How Much Crushed Stone for a 18x20 Parking Pad?
A 18 by 20 foot parking pad is 360 square feet. How much crushed stone for a 18x20 parking pad depends on depth: at 4 inches it is about 4.44 cubic yards or 6.2 tons. Suppliers usually sell by the ton, so the tonnage is the number to give them.
Volume and tonnage calculator →The math for a 18x20 parking pad
- Area: 18 × 20 = 360 sq ft.
- Depth in feet: 4 ÷ 12 = 0.333 ft.
- Cubic feet: 360 × 0.333 = 120.0 cu ft.
- Cubic yards: ÷ 27 = 4.44 yd³.
- Tons: × 1.4 = 6.2 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 | 2.22 | 3.1 | 3.4 |
| 3 in | 3.33 | 4.7 | 5.1 |
| 4 in | 4.44 | 6.2 | 6.8 |
| 6 in | 6.67 | 9.3 | 10.3 |
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. Ask your supplier for their own tons-per-yard figure, since stone source and moisture shift it.
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. 6.8 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.
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
Less suited to:
- 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 20x25 area at 3 inches takes about 6.5 tons.
- Weight used here: about 1.4 tons per cubic yard.
Where estimates go wrong
- 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.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
- 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 18x20 parking pad?
About 6.2 tons at 4 inches deep, or 6.8 tons with 10 percent extra.
How many cubic yards is a 18x20 parking pad at 4 inches?
About 4.44 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 18x20?
360 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 16x40 Parking Pad?
- How Much Crushed Stone for a 16x50 Parking Pad?
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