Rock Calculator

Estimate landscaping or construction rock volume, weight, truckloads, coverage, and cost.

Project Dimensions

Length

Width

Unit

Depth

Depth unit

Rock Information

Rock Type

Densityauto

lb/ft³

Crushed Stone · 1.4 tons/yd³ · Driveways, base, patios

Cost Settings

Price

Basis

Deliveryoptional

Which Rock for Your Project?

The right rock depends on the job — traffic, drainage, and looks all point to different materials. Here are the recommended rock types and coverage depths for common projects.

Driveway4–6"

Crushed StoneLimestoneGranite

Angular crushed stone and limestone interlock and compact into a firm, load-bearing surface that stands up to vehicle traffic without rutting.

Garden Bed2–3"

River RockLava RockDecorative Rock

Lightweight, attractive rock suppresses weeds and retains moisture while letting water reach roots, without compacting the soil around plants.

Drainage4–8"

Drainage Rock (#57)River RockCrushed Stone

Clean, angular #57 stone with no fines leaves open voids so water drains freely — the standard fill for dry wells and gravel drainage layers.

Decorative Landscaping2–3"

Marble ChipsSlate ChipsRiver RockDecorative Rock

Colourful chips and smooth stones create low-maintenance ground cover and eye-catching accents that never need mowing or watering.

Retaining Wall Backfill12"+ zone

Drainage Rock (#57)Crushed StoneRip Rap

A gravel drainage zone behind a wall relieves hydrostatic pressure, while rip rap armours the toe of slopes and shorelines against erosion.

Walkway2–3"

Pea GravelGraniteCrushed Stone

Pea gravel is comfortable and casual underfoot, while decomposed granite and crushed fines pack into a firmer, more stable path surface.

French DrainTrench fill

Drainage Rock (#57)River Rock

Washed drainage rock surrounds the perforated pipe so groundwater flows into the trench and away, without silt clogging the voids.

Rock Density Database

Crushed Stone1.4 t/yd³

100 lb/ft³ · Driveways, base, patios

Pea Gravel1.3 t/yd³

96 lb/ft³ · Walkways, patios, play areas

River Rock1.3 t/yd³

98 lb/ft³ · Decorative beds, dry creeks

Lava Rock0.5 t/yd³

40 lb/ft³ · Mulch beds, fire features

Limestone1.3 t/yd³

95 lb/ft³ · Driveways, paths, base

Granite1.4 t/yd³

103 lb/ft³ · Driveways, paths, accents

Marble Chips1.3 t/yd³

95 lb/ft³ · Decorative beds, borders

Drainage Rock (#57)1.4 t/yd³

100 lb/ft³ · French drains, dry wells, backfill

Rip Rap1.4 t/yd³

105 lb/ft³ · Erosion control, slopes, shorelines

Decorative Rock1.3 t/yd³

95 lb/ft³ · Accent beds, xeriscape

Sandstone1.2 t/yd³

92 lb/ft³ · Paths, decorative beds

Slate Chips1.2 t/yd³

90 lb/ft³ · Modern beds, borders, paths

Coverage per Ton

Approximate square feet a single ton of typical stone (~1.35 tons/yd³) covers at each depth.

Depth	Coverage / ton
1" deep	~240 sq ft
2" deep	~120 sq ft
3" deep	~80 sq ft
4" deep	~60 sq ft
6" deep	~40 sq ft

Lighter rock like lava rock covers considerably more; denser rip rap a little less.

How to Calculate How Much Rock You Need

Estimating rock comes down to three numbers: the area you're covering, the depth of the layer, and the density of the material. Multiply area by depth to get the volume, then multiply volume by density to get the weight. The only trick is keeping the units consistent — depth is measured in inches but area in feet, so a 3-inch layer is 0.25 feet deep in the formula.

This calculator handles all of that automatically and adds a waste allowance, truckload counts, and a cost estimate. To plan the rest of a landscaping or construction project, pair it with our Gravel Calculator, the Cubic Yard Calculator, the Concrete Calculator, the Mulch Calculator, and the Area Calculator for odd-shaped spaces.

The Rock Estimating Method

Measure the area

For a rectangle, multiply length by width. For a circle use π × radius², for a triangle ½ × base × height, or enter a known square footage directly. That gives the surface area you're covering.

Pick a coverage depth

Decide how thick the rock layer will be — 2 to 3 inches for decorative beds and paths, 4 inches or more for driveways and drainage. Multiply the area by the depth to get the volume.

Convert to weight

Divide the cubic-foot volume by 27 for cubic yards, then multiply by the rock's bulk density to get tons. Most stone runs about 1.4 tons per cubic yard; lightweight lava rock is far less.

