How Much River Rock for a 20 Foot Circle?
Round areas such as fire pit patios, tree rings and seating circles use less stone than a square of the same width. A 20-foot circle is about 314.2 square feet; at 3 inches that is 3.9 tons of river rock.
Volume and tonnage calculator →The math
- Area: 314.2 sq ft.
- Depth in feet: 3 ÷ 12 = 0.250 ft.
- Cubic yards: 314.2 × 0.250 ÷ 27 = 2.91 yd³.
- Tons: × about 1.35 tons per yard = 3.9 tons.
The gravel calculator does this for any size.
Related: How Much Gravel for a 20 Foot Circle?
River rock needed by depth
| Depth | Cubic yards | Tons of river rock | Tons +10% |
|---|---|---|---|
| 2 in | 1.94 | 2.6 | 2.9 |
| 3 in | 2.91 | 3.9 | 4.3 |
| 4 in | 3.88 | 5.2 | 5.8 |
| 6 in | 5.82 | 7.9 | 8.6 |
Using a circle of stone
Circles show up around fire pits, under swing sets, around trees and as seating areas. Steel or paver edging keeps the round shape crisp and holds loose stone in place. Rake the stone level after spreading and add a thin top-up after the first season.
Related: How Much River Rock for a 6 Foot Circle?
Buying the stone
Most quarries and landscape yards deliver by the ton; ask whether there is a minimum and a delivery fee, and where the driver can dump without damaging your lawn. River rock is smooth and decorative; larger sizes cover less area per ton at the same depth. Round up by about 10 percent for compaction and uneven ground.
Measuring the area
Use a long tape and measure each side twice. If the ground slopes, measure depth at the high and low ends and average them. Irregular outlines can be broken into simple rectangles, triangles and circles; add the pieces for the total square footage before converting to tons.
Tools for the job
For anything bigger than a small path, rent a plate compactor; hand tampers cannot match it. A wheelbarrow, shovels, a hard rake and stakes with string are the rest of the kit. Wet the stone lightly before compacting so it binds.
Questions people ask
How many tons of river rock for a 20 ft circle?
About 3.9 tons at 3 inches deep.
How many square feet is a 20 foot circle?
About 314.2 square feet.
How many tons of river rock are in a cubic yard?
Roughly 1.35 tons for planning, but suppliers vary with stone size and moisture.
Do I need to compact it?
Yes for anything that carries weight. Compact in lifts of a few inches with a plate compactor.
Related guides
- Gravel for a Fire Pit Area: Best Types and Depth
- How Much Does a Ton of Gravel Cover? Depth Chart
- Tons to Cubic Yards for Gravel: Conversion Chart
- Crushed Stone vs Gravel: Differences and Best Uses
- Geotextile Fabric for Driveways: Woven vs Nonwoven and How Much You Need
- Compacting a Driveway Gravel Base in Lifts
- How Much Gravel for an 18 Foot Circle?
- How Much Pea Gravel for a 20 Foot Circle?
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