River Rock Calculator
Figure out how much river rock you need for decorative beds, dry creeks, ground cover, or drainage. Pick your application to get a recommended depth, enter your project shape and dimensions, and see total tons, cubic yards, bag count, and coverage area. Add a price per ton for an estimated cost. River rock weighs about 110 lb per cubic foot (1,762 kg/m³).
Results
Estimates only. Actual yields vary by rock size grading, installation method, and compaction. Confirm minimum delivery quantities and bulk pricing with your supplier before ordering. TakeoffCalc isn't responsible for material over- or under-orders.
How to use this calculator
- 01Pick an application: decorative bed, dry creek, ground cover, drainage, or custom. The depth field auto-fills with a recommended value.
- 02Pick a shape: rectangle, circle, or custom area for irregular shapes.
- 03Enter your dimensions. For rectangle, that's length and width. For circle, diameter. For custom area, the total surface area.
- 04Adjust depth if needed. Add a waste percentage for spillage and compaction.
- 05Read total tons, cubic yards, bag count, and coverage area at the top of the results panel. Add a price per ton for cost estimation.
Understanding the math
River rock volume math is straightforward. Multiply the surface area by the depth to get cubic feet of material. Then multiply cubic feet by river rock’s bulk density (110 lb per cubic foot, or 1,762 kg/m³) to get pounds. Divide by 2,000 to convert pounds to tons. The waste and compaction percentage adds extra material to cover spillage, settling, and supplier minimums.
volume_ft3 = area_ft2 × depth_ft weight_lbs = volume_ft3 × 110 weight_tons = weight_lbs / 2000 volume_yd3 = volume_ft3 / 27
Worked example. A decorative bed 12 ft by 8 ft at 2 inches deep with 10% waste. Surface area is 12 × 8 = 96 sq ft. Depth in feet is 2 / 12 = 0.167 ft. Volume is 96 × 0.167 = 16 cubic feet. Weight is 16 × 110 = 1,760 lbs, which is 0.88 tons. With 10% waste added, you need about 0.97 tons (0.88 tonnes in metric).
River rock sizes and coverage
Typical coverage for common river rock sizes at recommended depths. Coverage assumes a level area with the rock spread evenly. Sloped areas, irregular surfaces, and over-compaction reduce effective coverage. Coverage figures pull from landscape supplier rules-of-thumb across the size range covered by this table. For structural rip rap installations on slopes, banks, or channels, see the dedicated Rip Rap Calculator.
| Size | Use Case | Recommended Depth | Coverage per Ton |
|---|---|---|---|
| 3/4 to 1 inch | Pathways, decorative borders | 2 in | 109 sq ft |
| 1 to 2 inch | Ground cover, decorative beds | 3 in | 73 sq ft |
| 2 to 4 inch | Decorative landscape, drainage | 4 in | 55 sq ft |
| 3 to 5 inch | Dry creek beds, accent rock | 4 in | 55 sq ft |
| 4 to 8 inch | Boulder accents, water features | 6 in | 36 sq ft |
| 6 to 12 inch | Erosion-control accent, large drainage | 12 in | 18 sq ft |
Frequently asked questions
How do I calculate how much river rock I need?
Multiply the surface area by the depth to get the volume of rock you need. For a decorative bed 12 ft by 8 ft at 2 inches deep, surface area is 12 × 8 = 96 sq ft, and depth in feet is 2 / 12 = 0.167 ft. Volume is 96 × 0.167 = 16 cubic feet.
To convert cubic feet to tons, multiply by river rock's density (about 110 lb per cubic foot) and divide by 2,000. So 16 × 110 / 2000 = 0.88 tons. Add a waste percentage of 5 to 10 percent to cover spillage and supplier minimums.
How many sq ft does 1 ton of river rock cover?
Coverage depends on depth. At 2 inches deep, 1 ton of river rock covers about 109 sq ft (11 m²). At 3 inches deep, coverage drops to about 73 sq ft (7 m²). At 4 inches deep, coverage is about 55 sq ft (5 m²). The reference table above shows coverage at common depths for typical river rock sizes.
The math works backward from density. 1 ton equals about 18 cubic feet of river rock at 110 lb per cubic foot. Divide that by your depth in feet to get the area covered.
How much is 4 yd of river rock?
Pricing varies by region, supplier, and rock size. As of 2025, decorative river rock typically runs 50 to 90 dollars per cubic yard delivered, so 4 cubic yards generally costs between 200 and 360 dollars. Larger boulder-size rock and specialty colors cost more. Bagged river rock from home improvement stores costs roughly 5 to 10 dollars per 0.5 cubic foot bag, which works out to 270 to 540 dollars for 4 cubic yards. Local landscape supply yards usually beat bagged pricing on volume orders.
Add the price-per-ton field in the calculator above to estimate your total cost based on your supplier's quote.
How much does a 3 to 5 inch river rock cover?
3 to 5 inch river rock is typically used for dry creek beds and accent landscaping at a 4-inch installed depth. At that depth, 1 ton covers about 55 sq ft (5 m²). For a 100-square-foot dry creek bed at 4 inches deep, you'd need about 1.8 tons of 3 to 5 inch river rock.
Larger rock has more void space than smaller rock, which means slightly less coverage per ton at the same nominal depth. The reference table above accounts for typical install depths by size.
What size river rock should I use?
Smaller sizes (3/4 to 2 inch) work best for pathways, decorative borders, and ground cover where smooth walking surfaces or dense visual texture matter. Midsize (2 to 5 inch) covers most decorative landscape and drainage uses. Larger sizes (4 to 12 inch) are reserved for dry creek beds, water-feature borders, and erosion control.
Match size to depth. A 2-inch decorative bed needs smaller rock for full coverage; a dry creek bed at 4 inches deep can use 3 to 5 inch rock effectively. The reference table above pairs typical sizes with recommended applications and depths.
Can I use this calculator with metric measurements?
Yes. The unit toggle at the top of the form switches every input between imperial and metric. Length and width fields accept feet or meters. Depth accepts inches or centimeters. Custom area accepts square feet or square meters.
The output panel shows tons in imperial mode and tonnes in metric mode. Volume rows flip between cubic yards / cubic feet and cubic meters. Bag count uses 0.5 cubic foot bags in imperial and 14 liter bags in metric, matching common retail bag sizes.
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