Field Calculators is built and used daily by a working commercial contracting team: estimators, project managers and foremen. These are the calculators we use to price and order our own work.
We built them because most free calculators online hand you a number with no source, no drawing and no way to check it — sometimes behind a form that wants your email first. Ours show every step of the math, say where each constant comes from, and draw the job so you can check it against the plan.
This is a community calculator for the construction trades. We check every number against its source, but mistakes are possible — and we keep adding calculators that people ask for.
What they are for
Quick, checkable quantities for pricing and ordering: cubic yards and bags of concrete, block and mortar, rebar and laps, drywall sheets, paint, shingles, pavers, insulation and more — typed in feet and inches the way you say them on site, or in metric. They are estimating tools. They do not replace your approved drawings, your specs or your engineer.
What we promise
- Free, with no login and no form before the number. Once a page has opened, it also works offline.
- The math is shown. Every step is on the page, and every constant names its source: a manufacturer data sheet, a code or a standard.
- A drawing of the job — plan, section or elevation — with the sizes you typed, so a mistake shows up before you order.
- A PDF with the same numbers, the same drawing and the same sources, ready to send to the GC, the supplier or the owner.
- No waste added unless you add it. Bags, sheets and pieces round up to what you can actually buy.
- Every page in Spanish as well as English, in US units.
If a number looks wrong
The quickest way is the “Report a problem or suggest something” box under every calculator: it can attach what you typed, so we check the same numbers.
Tell your PM: which calculator, what you typed and what you expected. We check it against the source, fix the engine, add a test so it stays fixed, and update the “Last reviewed” date on that page.