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How much for this rectangle?

Concrete Slab Calculator

Enter the rectangle you measured, or the square footage you already have, plus thickness in inches. An L-shape is two rectangles: add the first, change the numbers, add the second. The main result is cubic yards. That figure is a quantity estimate, not a concrete order.

Slab dimensions

ft
ft
ft²
Use this if you already have square footage. Length and width win if you fill both.
in
Four inches is a common patio starting point. Confirm the thickness your project actually needs.
$
Type a price you already have from a supplier. This is not a bid.

Add this rectangle, then enter the next piece of an L or a broken shape.

Your estimate

Assumptions

The calculator treats the pour as a flat rectangle of even thickness when you enter length and width. Thickness is divided by 12 so it is also in feet. Volume in cubic feet is length × width × thickness, or square feet × thickness in feet. Cubic yards equal that volume divided by 27.

A 10 ft by 10 ft slab that is 4 inches thick is 10 × 10 × (4 ÷ 12) = 33.33 cubic feet, which is 1.23 cubic yards. Empty fields and values of zero or less are rejected. The estimate does not add slope, thickened edges, or footings. A pad that is thin in the field and thick at the wall is two pieces: see thickened edges.

If the slab is an L-shape, add the first rectangle, change the numbers, and add the second. Do not count the corner twice. How to split an L. After the result, a 10 percent extra for waste, a one-inch thickness comparison, and typical bag counts are shown so you can decide the next step here.

A circle is a different formula. Use the round concrete calculator for a pad or a cardboard tube.

How thick should a slab be? · What to do before the pour