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Construction Calculators for UK Builders

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Construction calculators for real site estimates

Use these calculators to turn measured dimensions into practical material quantities, allowances and first-pass costs. They cover common jobs including concrete, roofing, drainage, paving, timber, paint and job margins, with units and assumptions shown alongside the result.

Treat every result as an estimating aid. Confirm dimensions on site, use the current supplier specification, add an appropriate waste allowance and obtain professional design where the work is structural or safety-critical. Results can then be carried into the Builder Tools quote flow instead of being typed out again.

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Showing 27 of 60 tools

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Cable Lookup

Preliminary lookup for named Doncaster 70°C multicore copper cables using published current-capacity and voltage-drop data. Final circuit design remains with a competent electrician.
CalculatorsElectrical
Pro

Concrete

Calculate concrete volumes for slabs, footings, columns, and steps. Get mix ratios and material quantities.
CalculatorsStructural
Free

Profit Checker

Check whether a quote covers materials, labour, overheads, contingency, and your target profit margin before you send it.
CalculatorsDocuments
Pro

Roofing

Calculate roof area, tiles needed, battens, felt, and ridge tiles for pitched roofs.
CalculatorsRoofing
Free

Spindle Spacing

Calculate equal spindle and end gaps against a designer-chosen clear-gap maximum. The complete guarding still needs verification.
CalculatorsCarpentry
Pro

Downlights

Calculate optimal downlight spacing and positioning for any room size.
CalculatorsElectrical
Pro

Steel Weight

Calculate indicative section weights and create a steel schedule. This is not structural member sizing.
CalculatorsStructural
Pro

Stone, Blocks & Bricks

Calculate stone, bricks, blocks, and mortar needed for walls. Supports stone walling, standard UK brick and block sizes.
CalculatorsBricklaying
Pro

StoneSmart

Calculate stone volumes and costs with labour and markup. Toggle m³/ft³. Save and load jobs to continue later.
CalculatorsStone Masonry
Pro

Fencing

Calculate fence panels, posts, concrete, and gravel boards for any fence run.
CalculatorsLandscaping
Pro

Patio

Estimate patio paving, compacted sub-base, bedding materials, jointing products, and excavation waste.
CalculatorsLandscaping
Pro

Plaster & Render

Calculate plaster and render quantities for walls and ceilings. Multi-coat support.
CalculatorsPlastering
Pro

Weight

Calculate weights of common construction materials by volume or dimensions.
CalculatorsGroundworks
Pro

Stair Geometry

Create a straight private-stair set-out and compare rise, going, pitch and 2R+G with Approved Document K guidance for England.
CalculatorsStructural
Pro

Scaffolding

Calculate scaffolding hire costs for independent, birdcage, and tower scaffolds. Erection, hire, and dismantle pricing.
CalculatorsStructural
Pro

Drainage Fall

Check bounded Approved Document H minimum falls using actual internal pipe size, design flow, connected WCs and run length.
CalculatorsGroundworks
Pro

Decking

Calculate decking boards, joists, noggins, posts, and fixings needed. Full materials list ready for the merchant.
CalculatorsLandscaping
Pro

Catnic Lintel

Check an engineer-supplied total UDL against Catnic's February 2026 TS90/100, TH90/100 and TX90/100 table for one defined cavity-wall build-up.
CalculatorsStructural
Pro

Timber Span Check

Capture the inputs needed for a current timber span-table check and identify when a project-specific structural design is required. No section size is inferred.
CalculatorsStructural
Pro

Gravel & Aggregate

Calculate tonnes of gravel, MOT, sand, topsoil, and aggregate needed. Built-in bulk densities, multi-area support, and bulk bag counts.
CalculatorsGroundworks
Pro

Tile Calculator

Calculate tiles, adhesive, and grout for floors and walls. Supports straight, brick bond, and diagonal layouts with wastage.
CalculatorsTiling
Pro

U-Value Estimate

Estimate an idealised layer-stack U-value and compare it with a selected current Part L limiting value. Not a compliance calculation.
CalculatorsRoofing
Pro

Gastite Lookup

Conservative lookup of Gastite Table 9.1 for its own CSST carrying natural gas under the published fixed conditions. For competent Gas Safe engineers only.
CalculatorsPlumbing & Heating
Pro

Voltage Drop

Calculate voltage drop using an exact public Doncaster table for named 90°C single-core copper cables. No cable selection or compliance claim.
CalculatorsElectrical
Pro

Turf & Lawn

Calculate turf rolls, topsoil, and fertiliser needed for any garden. Supports rectangle, L-shape, and circular lawns with waste allowance.
CalculatorsLandscaping
Pro

Paint

Calculate how much paint you need for any room. Accounts for doors, windows, coats, and tin sizes.
CalculatorsGeneral Building
Free

Radiator / BTU

Create a rough early-stage heating-load placeholder. Final emitter selection requires room-by-room heat-loss design and manufacturer output data at the actual system temperatures.
CalculatorsPlumbing & Heating
Pro