About QtyLab

QtyLab is a free collection of DIY material quantity calculators for common home and light jobsite projects. The goal is simple: help you turn measurements into bags, yards, gallons, sheets, bundles, or posts before you drive to the lumberyard or call a supplier.

Who we are and why this exists

QtyLab started because bag-yield charts, density tables, and “rule of thumb” waste factors are easy to misremember when you are standing in a parking lot with a tape measure. We built browser-based tools so anyone can enter length, width, and depth (or room dimensions) and get a transparent estimate — without creating an account or installing an app.

The site is aimed at homeowners planning a patio, bed, fence, roof, or paint job, and at contractors who want a quick second check before ordering ready-mix, gravel, shingles, or drywall. We keep the interface plain on purpose: clear inputs, labeled assumptions, and results you can share.

How the numbers work

• All calculator math runs in your browser. Your dimensions are not uploaded to QtyLab servers for computation.
• Waste factors, bag yields, and coverage rates are shown in the UI so you can see what the estimate assumes.
• Shareable URLs store inputs in the query string when you choose to copy a link — useful for bookmarks or sending a plan to a helper.

These are planning estimates, not engineered takeoffs. Always confirm bag labels, product density, local code, and supplier advice before you order. Soil, moisture, and installation method can change real-world needs.

What is free

Every calculator on QtyLab is free to use. There is no paywall, no login, and no required download. We don’t run ads. To help cover hosting and development, some links are affiliate links: shopping links to Amazon (as an Amazon Associate, QtyLab earns from qualifying purchases) and links to Angi for people who would rather hire a pro. If you buy or request quotes through one of these links, we may earn a commission at no extra cost to you — that disclosure also appears on calculator pages, in guides, and in the site footer.

Guides and calculators

Beyond the tools, we publish short how-to guides that walk through the same math in plain language (for example concrete bags, mulch depth, paint gallons, and shingle bundles). Use a guide when you want the reasoning; use a calculator when you already know the dimensions. See all of them on the Guides page.

Current calculators cover concrete, gravel, mulch, sod, lawn fertilizer, paint, drywall, tile, fence layouts, pavers, and roofing. Browse them from the site navigation or the home page calculator list.

Contact

Questions, a calculator idea, or a report of an error? Email admin@qtylab.com or visit the Contact page. We read mail; we do not offer phone support.