Concrete Slab Thickness Calculator

Measurement inputs

Enter slab size and concrete amount. Results update live.

Live calculation

Project name This name appears in the saved report.

Unit system

Concrete amount basis Use “includes waste” if this is the amount you plan to order.

Length

Enter a length greater than 0.

Width

Enter a width greater than 0.

Concrete amount

Enter a concrete amount greater than 0.

Waste

Waste cannot be negative.

Cost per cubic yard Optional. Leave blank if cost is not needed. Cost cannot be negative.

Compare with Reference only. Follow local code and engineer advice.

Calculated slab thickness

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Enter valid measurements to calculate thickness.

Slab area

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Base volume used

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Order volume with waste

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Concrete per 1 inch

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40 lb bags

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60 lb bags

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80 lb bags

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Estimated cost

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This is an estimate only. Confirm slab thickness, concrete strength, reinforcement, and base prep with a qualified contractor or engineer.

The calculator converts all measurements to feet before solving thickness.

Concrete slab thickness

Thickness = Concrete volume ÷ (Length × Width)