Home improvement calculators
Material quantities for walls, floors and building work, plus insulation and budget tools. Every calculator explains its formula and assumptions.
Walls: paint, wallpaper, tiles
Quantities for decorating and tiling walls.
Paint calculator
How much wall paint you need for a room, based on the number of coats and the coverage printed on the tin.
Wall tile calculator
The wall tile area for a bathroom or kitchen and the number of tiles, with openings deducted and waste included.
Wallpaper calculator
How many strips and rolls of wallpaper a room needs, taking the roll width and the pattern repeat into account.
Skim coat calculator
How many kilograms and bags of finishing skim coat the walls of a room need, in one or two coats.
Plasterboard calculator
How many plasterboard sheets a wall or ceiling needs, depending on the board size and waste.
Primer calculator
How many litres of primer the walls of a room need before skimming or painting.
Decorative render calculator
How many kilograms and packs of decorative render a façade or wall needs, depending on the grain size.
Acoustic panel calculator
The volume of sound-absorbing material and the number of acoustic panels for a wall or ceiling.
Floors: tiles, laminate, adhesive, grout
Order the right number of tiles and packs, with waste included.
Floor tile calculator
How many square metres and how many tiles to order for a floor, with cutting waste included.
Laminate flooring calculator
How many packs of laminate or wood flooring to buy, plus underlay and skirting, rounded to whole packs.
Tile adhesive calculator
How much tile adhesive, in kilograms and bags, for the area and trowel notch you'll use.
Grout calculator
Grout consumption per square metre and in total, from the tile size, tile thickness and joint width.
Parquet flooring calculator
How many packs of engineered or solid wood flooring a room needs, with cutting waste and rounding to whole packs.
Vinyl flooring calculator
How many running metres of sheet vinyl to order from the roll, depending on the roll width and the cutting reserve.
Building materials
Concrete, cement, masonry, roofing, insulation and reinforcement for building work.
Concrete calculator
The concrete volume for a footing, slab or path, and how much cement, sand, gravel and water to mix it.
Screed calculator
How many kilograms and bags of screed or self-levelling compound you need for a floor.
Cement calculator
How many bags of cement and how much sand a site-mixed screed, render or masonry mortar needs.
Sand calculator
How many cubic metres and tonnes of sand a bedding layer under paving, a path or a light foundation needs.
Gravel calculator
How many cubic metres and tonnes of gravel or hardcore a layer under a foundation, path or hardstanding needs.
Aerated concrete block calculator
How many aerated concrete blocks and how much thin-bed adhesive a wall needs, with openings deducted and waste included.
Brick calculator
How many solid bricks a 12.5, 25 or 37.5 cm wall needs, with openings deducted and waste included.
Mortar calculator
How many kilograms and bags of mortar or adhesive a brick or aerated-concrete wall needs, depending on the wall thickness.
Roof area calculator
The actual area of a pitched roof from the building's footprint and the roof pitch.
Roof tile calculator
How many roof tiles the actual roof area needs, depending on the tile type and waste.
Waterproofing membrane calculator
How many rolls of waterproofing membrane a terrace, flat roof or foundation needs, with the overlap included.
Mineral wool calculator
The volume of mineral wool and the number of packs or rolls an area needs at the chosen thickness.
OSB board calculator
How many OSB boards a floor, wall or roof deck needs, with cutting waste included.
Steel mesh calculator
How many 2 × 3 m welded mesh sheets a slab, screed or path needs, with the overlap included.
Rebar calculator
An estimate of the kilograms of reinforcing steel in a volume of reinforced concrete, by type of element.
Scaffolding calculator
How many scaffold bays a façade needs, from its length, height and the bay width.
Lime plaster calculator
An estimate of the lime a lime-based plaster needs, from the area and the coat thickness.
Plaster calculator
How many kilograms and bags of plaster or render an area needs, from the coat thickness.
