How Much Crushed Stone for a 20x36 Parking Pad?

A 20 by 36 foot parking pad is 720 square feet. How much crushed stone for a 20x36 parking pad depends on depth: at 4 inches it is about 8.89 cubic yards or 12.4 tons. Suppliers usually sell by the ton, so the tonnage is the number to give them.

Volume and tonnage calculator →

The math for a 20x36 parking pad

Area: 20 × 36 = 720 sq ft.
Depth in feet: 4 ÷ 12 = 0.333 ft.
Cubic feet: 720 × 0.333 = 240.0 cu ft.
Cubic yards: ÷ 27 = 8.89 yd³.
Tons: × 1.4 = 12.4 tons.

The volume and tonnage calculator does this for any size.

Crushed stone needed by depth

Depth	Cubic yards	Tons (approx.)	Tons +10%
2 in	4.44	6.2	6.8
3 in	6.67	9.3	10.3
4 in	8.89	12.4	13.7
6 in	13.33	18.7	20.5

About crushed stone

Crushed stone has fractured faces, so the pieces interlock when compacted. That is why it holds a driveway or pad shape better than round stone of the same size. 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. For parked vehicles, the depths in the table above are a reasonable starting range.

Ordering tips

Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
Delivery size. 13.7 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.

Where crushed stone fits

Works well for:

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

Think twice 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 14x28 area at 2 inches takes about 3.4 tons.
Weight used here: about 1.4 tons per cubic yard.

Where estimates go wrong

Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.

Questions people ask

How many tons of crushed stone for a 20x36 parking pad?

About 12.4 tons at 4 inches deep, or 13.7 tons with 10 percent extra.

How many cubic yards is a 20x36 parking pad at 4 inches?

About 8.89 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 20x36?

720 square feet.

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