How much concrete is an 18×20 driveway?
An 18-by-20-foot driveway covers 360 square feet. At the standard 5-inch thickness that's about 5.56 cubic yards of concrete before waste, or roughly 6.11 yards once you add a 10% allowance. At about 6.11 cubic yards a single ready-mix truck (roughly 10 cubic yards) delivers this in one load with room to spare. The calculator above is pre-filled to these dimensions; change the thickness or price to match your job.
Concrete for an 18×20 driveway by thickness
| Thickness | Concrete to order | 80 lb bags | Material cost |
|---|---|---|---|
| 5″ (standard) | 6.11 yd³ | 275 | $978 |
| 6″ | 7.33 yd³ | 331 | $1,173 |
| 8″ | 9.78 yd³ | 440 | $1,564 |
Material cost at $160/yd³ ready-mix, before delivery fees. Cost data updated June 2026.
Common questions
How many yards of concrete for an 18x20 driveway?
An 18x20 driveway at 5 inches thick needs about 5.56 cubic yards before waste. Add 5-10% extra so you don't come up short. Change the thickness in the calculator above to see how it affects the total.
How many bags of concrete for an 18x20 driveway?
At 5 inches thick that's roughly 275 eighty-pound bags with a 10% allowance. Past about 1 cubic yard (around 45 bags), ready-mix delivery is usually cheaper and far less work than mixing bags by hand.
What does an 18x20 driveway cost?
Material alone is a small share of the total. Installed, driveways this size run a wide range depending on thickness, finish, site prep, and region. Use the calculator's installed-cost range as a ballpark, then compare local quotes for a real price.