How Much Concrete Do You Need for a Driveway?
A 12 by 24 foot driveway poured 4 inches thick needs about 3.6 cubic yards of concrete. Multiply length by width by thickness in feet, then divide by 27. Add 5 to 10 percent for waste, so plan on ordering about 4 cubic yards for a typical single-car slab.
The short version of the math
Concrete is ordered by the cubic yard, but you measure a driveway in feet and inches. The conversion is the whole job: find the slab's volume in cubic feet, then divide by 27, because one cubic yard holds 27 cubic feet.
For a 12 ft × 24 ft driveway poured 4 inches thick, that is 12 × 24 × (4 ÷ 12) = 96 cubic feet, and 96 ÷ 27 = 3.56 cubic yards. That is the volume of the slab itself. It is not yet the amount you should order.
Driveway concrete quantity chart
The table below shows the slab volume for common driveway sizes at the two most common residential thicknesses. These are exact volumes with no waste allowance.
| Driveway size | Area | 4 in thick | 5 in thick |
|---|---|---|---|
| 10 × 20 ft (one car, short) | 200 sq ft | 2.47 yd³ | 3.09 yd³ |
| 12 × 24 ft (one car) | 288 sq ft | 3.56 yd³ | 4.44 yd³ |
| 12 × 30 ft (one car, long) | 360 sq ft | 4.44 yd³ | 5.56 yd³ |
| 20 × 20 ft (two car) | 400 sq ft | 4.94 yd³ | 6.17 yd³ |
| 20 × 24 ft (two car, deep) | 480 sq ft | 5.93 yd³ | 7.41 yd³ |
| 24 × 24 ft (two car, wide) | 576 sq ft | 7.11 yd³ | 8.89 yd³ |
To check your own numbers, use the concrete calculator. If your driveway is not a clean rectangle, split it into rectangles, calculate each one, and add the results. The square footage calculator helps with that, and the cubic yard calculator converts any volume you already have.
How thick should a driveway be?
Four inches is the common minimum for a driveway that carries ordinary passenger cars and light trucks on a compacted gravel base. Going to 5 inches adds about 25% more concrete by volume, as the table shows, and gives the slab more load capacity. Thickened edges, where the outer 4 to 8 inches of the slab are poured 1 to 2 inches deeper, are also common because the edges take the most punishment. If heavy vehicles such as delivery trucks or RVs will use the drive, ask your concrete contractor or local building department what thickness they specify. Local rules and soil conditions vary, so treat any chart as a starting point.
Add a waste allowance before you order
Real pours use more concrete than the geometry says. The subgrade is never perfectly level, forms bow slightly, and some concrete is lost in the chute and the truck. Most estimators add 5% to 10%. On the 12 × 24 ft driveway at 4 inches, a 10% allowance turns 3.56 cubic yards into about 3.9, so you would round up to 4 cubic yards.
Ordering slightly too much costs a little. Ordering too little means a second delivery, a cold joint where fresh concrete meets partly set concrete, and often a short-load fee. When in doubt, round up.
Do not forget the gravel base
A driveway slab sits on a compacted base, commonly 4 inches of crushed stone or gravel. That is a separate material order. Work out the base with the gravel calculator using the same length and width and a depth of 4 inches. Gravel is sold by the ton, so the calculator converts volume to weight for you.
Concrete or asphalt?
Both are common. Concrete usually costs more up front and lasts longer with less maintenance, while asphalt is cheaper to lay and easier to repair. If you are comparing the two, the asphalt calculator gives tons for the same footprint, so you can price both options on the same measurements.
Common mistakes
- Mixing units. Thickness is in inches, length and width are in feet. Forgetting to divide inches by 12 makes the answer 12 times too large.
- Measuring the finished surface instead of the forms. Measure the area the concrete will fill, including thickened edges.
- Skipping the waste allowance. Add 5% to 10% and round up to the next quarter or half yard.
- Ignoring slope. A driveway that slopes for drainage has a slightly varying depth. Measure the average thickness.
- Forgetting the base and reinforcement. Gravel, mesh or rebar, and expansion joint material are all extra.
Prices and minimum order sizes differ by region, so call two or three local ready-mix suppliers for a quote. The volumes in this guide are plain geometry, but your final order should reflect your site and your contractor's advice.
Calculators for this guide
Frequently asked questions
How many yards of concrete do I need for a 12 x 24 driveway?
A 12 by 24 foot driveway poured 4 inches thick needs 3.56 cubic yards, or about 4 cubic yards once you add 10% for waste. At 5 inches thick it needs 4.44 cubic yards before waste.
How thick should a concrete driveway be?
Four inches is the common minimum for passenger cars on a compacted gravel base. Five inches adds about 25% more concrete and more load capacity, and heavy vehicles may call for more. Ask a local contractor what applies to your site.
How much extra concrete should I order?
Most estimators add 5% to 10% for uneven subgrade, spillage and form movement, then round up to the next quarter or half yard.
Sources and further reading
- How Thick Should a Concrete Driveway Be? — The Concrete Network
More guides
Estimates only. Always confirm quantities with your supplier or a qualified contractor before ordering, and add extra for waste and site conditions.