Add waste and order

Add 5 to 10% for uneven ground, spillage, and settling, then round up to a sensible order quantity. The calculator turns that into truckloads and a cost estimate for you.

The Rock Volume Formula

Rectangle area

Length × Width

Circle area

π × (Diameter ÷ 2)²

Volume

Area × Depth

Cubic yards

Cubic feet ÷ 27

Weight (tons)

Cubic yards × density (t/yd³)

Order quantity

Weight × (1 + waste %)

One cubic yard equals 27 cubic feet, and most landscape and construction rock weighs about 1.3–1.5 tons per cubic yard. Always round the final order up and add a waste allowance.

3 Ways to Use This Calculator

Plan a landscape project

Turn a bed, border, or dry creek into exact tonnage and cubic yards so you order the right amount of decorative rock the first time, with no leftover pile or short delivery.

Estimate a driveway or base

Size a crushed-stone driveway or gravel base at the correct depth, see how many truckloads it takes, and price it per ton or per cubic yard before you call the quarry.

Compare rock types and depths

Use the what-if tool to swap rock types, test 2-inch against 4-inch depths, and watch the weight, coverage, and cost update instantly to find the most efficient plan.

Landscape Rock vs. Gravel

Decorative landscape rock

Landscape rock — river rock, marble chips, slate, lava rock, and decorative stone — is chosen mainly for looks. It's usually larger, smoother, and sold by colour and size for beds, borders, and ground cover. It sits on top of landscape fabric at 2–3 inches deep and rarely needs compacting.

Gravel & crushed stone

Gravel and crushed stone are workhorses — angular fragments and fines that compact into a firm base for driveways, paths, and drainage. They're spec'd by size number (like #57 or ¾") rather than colour, laid deeper (4 inches and up), and often compacted in lifts for strength.

Decorative Rock Guide

Decorative rock turns a plain bed into a low-maintenance, weed-suppressing feature that never needs mowing or watering. River rock gives a soft, natural look in beds and dry creeks; marble chips brighten shady corners and reflect light; slate chips suit modern, monochrome designs; and lava rock is a lightweight red or black mulch that's easy to spread around fire features.

Lay a quality landscape fabric first to block weeds and keep the rock from sinking into the soil, install solid edging to hold the stone in place, and spread it 2–3 inches deep so the ground is fully hidden. Lighter stones like lava rock cover more area per ton but can scatter in heavy wind or wash out in downpours.

Common Rock Applications

Crushed stone

Angular crushed stone is the go-to for driveways, road base, paver bedding, and compacted paths. The jagged faces interlock and lock in place, so it holds a grade and bears weight far better than smooth stone.

River rock

Smooth, rounded river rock shines in decorative beds, dry creek beds, and around downspouts where you want a natural look and some drainage. Its rounded shape means it shifts underfoot, so it's not ideal for driving surfaces.

Drainage rock

Clean, washed #57 stone with no fines leaves open voids that water flows through freely — the standard fill for French drains, dry wells, and the drainage zone behind retaining walls.

Understanding Material Density & the Waste Factor

Density is what turns a volume into a weight — and rock is sold by weight (the ton) as often as by volume (the cubic yard). Most stone runs about 1.3 to 1.5 tons per cubic yard, but the range is wide: porous lava rock is closer to half a ton per yard, while dense rip rap sits at the top of the range. Using an average density for the wrong material can throw your order off by tons, so this calculator lets you pick a specific type or enter your supplier's exact figure.

The waste factor is the extra material you buy beyond the exact calculated amount. A 5 to 10% cushion covers uneven ground, spillage while spreading, settling into low spots, and topping up thin areas later. Irregular, sloped, or heavily contoured sites justify 10 to 15%. Buying the exact amount almost always leaves you a wheelbarrow short — and a second small delivery costs more per ton plus another delivery fee.

Truckload Capacity Guide

How you haul rock depends on how much you need. A half-ton pickup like an F-150 can safely carry only about half a cubic yard — roughly one ton — despite its name, and overloading it is hard on the suspension and brakes. A one-ton truck or a small trailer handles about 1.5 cubic yards.

Half-ton pickup — ~½ cubic yard (~1 ton). Best for small bed top-ups and bagged material.
One-ton pickup / trailer — ~1.5 cubic yards (~2 tons). Good for a small path or a single bed.
Standard dump truck — ~10 cubic yards (~13 tons). The typical bulk delivery for a driveway or large bed.
Large commercial truck — 18+ cubic yards (~25 tons). Tri-axle or transfer trucks for big jobs and the lowest per-ton price.

