How much concrete for a patio?
Concrete patios are usually estimated from the formed patio footprint and planned thickness. Split L-shaped patios, extensions, and landings into separate rectangles for a cleaner estimate.
Patio slab examples
A 10 x 20 ft patio at 4 inches thick is about 2.47 cubic yards before waste. A 16 x 14 ft patio at 4 inches thick is about 2.77 cubic yards before waste.
Patio waste and finish planning
Waste helps cover base variation, forms, and ordering variance. Finish type, slope, control joints, reinforcement, and site prep should be planned separately from concrete volume.
Common concrete slab sizes
Cubic yards below are before waste. Add your project waste percentage before ordering.
| Slab size | 4 in thick | 5 in thick | 6 in thick |
|---|---|---|---|
| 10 ft x 10 ft | 1.23 cu yd | 1.54 cu yd | 1.85 cu yd |
| 10 ft x 12 ft | 1.48 cu yd | 1.85 cu yd | 2.22 cu yd |
| 12 ft x 12 ft | 1.78 cu yd | 2.22 cu yd | 2.67 cu yd |
| 20 ft x 20 ft | 4.94 cu yd | 6.17 cu yd | 7.41 cu yd |
| 24 ft x 24 ft | 7.11 cu yd | 8.89 cu yd | 10.67 cu yd |
| 30 ft x 40 ft | 14.81 cu yd | 18.52 cu yd | 22.22 cu yd |
Before you calculate
- Measure the patio length and width in feet, then enter the planned slab thickness in inches.
- Split L-shaped patios, steps, or widened seating areas into separate rectangles.
- Keep waste visible because patio edges, forms, and base variation can change the final order.
Common mistakes
- Using patio square footage alone without including slab thickness.
- Forgetting thickened edges, steps, curves, or separate landing areas.
- Comparing a concrete-only estimate with a full installed patio quote.
Formula
cubic yards = (length * width * (thickness / 12) / 27) * (1 + wastePercent / 100)
Assumptions
- Concrete quantity is a planning estimate, not structural design.
- Thickness, forms, subgrade, reinforcement, drainage, slopes, and local requirements should be checked separately.
- Round ready-mix, bags, forms, sealers, and accessories up before ordering.
Example
Estimated concrete needed (cubic yards): 0.9 cubic yards
How to use this calculator
- Enter length in ft.
- Enter width in ft.
- Enter thickness in in.
- Enter waste in %.
- Review the live estimate and compare it with the example result.
- Check the formula, assumptions, product labels, and site conditions before using the Patio Cooking Prep Counter Charcoal Storage Bench Concrete Pad Calculator result to plan materials.
Before you buy materials
- Use the cubic-yard result when discussing ready-mix minimums or bagged concrete alternatives.
- Confirm base, slope, reinforcement, finish, and local requirements before scheduling a pour.
FAQ
What is the example patio cooking prep counter charcoal storage bench concrete pad cubic-yard result?
Use length, width, thickness or depth, and waste, then calculate the planning result. In the default example, the result is 0.9 cubic yards.
How do I calculate concrete for a patio?
Multiply patio length by width, multiply by thickness in feet, divide by 27, then add waste if needed.
How much concrete for a 10 x 20 patio?
At 4 inches thick, a 10 x 20 ft patio needs about 2.47 cubic yards before waste. With 10% waste, plan about 2.72 cubic yards.
Should patio slope be included?
Slope affects layout and drainage more than the basic volume formula. For significant elevation changes or irregular base, calculate sections separately.
Do patio edges or steps change the estimate?
Yes. Thickened edges, steps, landings, and curves should be estimated separately because they add volume.
Related calculators
This calculator is for planning estimates only. Verify final quantities with product labels, project conditions, and a qualified professional when accuracy matters.