How Much Does 18 Tons of River Rock Cover?
How much does 18 tons of river rock cover depends on how deep you spread it. At about 1.35 tons per cubic yard, 18 tons is roughly 13.3 cubic yards. Spread 3 inches deep, that covers about 1,440 square feet. Go thinner and it covers more; go deeper and it covers less.
Volume and tonnage calculator →How the coverage is figured
- Tons to cubic yards: 18 ÷ 1.35 = 13.3 yd³.
- Cubic yards to cubic feet: × 27 = 360 cu ft.
- Divide by depth in feet: at 3 inches (0.250 ft), 360 ÷ 0.250 = 1,440 sq ft.
Coverage of 18 tons at different depths
| Depth | Square feet covered | Square yards |
|---|---|---|
| 2 in | 2,160 | 240 |
| 3 in | 1,440 | 160 |
| 4 in | 1,080 | 120 |
About river rock
River rock is mostly decorative and for drainage beds. It is not meant to be driven on and tends to roll if used as a walking surface. Weight runs about 1.25 to 1.45 tons per cubic yard, so treat the table as a planning range rather than an exact figure.
What 18 tons looks like on site
18 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 river rock
Best suited to:
- Dry creek beds and drainage swales
- Decorative borders and planting beds
- Around downspouts to stop splash erosion
Think twice for:
- Walking surfaces
- Driveways
- Bases under slabs or pavers
Quick reference numbers
- Per inch over 100 sq ft: about 0.42 tons of river rock (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.2 tons.
- Another size for comparison: a 20x25 area at 4 inches takes about 8.3 tons.
- Weight used here: about 1.35 tons per cubic yard.
Common estimating mistakes
- Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
- 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.
- Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
Questions people ask
How many cubic yards is 18 tons of river rock?
About 13.3 cubic yards at 1.35 tons per yard.
How many square feet does 18 tons of river rock cover at 3 inches?
About 1,440 square feet.
How many square feet does 18 tons cover at 2 inches?
About 2,160 square feet.
How much does a yard of river rock weigh?
About 1.25 to 1.45 tons.
Will 18 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
- How Much Does a Ton of River Rock Cover?
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Many Tons of Gravel in a Dump Truck? Loads and Coverage
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