All Construction & DIY Calculators
Browse our complete collection of 143 free calculators for construction, renovation, and DIY projects. Every tool supports both Imperial and Metric units with adjustable waste factors.
Browse by Category
Project Estimators(6)
Build a Shed Estimator
Full material list for a timber shed — floor, framing, cladding, roof sheathing, felt and fixings — from the shed size and roof style.
Build a Patio Estimator
Work out the slabs or pavers, sub-base, sand and cement needed to lay a patio of any size.
Build a Treehouse Estimator
Estimate the platform timber, decking boards, railings, roof and fixings for a raised treehouse or play platform.
Build a Driveway Estimator
Full driveway material list — sub-base, sand and surface (gravel, block paving, concrete or tarmac) for your driveway size.
Build a Deck Estimator
Complete decking material list — joists, deck boards, posts, fixings and concrete — from the deck dimensions.
Build a Retaining Wall Estimator
Estimate blocks or sleepers, backfill gravel, drainage pipe and concrete footing for a retaining wall.
Flooring & Tiling(5)
Tile Calculator
Calculate how many tiles, adhesive, and grout you need for floors or walls.
Flooring Calculator
This flooring calculator works out how much laminate, engineered or hardwood flooring you need for any room. Enter the room size and waste allowance to get the floor area, the number of packs and underlay, plus an optional latex screed estimate.
Carpet Calculator
This carpet calculator works out how much carpet, underlay and gripper rod you need for any room. Enter the room length and width, add a waste allowance and get the carpet area plus underlay and gripper quantities in a moment.
Flooring Cost Calculator
Estimate the cost of new flooring from the room area, price per pack or unit area, underlay and waste allowance.
Tile Cost Calculator
Estimate the cost of tiling a floor or wall from the area, tile size, price per tile or box, plus adhesive and grout.
Walls & Interior(8)
Countertop Calculator
Calculate the area and cost estimate for kitchen or bathroom countertops.
Paint Calculator
Calculate how much paint you need for walls, ceilings and trim based on room dimensions.
Drywall Calculator
Work out drywall sheets plus jointing tape, compound and screws for walls and ceilings.
Plaster Calculator
Estimate how much plaster you need for walls and ceilings, the number of bags and the total cost in metric or imperial units.
Insulation Calculator
Calculate the amount of insulation rolls, batts, or boards needed for walls, floors and lofts.
Wallpaper Calculator
Calculate the number of wallpaper rolls needed for any room, accounting for pattern repeat.
Crown Molding / Coving Calculator
Calculate crown molding or coving length, number of pieces, inside and outside corners for any room.
Baseboard / Skirting Board Calculator
Calculate baseboard or skirting board length needed for any room, accounting for doorways and corners.
Concrete & Masonry(20)
Concrete Calculator
Calculate how much concrete you need for slabs, footings, columns and walls in cubic yards or metres.
Brick Calculator
This brick calculator works out how many bricks and how much mortar you need for any wall. Enter the wall size, deduct openings and choose your brick size to get an instant brick and mortar estimate using standard UK brick dimensions.
Mortar Calculator
Estimate mortar volume and cement, lime, sand quantities for bricklaying and blockwork.
Concrete Block / CMU Calculator
Calculate the number of concrete blocks or CMUs needed for a wall plus mortar requirements.
Rebar Calculator
Calculate the number of rebar pieces, total length, and weight for slabs, footings, and walls.
Paver Calculator
Calculate how many pavers and how much sand and gravel you need for patios, walkways and driveways.
Paving Slab Calculator
Calculate how many patio paving slabs you need, plus sub-base and bedding, for standard UK slab sizes.
Foundation Calculator
Calculate concrete, rebar, and formwork needed for strip, pad, or raft foundations.
Grout Calculator
Calculate the amount of grout needed for tiling based on tile size, spacing, and area.
Post Hole Calculator
Calculate concrete and gravel needed for setting fence or deck posts in the ground.
Cement Calculator
Calculate the number of cement bags, sand and aggregate needed for a concrete or mortar mix by ratio.
