow in CFM and m³/h from room volume and target air changes per hour.

Estimate a dehumidifier extraction-capacity range from room area, ceiling height and damp severity.

Estimate electric-heater output for a room from size, insulation, glazing and climate conditions.

Estimate room heat loss in watts and BTU/h from floor area, ceiling height, insulation and design temperature difference.

Estimate the radiator heat-output target for a room from its size, insulation, windows and climate adjustment.

Estimate a single-room BTU/h and kW requirement from room size, insulation, glazing and climate conditions.

Calculate room volume from length, width and height for HVAC, ventilation or capacity planning.

Estimate underfloor-heating output from usable heated floor area and the selected design watts per square metre.

Calculate ventilation airflow in CFM or m³/h from room volume and a target air-change rate.

Calculate rectangular surface area from length and width from measured length and width.

Convert a known volume into cubic feet from metric or other imperial volume units using a true cubic conversion.

Convert a known volume into cubic metres for material, capacity or delivery calculations while preserving true cubic-unit conversion.

Convert material or excavation volume into cubic yards for bulk ordering, haulage and landscaping estimates.

Convert cubic yards to estimated tons using the actual bulk density of the material.

Calculate grade percentage from vertical elevation change and horizontal distance.

Convert a measured length into linear feet from metres, centimetres or other supported units for take-offs and stock planning.

Convert a length into linear metres from feet, inches or other supported length units while retaining calculation precision.

Add a chosen waste percentage to a measured base quantity and return the adjusted amount to purchase.

Calculate slope percentage, ratio and angle from vertical rise and horizontal run.

Convert an area from common metric or imperial units into square feet without confusing linear and squared conversion factors.

Convert floor, wall or land area into square metres from common imperial or metric area units.

Explore stair riser count, actual riser height and total run from floor-to-floor rise, target riser and tread depth.

Calculate rectangular volume from length, width and depth/height in metric or imperial units.