Coverage Table by Thickness
This is the table everyone's looking for. It shows how many square feet one cubic yard of concrete covers at different slab thicknesses.
| Slab Thickness | Coverage per Yard (sq ft) | Common Use |
|---|---|---|
| 2 inches | 162 sq ft | Overlay / thin topping |
| 3 inches | 108 sq ft | Light walkway |
| 4 inches | 81 sq ft | Patios, sidewalks, shed pads |
| 5 inches | 64.8 sq ft | Standard driveways |
| 6 inches | 54 sq ft | Heavy-duty driveways, garages |
| 8 inches | 40.5 sq ft | Structural slabs, foundations |
| 12 inches | 27 sq ft | Footings, heavy equipment pads |
At the standard 4-inch thickness, 1 cubic yard of concrete covers 81 square feet. Going to 6 inches drops that to just 54 square feet — a 33% reduction in coverage from just 2 extra inches of depth.
How This Coverage Number Is Calculated
The math behind the table is simple. Since 1 cubic yard = 27 cubic feet, you divide 27 by the thickness in feet:
Example at 4 inches:
- Convert 4 inches to feet: 4 ÷ 12 = 0.333 ft
- Divide: 27 ÷ 0.333 = 81 square feet
Example at 6 inches:
- Convert: 6 ÷ 12 = 0.5 ft
- Divide: 27 ÷ 0.5 = 54 square feet
That's why the coverage numbers change so dramatically with thickness. Every extra inch of depth uses a lot more material than you'd expect.
Reverse Calculation: Square Feet → Yards Needed
More often, you know your area and want to figure out how many yards to order. Here's how to flip the formula around.
Or the shortcut version if your thickness is in inches:
Quick Examples
| Project Area | At 4″ Thick | At 6″ Thick |
|---|---|---|
| 100 sq ft | 1.23 yd³ | 1.85 yd³ |
| 200 sq ft | 2.47 yd³ | 3.70 yd³ |
| 300 sq ft | 3.70 yd³ | 5.56 yd³ |
| 400 sq ft | 4.94 yd³ | 7.41 yd³ |
| 500 sq ft | 6.17 yd³ | 9.26 yd³ |
| 750 sq ft | 9.26 yd³ | 13.89 yd³ |
| 1,000 sq ft | 12.35 yd³ | 18.52 yd³ |
These numbers don't include the 10% waste factor. Add 10% to whatever number you look up before ordering.
Get an Exact Number for Your Project
Plug in your dimensions and get cubic yards, bags, and cost — with waste factor built in.
Open Concrete Yard Calculator →Multi-Yard Coverage at a Glance
If you already know how many yards you're ordering (or your supplier quotes a truck load), this table shows what that covers.
| Cubic Yards | At 4″ Thick | At 5″ Thick | At 6″ Thick |
|---|---|---|---|
| 1 yard | 81 sq ft | 65 sq ft | 54 sq ft |
| 2 yards | 162 sq ft | 130 sq ft | 108 sq ft |
| 3 yards | 243 sq ft | 194 sq ft | 162 sq ft |
| 5 yards | 405 sq ft | 324 sq ft | 270 sq ft |
| 7 yards | 567 sq ft | 454 sq ft | 378 sq ft |
| 9 yards | 729 sq ft | 583 sq ft | 486 sq ft |
| 10 yards | 810 sq ft | 648 sq ft | 540 sq ft |
| 15 yards | 1,215 sq ft | 972 sq ft | 810 sq ft |
| 20 yards | 1,620 sq ft | 1,296 sq ft | 1,080 sq ft |
Why Depth Matters More Than You Think
Here's the part that catches people off guard. Going from 4 inches to 6 inches seems like a small change — just 2 extra inches. But in terms of concrete volume, it's a 50% increase.
Let's say you're pouring a 20 × 20 ft patio:
- At 4 inches: 20 × 20 × 0.333 ÷ 27 = 4.94 yards
- At 6 inches: 20 × 20 × 0.5 ÷ 27 = 7.41 yards
That's 2.47 extra cubic yards — which at $150/yard is about $370 more in concrete. For a patio, 4 inches is perfectly fine. Don't go thicker than you need.
Only for driveways that handle trucks, garage slabs, or areas with poor soil. Patios, walkways, and shed pads are almost always fine at 4 inches on a properly compacted base.
Real Project Scenarios
Let's put these numbers to work with actual projects people pour concrete for.
Patio: 12 × 16 ft, 4 inches thick
- Area: 192 sq ft
- Yards needed: 192 × 4 ÷ 324 = 2.37 yd³
- With 10% waste: 2.60 yd³ → Order 3 yards
Driveway: 12 × 40 ft, 5 inches thick
- Area: 480 sq ft
- Yards needed: 480 × 5 ÷ 324 = 7.41 yd³
- With 10% waste: 8.15 yd³ → Order 8.5 yards
Garage Floor: 24 × 24 ft, 6 inches thick
- Area: 576 sq ft
- Yards needed: 576 × 6 ÷ 324 = 10.67 yd³
- With 10% waste: 11.73 yd³ → Order 12 yards
The coverage table shows theoretical coverage. In practice, uneven subgrade, spillage, and form flex always eat up extra concrete. Budget 10% more than the math says you need. Read more about why in our concrete yardage guide.
Let the Calculator Handle It
The tables above give you fast estimates. For exact numbers — with unit conversion, waste factor, and bag estimates — use our free calculator.
Free Concrete Coverage Calculator
Enter your length, width, and thickness. Get cubic yards, bags, tons, and cost — instantly.
Calculate Concrete Coverage →Related Guides
- How to Calculate Concrete Yardage — Full formula for slabs, driveways, footings, and cylinders
- How Many Bags of Concrete in a Yard? — 40, 60, and 80 lb bag counts
- How Many Cubic Yards Do I Need? — Master guide for all materials
- How Many Cubic Feet in a Cubic Yard? — The 27-cubic-feet conversion
- Concrete Cost Per Yard Calculator — Estimate total project cost
- Concrete Square Yard Calculator — Area-based concrete estimates