How Much Does 21 Tons of #57 Stone Cover?
How much does 21 tons of #57 stone cover depends on how deep you spread it. At about 1.35 tons per cubic yard, 21 tons is roughly 15.6 cubic yards. Spread 4 inches deep, that covers about 1,260 square feet. Every added inch of depth cuts the coverage noticeably.
Volume and tonnage calculator →How the coverage is figured
- Tons to cubic yards: 21 ÷ 1.35 = 15.6 yd³.
- Cubic yards to cubic feet: × 27 = 420 cu ft.
- Divide by depth in feet: at 4 inches (0.333 ft), 420 ÷ 0.333 = 1,260 sq ft.
Coverage of 21 tons at different depths
| Depth | Square feet covered | Square yards |
|---|---|---|
| 2 in | 2,520 | 280 |
| 3 in | 1,680 | 187 |
| 4 in | 1,260 | 140 |
| 6 in | 840 | 93 |
About #57 stone
#57 stone is a clean crushed stone in roughly the 1/2 to 1 inch range with very few fines. It drains fast, which suits drainage layers and the top of a gravel drive, but it does not pack into a hard crust by itself. Weight runs about 1.3 to 1.45 tons per cubic yard, so treat the table as a planning range rather than an exact figure.
What 21 tons looks like on site
21 tons will usually take two or more truck loads, though legal limits vary by truck and state. Spread from the pile with a loader, skid steer or wheelbarrow, then rake to depth before compacting if the material calls for it.
- Check depth as you go. Stakes marked at the target depth help keep the spread even.
- Expect some loss. Compaction and uneven ground use more than the flat-math figure. Keep about 10 percent in reserve.
- Ask about moisture. Wet material weighs more, so a ton of it covers less.
To run your own numbers, use the volume and tonnage calculator.
Good and poor uses for #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 12x24 area at 2 inches takes about 2.4 tons.
- Weight used here: about 1.35 tons per cubic yard.
Common estimating mistakes
- Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
- Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
- Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
Questions people ask
How many cubic yards is 21 tons of #57 stone?
About 15.6 cubic yards at 1.35 tons per yard.
How many square feet does 21 tons of #57 stone cover at 4 inches?
About 1,260 square feet.
How many square feet does 21 tons cover at 2 inches?
About 2,520 square feet.
How much does a yard of #57 stone weigh?
About 1.3 to 1.45 tons.
Will 21 tons fit in one truck?
It depends on the truck. Single-axle dump trucks often carry under 10 tons and tandems around 13 to 16; your supplier will know their limits.
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 19 Tons of #57 Stone Cover?
- How Much Does 20 Tons of #57 Stone Cover?
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