Common Material Estimation Mistakes

1
Forgetting to convert depth. Depth is measured in inches but area in feet — spreading rock 3 inches deep means 0.25 feet in the volume formula, not 3. Mixing the units is the single most common estimating error.
2
Skipping the waste factor. Ordering the exact calculated amount usually leaves you short once the rock settles into dips and low spots. A 5 to 10% cushion covers uneven ground and spillage.
3
Using the wrong density. Rock types vary widely in weight — lava rock is a fraction of the weight of crushed stone, so using an average density can throw the tonnage off badly. Match the density to the material.
4
Choosing smooth rock for a driveway. Rounded pea gravel and river rock shift and roll under tires. Driveways need angular crushed stone that locks together and compacts into a firm surface.
5
Spreading decorative rock too thin. Under 2 inches lets soil or landscape fabric show through and doesn't suppress weeds well. Two to three inches gives full, even coverage that lasts.

Rock quantities on this page use standard material-estimating practice — geometric area and volume math, recognised bulk densities for common landscape and construction rock, and coverage figures derived from those densities. Results are educational planning estimates, not a supplier quote; actual quantities vary with compaction, moisture, particle size, and site conditions. Confirm final amounts and pricing with your supplier before purchasing. Last reviewed 2026-07-15. See our methodology and editorial standards.

Frequently Asked Questions

Multiply the area you're covering (length × width in feet) by the depth in feet, which gives the volume in cubic feet. Divide by 27 to get cubic yards, then multiply by the rock's density to get the weight in tons. For example, a 20 × 10 ft bed at 3 inches deep is 50 cubic feet, about 1.85 cubic yards, or roughly 2.5 tons of typical stone. This calculator does all of that automatically and adds waste, cost, and truckloads.

Measure the length and width of the area and decide how deep you want the rock — usually 2 to 3 inches for decorative beds and paths. Multiply length × width × depth (all in the same unit) to get the volume, convert to cubic yards or tons, and add about 10% for waste and settling. Enter those numbers above and the calculator returns the exact volume, weight, number of truckloads, and estimated cost.

Most landscape and construction rock weighs about 1.3 to 1.5 tons per cubic yard — a common rule of thumb is roughly 1.4 tons per yard. Crushed stone, gravel, river rock, and limestone all fall in this range. Lightweight lava rock is a big exception at closer to half a ton per yard, while dense rip rap can run a little higher. This calculator uses the specific density of the rock type you choose.

For decorative ground cover and garden beds, spread rock 2 to 3 inches deep so it fully hides the soil or landscape fabric and suppresses weeds. Walkways and paths work well at 2 to 3 inches, while driveways and heavy-traffic areas need 4 inches or more over a compacted base. Drainage rock in French drains or dry wells is usually 4 to 8 inches or fills the whole trench.

It depends on the depth. At 2 inches deep, one ton of typical stone covers roughly 100 square feet; at 3 inches about 70 square feet; and at 4 inches around 50 square feet. Deeper coverage means less area per ton. Lightweight lava rock covers much more ground per ton because it weighs less. The coverage analyzer above shows the exact square footage per ton for your chosen rock and depth.

Angular crushed stone is the best choice for driveways because the jagged edges lock together and compact into a firm, stable surface that resists rutting under vehicle traffic. Crushed limestone and crushed granite work well too, especially with stone dust or fines that pack tight. Avoid smooth, rounded stones like pea gravel and river rock for driving surfaces — they shift and roll under tires.

Yes. Adding 5 to 10 percent extra material accounts for uneven ground, spillage while spreading, settling over time, and topping up low spots later. Irregular or sloped sites can justify 10 to 15 percent. Ordering the exact calculated amount often leaves you short once the rock settles into dips and hollows, and a second small delivery usually costs more per ton plus another delivery fee.

A standard single-axle dump truck typically holds about 10 cubic yards, which is roughly 13 tons of most stone. Larger tri-axle and transfer trucks carry 18 cubic yards or more — around 25 tons. A half-ton pickup safely hauls only about half a cubic yard (one ton), and a one-ton pickup or small trailer about 1.5 cubic yards. The truckload estimator above shows how many loads each vehicle needs for your project.

Match the rock to the job. Use crushed stone or limestone for driveways and base, clean drainage rock for French drains and dry wells, pea gravel for casual walkways and play areas, and river rock, marble chips, slate chips, or lava rock for decorative beds. Rip rap armours slopes and shorelines against erosion. The project recommendation section above suggests the best materials for each common use.

The area, volume, and weight math is exact for the dimensions you enter, and the densities are standard industry figures you can override with your supplier's spec. Real quantities still vary with compaction, moisture content, particle size, how evenly you spread the rock, and site conditions, so treat the result as a reliable planning estimate. Order an extra 5 to 10 percent for waste and confirm quantities with your supplier before a large purchase.