20 × 20 driveway: concrete by thickness
| Thickness | Cubic yards | Ready-mix at $175/yd |
|---|---|---|
| 4 in | 5.43 | $951 |
| 5 in | 6.79 | $1,188 |
| 6 in | 8.15 | $1,426 |
Driveways this size are always poured from a ready-mix truck; it would take over 300 bags by hand. Concrete trucks typically carry 8 to 10 cubic yards, so a 20 × 20 driveway at 6 inches is about one full truck.
How thick should a driveway be?
Four inches is the minimum for passenger cars. Five to six inches is better for heavier vehicles, trucks and cold climates, and the thicker slab costs only about 20% to 50% more in concrete.
Frequently asked questions
How many yards of concrete for a 2-car driveway?
A typical 20 × 20 ft two-car driveway needs about 5.4 cubic yards at 4 inches or 8.2 cubic yards at 6 inches, including 10% extra.
Do I need gravel under a concrete driveway?
Yes. Most driveways sit on 4 to 6 inches of compacted gravel base. Use the gravel calculator to size it.
Last reviewed: 2026-10-31