Screed Calculator
Calculate floor screed volume plus sand and cement quantities for any floor area and thickness.
Concrete Footing Calculator
Calculate the concrete volume and number of bags needed for strip, pad and pier footings.
Concrete Mix Calculator
Work out the cement, sand and aggregate (ballast) quantities for a concrete mix by volume and ratio.
Concrete Cost Calculator
Estimate the total cost of concrete for a slab, footing or footpath from the volume and your price per cubic yard or metre.
Reinforcing Mesh Calculator
Work out how many sheets of steel reinforcing mesh (A142, A193, A252, A393) you need for a slab, allowing for overlaps.
Block Fill Calculator
Estimate the concrete or grout needed to fill the cores of concrete blocks (CMU) for a wall, in bags or cubic metres.
Concrete Steps Calculator
Calculate the volume of concrete and number of bags needed to pour a flight of concrete steps from the rise, run and width.
Concrete Weight Calculator
Estimate the weight of a concrete slab, footing or volume from its dimensions, using standard concrete density.
Shed Base Calculator
Work out the concrete, paving slabs or gravel and sub-base for a shed base, sized to fit your shed.
Roofing & Structural(23)
Roofing Calculator
Calculate roofing materials including shingles, underlayment, and ridge caps for your roof.
Roof Pitch Calculator
Find the pitch, angle, and slope of your roof from rise and run measurements.
Rafter Calculator
Calculate rafter length, birdsmouth cut, ridge height and tail length for common rafters.
Staircase / Stair Calculator
Calculate rise, run, number of steps, stringer length, and headroom for any staircase.
Lumber / Timber Calculator
Calculate board feet, linear feet, and total lumber or timber needed for framing and woodworking projects.
Deck Calculator
Calculate decking boards, joists, posts, and hardware for building a deck.
Stud Spacing Calculator
This stud spacing calculator (also a handy stud calculator and wall framing calculator) works out how many studs, top and bottom plates and framing timber you need at 400 or 600 mm centres for any partition or load-bearing wall.
Joist Calculator
Calculate the number of joists, hangers, and blocking needed for floors and ceilings.
Beam / Load Calculator
A beam span and load calculator that works out the maximum span, beam size and load-bearing capacity for structural beams.
Timber Fastener Spacing Calculator
This timber fastener spacing calculator works out how many nails, screws or bolts you need — and the correct spacing — for any timber connection. It doubles as a timber screw spacing calculator and a general timber connection calculator for decking, framing and structural joints.
Deck Board Calculator
Calculate how many deck boards you need based on deck size, board width and the gap between boards.
Deck Joist Spacing Calculator
Calculate the number of deck joists, spacing and total joist length for your decking frame.
Decking Screw Calculator – How Many Decking Screws Do I Need?
Work out how many decking screws you need and how far apart to space them, based on your deck size, board width and joist centres.
Plywood / OSB Sheet Calculator
Calculate how many sheets of plywood or OSB you need to cover a floor, wall or roof area, including a waste allowance.
Roof Sheathing Calculator
Calculate the number of plywood or OSB sheathing boards needed to deck a roof, allowing for pitch and waste.
Decking Cost Calculator
Estimate the cost of a deck from the deck area, board price and optional joist, post and fixings costs.
Roof Area Calculator
Calculate the true sloped surface area of a roof from its footprint and pitch, in square feet, square metres and roofing squares.
Joist Span Calculator
Find the maximum allowable span for floor and ceiling joists from the joist size, spacing and timber grade.
Stair Stringer Calculator
Calculate stair stringer length, the number of notches and the rise and run cut marks for laying out a stringer board.
Roof Truss Calculator
Work out the number of roof trusses and the truss height for a roof from its length, span, pitch and truss spacing.
Lumber Weight Calculator
Estimate the weight of timber and lumber from its dimensions and species, for softwood, hardwood and green timber.
Baluster Spacing Calculator
Work out evenly spaced balusters or spindles for a railing while keeping gaps within the 100mm (4in) safety limit.
Metal Roofing Calculator
Calculate how many metal roofing sheets or panels you need from the roof area and the panel coverage width.
