River Rock Calculator, Beds and Borders
Arizona, Colorado, Mexican. River rock gets sold under a dozen names, and not one of them changes what a cubic yard weighs. What does change your number is the size of the stone and how deep you lay it. This river rock calculator asks for both, adds every bed and border in one go, and gives you yards, tons and bags. Put in a price per ton and it doubles as a cost estimator.
What is river rock?
River rock is stone that water has rounded off, either in a real riverbed or in a machine that imitates one. No sharp edges, which is why it's comfortable underfoot and why it looks finished rather than industrial. It comes in sizes from about an inch up to five, and in whatever color the local stone happens to be.
You'll see it sold as Arizona, Colorado or Mexican river rock. Those names change the color and the price. They don't change what a cubic yard weighs, so the quantity math is the same whichever you buy.
So why work it out first? Because you buy river rock by weight and lay it by area, and nothing about a pile of stone tells you which is which. A ton sounds like plenty until it's spread out. And coming up short means paying a second delivery charge for a fraction of a load, which is why the tool leaves a little headroom by default.
Calculate river rock by area and depth
Square feet × depth in inches ÷ 12 ÷ 27 = cubic yards. That’s all there’s to it. What trips people up? River rock gets measured by volume but sold by weight. So there’s one more step before you reach tons.
- Measure the area in feet. Length × width for a bed or path. For a circle, measure straight across the widest point. For an odd shape, break it into rectangles and add them up, or use the irregular option and enter the square footage.
- Choose a depth in inches. Two inches for plain ground cover, 3 inches for beds, 4 inches for drainage and slopes.
- Convert. Square feet × depth in inches ÷ 12 ÷ 27 = cubic yards. Multiply cubic yards by 1.35 to get tons of typical 1–3 inch stone.
- Add about 10%. Stone settles, ground is never flat, and the edges swallow more than you would think.
Picture a bed 20 ft by 8 ft, with 3 inches of stone going into it. That’s 160 sq ft. So 160 × 3 ÷ 12 = 40 cubic feet, which is 1.48 cubic yards. At 2,700 lb per yard you’re looking at 2 tons. Add the 10% and you order 2.5.
How much river rock do I need?
One cubic yard covers 108 square feet at 3 inches deep. One ton covers about 80. At 2 inches those become 162 and 120 square feet, and at 4 inches they drop to 81 and 60.
Depth is doing all the work in those numbers. Going from 2 inches to 4 halves what a yard covers, so a bed you thought needed one delivery needs two. Settle on the depth before you price anything.
The chart below gives every common depth for 1–3 inch stone. Read across from your depth to see what a yard and a ton each cover. Then check that against whatever the calculator above told you.
| Depth | 1 cubic yard covers | 1 ton covers | Typical use |
|---|---|---|---|
| 1" | 324 sq ft | 240 sq ft | Too thin, soil shows through |
| 2" | 162 sq ft | 120 sq ft | Minimum ground cover |
| 3" | 108 sq ft | 80 sq ft | Standard planting beds |
| 4" | 81 sq ft | 60 sq ft | Drainage, slopes, dry creek beds |
For a full breakdown by area size and stone type, see river rock coverage.
River rock coverage per ton, at every depth
A ton of 1–3 inch river rock covers 120 square feet at 2 inches, 80 at 3, and 60 at 4. Bulk stone is priced by the ton, so this is the table that tells you what your money actually buys in ground covered.
Use it to sanity-check the order the calculator just gave you. Find your tonnage in the first column, read across to your depth, and the square footage should land near the area you measured.
| Tons | Cubic yards | At 2" deep | At 3" deep | At 4" deep |
|---|---|---|---|---|
| 1 | 0.74 | 120 sq ft | 80 sq ft | 60 sq ft |
| 2 | 1.48 | 240 sq ft | 160 sq ft | 120 sq ft |
| 3 | 2.22 | 360 sq ft | 240 sq ft | 180 sq ft |
| 5 | 3.7 | 600 sq ft | 400 sq ft | 300 sq ft |
| 10 | 7.41 | 1,200 sq ft | 800 sq ft | 600 sq ft |
One ton is about three-quarters of a cubic yard, so if a supplier quotes you a “yard” of stone you're getting roughly 1.35 tons.
