River rock calculator
Enter the area, depth and rock size to get tons (how yards sell it), coverage per ton and the fabric underneath.
Enter your measurements
More options: Compaction · Waste · Price …
- Loose volume (as delivered)
- 0.97 cu yd (26.3 cu ft)
- Or in 0.5 cu ft bags
- 53 bags
- Landscape fabric (with 10% for overlaps)
- 110 sq ft
- Coverage per ton at this depth
- 80 sq ft per ton
- Bulk order (rounded up)
- 1.5 tons (sold by the half ton)
10 ft × 10 ft = 100 sq ft
100 sq ft × 3 in ÷ 12 = 25 cu ft ÷ 27 = 0.93 cu yd
0.93 cu yd compacted × 1 = 0.93 cu yd loose × 1.35 tons/cu yd = 1.25 tons
+ 5% waste = 1.31 tons
Effective rate: ≈ 1.42 tons per cu yd compacted
Bulk: 1.31 tons rounded up to the next ½ ton = 1.5 tons
Quick answers for common sizes
| Example | Answer |
|---|---|
| How much river rock for a 3×40 ft strip by the house | 1.58 tons |
| How much river rock for a 3×25 ft dry creek bed | 1.31 tons |
River rock needed by depth
| Depth | River rock to order | Loose volume (as delivered) | Coverage per ton at this depth |
|---|---|---|---|
| 2 in | 0.88 tons | 0.65 cu yd | 120 sq ft per ton |
| 3 in | 1.31 tons | 0.97 cu yd | 80 sq ft per ton |
| 4 in | 1.75 tons | 1.3 cu yd | 60 sq ft per ton |
| 6 in | 2.63 tons | 1.94 cu yd | 40 sq ft per ton |
Decorative stone should be deep enough to hide the fabric underneath. A common rule of thumb: for small stone (under about 1½ in), about twice the stone size; for larger rock, one stone deep plus about an inch, so 3–5 in stone ends up about 4–5 in deep.
How the river rock estimate works
River rock is rounded, water-worn stone. The piles have a lot of air between the stones, so it tends to be a little lighter per cubic yard than crushed gravel — somewhere around 1.3–1.4 tons per cubic yard is typical. The calculator gets volume from area × depth and multiplies by that density. Nobody compacts decorative rock, so there is no compaction allowance, just 5% for spillage and uneven ground. (A cubic yard is 27 cubic feet, a box 3 ft on each side.)
Yards sell river rock by the ton, usually in half-ton steps, so the result also shows the order rounded up. Under More options you can add the price per ton, the yard’s minimum order, truck size and delivery fee to see the delivered cost.
cubic yards = area (sq ft) × depth (in) ÷ 12 ÷ 27 tons = cubic yards × density (≈ 1.35) sq ft per ton = 2,000 lb ÷ (density in lb/cu ft × depth in ft)
Depth by rock size
| Rock size | Typical depth | Coverage per ton (approx.) |
|---|---|---|
| ¾–1½ in | 2–3 in (about twice the stone size) | ~120 sq ft at 2 in |
| 1–3 in | 3 in | ~80 sq ft |
| 3–5 in | 4–5 in (one stone deep plus about an inch) | ~60 sq ft at 4 in |
| 5 in+ cobbles | 6 in or more | ~40 sq ft at 6 in |
Worked examples
- How much river rock for a 3×40 ft strip by the house — a foundation border in 1–3 in rock.
- How much river rock for a 3×25 ft dry creek bed — larger stone in a dug channel, and why it takes more than the flat area suggests.
Rock versus mulch next to plants
Rock doesn’t break down or feed the soil, and it holds heat. University of Nevada, Reno Extension notes that rock mulches absorb heat and raise the temperature of both the soil and the air around plants, and Colorado State Extension says gravel transfers more heat to the soil than wood chips. Use rock where there are few plants, or plants that like it hot and dry; use organic mulch around thirsty shrubs.
Tips
- Lay a woven or heavy non-woven landscape fabric first; river rock pressed into bare soil disappears over time. UNR Extension suggests fabric (not plastic sheet) under about 2 in of rock for weed control.
- Keep rock a few inches back from the house foundation if you have wood siding, and make sure the ground slopes away from the house.
- For dry creek beds, use a mix of sizes — large stones along the edges, smaller ones in the channel — and plan on more tonnage than the flat area suggests, because the channel is dug in.
What you’ll need
- Landscape fabric (woven or heavy non-woven)Budget price
Separates stone from soil under gravel and rock. Less useful under wood mulch, which breaks down into soil on top of it anyway.
See options on Amazon (opens in a new tab) - Landscape fabric staplesBudget price
Pins fabric and edging down. Budget roughly one every few feet along seams and edges.
See options on Amazon (opens in a new tab) - Wheelbarrow (6 cu ft class)Mid-range price
Most home wheelbarrows hold 4–6 cubic feet — so a cubic yard of mulch is five or six trips. Two wheels are steadier on soft ground.
See options on Amazon (opens in a new tab) - Coated work glovesBudget price
Grippy, cut-resistant palms for handling stone, block and bags. Buy a couple of pairs — they wear out fast on concrete block.
See options on Amazon (opens in a new tab) - Steel or aluminum landscape edgingMid-range price
Rigid edging that holds gravel and pea gravel in place and keeps a clean line against lawn.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How much area does a ton of river rock cover?
Roughly 120 sq ft at 2 in deep, about 80 sq ft at 3 in, and about 60 sq ft at 4 in, assuming around 1.35 tons per cubic yard.
How deep should river rock be?
Deep enough to hide the fabric. A common rule of thumb for small stone (under about 1½ in) is about twice the stone size, so 2–3 in; for larger rock, one stone deep plus about an inch, so 3–5 in rock ends up about 4–5 in deep. Cobbles go deeper still.
How much river rock do I need for a 10 × 10 area?
At 3 in deep, about 0.93 cubic yards, or roughly 1.25 tons before extra. With a 5% allowance, about 1.3 tons.
Related guides
Sources
- University of Nevada, Reno Extension — Mulches for Nevada Landscapes (opens in a new tab) — Landscape fabric under about 2 in of rock; rock mulches raise soil and air temperature
- Colorado State University Extension — Mulching (opens in a new tab) — Gravel mulch transfers more heat to the soil than wood chips
- Gravel Monkey — How many tons of gravel in a dump truck? (opens in a new tab) — Typical payloads: single-axle about 6–10 tons, tandem 12–16, tri-axle 18–25; gravel hits the weight limit before the bed is full.