River Rock Calculator
Find how much decorative river rock or landscape stone you need for a bed, path, or ground-cover area. Enter the coverage length and width and the rock depth, pick a stone type, and get the volume in cubic yards, the weight in tons, the number of bags, and the cost by the ton — with by-depth and by-stone tables and a downloadable PDF.
| Depth | Cubic yards | Tons | Bags |
|---|---|---|---|
| Enter coverage to see depths | |||
| Stone | Density | Tons | Cost |
|---|---|---|---|
| Enter a volume to compare stone | |||
How to use the river rock calculator
Enter the coverage length and width and the rock depth, pick the stone type, add a waste allowance and a price per ton, and get the volume in cubic yards, the weight in tons, the number of bags, and the cost — plus reference tables for depth and stone type.
Enter the coverage
Length, width and depth, each with its own unit. 2–3 inches deep is typical for decorative ground cover.
Pick the stone
Choose small, medium or large river rock, pea gravel, beach pebble or crushed stone — it sets the density.
Add waste & price
Set a ~10% overage for settling and edging, a price per ton, and a bag size if you’re buying bagged.
Read tons & save a PDF
See tons, cubic yards, bags and cost, compare depths and stone types, and download the report.
How a river rock order is calculated
It’s a volume problem with two ways to buy. Work out the cubic yards of stone, add an overage, then convert to tons for bulk delivery using the stone’s density — or to bags for a small job by dividing the cubic feet by the bag size.
Worked example — a 20 × 12 ft bed, 3 in of small river rock, 10% waste
Volume: 20 × 12 × 0.25 = 60 ft³
Cubic yards: 60 ÷ 27 = 2.22 yd³
With waste: 2.22 × 1.10 = 2.44 yd³
Tons: 2.44 × 1.35 = 3.3 tons
Or bags: roundup(66 ÷ 0.5) = 132 bags
About 3.3 tons of small river rock for 240 sq ft at 3 inches — or 132 half-cubic-foot bags, which is why bulk wins at this size.
River rock coverage & tonnage charts
The lookups that come up most — how far a ton goes at each depth, density by stone type, tons by coverage area, and bags per cubic yard for small jobs.
| Depth | Sq ft per ton | Sq ft per yd³ | Tons per 100 sq ft |
|---|---|---|---|
| 1 in | 240 sq ft | 324 sq ft | 0.4 tons |
| 2 in | 120 sq ft | 162 sq ft | 0.8 tons |
| 3 in | 80 sq ft | 108 sq ft | 1.3 tons |
| 4 in | 60 sq ft | 81 sq ft | 1.7 tons |
| 6 in | 40 sq ft | 54 sq ft | 2.5 tons |
Coverage per ton halves when depth doubles — depth is a straight multiplier on how much stone an area needs. Figures use a density of about 1.35 tons per cubic yard before waste; denser stone covers slightly less.
| Stone | Density | Tons per yd³ | Best for |
|---|---|---|---|
| Small river rock (1–2″) | 2,700 lb/yd³ | 1.35 t/yd³ | General ground cover, beds |
| Crushed stone | 2,700 lb/yd³ | 1.35 t/yd³ | Paths, firmer surfaces |
| Medium river rock (2–4″) | 2,800 lb/yd³ | 1.40 t/yd³ | Borders, chunkier look |
| Pea gravel | 2,800 lb/yd³ | 1.40 t/yd³ | Walkable paths, patios |
| Large river rock (3–5″) | 2,900 lb/yd³ | 1.45 t/yd³ | Accents, dry creek beds |
| Beach pebble | 3,000 lb/yd³ | 1.50 t/yd³ | Polished decorative feature |
The same volume weighs more in denser, well-graded stone, which is why the stone choice shifts the tonnage you order. Volume stays the same for any stone — only the weight changes.
| Area | Cubic yards | Tons | Bulk or bags? |
|---|---|---|---|
| 50 sq ft | 0.46 yd³ | 0.6 tons | Bags OK (25) |
| 100 sq ft | 0.93 yd³ | 1.3 tons | Bulk cheaper |
| 200 sq ft | 1.85 yd³ | 2.5 tons | Bulk |
| 300 sq ft | 2.78 yd³ | 3.8 tons | Bulk |
| 500 sq ft | 4.63 yd³ | 6.3 tons | Bulk |
| 1,000 sq ft | 9.26 yd³ | 12.5 tons | Bulk (delivery) |
Scale for your depth: 2 inches is two-thirds of the tons shown, 4 inches is one-third more. Bagged stone only makes sense for the smallest beds — past roughly half a cubic yard, bulk is far cheaper per unit.
| Bag size | Bags per cubic yard | Bags per 100 sq ft at 2″ |
|---|---|---|
| 0.5 ft³ | 54 bags | 34 bags |
| 0.75 ft³ | 36 bags | 23 bags |
| 1 ft³ | 27 bags | 17 bags |
| 2 ft³ | 14 bags | 9 bags |
A cubic yard is 27 cubic feet, so it takes 54 half-cubic-foot bags to fill one. Bags round up to whole bags, since you can’t buy part of one — another reason bulk wins on any sizeable area.
A river rock bed is a layer of stone at a chosen depth over a coverage area, usually on landscape fabric. You calculate the volume, then buy it by the ton in bulk or by the bag for a small job.
- Depth drives the order — it’s a direct multiplier, so 3″ instead of 2″ is 50% more stone and cost.
