Concrete Driveway Volume Calculator

Enter Calculation

Length (ft)

Width (ft)

Thickness (in)

Formula

Show calculation steps (1)

1. Number of Bags Required

   

   V = cubic feet of concrete; each 80 lb bag yields 0.6 cu ft, each 60 lb bag yields 0.45 cu ft (rounded up)

Results

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Concrete Needed

5.93

cubic yards

Volume (cubic feet)	160 ft³
With 10% waste	6.52 yd³
80 lb bags needed	267
60 lb bags needed	356

What this calculator does

The Concrete Driveway Volume Calculator estimates how much concrete you need to pour a rectangular driveway, slab, patio or footing. Enter the length and width in feet and the slab thickness in inches, and it returns the volume in cubic yards and cubic feet, a recommended amount including 10% waste, and the number of 80 lb and 60 lb pre-mix bags required.

A driveway slab measured by length (L), width (W) and thickness (T).

How to use it

Measure the area you plan to pour. Enter the length and width in feet and the desired thickness in inches (4 inches is typical for a residential driveway, 6 inches for heavy vehicles). Read the cubic yards figure — concrete is usually ordered by the yard. For small jobs, use the bag counts instead.

The formula explained

Volume in cubic feet is length × width × thickness, but thickness must first be converted from inches to feet by dividing by 12. There are 27 cubic feet in one cubic yard, so cubic yards = cubic feet ÷ 27. We add 10% to account for spillage, uneven subgrade and over-excavation.

$$\text{Cubic Yards} = \frac{\text{Length (ft)} \times \text{Width (ft)} \times \frac{\text{Thickness (in)}}{12}}{27}$$

The number of pre-mix bags required is:

$$\begin{gathered} \text{Bags}_{80} = \left\lceil \frac{V}{0.6} \right\rceil, \qquad \text{Bags}_{60} = \left\lceil \frac{V}{0.45} \right\rceil \\[1.5em] \text{where}\quad V = \text{Length (ft)} \times \text{Width (ft)} \times \frac{\text{Thickness (in)}}{12} \end{gathered}$$

Multiply length, width and thickness (in feet), then divide by 27 to get cubic yards.

Worked example

For a 40 ft × 12 ft driveway at 4 inches thick: cubic feet = \(40 \times 12 \times (4 \div 12) = 160 \text{ ft}^3\). Cubic yards = \(160 \div 27 \approx 5.93 \text{ yd}^3\). With 10% waste \(\approx 6.52 \text{ yd}^3\). Bags: \(160 \div 0.6 = 267\) (80 lb) or \(160 \div 0.45 = 356\) (60 lb) — which is why large pours are ordered ready-mix rather than bagged.

FAQ

How thick should a driveway be? Four inches suits cars; use six inches for trucks or RVs.

How many bags in a cubic yard? Roughly 45 × 80 lb bags or 60 × 60 lb bags per cubic yard.

Should I round up my order? Yes — always order a little extra; running short mid-pour creates a cold joint.