River Rock Calculator
Cubic yards, tons or bags of river rock for dry creek beds, borders and low-water landscaping.
Quick estimating rule of thumb
For river rock: length (ft) × width (ft) × depth (in) ÷ 324 = cubic yards. Decorative rock is sold by the ton, about 1.4 tons per yard. A 2 to 3 inch mulch-replacement layer is usual; larger cobbles need to sit deeper so they do not roll. Add 10% for gaps.
This river rock calculator converts an area and depth into cubic yards, tons or bags of smooth river rock for a dry creek bed, a mulch-free border, drainage swales, or xeriscaping.
River rock is sold in size grades (typically 1–2 inch, 2–4 inch, and larger). Larger rock needs a deeper layer to hide the ground beneath, which the depth input lets you account for.
How deep for full coverage
To hide soil or fabric completely, spread river rock at least twice the diameter of the largest stones: about 2 inches for 1-inch rock, 3 inches for 1–2 inch rock, and 4 inches or more for 2–4 inch rock. Skimp and you will see dirt between the stones the first time it rains.
One cubic yard covers about 160 square feet at 2 inches, or 80 square feet at 4 inches.
Dry creek beds
A convincing dry creek bed uses two or three sizes: larger 3–8 inch stones along the edges and as accents, a 1–2 inch bed in the channel, and a scatter of boulders. Excavate a shallow, meandering channel, line it with fabric, and size the width to look natural, usually two to three times the width of the largest boulders.
Weight and handling
A cubic yard of river rock weighs about 1.4 tons and is sold by the ton. Larger grades are placed by hand, which is slow, so factor the labour. Bagged river rock (0.5 cu ft) is only economical for small accent areas. Order about 10% extra for uneven coverage.
Common river-rock mistakes
Too shallow for the stone size. Cover to at least twice the largest stone diameter or you will see soil between the rocks.
One size everywhere. A natural dry creek uses a channel grade, edge stones and a few boulders, not a uniform field.
Thin non-woven fabric. It tears under stone; use a woven geotextile.
Underestimating placement labour. Large grades are set by hand, which is slow, so budget the time.
| Material | lb / ft³ | tons / yd³ | Sold by | Typical use |
|---|---|---|---|---|
| Pea gravel (3/8″, rounded) | 100–105 | 1.35 | ton or yd³ | Paths, patios, dog runs, drainage |
| #57 crushed stone (3/4″, washed) | 100–105 | 1.35 | ton | Drainage, slab sub-base, French drains |
| 3/4″ minus / dense-grade | 105–115 | 1.45 | ton | Driveway base, paver base, road pack |
| Crushed concrete (RCA) | 100–110 | 1.35 | ton | Driveway base, structural fill (cheaper) |
| River rock (1–3″) | 95–105 | 1.40 | ton or yd³ | Dry creek beds, borders, xeriscape |
| Decomposed granite | 110–120 | 1.50 | ton | Paths, patios, natural-look driveways |
| Road base / Class 5 | 110–120 | 1.50 | ton | Compacted base under pavers, slabs, drives |
Background reading: how much a yard of gravel weighs and gravel cost per ton and per yard.
Frequently asked questions
How much river rock do I need?
Multiply area by depth and divide by 27 for cubic yards, then by about 1.4 for tons. A 100 square foot border at 3 inches needs roughly 0.9 cubic yards, about 1.3 tons.
How deep should river rock be?
At least twice the size of the largest stones for full coverage: about 2 inches for small rock, 3 to 4 inches for 2-inch and larger.
How much does a cubic yard of river rock weigh?
About 1.4 tons (2,800 lb).
How much area does a ton of river rock cover?
Roughly 110 square feet at 2 inches deep, or 55 square feet at 4 inches.
How many bags of river rock in a cubic yard?
About 54 bags of 0.5 cubic foot.
What size river rock is best for landscaping?
1–2 inch rock is the most versatile for beds and borders. Use 3–8 inch and larger for dry creek edges and accents, and 3/8 inch pea-size for paths.
Do I need landscape fabric under river rock?
Yes. It slows weeds and keeps the rock from working into the soil. Choose a woven fabric; the thin non-woven type tears under stone.
How wide should a dry creek bed be?
Usually two to three times the width of the largest boulders you are using, with a meandering rather than straight line.
How much river rock do I need for a 100 square foot bed?
At 3 inches deep with 1–2 inch stone, about 0.9 cubic yards or 1.3 tons.
What size river rock for landscaping?
1–2 inch is the versatile choice for beds and borders; 3–8 inch for dry-creek edges and accents; 3/8 inch pea size for paths.
Does river rock let weeds through?
Seeds still blow in and root in the dust between stones. A woven fabric underneath and occasional spot-spraying keeps it clean.
How much does a pallet of river rock cover?
A pallet is usually about 1.5 to 2 tons, or roughly 120 to 200 square feet at 2 to 3 inches deep depending on stone size.
Can you walk on river rock?
1–2 inch rounded rock is uncomfortable to walk on. For a path, use pea-size gravel or set flagstone steppers into the rock.