ConcreteCalc

Concrete Slab Calculator

Concrete slab calculator: enter the dimensions to get cubic yards, 80 lb/60 lb bag counts and an estimated cost.

Runs locally in your browser — no upload, no tracking
ft
ft
in
%

Try: Length=10, Width=10, Thickness=4, Waste allowance=10 → 36.7 ft³, 1.36 yd³, 62 (≈61.1), 82 (≈81.5), $204

How to use

A slab is a flat rectangle — the most common residential pour. Patios and garage floors are usually 4 in thick; a shop or anything with heavy point loads wants 5–6 in. Press Calculate for cubic yards, bag counts and a rough cost. All math runs in your browser.

Reviewed by contractor Tom K.

FAQ

How thick should a concrete slab be?

Enter your dimensions in feet (and thickness in inches), add a 10% waste allowance, then the calculator converts the volume to cubic yards by dividing cubic feet by 27. Bag counts use ~0.6 ft³ per 80 lb bag and ~0.45 ft³ per 60 lb bag.

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