River Rock Calculator
Find exactly how much river rock you need — in cubic yards, tons, and bags — and what it will cost. Supports any shape, multiple areas, depth, and waste.
Calculate your river rock
Using 100 lb/ft³ (≈ 1.35 tons per cubic yard).
What is river rock?
River rock is smooth, rounded stone shaped naturally by flowing water. Over thousands of years, moving water in rivers and creeks tumbles sedimentary, igneous, and metamorphic stone, wearing away the sharp edges until the stones are smooth and rounded. Most landscape river rock is quarried from ancient riverbeds and gravel deposits rather than active rivers, then screened into sizes. It appears in dozens of natural colors — gray, tan, brown, white, and multicolored blends — which is why it's prized as a durable, low-maintenance landscaping material.
River rock differs from gravel, which is crushed and angular, and from mulch, which is organic and decomposes. Its rounded shape makes it ideal for decorative beds, borders, dry creek beds, and ground cover. Learn more about the different sizes and what each is best for, or explore all types of river rock.
How much river rock do I need?
To find how much river rock you need, measure the area you want to cover and choose a depth. Multiply area (square feet) by depth in feet to get the volume in cubic feet, then convert to the unit your supplier uses — cubic yards for bulk, tons for delivery, or bags for a smaller project. The calculator above does all of this at once and adds an overage allowance so you don't run short.
River rock coverage chart
This chart shows roughly how far one ton or one cubic yard of river rock goes at common depths (based on generic river rock at about 100 lb/ft³).
| Depth | Sq ft per ton | Sq ft per cubic yard |
|---|---|---|
| 1" | 240 | 324 |
| 2" | 120 | 162 |
| 3" | 80 | 108 |
| 4" | 60 | 81 |
Worked example
Say you're covering a 20 ft × 15 ft bed (300 sq ft) with 2 inches of river rock. That's 300 × (2 ÷ 12) = 50 cubic feet. Adding 10% overage gives 55 cubic feet — about 2.04 cubic yards or 2.75 tons. If a supplier charges $60 per cubic yard plus $50 delivery, that's roughly $172 delivered.
The formula
Volume (ft³) = Area (ft²) × Depth (in) ÷ 12, then × (1 + waste). Cubic yards = ft³ ÷ 27. Tons = ft³ × density (lb/ft³) ÷ 2,000. See our step-by-step guide and data sources.
Frequently asked questions
How much river rock do I need?
Multiply your area in square feet by your depth in feet (depth in inches ÷ 12) to get cubic feet. Divide by 27 for cubic yards, or multiply cubic feet by about 100 lb/ft³ and divide by 2,000 for tons. Add 10% for waste.
How much area does a ton of river rock cover?
At 2 inches deep, one ton of river rock covers roughly 120 square feet. At 1 inch it covers about 240 sq ft, and at 3 inches about 80 sq ft.
How many cubic yards are in a ton of river rock?
River rock weighs roughly 1.3–1.4 tons per cubic yard, so one ton is about 0.7–0.75 cubic yards. Exact figures vary by stone size and type.
How deep should river rock be?
For ground cover use about 2 inches for small stone and 3–4 inches for larger 1"–3" or 3"–5" rock. Drainage and dry creek beds are usually deeper.
How much does river rock weigh?
River rock weighs roughly 1.3–1.4 tons per cubic yard, or about 100 pounds per cubic foot, though it varies by stone type and size. Lighter stone like lava rock weighs much less, and dense stone weighs more. The calculator uses the density of your chosen rock type to estimate the total weight in tons.