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How Much Crushed Stone for a 12x20 Parking Pad?

How much crushed stone for a 12x20 parking pad is a quick volume problem. 240 square feet at 4 inches comes to 2.96 cubic yards. Crushed stone usually weighs about 1.35 to 1.5 tons per cubic yard, so plan on roughly 4.1 tons.

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The math for a 12x20 parking pad

  1. Area: 12 × 20 = 240 sq ft.
  2. Depth in feet: 4 ÷ 12 = 0.333 ft.
  3. Cubic feet: 240 × 0.333 = 80.0 cu ft.
  4. Cubic yards: ÷ 27 = 2.96 yd³.
  5. Tons: × 1.4 = 4.1 tons.

The volume and tonnage calculator does this for any size.

Crushed stone needed by depth

DepthCubic yardsTons (approx.)Tons +10%
2 in1.482.12.3
3 in2.223.13.4
4 in2.964.14.6
6 in4.446.26.8

About crushed stone

Most quarries sell crushed stone by a size number or a screen size. Clean crushed stone drains well; stone with fines packs harder but sheds water more slowly. If the yard sells by the cubic yard instead of the ton, use the cubic-yard column directly.

Preparing the parking pad

Dig out organic soil, compact the subgrade and set an edge so the stone does not migrate onto the lawn. A pad that holds parked weight for long periods benefits from a dense base under the surface stone. Since the parking pad carries parked vehicles, a little extra depth is cheap insurance.

Ordering tips

  • Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
  • Delivery size. 4.6 tons fits in a single 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 parking pad as firm ground allows.

Good and poor uses for crushed stone

Works well for:

  • Driveway top courses and parking pads
  • Shed and hot tub bases
  • Backfill behind walls when a clean size is used

Poor fit for:

  • Barefoot areas, since angular stone is rough
  • Play areas
  • Places that need a smooth rolling surface for wheels

Quick reference numbers

  • Per inch over 100 sq ft: about 0.43 tons of crushed stone (0.31 cubic yards).
  • Per inch over 1,000 sq ft: about 4.3 tons.
  • Another size for comparison: a 8x16 area at 3 inches takes about 1.7 tons.
  • Weight used here: about 1.4 tons per cubic yard.

Common estimating mistakes

  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
  • Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
  • Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.

Questions people ask

How many tons of crushed stone for a 12x20 parking pad?

About 4.1 tons at 4 inches deep, or 4.6 tons with 10 percent extra.

How many cubic yards is a 12x20 parking pad at 4 inches?

About 2.96 cubic yards.

How much does a cubic yard of crushed stone weigh?

Usually around 1.35 to 1.5 tons, depending on stone size, fines and moisture.

How deep should crushed stone be for a parking pad?

The table above shows 2 to 6 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 12x20?

240 square feet.

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