Rectangular volume
length × width × depth ÷ 12Converts an inch depth into cubic feet for the slab footprint.
Inputs
Adjust the project details to update the estimate.
Planning estimates use standard formulas. Verify quantities with your supplier before ordering.
Estimate
Know the volume before the pour.
Concrete volume
Cubic yards with a practical allowance for a short pour.
1.36 cu yd
80-pound bags
Approximate bag count for common retail mixes.
62
Material range
A planning window that excludes pumping, delivery, labor, and reinforcement.
$177–$272
Rectangular volume: length × width × depth ÷ 12
Estimates use standard planning formulas. Verify quantities with your supplier or contractor before ordering.
See your project with AIConcrete volume
Concrete Calculator
Enter length, width, depth, and the concrete format you plan to buy. Get a volume estimate for a slab, pad, or small footing before calling a supplier.
Free to use Instant results Planning estimate
How to estimate concrete for a slab
Measure the finished length and width, then confirm the actual slab depth at several points. A thicker edge, slope, step, or thickened footing can make a simple rectangle understate the order.
Ready-mix is commonly ordered by cubic yard, while smaller jobs may use 60- or 80-pound bags. Bag coverage varies by manufacturer, so the label is the final authority for retail quantities.
Add reinforcement, forms, vapor barrier, excavation, delivery, pumping, finishing, curing, and disposal to a complete project scope. Never rely on a volume estimate for structural design.
Formulas used
Cubic yards
cubic_feet ÷ 27 × 1.10Converts cubic feet to yards and adds a ten percent planning reserve.
Retail bags
cubic_feet ÷ bag_coverageUses the coverage printed on the chosen bag size.
Frequently asked questions
What to know before you order.
How many bags of concrete are in a cubic yard?
The count varies by bag weight and product yield. Use the bag's stated coverage instead of a fixed conversion.
Does the result include reinforcement?
No. Rebar, mesh, fiber, forms, and finishing materials need separate quantities.
Can I use this for footings?
It can estimate a rectangular footing volume, but structural dimensions and reinforcement should come from the plan or a qualified professional.
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