Energy, heating and solar
Insulation, heating and cooling sizes, solar panels, batteries and appliance consumption.
Insulation board calculator
The number of insulation boards and the insulation volume for a wall, façade or floor, with cutting waste.
U-value calculator for walls
A wall's U-value before and after insulation, the drop in heat loss and the thickness needed for a target U-value.
Appliance energy calculator
How many kWh an electrical appliance uses per day and per month, from its power and hours of use.
Solar panel calculator
How many solar panels and what system size you need to cover your home's annual electricity use.
Solar output calculator
How many kWh a solar PV system produces per year and per month, from its power and the local specific yield.
Radiator size calculator
The heat output a room needs and how many radiator sections it takes, by floor area and insulation.
Heating energy calculator
An estimate of the kWh your home uses for space heating per year, from its floor area and insulation.
Battery storage calculator
What battery capacity you need to cover part of your daily electricity use from stored energy.
Heat pump size calculator
An estimate of the heat pump output your house needs, from the heated area and the insulation level.
Boiler size calculator
The heating power your house needs to choose the right boiler, from the heated area and the insulation.
Underfloor heating pipe calculator
How many metres of pipe water underfloor heating needs, from the area and the pipe spacing.
Air conditioner BTU calculator
The cooling capacity a room needs and which standard air conditioner size fits it.
Water heater size calculator
What size water heater or hot water cylinder your household needs.
Plumbing and electrics
Pipe and cable lengths, consumer unit, water tank, pump and bathroom fan sizes.
Electrical cable calculator
An estimate of the electrical cable a home's sockets and lights need.
Water pipe calculator
An estimate of the water supply pipe a home's taps and mixers need.
Drain pipe calculator
An estimate of the drain pipe from each waste point to the stack.
Consumer unit size calculator
How many circuits a home has and how many modules the consumer unit needs.
Water tank size calculator
What water tank volume a household needs, from people, daily use and days of autonomy.
Booster pump calculator
The flow a home booster pump needs, from how many outlets can run at once.
Bathroom fan calculator
The airflow a bathroom extractor fan needs, from the room volume and air changes per hour.
Interiors
Curtain fabric, rug size and room lighting.
Curtain fabric calculator
How many metres of fabric curtains need, from the window width, the drop and the fullness.
Rug size calculator
What size rug fits a room, leaving a visible border of floor around it.
Room lighting calculator
The lumens a room needs and how many bulbs or spots, from the area and the room type.
Garden and outdoors
Fence, paving, decking, pergola, lawn, hedge, irrigation, lighting and pool.
Grass seed calculator
How many kilograms of grass seed a lawn needs, from the area and the seed rate.
Fence calculator
How many posts and how much mesh or panel area a fence needs, from its length, height and post spacing.
Paving calculator
How many pavers a path, driveway or patio needs, with cutting waste included.
Pergola timber calculator
How many running metres of timber beams a pergola roof needs, by size and beam density.
Pool volume calculator
The water volume of a pool and how much shock chlorine the first fill needs.
Garden lighting calculator
How many outdoor lights and how much cable a garden path needs, from its length and the light spacing.
Sprinkler calculator
How many sprinklers a lawn needs, from its area and the throw radius.
Decking calculator
How many running metres of decking boards a deck needs, from the board width and waste.
Hedge plant calculator
How many plants a hedge needs, from its length and the planting distance.
DIY, repairs and security
Furniture paint, sealant, filler, dust sheets and security cameras.
Furniture paint calculator
How much paint, varnish or oil a piece of furniture needs, from its surface and the number of coats.
Silicone sealant calculator
How many 300 ml sealant cartridges your joints need, from their length and width.
Dust sheet calculator
How many protective sheets or rolls cover the floor and furniture before painting.
Wall filler calculator
An estimate of the filler needed for holes and cracks in a wall.
Security camera calculator
How many security cameras a house needs, from its entrances, corners and garden.
Renovation budget
Add up quotes and plan a contingency reserve.
