How these tools work
A useful result should be understandable and repeatable. Our calculators use the values you enter and the formula described on the page. Read that formula and its worked example before applying the result to a job.
Inputs, units and rounding
Read each field’s unit. Feet and inches, square feet and cubic yards, watts and volt-amperes are not interchangeable. Some calculators multiply user-selected factors such as waste, routing or demand; those factors are assumptions, not measurements or a declaration of an applicable requirement.
Most displayed decimal results are rounded for readability. Piece, sheet, box and pallet estimates may round up to the next whole unit. A rounded purchase quantity can exceed the measured need. Check supplier packaging before ordering.
What a worked example proves
The numeric examples show how the page’s current formula behaves for stated inputs. We compare those examples with calculator output and check that invalid inputs do not silently produce a normal result. That verifies the arithmetic and page behavior for the example; it does not certify that the model is a complete design method for your project.
Illustrative costs and rates are not local price quotes. An area-based takeoff is not a cutting layout, a cooling conversion is not an equipment load calculation, and a reference electrical size is not installation approval.
Simple models have boundaries
Several tools are deliberately small planning models. The connected-load calculator adds entered watts; the service planner applies an entered percentage. The water-heater tool uses a simple weighting; the airflow tool converts volume and an entered air-change rate. Read the specific explanation rather than treating a generic “sizing” label as a complete specification.
For final product selection, engineering, regulated installations and required approvals, use the applicable project documents, manufacturer information and qualified professionals. Official references in the resource center are starting points; local adoption and project conditions still need verification.
Check linked steps in a project
Transferring a takeoff to an estimate moves quantities, not verified supplier prices. Importing a full proposal into an invoice starts with the full proposal value; adjust the invoice to the actual approved amount due now and review prior payments. A saved draft is not a customer approval or payment confirmation.
Most drafts stay in this browser on this device. Account business profiles and customer portal records use separate server features. Download backups or customer PDFs where provided, and keep copies of approved job documents.
Found something that does not add up?
Use Contact to send the page address, exact inputs and units, displayed output and your expected calculation. A short reproducible example is more useful than a description such as “the total is wrong.” We can compare the implementation, explanation and example to identify what needs changing.
The site and tools can change. Recheck assumptions when revisiting a saved estimate rather than relying on an old output without its input notes.