Concrete Slab Calculator is a free online toolkit for sizing concrete pours. Every calculator on this site uses standard volume formulas, manufacturer-published bag yields, and a documented planning density of 150 lb/ft³ for normal-weight concrete — then surfaces results in the units suppliers actually quote (cubic yards delivered, bags retailed, tons trucked).
What we built
Calculators that share the same underlying math, so results stay consistent across tools:
- Concrete Slab Calculator — yards, bags, weight, and cost from length × width × thickness
- Project tools for driveways, patios, sidewalks, garage floors, shed slabs, round slabs, thickness planning, rebar, and gravel base.
- Footing and round column calculators for foundations and pillars
- Bag, cubic yard, and cost calculators for spot-sizing
Who it's for
Homeowners use it to plan DIY pours and verify contractor quotes. Concrete contractors use it to quote on the spot during site visits. Builders and remodelers use it during the budget phase before structural drawings are finalized.
What we don't do
We don't store your inputs, sell leads to contractors, or run ads against calculator results. Every calculator runs entirely in your browser — dimensions and pricing never leave the page. We don't require an account, an email, or a phone number to use any tool.
How estimates are reviewed
The site operator reviews shared formulas, defaults, and worked examples whenever a calculator changes. Volume conversions are deterministic, but a real pour can vary because of measurement error, subgrade movement, form deflection, spillage, and supplier practices. For structural footings or commercial slabs, follow engineered drawings and confirm code requirements with your local building department. Our assumptions and primary references are documented on the methodology page.
Corrections
Found a calculation, source, or wording problem? Send the calculator URL, the inputs used, the result shown, and the result you expected through the contact page. Reproducible calculation errors are prioritized for review.
Get in touch
Spotted a bug, have a feature request, or want to suggest a new calculator? Hit the contact page.