How much concrete is a 10×20 slab?
A 10-by-20-foot slab covers 200 square feet. At the standard 4-inch thickness that's about 2.47 cubic yards of concrete before waste, or roughly 2.72 yards once you add a 10% allowance. At about 2.72 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 a 10×20 slab by thickness
| Thickness | Concrete to order | 80 lb bags | Material cost |
|---|---|---|---|
| 4″ (standard) | 2.72 yd³ | 123 | $435 |
| 5″ | 3.40 yd³ | 153 | $543 |
| 6″ | 4.07 yd³ | 184 | $652 |
Material cost at $160/yd³ ready-mix, before delivery fees. Cost data updated June 2026.
Common questions
How many yards of concrete for a 10x20 slab?
A 10x20 slab at 4 inches thick needs about 2.47 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 a 10x20 slab?
At 4 inches thick that's roughly 123 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 a 10x20 slab cost?
Material alone is a small share of the total. Installed, slabs 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.