Two things sit outside this table. How the figures change with stone size, and what the same numbers look like starting from a supplier quote rather than an area. Both are on calculating river rock coverage, along with the depth each grade needs before it covers anything at all.
Choosing your rock size: 1–3", 2" and 3–5"
Pick 1–3 inch unless you’ve a reason not to. It’s the most widely stocked size and the cheapest per ton, and it suits most beds and paths. Size also sets how deep you go. Bigger stone holds more air gaps, so it weighs less per yard and needs more depth to cover.
| Stone size | Weight per cubic yard | Minimum depth | Best for |
|---|---|---|---|
| 3/4"–1" (pea-size) | 2,800 lb | 2" | Paths, patios, tight ground cover |
| 1"–3" (most common) | 2,700 lb | 2" | Beds, borders, general landscaping |
| 2" | 2,700 lb | 3" | Beds and dry creek beds |
| 3"–5" | 2,500 lb | 4" | Drainage, erosion control, accent areas |
There's a reason 1–3 inch is the default. It’s big enough not to scatter underfoot and small enough to rake level. And being the most widely stocked size, it’s usually cheapest per ton. Go up to 3–5 inch only where you want water moving through the stone. Or where you need visual weight against a big wall or slope.
How deep should river rock be?
Three inches is the answer for most planting beds. Below 2 inches, the soil or fabric shows through the moment the stone shifts. Above 4 inches, you’re paying for stone nobody sees.
- 2 inches
- Decorative ground cover over fabric, where nothing will walk on it.
- 3 inches
- Standard for beds and borders. Deep enough to block light and stop most weeds germinating.
- 4 inches or more
- Slopes, dry creek beds, French drains and anywhere water runs. Also use this for 3–5 inch stone.
The rule that catches people out: your depth must be at least as deep as your stone. Spreading 3–5 inch rock 2 inches deep is physically impossible. You get a single scattered layer with gaps in it. What each grade needs before it hides the ground is set out on river rock coverage.
Do I need landscape fabric underneath?
For decorative beds, yes. Fabric stops the stone sinking into the soil and keeps most weeds down. It does nothing about seeds that blow in on top, which is why 3 inches of depth matters more than the fabric does. For drainage work, use a permeable geotextile and never plastic sheet.
River rock weight and delivery: what a pickup can safely take
A cubic yard of 1–3 inch river rock weighs about 2,700 lb dry, or 1.35 tons. That is more than double what a half-ton pickup is rated to carry, so the estimator above tells you how many trips your quantity really needs. Full figures by stone size, wet and dry, are on weight of river rock per yard.
Which leaves delivery, and that is worth planning before you order. Bulk stone arrives in a single-axle dump truck carrying 5–7 tons, or a tandem carrying 12–14. Anything under about five yards fits the smaller one.
Most yards charge a flat fee inside a set radius, with a 1-ton minimum. Below that minimum you are paying to send a truck out rather than to move stone, which is why very small jobs come out cheaper in bags despite the higher price per cubic foot.
Tell them where to tip it, too. A dump truck needs overhead clearance and room to raise a bed, and stone put down in the wrong spot has to be moved a second time by hand.
Bags vs bulk: when each makes sense
It takes 54 of the 0.5 cu ft bags to make one cubic yard, so bags stop making sense faster than most people expect. Under about half a ton they still win, because you skip the delivery fee and can fit them in a car. Past a ton, bulk is almost always cheaper per unit even after delivery.
Put both prices into the calculator and it finds the crossover for your own quantity rather than a generic one.
River rock cost estimate, and what moves the price
River rock runs $40–$150 per ton for natural stone you collect from the yard. That spread is mostly stone size and how far you are from the quarry. Bagged rock is $4–$9 per 0.5 cu ft bag, so $216–$486 for the equivalent of one cubic yard.
