CalcCommons
Construction & Measurement

Concrete Calculator

Estimate concrete for slabs, pads, footings, walls, and columns, with waste, bag yield, and cost.

Your inputs

Choose a quick value or enter your own. Example inputs are filled in to get you started.

Cubic feet per mixed bag. Common example yields: 0.30, 0.45, 0.60. Enter your product’s actual yield; leave empty to omit bags.
EXAMPLE RESULT

Enter your measurements and calculate.

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How to use

Choose slab/pad, footing, wall, or column. Enter dimensions and separate depth units, quantity, and waste allowance. For columns use diameter and height; for walls use length, wall height as width, and thickness as depth. Bag yield and unit price are optional.

For related tasks, try the Cubic Yard Calculator.

Formula & how it works

Rectangular volume = length × width × depth. Column volume = π × (diameter/2)² × height. Order estimate = volume × quantity × (1 + waste/100). Bags = ceiling(volume ÷ bag yield).

Rectangular slab with length, width, and thickness dimensions.

Worked examples

Example 1

A 10 ft × 10 ft slab at 4 in thick uses 33.3333 ft³ = 1.2346 yd³ before waste. At 10% waste: 1.3580 yd³.

Example 2

A 2 ft diameter column 3 ft high uses π × 1² × 3 = 9.4248 ft³. At 0.60 ft³ per bag and no waste, round up to 16 bags.

Assumptions & practical notes

Slab/pad and footing use the rectangular formula. For a wall, enter length, height as width, and wall thickness as depth.

Bag yields are illustrative and vary by product. Verify manufacturer yield and water requirements. This estimates quantity, not reinforcement, structural adequacy, or code compliance.

See our calculation methodology for unit definitions and testing practices.

Results are estimates for planning purposes. Verify measurements, product specifications, and applicable building codes before purchasing materials or starting work.

Frequently asked questions

How much waste should I add?

The default 10% is an adjustable planning allowance, not a specification. Form irregularity and delivery practices affect your order.

Is bag weight the same as yield?

No. Yield is the mixed volume produced by one bag. Use the stated cubic-foot yield on your product label.

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