Gravel Driveway Calculator

How Much Gravel Do I Need for a Driveway?

How much gravel do I need? Measure the driveway’s length and width, decide on a depth, and convert the volume to the tons or cubic yards your supplier sells, with a small allowance on top. This guide walks through each step, including curved and irregular drives, and the mistakes that most often lead to a short order.

Written by Mubarak Hussain · Numbers checked against the gravel driveway calculator · Report an error

Quick example: a 12 × 40 ft driveway needs about 6.84 tons of crushed stone for a 3 inch top-up, or 13.69 tons for a 6 inch new layer, both with a 10% allowance. You would order 7 and 14 tons. Open the calculator to use your own measurements.

Step 1: Measure the length and width

Every estimate starts from the surface area. A long tape or a measuring wheel makes this easier.

  • Straight driveways: measure the length from the road edge to the garage or parking area, and the width in several places. If the width changes, use the average or measure it in sections.
  • Curved driveways: measure along the centre line of the curve to get the true length. If the drive widens at bends, treat the wider parts as separate sections.
  • Parking pads and turnarounds: split odd shapes into rectangles (length × width) and triangles (base × height ÷ 2), work out each area and add them up.

Step 2: Choose the depth

Depth has the biggest effect on the quantity, and it is the step people most often underestimate. Common planning starting points are about 2 inches to top up a firm existing drive, 3 to 4 inches to resurface, and 6 inches or more in two layers for a new drive. The right depth for your drive depends on soil, drainage and traffic: see the gravel driveway depth guide for the layers and the limits of these ranges.

Step 3: Work out the cubic yards

Convert the depth from inches to feet by dividing by 12, multiply by the area, then divide by 27 to get cubic yards.

area (ft²) = length × width
cubic yards = area × (depth in inches ÷ 12) ÷ 27

For the 12 × 40 ft example at 6 inches: 480 × 0.5 = 240 cubic feet, and 240 ÷ 27 = 8.89 cubic yards.

Step 4: Add an allowance

Ordering the exact volume usually leaves you short: the ground is uneven, some stone is lost at the edges, and loose gravel settles when it is rolled or driven on. Many people add 10% to 15%. The calculators start at 10% (15% for a base layer); that is a planning choice, so use your supplier’s or contractor’s figure if they give one. For the example, 8.89 × 1.10 = 9.78 cubic yards.

Step 5: Convert to tons and round up

Multiply the cubic yards by the material’s density in tons per cubic yard. This site’s planning values are 1.40 for clean crushed stone such as #57 and 1.50 for dense road base or crusher run. Ask your supplier for the figure for their material. For the example, 9.78 × 1.40 = 13.69 tons, so you would order 14 tons. Most suppliers sell whole tons, so round up. The tons to cubic yards calculator converts in either direction.

Common mistakes that lead to a short order

  • Forgetting to divide the depth in inches by 12, or the cubic feet by 27.
  • Measuring the width at the narrowest point only.
  • Leaving out parking areas, turnarounds or the apron at the road.
  • Ordering the exact volume with no allowance.
  • Using a density for a different material from the one being delivered.
  • Mixing up US tons (2,000 lb) and metric tonnes (1,000 kg).