State the measured scope
An estimate is easier to check when each quantity has a unit, a date and a scope description. Separate the work measured from the work assumed. State which faces, layers, openings or roof sections you included. A simple calculator cannot infer access restrictions, disposal requirements or a change to the programme from a single area input.
Separate allowances from quantities
Waste increases a physical order quantity; contingency reserves money for uncertainty. Labour and equipment are separate cost allowances, not automatic percentages of profit. In the quantity calculators, tax applies to the complete subtotal including contingency. Change the scenario or calculate an appropriate tax base separately if that is not how your project is treated.
Keep the record with the decision
Download the inputs and results together so that a client or colleague can reproduce the scenario. A shared estimate link includes its values in the address and can appear in hosting logs; avoid confidential figures when that matters. Confirm the supplier quote, contract terms and local requirements before ordering. Exported files are snapshots and will not update when the assumptions change.
On your side of the Atlantic
Canadian projects often mix metric drawings with imperial products. Confirm the supplier’s units and the applicable GST, HST or PST treatment for your province.
Open calculator ↗Planning estimate only. Not a substitute for a professional quote or local building-code compliance. Verify quantities, tax treatment and contract requirements.