River Rock Calculator

River rock is smooth, rounded stone sold in sizes from small pebbles to fist-sized cobbles. The bigger the stone, the deeper the layer needs to be to cover the soil: plan on about twice the stone size. Small rock looks finished at 2 inches; 2 to 3 inch cobbles need 3 to 4 inches.

It is one of the pricier landscape stones, so it pays to measure carefully and subtract anything you are not covering.

Measure the length and width in feet, multiply for square feet, then decide the depth in inches. For odd shapes, split the area into rectangles, circles, and triangles and add them up; the calculator lets you add as many areas as you need and subtract cut-outs like a tree ring or an air-conditioner pad.

No tape measure? Open the Draw on satellite map tab, find your address, and trace the outline. Or use Pace it off: count steps along each side. Measure depth in a few spots, because ground is rarely flat.

Want the area on its own first? The lawn size calculator measures any part of your yard and carries it into the other calculators.

One cubic yard covers about 162 sq ft at 2 in deep.

A cubic yard of river rock weighs 2,500 to 2,900 lb (about 1.35 tons typical). Moisture is the big swing: the same pile weighs more after rain.

See every material side by side on the material weights chart.

It takes 54 bags of 0.5 cu ft to make one cubic yard, and each bag weighs about 50 lb. Bags cost more per yard but skip the delivery fee and the minimum order. Bulk is cheaper per yard once the delivery fee is spread over enough material.

With example prices of $7 a bag, $90 a yard in bulk, and $100 delivery, bulk starts winning at about 0.5 cubic yards. These are examples, not your local prices: type your own into the Order Ticket above and it recalculates the break-even.

Do not forget the labor. One cubic yard in bags means lifting 54 bags, about 2,700 lb in total, twice: into the cart and out of the car.

One cubic yard of river rock weighs about 2,700 lb. A full-size half-ton pickup typically carries 1,500 to 2,300 lb, and a midsize pickup 1,100 to 1,700 lb. Your exact number is on the Tire and Loading Information sticker on the driver's door jamb.

That means weight runs out first. At the low end of a half-ton's payload, you can carry only about 0.56 cubic yards per trip, even though a 6.5 ft bed holds about 2.1 level full. A bed that looks half empty can already be over the limit.

The Haul Check in the calculator does this math for your truck and your load, and tells you how many trips it takes.

• Lay landscape fabric first. Rock on bare soil sinks in and weeds grow up through it. (Washington State University Extension)
• Rock holds heat. Next to a south-facing wall it can stress nearby plants. (University of Florida IFAS Extension)

• Laying it without fabric.
• Spreading large stone too thin, so soil shows between rocks.
• Ordering by the yard from a yard that quotes by the ton.