Graftum

Free calculators for every trade

Quick answers on site and in the van — no sign-up. When you're ready to price, run and get paid for the whole job, that's what Graftum is for.

⚡ Electrical

Max Zs tableBS 7671 A4 limits for MCBs, RCBOs and fuses, with the 80% check for your readings.Voltage dropmV/A/m × current × length — inside 3% or 5%?Cable sizeTwin & earth by installation method, correction factors and volt drop.
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🔥 Plumbing & heating

BTU / radiator sizeHeat needed per room in watts and BTU, and the radiator for ΔT50 or a heat pump.Boiler sizeWhat kW for the house: bedrooms, bathrooms, combi or system.
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🧱 Building & bricklaying

Bricks & mortarBricks per m², sand and cement for any wall.Blocks & cavity wallsBlocks, mortar and wall ties.
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🪚 Drylining & plastering

PlasterboardBoards, screws, tape and finish for walls and ceilings.PlasterBags of skim or undercoat for the area and thickness.
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🎨 Finishes

PaintLitres and tins for walls and ceilings, with a mist coat.Tiles, adhesive & groutTiles with wastage, adhesive by trowel and grout by joint.Flooring & screedPacks, underlay, skirting — and screed volume and bags.
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🏠 Roofing

Roof pitch & areaPitch in degrees, rafter length and true roof area.Roof tiles & battensTiles or slates, battens and ridge for the roof.
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🚜 Groundworks & concrete

ConcreteSlabs, footings, post holes — m³, ready-mix or bags.Aggregate & MOT Type 1Tonnes and bulk bags of sub-base, sand, gravel, topsoil.Excavation & spoilDig volume, bulking, skips and grab lorries.
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🪜 Carpentry

Stairs (Part K)Risers, going, pitch and the 2R+G check.
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💷 Money & pay (all trades)

Was I paid right? + invoiceCIS 20% or 30%, what was taken, and your invoice in English.CIS deductionWork out the 20% / 30% CIS deduction.CIS tax refundEstimate what you get back.Day rateWhat to charge per day.Payment notice datesPayment notice and pay-less dates for your contract.
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