Concrete Driveway Calculator
Use this concrete driveway calculator to size residential driveways, parking aprons, and garage approaches. Calculate exact cubic yardage, ready-mix truckloads, rebar grids, and project material costs.
How to Use This Calculator
- Enter your dimensions — feet for lengths, inches for thickness.
- Adjust the options — waste percentage, bag size and your local concrete price.
- Read your results — volume, bags, weight and cost update live as you type.
The Formula
Driveway volume (yd³) = (Length ft × Width ft × Thickness in ÷ 12) ÷ 27 Worked example: A 20 × 40 ft driveway at 5 in (0.417 ft): 800 ft² × 0.417 = 333.6 ft³ ÷ 27 ≈ 12.35 yd³ — order 13.5 yd³ with 10% waste.
A concrete driveway calculator helps you plan one of the largest concrete investments on a residential property. While standard patios are poured 4 inches thick, professional flatwork contractors and civil standards recommend a minimum of 5 inches for passenger vehicles and 6 inches for heavier trucks, motorhomes, or delivery vehicles.
Driveways require proper subgrade preparation: at least 4 to 6 inches of compacted crushed stone (3/4 inch minus aggregate), #4 rebar on an 18-inch grid supported by chairs, and control joints saw-cut every 10 to 12 feet to manage thermal expansion and shrinkage cracking.
Ready-mix delivery is virtually mandatory for driveways: a typical 2-car 20 × 40 ft driveway requires over 12 cubic yards of concrete (the equivalent of more than 550 bags of 80 lb concrete). Enter your driveway dimensions above to calculate required yardage, 4,000 PSI mix costs, and steel reinforcement.
Frequently Asked Questions
Common questions about the concrete driveway calculator.
How thick should a concrete driveway be?
5 inches is the recommended standard for residential driveways carrying passenger cars and SUVs. Use 6 inches if parking heavy trucks, campers, or equipment.
How much concrete do I need for a 20x40 driveway?
At 5 inches thick, an 800 sq ft driveway requires approximately 12.35 cubic yards (334 cubic feet). With a 10% waste and subgrade variation allowance, order 13.5 cubic yards.
Do I need rebar in a concrete driveway?
Yes. Grade 60 #4 (1/2 inch) rebar placed on an 18-inch grid prevents differential settlement and keeps slab panels tightly tied together if shrinkage cracks occur.
How many days until I can park on a new driveway?
Wait at least 7 days before driving standard passenger cars on new concrete, and 28 days for heavy trucks or RVs.
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