How Much #57 Stone for a 20x40 Driveway?
How much #57 stone for a 20x40 driveway: at 4 inches deep you need about 9.88 cubic yards, which is roughly 13.3 tons at 1.35 tons per yard. The driveway covers 800 square feet, so every inch of depth adds about 2.47 yards.
Volume and tonnage calculator →The math for a 20x40 driveway
- 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: × 1.35 = 13.3 tons.
The volume and tonnage calculator does this for any size.
#57 stone needed by depth
| Depth | Cubic yards | Tons (approx.) | Tons +10% |
|---|---|---|---|
| 2 in | 4.94 | 6.7 | 7.3 |
| 3 in | 7.41 | 10.0 | 11.0 |
| 4 in | 9.88 | 13.3 | 14.7 |
| 6 in | 14.81 | 20.0 | 22.0 |
About #57 stone
Since #57 is washed and open-graded, it moves a little underfoot. Many installers put it over a compacted base of a dense-graded stone rather than straight on soil. If the yard sells by the cubic yard instead of the ton, use the cubic-yard column directly.
Preparing the driveway
Strip sod and soft topsoil, grade for drainage and compact the subgrade before any stone goes down. Gravel drives last longer with a compacted base layer under the top stone and a slight crown so water runs off. Since the driveway carries car and truck traffic, 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. 14.7 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 driveway as firm ground allows.
When to choose #57 stone
Good uses:
- French drains and drainage layers
- The top course of a gravel driveway
- Under sheds where water needs to drain away
Less suited to:
- A standalone base, since it does not pack hard without fines
- Paver setting beds
- Walk paths meant for strollers or wheelchairs
Quick reference numbers
- Per inch over 100 sq ft: about 0.42 tons of #57 stone (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.2 tons.
- Another size for comparison: a 14x28 area at 4 inches takes about 6.5 tons.
- Weight used here: about 1.35 tons per cubic yard.
Common estimating mistakes
- Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
- 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 #57 stone for a 20x40 driveway?
About 13.3 tons at 4 inches deep, or 14.7 tons with 10 percent extra.
How many cubic yards is a 20x40 driveway at 4 inches?
About 9.88 cubic yards.
How much does a cubic yard of #57 stone weigh?
Usually around 1.3 to 1.45 tons, depending on stone size, fines and moisture.
How deep should #57 stone be for a driveway?
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
- Number 57 Stone: Size, Weight, Uses, and Coverage
- 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 #57 Stone for a 20x30 Driveway?
- How Much #57 Stone for a 20x35 Driveway?
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