About The Build Calculator

The Build Calculator is a free collection of construction and landscaping calculators built for homeowners, DIYers and tradespeople. Each tool answers one practical question — how much gravel, how many sheets of drywall, how long a rafter — in the units suppliers actually sell: cubic yards and tons, bags and bundles, sheets and sticks.

The site exists because of a gap we kept running into ourselves: most material calculators online either give you a raw number with no context, or bury the tool under three screens of ads. We wanted the version a good estimator would build — the calculation, the formula behind it, the reference table it came from, and honest buying advice, all on one fast page.

How our calculators work

Every calculator uses the standard industry formulas and material densities that estimators and suppliers use, and each page shows its formula so you can verify the math yourself. We include the reference tables (coverage rates, densities, code limits) alongside every tool so you understand the number, not just receive it.

Where the trade has a rule of thumb — 5% waste on simple tile layouts, 20% compaction on crusher run, two screws per deck board per joist — we build it in and say so, rather than leaving you to discover it at the supplier's counter. Results update as you type, work in both imperial and metric, and never require an account or an email address.

Accuracy and limitations

All results are estimates for planning and budgeting. Real-world quantities vary with site conditions, compaction, moisture and product differences — always confirm final quantities with your supplier, and check local building codes before construction. Structural decisions (spans, footings, retaining walls over code height) should always go through an engineer or your local building department.

We review the formulas and reference figures against supplier documentation and industry standards, and we correct anything readers catch. If you spot an error or a number that disagrees with your supplier, please tell us — accuracy reports are genuinely the most useful feedback we get.

How the site is funded

The Build Calculator is free to use and supported by advertising. Ads never affect the results our calculators produce, and we don't sell or share anything you type into a calculator — the math happens entirely in your browser. See our privacy policy for the full detail.