🧱 Construction
Concrete Yard Coverage Calculator
Enter cubic yards and slab thickness, then press Calculate to get the square footage it covers.
About the Concrete Yard Coverage Calculator
A cubic yard is 27 cubic feet, so coverage depends entirely on thickness: 27 ÷ (thickness in feet) gives square feet. At 4 inches that is 81 sq ft, at 5 inches 64.8 sq ft and at 6 inches 54 sq ft.
Order 5-10% more than the calculated volume. Running short mid-pour is a serious problem — a cold joint is weak and visible — while a little left over is cheap by comparison.
How the calculation works
- Square feet = cubic yards × 27 × 12 ÷ thickness (inches)
- 1 cubic yard = 27 cubic feet
- 4 in slab: 81 sq ft per yard · 6 in slab: 54 sq ft
Reference values
| Thickness | Coverage per yard | Yards for 100 sq ft |
|---|---|---|
| 3 in | 108 sq ft | 0.93 yd³ |
| 4 in | 81 sq ft | 1.23 yd³ |
| 5 in | 64.8 sq ft | 1.54 yd³ |
| 6 in | 54 sq ft | 1.85 yd³ |
| 8 in | 40.5 sq ft | 2.47 yd³ |
| 12 in | 27 sq ft | 3.70 yd³ |
Worked examples
- Cubic yard at 4 in covers 81 sq ft, so a 10 × 10 ft slab needs 1.23 yd³.
- At 6 in the same yard covers 54 sq ft, so the same slab needs 1.85 yd³.
- A 24 × 24 ft driveway at 4 in is 576 sq ft, or 7.1 yd³ — order 8.
Why thickness dominates
Coverage is inversely proportional to thickness, so going from 4 in to 6 in cuts the area a yard covers by a third. That relationship catches people out on driveway estimates, where the difference between a light-use slab and a vehicle slab is exactly the thickness step that halves the yield.
Common mistakes
- Ordering by area instead of volume — concrete is sold by the cubic yard.
- Forgetting a sub-base, which adds 4-6 in of compacted gravel under the slab.
- Pouring in one go on a hot day without a retarder, which sets faster than you can finish it.
A last check on the Thickness table: 3 in 108 sq ft sits at the base of the chart, and the rows above it step in the same proportion, so you can scale from that first row instead of reading every line. If a figure you were quoted falls between two rows, it is the Coverage per yard side that has been rounded, not the conversion itself.