River rock is decorative, so you spread it as a top layer rather than building anything structural with it. Measure the bed length times its width to get square footage, plan on 2 to 3 inches of depth, and figure roughly 1 ton of river rock covers 70 to 90 square feet at 2 inches. Larger stone covers less area per ton, so where you land in that range depends on the size you pick.
The simple method
Three steps get you most of the way there:
- Measure the area. Length times width in feet gives you square footage. For an odd shape, break it into rectangles, figure each one, and add them up.
- Pick a depth. River rock looks best and hides the ground at 2 to 3 inches. Two inches is plenty for a decorative bed; go to 3 for a path or anywhere you want full coverage.
- Convert to tons. At 2 inches, one ton covers about 70 to 90 square feet. Divide your square footage by that range to get a tonnage, then add about 5 to 10 percent for waste and settling.
River rock is sold by the ton, so the answer comes out in tons. Smaller, rounded stone packs tighter and covers toward the high end. Larger river rock leaves more gaps and covers toward the low end, so plan for less area per ton with bigger stone.
A worked example
Say you have a small bed along the side of the house, 12 feet long and 4 feet wide.
- Area: 12 times 4 equals 48 square feet.
- Depth: 2 inches for a clean decorative look.
- Coverage: at about 80 square feet per ton, 48 divided by 80 is roughly 0.6 tons.
- Waste: add 5 to 10 percent, so call it about 0.65 tons.
For a job that small you would round up to a manageable amount and keep a little extra for topping off later. The coverage calculator does this math for you and returns the exact tonnage for your dimensions and depth.
Lay it over weed fabric
River rock works best over a layer of landscape weed fabric. The fabric blocks weeds from pushing up through the stone and keeps the rock from sinking into bare soil, which is what makes a 2 inch layer thin out and look patchy a year later. Roll the fabric out first, pin it down, then spread the rock on top.
Keep it in place with edging
Loose river rock migrates. It travels onto lawns, into beds, and off the edge of a path unless something holds the line. A solid border of landscape edging keeps the rock where you put it and gives the bed a finished edge. It also means you can run a slightly shallower layer without the stone spilling out, which stretches your material.
Picking the stone
River rock comes in a range of sizes and colors. Smaller, rounded river rock reads smooth and tidy, while larger stone makes more of a statement and suits dry creek beds and accent areas. If you want a finer, beachy look, beach pebbles give you smaller polished stone. For ideas on combining sizes and colors, our guide on landscaping with river rock and pebble walks through the options.
Frequently asked questions
How many square feet does a ton of river rock cover?
At 2 inches deep, roughly 70 to 90 square feet per ton. Smaller, rounded stone packs tighter and covers toward the high end; larger river rock leaves more gaps and covers toward the low end.
How deep should river rock be?
Two to three inches. Two inches is enough for a decorative bed; three inches gives full coverage for a path or a spot where you do not want the ground showing through.
Do I need weed fabric under river rock?
It helps a lot. Fabric blocks weeds from growing up through the stone and stops the rock from sinking into bare soil, which keeps a thin layer looking full instead of patchy over time.
How much extra river rock should I order?
Add about 5 to 10 percent over your calculated amount for waste, settling, and topping off later. It is easier to keep a little extra than to order a second small load.
How do I keep river rock from spreading?
Install edging around the bed or path. A firm border holds the stone in place, keeps it off lawns and walkways, and lets you run a slightly shallower, more economical layer.
Get the materials
Browse river rock and beach pebbles, pair them with edging to hold the bed, and run your numbers through the coverage calculator before you order. For a large bed or a long haul, request a quote and we will work out freight. We deliver nationwide from our California yards.