How Much Asphalt Millings for a 20x20 Parking Pad?

How much asphalt millings for a 20x20 parking pad is a quick volume problem. 400 square feet at 4 inches comes to 4.94 cubic yards. Asphalt millings usually weighs about 1.2 to 1.4 loose tons per cubic yard, so plan on roughly 6.4 tons.

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The math for a 20x20 parking pad

Area: 20 × 20 = 400 sq ft.
Depth in feet: 4 ÷ 12 = 0.333 ft.
Cubic feet: 400 × 0.333 = 133.3 cu ft.
Cubic yards: ÷ 27 = 4.94 yd³.
Tons: × 1.3 = 6.4 tons.

The volume and tonnage calculator does this for any size.

Asphalt millings needed by depth

Depth	Cubic yards	Tons (approx.)	Tons +10%
3 in	3.70	4.8	5.3
4 in	4.94	6.4	7.1
6 in	7.41	9.6	10.6

About asphalt millings

Millings vary by source: some loads are fine and uniform, others carry chunks. Ask the supplier for a screened product if you want a smoother finish, and check local rules, since some areas restrict their use near water. 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. This parking pad sees parked vehicles, 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. 7.1 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 asphalt millings fits

Best suited to:

Rural driveways and farm lanes
Parking areas where a dust-free surface is wanted
Low-cost base under a future paved surface

Think twice for:

Areas near wells or streams where local rules limit them
Decorative or barefoot areas
Jobs needing a uniform, clean look

Quick reference numbers

Per inch over 100 sq ft: about 0.40 tons of asphalt millings (0.31 cubic yards).
Per inch over 1,000 sq ft: about 4.0 tons.
Another size for comparison: a 15x30 area at 4 inches takes about 7.2 tons.
Weight used here: about 1.3 tons per cubic yard.

Common estimating mistakes

Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
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 asphalt millings for a 20x20 parking pad?

About 6.4 tons at 4 inches deep, or 7.1 tons with 10 percent extra.

How many cubic yards is a 20x20 parking pad at 4 inches?

About 4.94 cubic yards.

How much does a cubic yard of asphalt millings weigh?

Usually around 1.2 to 1.4 loose tons, depending on stone size, fines and moisture.

How deep should asphalt millings be for a parking pad?

The table above shows 3 to 6 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 20x20?

400 square feet.

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