How Much Crushed Stone for a 20x40 Parking Pad?
How much crushed stone for a 20x40 parking pad: at 4 inches deep you need about 9.88 cubic yards, which is roughly 13.8 tons at 1.4 tons per yard. The parking pad covers 800 square feet, so every inch of depth adds about 2.47 yards.
Volume and tonnage calculator →The math for a 20x40 parking pad
- Area: 20 × 40 = 800 sq ft.
- Depth in feet: 4 ÷ 12 = 0.333 ft.
- Cubic feet: 800 × 0.333 = 266.7 cu ft.
- Cubic yards: ÷ 27 = 9.88 yd³.
- Tons: × 1.4 = 13.8 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 | 4.94 | 6.9 | 7.6 |
| 3 in | 7.41 | 10.4 | 11.4 |
| 4 in | 9.88 | 13.8 | 15.2 |
| 6 in | 14.81 | 20.7 | 22.8 |
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. Weight per yard is a planning number; the scale ticket at the yard is the real one.
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. 15.2 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 parking pad as firm ground allows.
When to choose crushed stone
Good uses:
- 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 12x24 area at 2 inches takes about 2.5 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.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
- Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
- Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
Questions people ask
How many tons of crushed stone for a 20x40 parking pad?
About 13.8 tons at 4 inches deep, or 15.2 tons with 10 percent extra.
How many cubic yards is a 20x40 parking pad at 4 inches?
About 9.88 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 20x40?
800 square feet.
Related guides
- How Much Does a Ton of Crushed Stone Cover?
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Many Tons of Gravel in a Dump Truck? Loads and Coverage
- How Much Does a Ton of Gravel Cover? Depth Chart
- How Much Crushed Stone for a 20x30 Parking Pad?
- How Much Crushed Stone for a 20x36 Parking Pad?
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