Concrete Calculator
Calculate how many cubic yards of concrete you need for a slab, walkway, or pad.
Enter your numbers and select Calculate to see results.
About This Calculator
This calculator computes the volume of concrete needed for a slab, driveway, walkway, or pad based on its length, width, and thickness, converting to cubic yards — the standard unit concrete is typically ordered in.
How This Is Calculated
Volume (cubic yards) = (Length × Width × Thickness in feet) ÷ 27
A 20×10 ft slab at 4 inches thick needs about 2.47 cubic yards of concrete.
Assumptions
- Assumes a flat, rectangular pour area — irregular shapes need to be broken into rectangular sections and summed.
- Does not include rebar, forms, or labor costs.
Frequently Asked Questions
Related Calculators
Square Footage Calculator
Calculate the square footage of any room or space.
Home Renovation Cost Calculator
Estimate the total cost of a home renovation project, with a contingency buffer built in.
Flooring Calculator
Calculate how much flooring material you need, including a waste allowance.
Roofing Calculator
Calculate how many roofing squares you need and the estimated material cost.
Last updated January 15, 2026. Results are estimates for informational purposes only — read our disclaimer.