Concrete for a 20 × 30 Driveway at 4″
A 20 × 30 ft driveway poured 4 inches thick needs about 8.15 cubic yards (≈ 6.23 m³) of concrete (including a 10% waste buffer) — roughly 367 bags of 80 lb mix, weighing about 16.5 tons. Car driveways are typically 4 inches thick; go thicker for heavy vehicles.
This is over ~1 cubic yard — it fits in one ready-mix truck (~10 cu yd each). Ready-mix delivery is usually cheaper than mixing 367 bags by hand.
Adjust the numbers
Pre-filled for a 20 × 30 ft slab — change anything to match your project.
A flat, solid pad of concrete — a patio, shed floor, walkway, or driveway. Measure how long and how wide it is, and how thick to pour it (4 inches is typical).
Bag & ready-mix counts include your 10% waste buffer.
Estimate only. These figures help you plan how much to buy — they are not engineering or structural advice. Actual needs vary with site conditions, waste, and installation method, so order a little extra and confirm final quantities with your supplier or contractor before you buy or start the job.
Other driveway sizes
Frequently asked questions
How much concrete do I need for a 20x30 driveway?
A 20 × 30 ft driveway at 4 inches thick contains 200 cubic feet of concrete — about 7.41 cubic yards. With a 10% waste buffer, order 8.15 cubic yards.
How many bags of concrete for a 20x30 driveway at 4 inches?
Roughly 367 bags of 80 lb mix, 489 bags of 60 lb, or 734 bags of 40 lb (including 10% waste). At this size, ready-mix delivery is usually cheaper and easier than mixing bags.
How much does the concrete for a 20x30 driveway weigh?
About 16.5 tons (33,000 lb) of wet concrete.
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