Estimate concrete for your slab
Enter slab dimensions to calculate volume, concrete bags, and estimated material cost.
Enter your measurements
Use the planned concrete thickness, not the gravel-base thickness. Structural thickness and reinforcement requirements must be determined separately.
Your estimate
Enter your dimensions to see your material estimate.
Calculate first. Order with confidence.
Rectangular slabs: length × width × thickness (feet). Round slabs: π × radius² × thickness (feet). Divide by 27 to get cubic yards, then add your chosen allowance.
Results are estimates, not a substitute for checking on-site dimensions, local requirements, packaging labels, or supplier specifications. Cost fields do not include delivery, taxes or labor unless you incorporate them into your entered price.
Understand the calculationsKnow what is included
Volume conversions use 27 cubic feet per cubic yard. Concrete bag-yield presets come from the QUIKRETE Concrete Mix No. 1101 data sheet. Gravel bulk-density values are editable examples—not universal constants.
View sources and accuracy notesCommon questions
How do I calculate concrete for a 10 × 10 slab?
Multiply 10 feet × 10 feet × slab thickness in feet. A 4-inch depth equals 4/12 feet, so the volume is about 1.235 cubic yards before allowance.
Does this calculate reinforcement or the gravel base?
No. It estimates concrete volume, plus alternative bag counts. Reinforcement, drainage, site conditions and foundation design need their own assessment.
Can I calculate a circular concrete slab?
Yes. Switch the slab shape to Round and enter the diameter and thickness.
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