Typical Concrete Depths by Project
| Project Type | Typical Depth |
|---|---|
| Patio / walkway | 3–4 inches |
| Driveway | 4–6 inches |
| Garage floor | 4–6 inches |
| Foundation / footing | 8–12 inches |
| Structural slab | 6–8 inches |
Concrete Cost Calculator
Estimate the total cost of your concrete project. Calculate cubic yards needed and material costs for slabs, driveways, patios, sidewalks, and footings. Includes waste factor for accurate ordering.
Concrete Project Estimator
Frequently Asked Questions
How much does concrete cost per yard?
Ready-mix concrete typically costs $125–$200 per cubic yard depending on region, mix strength, and additives. Delivery charges (short-load fees, distance) can add $50–$150. A standard 4-inch patio slab requires about 1.23 cubic yards per 100 square feet. Most ready-mix companies have a minimum order of 3–4 yards, with extra charges for smaller amounts.
How many cubic yards of concrete do I need?
Cubic yards = (Length × Width × Depth) ÷ 27. All dimensions must be in feet first — convert depth from inches by dividing by 12. Always add 5–10% for waste from spillage, over-excavation, and uneven subgrade. For example: a 20ft × 10ft × 4-inch slab = 20 × 10 × (4/12) ÷ 27 = 2.47 cubic yards. Add 10% = 2.72 yards to order.
How to Calculate Concrete Needed
Calculating the right amount of concrete prevents costly over-ordering and time-wasting return trips to the supply store. The key variables are area (length × width) and depth — which together give you volume. Most materials are sold by the cubic yard (27 cubic feet) or by the bag/pallet.
The Basic Formula
Volume (cubic feet) = Length (ft) × Width (ft) × Depth (ft)
Cubic yards = Cubic feet ÷ 27
Always add 10% for waste, spillage, and uneven surfaces. It's cheaper to have a little extra than to run short mid-project.
How to Use This Calculator
- Measure your area in feet (length and width, or use square footage if you know it)
- Enter the required depth or thickness in inches
- Click Calculate to see cubic yards, cubic feet, and approximate bag quantities
- Add 10% to the result for waste before placing your order
Common Depth Guidelines
- Walkways and patios (concrete): 4 inches thick minimum
- Driveways (concrete): 6 inches thick for passenger vehicles
- Gravel driveways: 4–6 inches deep
- Mulch: 2–3 inches for weed suppression; 3–4 inches in hot climates
- Topsoil for lawns: 4–6 inches minimum for good root development
Ordering Tips
Ready-mix concrete is delivered in trucks and is cost-effective for large pours (over 1 cubic yard). For smaller projects, bagged concrete mix works well — an 80-lb bag covers about 0.6 cubic feet when mixed. Calculate the number of bags by dividing your total cubic feet by 0.6.