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How Much Road Base for a 24x40 Driveway?

A 24 by 40 foot driveway is 960 square feet. How much road base for a 24x40 driveway depends on depth: at 4 inches it is about 11.85 cubic yards or 17.8 tons. Suppliers usually sell by the ton, so the tonnage is the number to give them.

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The math for a 24x40 driveway

  1. Area: 24 × 40 = 960 sq ft.
  2. Depth in feet: 4 ÷ 12 = 0.333 ft.
  3. Cubic feet: 960 × 0.333 = 320.0 cu ft.
  4. Cubic yards: ÷ 27 = 11.85 yd³.
  5. Tons: × 1.5 = 17.8 tons.

The volume and tonnage calculator does this for any size.

Road base needed by depth

DepthCubic yardsTons (approx.)Tons +10%
4 in11.8517.819.6
6 in17.7826.729.3
8 in23.7035.639.1

About road base

Road base is meant to be compacted at close to the right moisture. Dry base rock does not lock up well; a light spray of water before rolling helps. If the yard sells by the cubic yard instead of the ton, use the cubic-yard column directly.

Preparing the driveway

Strip sod and soft topsoil, grade for drainage and compact the subgrade before any stone goes down. Gravel drives last longer with a compacted base layer under the top stone and a slight crown so water runs off. This driveway sees car and truck traffic, so match the depth to that load rather than to the minimum.

Ordering tips

  • Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
  • Delivery size. 19.6 tons may take more than one typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
  • Bulk vs bags. At this size bulk delivery is usually the practical choice.
  • Where it drops. Have the truck dump as close to the driveway as firm ground allows.

When to choose road base

Good uses:

  • Base under asphalt and concrete
  • Gravel roads and drives
  • Equipment and shed pads

Poor fit for:

  • Drainage layers
  • Decorative surfaces
  • Surfaces that will stay uncompacted

Quick reference numbers

  • Per inch over 100 sq ft: about 0.46 tons of road base (0.31 cubic yards).
  • Per inch over 1,000 sq ft: about 4.6 tons.
  • Another size for comparison: a 10x20 area at 3 inches takes about 2.8 tons.
  • Weight used here: about 1.5 tons per cubic yard.

Where estimates go wrong

  • Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
  • Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
  • Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.

Questions people ask

How many tons of road base for a 24x40 driveway?

About 17.8 tons at 4 inches deep, or 19.6 tons with 10 percent extra.

How many cubic yards is a 24x40 driveway at 4 inches?

About 11.85 cubic yards.

How much does a cubic yard of road base weigh?

Usually around 1.4 to 1.65 compacted tons, depending on stone size, fines and moisture.

How deep should road base be for a driveway?

The table above shows 4 to 8 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 24x40?

960 square feet.

Related guides

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