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 the NRMCA normal-weight concrete density of 150 lb/ft³ — 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
- 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 accurate is it?
The volume math is exact. Real-world variance comes from sub-grade settling, form deflection, and supplier batch variation — typically ±3–5% on a residential pour. For structural footings or commercial slabs, follow your engineered drawings and confirm code requirements with your local building department. Our methodology is documented on the methodology page.
Get in touch
Spotted a bug, have a feature request, or want to suggest a new calculator? Hit the contact page.