How to Use This Calculator
Enter your driveway length and width in feet. Set the thickness: 4 inches for standard passenger vehicles, 5 to 6 inches for heavier use. The calculator returns cubic yards for your ready-mix order and bag counts for 80lb, 60lb, and 40lb bagged mixes. Results include a 10% waste factor for form overflow, uneven subgrade, and mixing loss. For driveways with a flare at the street or a curved section, calculate the main rectangle separately and add the flare area. Use the preset buttons to instantly populate common driveway dimensions and see the concrete requirement right away.
How to Calculate Concrete for a Driveway
Formula: cubic yards = (length × width × thickness ÷ 12) ÷ 27. Divide thickness in inches by 12 to get feet. Multiply all three dimensions to get cubic feet. Divide by 27 — the number of cubic feet in one cubic yard.
Worked example: a 20 × 20 driveway at 5 inches thick. Convert thickness: 5 ÷ 12 = 0.417 ft. Multiply: 20 × 20 × 0.417 = 166.7 cubic feet. Divide: 166.7 ÷ 27 = 6.17 cubic yards. Add 10% waste: 6.17 × 1.10 = 6.79. Order 7 cubic yards from your ready-mix plant.
For bag counts at 5-inch depth with 80lb bags (0.60 cubic feet each): 166.7 × 1.10 = 183.3 cubic feet ÷ 0.60 = 306 bags. That's clearly a ready-mix job — but knowing the number confirms why. Any pour over 2 cubic yards where you're relying on bagged concrete means running out mid-pour and creating a cold joint. Ready-mix eliminates that risk.
Concrete Driveway Tips
Thickness is the most important decision you'll make. The difference between a 4-inch and 6-inch driveway is roughly 50% more concrete. That extra material costs money upfront but prevents cracking under vehicle loads and in freeze-thaw conditions. Driveways that crack in the first few years almost always used insufficient thickness for the soil conditions and vehicle weights involved.
Specify air-entrained concrete in cold climates. This is a standard admixture at every ready-mix plant. It distributes microscopic air bubbles through the mix that give the concrete room to expand when water in the slab freezes. Without air entrainment, a driveway in a hard-freeze climate will surface scale — thin layers peeling off — within three to five winters regardless of PSI strength.
Place fiber mesh or rebar before the pour. Never lay reinforcement directly on the subgrade. Use plastic chairs or dobies to hold wire mesh or rebar at mid-depth (1.5 to 2 inches above the base for a 4-inch slab). Reinforcement sitting on the bottom provides no tensile benefit — it must be centered in the slab depth to resist cracking under load.
What to Buy
For driveways under 1 cubic yard (small repairs or short apron sections): QUIKRETE 5000 PSI or Sakrete High Strength 80lb bags. Both cure to structural strength faster than standard mix and are appropriate for driveway loads.
For complete driveways, always use ready-mix concrete. Call your local plant 24 to 48 hours in advance. Specify 3,500 PSI minimum, 4,000 PSI air-entrained for cold climates. Have all forming, base preparation, and reinforcement placement complete before the truck arrives. The clock starts when concrete is batched — not when it arrives. Most plants hold trucks 90 minutes max. Have enough people on site to place and finish the entire pour in one continuous operation.