Concrete Driveway Calculator: Estimate Cubic Yards & Bags for Your Slab
Enter your driveway's length, width, and thickness and this calculator returns the exact cubic yards of concrete you need, plus a ready-mix cost estimate. Since most residential driveways are poured 5 to 6 inches thick and reinforced with rebar or wire mesh, it defaults to those specs for a load-ready slab.
Estimated concrete
Estimates only. Add ~5–10% for waste. Bag yields: 40 lb ≈ 0.30, 60 lb ≈ 0.45, 80 lb ≈ 0.60 cu ft. Concrete ≈ 150 lb per cu ft.
How to Use the Concrete Driveway Calculator
- 1
Enter your dimensions
Type the length, width and thickness of your slab, footing or pad and choose your units, feet, inches or meters.
- 2
Get instant volume
See the result in cubic yards, cubic feet and cubic meters, plus weight, the moment you type, no page reloads.
- 3
Buy the right amount
We convert volume into the exact number of 40, 60 and 80 lb bags, truck loads and cost so you order without waste or shortfalls.
The formula
ft3 = Length_ft x Width_ft x (Thickness_in / 12); yd3 = ft3 / 27; cost = yd3 x price + delivery
- ·Length_ft = driveway length (feet)
- ·Width_ft = driveway width (feet)
- ·Thickness_in = slab thickness (inches)
- ·price = concrete price per cubic yard (default $145)
- ·delivery = flat delivery/short-load fee
Residential driveways are usually 4 inches thick, or 5-6 inches where trucks or RVs park. A default 10% waste is added before pricing.
Worked examples
Example 1: Single driveway 16x40 ft, 4 in thick
- Volume = 16 x 40 x (4 / 12) = 213.3 ft3
- Cubic yards = 213.3 / 27 = 7.9 yd3
- Add 10% waste: 7.9 x 1.1 = 8.7 yd3
Result: about 8.7 cubic yards
Example 2: Cost of a 24x24 ft driveway, 5 in thick, at $145/yd plus $120 delivery
- Volume = 24 x 24 x (5 / 12) = 240 ft3 = 8.89 yd3
- With 10% waste: about 9.8 yd3
- Cost = 9.8 x $145 + $120 = $1,421 + $120
Result: about $1,540 for concrete plus delivery
Concrete calculators by project type
Concrete bag yield & coverage
How much mixed concrete a standard bag yields, and how far a cubic yard goes at common slab depths.
| Bag size | Yield (cu ft) | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 | 90 |
| 60 lb | 0.45 | 60 |
| 80 lb | 0.60 | 45 |
- 40 lb
- 60 lb
- 80 lb
Related guides
Concrete Driveway Calculator FAQs
How thick should a concrete driveway be?
A standard residential driveway is poured 5 to 6 inches thick. Use 5 inches for cars and light trucks, and step up to 6 inches if you regularly park RVs, trailers, or heavy vehicles.
How many yards of concrete do I need for a 2-car driveway?
A typical 20 ft by 20 ft two-car driveway at 5 inches thick needs about 6.2 cubic yards. Enter your exact dimensions above for a precise number, and add 5-10% for waste and uneven subgrade.
How much does it cost to concrete a driveway?
Ready-mix concrete runs roughly $125 to $165 per cubic yard for materials. For a 6-yard driveway that's about $750 to $990 in concrete alone, before labor, rebar, gravel base, and finishing.
Do I need rebar in a concrete driveway?
Rebar or welded wire mesh is strongly recommended to control cracking and handle vehicle loads. Most contractors run #3 or #4 rebar in a grid, or lay 6x6 wire mesh, positioned in the middle of the slab thickness.
How much extra concrete should I order for a driveway?
Order 5 to 10% more than the calculated volume to cover spillage, an uneven subgrade, and slight over-excavation. Running short mid-pour risks a cold joint, so it's safer to have a little extra.
Can I pour a driveway with bagged concrete instead of a ready-mix truck?
You can for very small driveways, but it takes about 45 eighty-pound bags per cubic yard, so a full driveway means hundreds of bags. For anything over roughly a cubic yard, a ready-mix truck is faster and cheaper.
What slope should a driveway have for drainage?
Grade the surface at least 1 to 2 percent, roughly 1/8 to 1/4 inch per foot, away from the garage and house. Proper slope keeps water from pooling and freezing, which is a leading cause of surface scaling.
How long before I can drive on a new concrete driveway?
Keep foot traffic off for about 24 hours, wait 7 days before driving a passenger car on it, and hold off heavy trucks or RVs for the full 28-day cure. Early loading is a common cause of cracks.
How far apart should driveway control joints be?
Space joints in feet at about 24 to 30 times the slab thickness in inches, so a 4 inch driveway gets joints every 8 to 10 feet. Keep panels close to square to limit random cracking.
What PSI concrete is best for a driveway?
Use a 3,500 to 4,000 PSI mix, and in freeze-thaw regions specify air-entrained concrete so it resists scaling from ice and deicing salts. Higher strength adds durability for the price.
How deep should the gravel base under a driveway be?
Plan on 4 to 8 inches of well-compacted crushed gravel, using the thicker end for soft or clay soils. A solid, uniform base does more to prevent cracking than simply adding concrete thickness.
Should driveway edges be thickened?
Yes, thicken the edges to 6 to 8 inches, especially at the apron where vehicles drive on and off. Edges take the highest stress, so a thickened perimeter greatly reduces edge cracking.
Do I need reinforcement in a concrete driveway?
Most residential driveways use either wire mesh or a grid of #4 rebar placed at mid-depth to hold cracks tight and add load capacity. Reinforcement matters most on expansive soils or where trucks will park.