Landscaping calculator
Landscape rock calculator: how much rock do I need?
Measure the bed, pick the rock, and this rock calculator gives you how much landscape rock you need in tons, cubic yards, bags and dollars — plus the tons per square foot, the fabric and the edging that keep it where you put it.
Your project
Product changes the weight per yard and the price per ton, not the volume you need.
Rule of thumb: 2" for pebbles under 1/2", 3" for 1"-2" rock, 4"+ for anything larger.
Crews typically order 5-10% extra to cover compaction, spillage and uneven subgrade.
Most yards quote decorative rock by the ton. Pea gravel and limestone are cheapest; beach pebble is the outlier.
Rock needed
6.3
tons of river rock · includes 5% waste
- Area
- 480 sq ft
- Volume in cubic yards
- 4.67 cu yd
- Volume in cubic feet
- 126 cu ft
- Weight in pounds
- 12,600 lb
- 50 lb bags (if buying bagged)
- 252 bags
- Coverage per ton at this depth
- 80 sq ft
- Landscape fabric needed
- 528 sq ft
- Rock cost
- $473
- Estimated total with delivery
- $563
Decorative rock is sold by weight but ordered by area, and the two only line up once you fix the depth. Lava rock is the exception in this list — it weighs less than half what river rock does, so a ton of it covers more than twice the ground.
The shareable link reopens this calculator with your exact inputs.
How much landscape rock do I need?
Start with volume, not weight. Area in square feet, times depth in feet, divided by 27, gives cubic yards. A 300 sq ft bed at 3 inches deep is 75 cubic feet, or 2.8 cubic yards. Only then convert to tons, because most rock yards sell by the ton and every product weighs something different.
The conversion that matters is roughly 1.4 tons per cubic yard for ordinary gravel and river rock, 1.35 for marble chips, and about 0.6 for lava rock. Use the product weight rather than a blanket 1.5 tons a yard, or you will be short on the light products and over on the heavy ones.
The quick field shortcut: one ton of average rock covers about 80 square feet at 3 inches, 120 square feet at 2 inches, or 60 square feet at 4 inches. Divide your bed area by those numbers and you are within a wheelbarrow of the right order.
How deep should landscape rock be?
Match depth to stone size. Small pebbles like pea gravel and 3/8 inch chips only need two inches — go deeper and they behave like dry sand underfoot. One to two inch river rock wants three inches so no soil shows between stones. Anything four inches or bigger needs a depth of at least twice the stone size to sit stable.
Two inches is the practical minimum for weed suppression on any product. Below that, light reaches the fabric seams and the soil beneath, and windblown seed finds the gaps within a season.
Drainage and splash zones are the exception. Downspout aprons, dry creek beds and French drain caps run four to six inches deep, because the rock is doing hydraulic work rather than just covering ground.
Rock beds only stay clean if you build them right
Put woven landscape fabric — not the thin spun stuff — under the rock, overlap the seams six inches, and pin it every three feet. Order about ten percent more fabric than the bed area to cover the overlaps and the turn-up at the edges.
Edge the bed. Steel, aluminium or heavy poly edging keeps rock out of the lawn, and rock in a lawn is a mower-blade problem that never stops. This is the step people skip and regret in year two.
Understand what rock does not do. It suppresses weeds but does not feed anything, it stores and radiates heat against nearby plants, and it never breaks down, so the first install is more or less permanent. Removing a rock bed later is a shovel-and-screen job measured in days, not hours.
Rock coverage per ton by depth
Square feet covered by one ton of average 100 lb/cu ft rock, before waste.
| Depth | Sq ft per ton | Sq ft per cubic yard | Tons per 100 sq ft |
|---|---|---|---|
| 1" | 240 | 324 | 0.42 |
| 2" | 120 | 162 | 0.83 |
| 3" | 80 | 108 | 1.25 |
| 4" | 60 | 81 | 1.67 |
| 6" | 40 | 54 | 2.5 |
Landscape rock weight, size and price
Loose delivered weight and typical yard pricing per ton.
| Rock | Size | lb / cu ft | Tons / cu yd | $ / ton | Best for |
|---|---|---|---|---|---|
| Pea gravel | 3/8" | 96 | 1.3 | $45 | paths, play areas and patio infill — rolls underfoot on slopes |
| River rock | 1"-3" | 100 | 1.35 | $75 | dry creek beds, beds and downspout splash zones |
| Lava rock | 1/2"-1" | 45 | 0.61 | $150 | lightweight beds and xeriscape — half the weight per yard |
| Decomposed granite | 1/4" minus | 105 | 1.42 | $50 | compacted paths and patios that need a firm surface |
| Crushed limestone | 3/4" | 100 | 1.35 | $40 | drives, borders and base under rock beds |
| White marble chips | 1/2" | 95 | 1.28 | $130 | bright formal beds and contrast borders |
| Mexican beach pebble | 1"-2" | 105 | 1.42 | $340 | feature beds and water features — sold as a premium product |
| Rip rap / boulders | 4"-12" | 105 | 1.42 | $60 | erosion control, swales and slope armouring |
Frequently asked questions
+How much rock do I need for landscaping?
Multiply the bed area in square feet by the depth in inches, then divide by 324 for cubic yards. Multiply cubic yards by about 1.4 to get tons for gravel or river rock. A 300 sq ft bed at 3 inches is 2.8 cubic yards, roughly 3.9 tons.
+How many square feet does a ton of landscape rock cover?
About 80 square feet at 3 inches deep, 120 at 2 inches and 60 at 4 inches, for typical 100 lb per cubic foot rock. Lava rock covers more than double that because it is so much lighter.
+How much does a yard of landscape rock weigh?
Around 2,700 lb — about 1.35 tons — for river rock, pea gravel or crushed stone. Lava rock is closer to 1,200 lb a yard, and wet rock can run 10% heavier than the quoted dry weight.
+How deep should landscape rock be over fabric?
Two inches for small pebbles, three for 1 to 2 inch rock. Anything shallower lets light reach the fabric and UV degrades it, and you will see the black weave through the stone within a year.
+Is landscape rock cheaper than mulch?
Higher upfront, cheaper over time. Rock runs roughly $75-$150 per ton installed versus $30-$70 a yard for mulch, but mulch is replaced every year or two and rock is a one-time purchase that only needs an occasional blow-off and top-up.
+How much does landscape rock cost delivered?
Common products run $35 – $150 per ton plus a haul fee of $60-$150 per load. Speciality stone like Mexican beach pebble can exceed $300 a ton, and premium products are often sold by the bag rather than in bulk.
+Do I need landscape fabric under rock?
Yes, use woven fabric rather than spun. It stops the stone sinking into soil, which is the real failure mode — weeds eventually root in the dust and leaf litter that collects on top regardless, but rock sunk into mud can never be cleaned up.