Those ranges are wide because stone is heavy and freight dominates the price. What you actually pay comes down to how far you’re from the quarry first, then color and size. White and black river rock carry a premium over natural mixed stone, and oversized 3–5 inch stone costs more per ton than 1–3 inch.
That's why the calculator asks for your price per ton instead of showing a national average. Put in a real quote, get a real total. For the full picture, including what a bag works out at and where bulk overtakes it, see the price of river rock per ton.
Types of river rock: sizes and colors, and what each is good for
River rock really comes down to two things. Size and color. Color changes the price and, indirectly, how much you need. Darker stone shows every gap, so it wants the full 3 inches.
- Natural mixed river rock
- Whatever the riverbed gave up, mostly gray with some tan running through it. Cheapest of the four and the most widely stocked. Hides dust and leaf litter well.
- White river rock
- High contrast against dark mulch or green planting. It also shows dirt and algae, so plan on rinsing it down every year or two. Expect to pay a premium over natural stone.
- Black river rock
- Strong modern look, but it holds a lot of heat in full sun. Keep it away from anything shallow-rooted. Usually the most expensive of the three colors.
- Large river rock (3–5 inch and up)
- Accent stone, dry creek beds, and anywhere you need something that won’t wash away. Sold by the ton, and above about 8 inches often by the individual stone.
A lot of river rock is sold by where it comes from rather than a plain color name. Arizona river rock runs to warm rust, gold and tan desert tones. Colorado river rock is the cooler gray, brown and earth-toned mix. Mexican beach pebble is the smooth, near-black polished stone people use around water features and modern planting. They’re the same volume math as any other rock. So pick on look and local price, then size the order with the calculator above.
Color doesn’t change the weight per cubic yard, so the quantity math is the same whichever you pick. Size does change it, and the calculator already accounts for that.
River rock calculator FAQ
How much river rock do I need?
Multiply your area in square feet by the depth in inches, divide by 12, then divide by 27 to get cubic yards. A 10 ft × 10 ft bed at 3 inches needs 0.93 cubic yards, which is about 1.25 tons. The calculator above does this for several beds at once.
How many tons of river rock do I need for 100 square feet?
About 1.25 tons at 3 inches deep, or 0.85 at 2 inches and 1.7 at 4. The calculator above takes any area and depth and returns the tonnage, the cubic yards and a bag count together, so you can order in whichever unit your supplier uses.
How much river rock is in a yard?
A cubic yard is 27 cubic feet of stone and weighs about 2,700 lb, so roughly 1.35 tons. Spread 3 inches deep it covers about 108 square feet. At 2 inches it covers 162 square feet. That’s 54 of the 0.5 cu ft bags sold at garden centers.
How many yards of river rock are in a ton?
About 0.74 cubic yards per ton, based on a dry weight of 2,700 lb per cubic yard. Put the other way round, one cubic yard is roughly 1.35 tons. Suppliers usually sell bulk river rock by the ton but quote coverage by the yard, which is where most ordering mistakes start.
Will a yard of river rock fit in a pickup truck?
It fits, but it should not go in. A yard of 1–3 inch stone is about 2,700 lb and a half-ton pickup is rated near 1,250 lb of payload, so one yard is over double the limit. Split it across three trips, or have it delivered.
How deep should river rock be for landscaping?
Two inches is the minimum that hides the soil. Three inches is standard for planting beds and properly suppresses weeds. Four inches suits slopes, drainage and dry creek beds. Always go at least as deep as your stone size, or single stones will sit proud and show gaps.
Is river rock sold by the ton or the yard?
Both, and it varies by supplier. Bulk stone is most often priced by the ton but delivered by the scoop, which is measured in cubic yards. Bagged rock is sold by volume in 0.5 cu ft bags. The calculator gives all three figures so you can order in whichever unit your yard uses.
How do I calculate how much river rock I need?
Length × width gives square feet. Multiply by depth in inches, divide by 12 for cubic feet, then by 27 for cubic yards. Multiply cubic yards by 1.35 to get tons. Add about 10% for settling and uneven ground so you’re not short at the end of the job.