- Match depth to stone size — the layer needs to be a few stones deep, so larger rock wants a deeper bed.
- Fabric is separate — this sizes the stone only; budget landscape fabric on its own to block weeds.
Everything the calculator works out
One set of measurements gives you the volume, the tonnage, a bag count and the cost, plus a comparison across depths and stone types — and a report you can take to the yard.
The figures behind every rock bed
Built for anyone laying decorative stone
A front-yard bed, a dry creek feature, a gravel path, a whole xeriscape — the volume-to-tons math is the same, and knowing whether to buy by the bag or the ton is what keeps the job on budget.
Refreshing a flower bed or foundation border with decorative stone, and deciding whether a few bags or a bulk drop makes more sense.
- Start with 2–3″ depth
- Lay fabric under the rock
- Compare bags vs a bulk ton
Covering a large low-water yard in stone and needing accurate bulk tonnage across several beds and a dry creek run.
- Add each bed as an area
- Match stone size to the use
- Order bulk by the ton
Pricing a stone install, comparing stone types on weight and cost, and handing the client a clear material estimate.
- Compare stone types on cost
- Confirm the coverage rate
- Save the PDF with the quote
7 tips for ordering river rock without errors
The assumptions that quietly put a stone order short — or leave a bed looking thin — and the checks that catch them before the delivery lands.
River rock FAQ
The coverage, depth and buying questions people ask most when laying decorative stone.
Multiply length by width by depth, all in feet, then divide by 27 for cubic yards. Multiply the cubic yards by the stone’s density in tons per cubic yard for the tonnage, since bulk rock is sold by the ton.
For a 20-by-12-foot bed at 3 inches: 20 × 12 × 0.25 = 60 ft³, or 2.22 yd³, which is roughly 3 tons of small river rock before waste. For a small job, divide the cubic feet by the bag size for a bag count instead.
A 2-to-3-inch depth is common for decorative ground cover, hiding the soil or fabric while keeping cost reasonable. Go to 3–4 inches for paths and high-traffic areas, and deeper for a true driveway base.
Depth should suit the stone size — the layer needs to be two to three stones deep to cover, so larger 3-to-5-inch rock wants a deeper bed than 1-inch stone. Depth is a direct multiplier on volume, so 2 to 3 inches raises the order by half.
At 2 inches deep, a ton covers roughly 100 square feet; at 3 inches, about 70; at 4 inches, about 50. Those assume a density of around 1.35–1.4 tons per cubic yard and shift with the stone type.
Coverage per ton falls as depth rises, because depth is a straight multiplier. Smaller, denser stone also covers slightly less per ton than large rock, so treat these as planning numbers and confirm the rate with your supplier.
In bulk, river rock is sold by the ton or cubic yard, loose and often delivered — the economical way for any sizeable area. For small jobs it’s also bagged at home-improvement stores, commonly in 0.5-cubic-foot bags.
Bulk is far cheaper per unit once you need more than about half a cubic yard, but bags are easier to handle, need no delivery, and let you buy an exact small amount. The calculator gives both so you can compare for your job size.
A cubic yard is 27 cubic feet, so it takes 54 half-cubic-foot bags to equal one cubic yard, or 27 one-cubic-foot bags. That’s a lot of bags, which is exactly why bulk delivery is cheaper once a job gets past a few square yards.
Use the bag count for small decorative areas where delivery isn’t worth it, and switch to bulk tons or yards for anything larger. The calculator rounds bags up to whole bags, since you can’t buy a partial one.
For most decorative beds, yes. Fabric between the soil and the stone blocks weeds and stops the rock working down into the soil and disappearing, which keeps the bed looking full and cuts maintenance.
Lay it over graded, weed-free soil, overlap seams and pin it before spreading the rock. The fabric is a separate material this calculator doesn’t size, so budget for it on its own. Skipping it is the usual reason a bed looks thin and weedy within a season or two.
Small 1-to-2-inch rock is the most popular for general ground cover and beds — it spreads evenly and is comfortable underfoot. Medium 2-to-4-inch suits borders and drainage; large 3-to-5-inch is for accents, dry creek beds and erosion spots.
Pea gravel and smaller crushed stone are best for paths because they pack firmer. Match the stone size to the use and the bed depth — larger stone needs a deeper layer to cover the ground fully.
River rock is smooth, rounded stone shaped by water, usually from about 1 inch up to 5 inches, used as decorative cover in beds, borders and dry creek features. Pea gravel is small rounded stone, roughly 3/8 inch, that packs into a firmer, walkable surface.
For a path or seating area you can walk on comfortably, pea gravel or small crushed stone is the better choice because it locks together. For a decorative accent where the stones are the look, larger river rock stands out. Both estimate the same by volume; only density and coverage differ.
Estimation Only — Confirm Coverage and Tonnage: This calculator works out decorative river rock volume from the dimensions you enter (volume = length × width × depth ÷ 27) and converts it to tons using typical stone densities, or to bags by the bag size you choose. Densities and coverage rates vary with stone size, type, grading and moisture, so the tonnage and bag counts are estimates. A 2–3 inch depth is typical for decorative ground cover; deeper layers suit paths and larger stone. The calculator sizes the stone only, not the landscape fabric or edging beneath and around it. Volume and bag counts do not include a waste allowance beyond what you enter and rounding up to whole bags — add overage for settling, uneven ground and edges. Prices shown are whatever rate you enter and are not quotes. For estimation purposes only; confirm coverage, tonnage and stone size with your supplier before ordering.