Landscaping & Outdoor(25)
Gravel Calculator
Calculate the volume and weight of gravel needed for driveways, paths, and landscaping.
Mulch Calculator
Calculate the volume of mulch needed for garden beds, paths, and landscaping areas.
Topsoil Calculator
Calculate the volume of topsoil needed for raised beds, lawns, and garden projects.
Sand Calculator
Calculate the volume and weight of sand needed for levelling, filling, and construction.
Sod / Turf Calculator
Calculate how many rolls or pallets of sod/turf you need for your lawn.
Fence Calculator
Calculate posts, rails, pickets and concrete needed for building a fence.
Asphalt Calculator
Calculate the tonnage of asphalt needed for driveways, roads and parking areas.
Excavation Calculator
Calculate the volume of soil to excavate and the number of skip loads or truck loads needed.
Retaining Wall Calculator
Calculate blocks, backfill gravel, and drainage materials for a retaining wall.
Driveway Calculator
Calculate materials for a new driveway including sub-base, base, and surface course.
Fence Post Spacing Calculator
Calculate how many fence posts you need and the exact spacing between them for any fence run.
Fence Panel Calculator
Calculate how many fence panels, posts and gravel boards you need for your fence line.
MOT Type 1 Calculator
Calculate how much MOT Type 1 sub-base aggregate you need in tonnes and cubic metres.
Crushed Stone Calculator
Calculate the volume and weight of crushed stone needed for driveways, paths and drainage.
Aggregate Calculator
Calculate the tonnage and volume of any aggregate – gravel, sand, ballast, MOT or crushed stone.
Hardcore Calculator
Calculate how much hardcore fill you need in tonnes and cubic metres for foundations and sub-bases.
Xeriscape Calculator
Estimate the number of drought-tolerant plants, mulch volume and total cost for a water-saving xeriscape landscape.
Landscape Edging Calculator
Estimate the total edging length, number of pieces and cost for a garden border, path or flower bed in metric or imperial units.
Grass Seed Calculator
Work out how much grass seed you need for a new lawn or overseeding based on lawn area and sowing rate.
Fence Cost Calculator
Estimate the cost of a fence from its length, panel or picket price and post, rail and concrete costs.
Polymeric Sand Calculator
Estimate the number of bags of polymeric jointing sand needed to fill the joints of a paver or patio installation.
River Rock Calculator
Work out how much decorative river rock or stone you need by volume and weight for a given area and depth.
Artificial Grass Calculator
Work out how much artificial grass, weed membrane, sand infill and jointing tape you need for a garden.
Skip Size Calculator
Estimate your volume of waste and get the recommended UK skip size, from a mini skip to a maxi.
Herb Garden Calculator
Plan a herb bed or planter: how many of each herb fits your space, compost needed, plus which herbs to grow together or apart, and how to water and prune them.
Exterior(4)
Siding / Cladding Calculator
Estimate how many squares of siding or cladding, starter strips, and trim you need for your project.
Gutter Calculator
Calculate gutter length, downspouts, hangers, end caps, and connectors needed for your roof.
Guttering Length Calculator
Add up your gutter runs to work out the total guttering length, how many standard lengths to buy and the estimated cost.
Decking & Fence Stain Calculator
Calculate how many litres of decking or fence stain you need based on the area and number of coats.
Area & Volume(5)
Area Calculator
Calculate the area of rectangles, circles, triangles and trapezoids in square feet, square metres and more.
Square Footage Calculator
Work out the square footage (or square metres) of a room or area from length and width, across multiple rooms.
Volume Calculator
Calculate the volume of boxes, cylinders, cones and spheres in cubic feet, cubic metres, litres and gallons.
Cubic Yard Calculator
Calculate cubic yards (and cubic metres) of material needed from length, width and depth — ideal for concrete, soil and aggregate.
Cubic Yards to Tons Calculator
Convert a volume of material into weight in tons and tonnes using common material densities.
Water & Misc(3)
Pond Liner Calculator
Calculate the size of pond liner needed based on pond dimensions and depth.
