Builders' calculators

Free calculators for the sums that come up on site: bricks, blocks, concrete, excavation and muck-away, Type 1, volumes, roofs, slates, stairs, U-values, plaster, tiles and screed. Most use the same sums as the SiteHelm app, and each page has a worked example.

Put these calculators on your phone, free

They work like an app from your home screen, even with no signal on site. On an iPhone: tap Share, then Add to Home Screen. On Android: tap the menu (⋮), then Add to Home screen or Install app.

The free SiteHelm phone app for iPhone and Android is on its way, with every calculator in it. Tell me when it's out

Brick calculatorType the wall's length and height and take off the openings. You get the bricks to order, the mortar, the bags of cement and the sand.Block calculatorHow many concrete blocks for a wall, with the mortar, bags of cement and sand. Choose 100, 140 or 215 mm blocks, and take off the openings.Concrete calculatorWork out the concrete for a slab, footing, pad or pier, the ready-mix to order, and the cement, sand and gravel if you mix it yourself.Type 1, gravel and sand calculatorHow many tonnes of Type 1, gravel, sand, ballast or topsoil for an area and depth, with the bulk bags or lorry loads to order.Excavation and muck-away calculatorHow much comes out of the ground once it's dug: the volume in the ground, the bulked volume by soil type, the tonnes, and the skips or grab lorry loads to take it away.Volume calculatorCubic metres and litres for a box, a cylinder, a cone or pyramid, or a sloping wedge: for tanks, pits, piles, ramps and soakaways.Roof pitch and rafter calculatorFor a simple pitched roof: the pitch or the rise, the rafter length including the overhang, the stock length to buy, how many rafters, and the roof area.Stair calculatorType the floor-to-floor height. You get the number of risers, the rise and going, the pitch and the length of the flight, each checked against Approved Document K.U-value calculatorBuild up a wall, roof or floor layer by layer, from outside to inside. You get the U-value, whether it meets the Part L target, and how thick the insulation needs to be to pass.Roof slate and batten calculatorFrom the roof area, the slate size and the headlap: the batten gauge, slates per m², slates to order, metres of batten and the nails.Plaster calculatorBags of finish plaster for a skim, or backing and finish for float and set, from the area of the walls and ceilings.Tile calculatorHow many tiles for a wall or floor, the boxes to buy, and the adhesive and grout, for your tile size, joint and pattern.Screed calculatorThe volume of screed for a floor, and the cement and sharp sand for a 1:4 sand and cement screed, or the liquid screed to order.

Do more with SiteHelm PRO

Measure straight off the drawing with Take-off, and the quantities go into material orders and quotes, priced from your Book of rates. Save every figure to the job.

Free on your phone. Every builders' calculator will be free in the SiteHelm phone app for iPhone and Android, coming soon. Tell me when it's out.

Every builders' calculator is in SiteHelm PRO for your Windows PC, alongside take-off, RAMS, quotes, invoices and 40+ more tools. The first 100 get a free 1-year licence.

Get a free 1-year licence See the prices