Water Volume Calculator
This water volume calculator works out how much water a tank, pool, pond or container holds. Enter the shape and dimensions and it gives the capacity in litres, cubic metres and gallons in an instant.
Pool Volume Calculator
Calculate the water volume of a swimming pool in litres and gallons for rectangular, round and oval pools.
Electrical & Wiring(6)
Cable Size Calculator (UK)
This cable size calculator UK tool works out the minimum cable size you need from the voltage drop, current load, cable run length and installation method, following BS 7671 (IET Wiring Regulations 18th Edition). Supports Twin & Earth and SWA cables.
Voltage Drop Calculator
Calculate the voltage drop and percentage loss along a cable run from the conductor size, current and length, for both UK and US wiring.
Breaker Size Calculator
Work out the correct circuit breaker or fuse rating (MCB / breaker) for a load from its power, voltage and continuous-load factor.
Cable Length Calculator
Work out how many metres or feet of electrical cable you need for a job. Add multiple cable runs, pick the circuit type, and get a total length with waste allowance — so you buy the right reel size first time.
Conduit Fill Calculator
Check how many cables or conductors fit in a conduit and the percentage fill against the 40% maximum, for UK and US conduit sizes.
Solar Panel Calculator
Estimate your solar PV system size, annual and daily electricity generation, roof area needed and potential bill savings from your panel count and wattage.
Heating & HVAC(4)
Duct Size Calculator
Size round and rectangular ductwork from the required airflow and target air velocity for heating, cooling and ventilation systems.
Heat Loss Calculator
Estimate the heat loss and radiator or boiler size needed for a room from its dimensions, insulation level and target temperature.
Radiator BTU Calculator
The quick “what size radiator do I need” tool – get the BTU and kW output to warm any room.
Room BTU Requirement Calculator
Work out the BTU/hr needed to heat a room from its size, type, insulation and external walls, with an optional radiator cost estimate.
Plumbing(5)
Pipe Sizing Calculator
Calculate the correct pipe diameter for water supply, heating or combined systems based on flow rate, pipe run length, pressure and material.
Pipe Volume Calculator
Calculate the internal volume of a pipe in litres and gallons from its diameter and length, for plumbing and heating systems.
How Much Heat Does a Radiator Produce? Radiator BTU Calculator
Find out how much heat your radiator produces with our BTU calculator. Enter room size and details to estimate radiator output and cost. Metric & imperial units.
Radiator BTU Calculator Considering Insulation
Accurately calculate radiator BTU needs for any room, factoring in insulation, size, and climate. Supports metric & imperial units and cost estimation.
BTU to Watts Converter – Convert Radiator BTU to Watts Easily
Instantly convert BTU to watts for radiator sizing. Use our BTU to watts converter to ensure accurate heating power for your room. Metric & imperial units supported.
Measurement & Conversion(7)
Squaring Calculator
Check whether a layout is square using the 3-4-5 method and diagonal measurements for foundations, decks and walls.
Slope & Grade Calculator
Convert between slope as a percentage, angle in degrees, ratio and rise over run for drainage, ramps and ground works.
Feet and Inches Calculator
Add, subtract and convert feet and inches measurements, with results in decimal feet, inches, centimetres and metres.
Inch Fraction Calculator
Convert between inch fractions, decimal inches and millimetres, with the nearest fraction to any decimal or metric value.
Scale Calculator
Convert between real size and scaled size for models, drawings and maps using any scale ratio such as 1:50 or 1:100.
Linear Feet Calculator
Convert between linear feet and square feet using the material width, for flooring, decking, fencing and boards.
Square Feet to Cubic Feet Calculator
Convert an area in square feet to a volume in cubic feet and cubic yards using the depth or height of the material.
More Calculators(22)
How Many Bin Bags Fit in a Skip? Skip Size & Capacity Calculator
Find out how many bin bags fit in any skip size. Use our skip capacity calculator to compare sizes in yards or metres and estimate total cost.
Wall Area Calculator for Plastering
Easily calculate wall area for plastering. Enter wall sizes in metric or imperial, get area, plaster quantity & cost. Perfect for DIY & trade projects.
What Does a 6 Yard Skip Hold? Skip Size & Capacity Calculator
Find out exactly how much a 6 yard skip holds in volume, size, and weight. Calculate waste, soil, or rubble capacity and total cost in your chosen unit and currency.
What Does a 6 Yard Skip Hold? Capacity, Dimensions & Weight Calculator
Find out exactly what a 6 yard skip holds: volume, weight, and dimensions. Calculate how much waste, soil, or rubbish fits in a 6 yard skip, plus cost.
Plaster Coverage Per Bag Calculator
Use our plaster coverage per bag calculator to find out how much area one bag of plaster covers. Supports metric & imperial units, plus cost calculation.
Partition Wall Material Calculator – Stud Wall Estimator
Estimate materials and cost for partition stud walls. Calculate studs, plasterboard, insulation & total cost in metric or imperial units. Fast, accurate results.
Two Coat Plaster Calculator – Accurate Plaster Quantity & Cost
Easily work out how much plaster you need for two coat plastering. Calculate material quantities & total cost for any wall or ceiling area, metric & imperial.
Cement Plaster Mix Calculator – Accurate Ratios & Quantities
Easily calculate cement, sand, and water needed for cement plaster. Supports metric & imperial units, price options, and custom mix ratios. Fast, reliable results.
Stud Wall Cladding Calculator – Estimate Materials & Cost
Calculate the cladding materials and cost needed for your stud wall. Supports metric & imperial units. Quick, accurate stud wall cladding estimator.
How Many Plants Per Square Foot Landscaping Calculator
Calculate how many plants per square foot you need for landscaping. Supports metric & imperial units, plant spacing, and cost estimation. Easy, accurate results.
Stud Wall Material Estimator – Calculate Studs, Plasterboard & Cost
Quickly estimate the studs, plasterboard and total cost for your stud wall project. Supports metric & imperial units, plus multi-currency cost calculation.
Stud Wall Frame Calculator – Estimate Studs & Materials
Easily estimate the number of studs, plates, and total cost for your stud wall frame. Supports metric & imperial units. Includes stud spacing and door opening.
Landscaping Cost Estimator: Calculate Your Landscaping Project Costs
Estimate landscaping costs per m² or ft² for gardens, lawns, and yards. Compare hourly rates, materials, and get a total project cost in your currency.
Plasterboard Screw Quantity Calculator
Easily calculate how many screws you need for plasterboard. Enter sheet size, number, fixing centres, and get total screws and cost. Metric & imperial supported.
Garden Bed Size Calculator – Calculate the Perfect Garden Bed Dimensions
Easily calculate the best garden bed size for your space and planting needs. Supports metric & imperial units, includes cost estimate, & works for raised beds.
Irrigation System Calculator: Estimate Water Needs & Costs
Calculate irrigation system water requirements and total cost for your garden or landscape. Supports metric & imperial units and multiple currencies.
Plaster Sand Quantity Calculator – Calculate Sand Needed for Plastering
Easily calculate the plaster sand quantity needed for any project. Enter wall size, thickness, and mix to find sand required per m²/ft² and total cost.
Garden Turf Calculator – Estimate Turf Rolls & Cost for Your Garden
Easily calculate how many turf rolls you need and the total cost for your garden. Supports metric & imperial units, multiple currencies, and custom roll sizes.
Plastering Cost Calculator – Estimate Plastering Costs Per m² or ft²
Quickly estimate your plastering costs per m² or ft². Calculate material & labour costs for walls, ceilings, or entire rooms with this plastering cost calculator.
Fencing Area Calculator – Calculate Square Footage or Metres for Fencing
Easily calculate the area for your fencing project in square metres or feet. Enter length and height to get total fencing area and cost. Try our fencing area calculator now.
Raised Bed Soil Calculator – Estimate Soil Volume & Cost
Easily calculate soil volumes & costs for raised beds. Enter your bed's size, choose units, and get instant results in litres, cubic feet, & total price.
Plasterboard Calculator – Estimate Sheets and Cost
Use our plasterboard calculator to work out how many sheets you need and total cost. Supports metric & imperial units. Fast, accurate drywall estimates.