Gravel Calculator

Although gravel is sold by tonnage, it is quantified in cubic yards, and this is precisely where errors often arise when ordering for a driveway or path. You determine a volume, the supplier specifies a weight, and the two values only align if you know the material’s weight per cubic yard. A gravel calculator removes that step from the equation.

Enter the surface area and depth into the gravel calculator below. The tool determines the quantity in cubic yards and tons for various materials (gravel, pea gravel, crushed stone, crusher run, river rock, sand, topsoil, or mulch) and calculates the cost based on your local supplier’s rates.

How the Gravel Calculator Works

Calculating the volume itself is simple: multiply the length by the width to get the surface area, multiply that result by the depth, and divide the total by 27 to get the value in cubic yards. The challenge lies in the fact that depth is almost always specified in inches, while length and width are measured in feet; therefore, the depth must first be divided by 12.

Take, for example, a driveway 40 feet long and 10 feet wide, with a layer thickness of 4 inches. This yields a surface area of 400 square feet; multiplying by the depth of 0.333 feet results in 133 cubic feet. Dividing this value by 27 gives 4.94 cubic yards.

Next, the conversion to weight must be performed. Gravel weighs an average of about 1.4 tons per cubic yard; therefore, the 4.94 cubic yards equate to approximately 6.9 tons, or close to 13,800 pounds. This tonnage is the figure you actually provide to the supplier, and the gravel calculator handles both steps in one pass.

If the area is not a simple rectangle, start by calculating the area first and use that total as the area value. Our square footage calculator also supports L-shapes, circles, and surfaces divided into multiple sections.

How Much Does a Yard of Gravel Weigh?

A cubic yard of dry gravel weighs approximately 2,800 pounds, which is 1.4 tons. This figure serves as a baseline for any gravel order, but it varies depending on the type of material:

• Gravel and crushed stone: approx. 1.4 tons, or roughly 2,800 pounds, per cubic yard
• Crusher run or road base: approx. 1.5 tons, as fine particles compact into the voids between the stones
• Pea gravel: approx. 1.35 tons, as the rounded stones leave more air gaps
• River rock: approx. 1.3 tons, which is the lightest type of stone among those mentioned
• Sand: approx. 1.35 tons when dry, and considerably more when wet
• Topsoil: approx. 1.1 tons, depending on moisture and organic matter content
• Bark mulch: approx. 0.5 tons, which is why mulch is usually sold by volume in cubic yards rather than by weight in tons

The gravel calculator applies each of these densities automatically as soon as you change the material in the dropdown, so the cubic yards stay the same while the tonnage adjusts.

Two factors can increase these weights. The most important is water: a cubic yard of gravel exposed to rain for a week can weigh several hundred pounds more than the same amount when dry. The second factor is compaction, and consequently crusher run weighs more per cubic yard than loose gravel derived from the same rock.

Quarries also differ from one another. Limestone, granite, and basalt have different densities, and construction sand and gravel is produced at thousands of sites across the country, as the US Geological Survey records in its national aggregate surveys. If you need an exact figure, ask your supplier for the material’s weight per cubic yard and calculate accordingly.

How Many Yards Are in a Ton of Gravel?

The gravel calculator works this out in reverse as well. A ton of gravel equals approximately 0.71 cubic yards; this figure is obtained by dividing 1 by the weight of 1.4 tons per cubic yard. In practice, therefore, a ton of gravel represents slightly more than two-thirds of a cubic yard.

This conversion is important when a supplier lists prices per ton and you need to know if the quantity will be sufficient to cover your area. A ton of gravel covers about 115 square feet at a depth of 2 inches. At 3 inches the covered area is about 77 square feet, and at 4 inches it is about 58 square feet. If the layer thickness is doubled, the covered area is halved.

It is also worth noting the definition of the term “ton.” In the United States, a ton equals 2,000 pounds, known as a short ton, and this is the value used by the gravel calculator. A metric ton equals 2,205 pounds, while a British long ton equals 2,240 pounds. The National Institute of Standards and Technology publishes the official conversion tables if you need to check one. If you are consulting a technical specification sheet from abroad, confirm which unit is used before placing your order.

How Deep Should a Gravel Driveway Be?

Layer thickness is the deciding factor when calculating the quantity to order, and it is the figure the gravel calculator is most sensitive to, yet it is a value many people underestimate. It all depends on the load the surface needs to bear.

• 2 inches: to top up an existing gravel path or walkway where the layer has thinned out.
• 3 to 4 inches: for decorative beds, garden paths, or as a new top layer over a surface that already has a solid base.
• 4 inches: the standard thickness for a single layer on low-traffic surfaces or as a base for a garden shed.
• Total of 8 to 12 inches: for a new driveway built from bare ground, using multiple layers.

This last point is precisely where most people make calculation errors. A well-constructed driveway is not just a single thick layer of gravel. It generally consists of three layers: a coarse base layer of large stones at approximately 4 inches, an intermediate layer of crusher run at 3 to 4 inches, and the visible top layer of gravel for traffic at another 2 to 3 inches. Each layer is compacted before the next one is laid.

Therefore, for a new driveway, run the gravel calculator three times, once for each layer, accounting for the specific material and thickness, before adding up the total tonnage. If you are simply resurfacing an existing driveway, a single application with a layer thickness of 2 to 3 inches is sufficient.

Pea Gravel, Crusher Run, and River Rock

These materials are not interchangeable, and choosing the wrong one is an expensive mistake to walk on.

Crusher run, also sold as road base or quarry process, consists of crushed rock mixed with stone dust. The fine particles fill the voids and, once compacted, ensure the entire layer holds together firmly; this makes it the ideal choice for base layers or driveways that must maintain their shape under the weight of a car. Furthermore, it is the most economical of the three options in most markets.

Pea gravel consists of small, smooth, rounded stones, making it pleasant to walk on and popular for pathways, patios, and play areas. However, due to their rounded shape, the stones do not interlock; under a load, they shift and spread sideways. Therefore, for a driveway, an edging must be installed to keep the gravel in place, and it is not suitable as a sub-base material.

River rock is larger and smoother, and is used primarily for decorative purposes. It is ideal for drainage beds, dry creek beds, and borders that do not see foot traffic. Of the three materials mentioned, it is the most expensive per ton and offers the least stability for vehicle traffic.

Crushed stone, often classified by its particle size such as 3/4 inch or number 57 stone, falls into an intermediate category. Thanks to its angular shape, the material interlocks well, and because it lacks fine particles to fill the voids, it is water-permeable. It is frequently used as a finishing layer and is also suitable for areas near foundations, as well as for French drains. Each of these materials sits in the gravel calculator dropdown with its own density already applied.

Crushed Stone Calculator: Number 57, 3/4 Inch, and Base Rock

Used as a crushed stone calculator, the tool above handles every grade in the same pass. Crushed stone is sold by size rather than by name, and the numbering system confuses almost everyone the first time they order. The numbers refer to the screen the stone passed through at the quarry, so a lower number means a larger rock.

• Number 57 stone: roughly 3/4 inch, angular, with no fines. The most widely used size in the country, suitable for driveways, drainage, French drains, and as aggregate in concrete.
• Number 8 stone: roughly 3/8 inch, a smaller chip often used as a top dressing or between pavers.
• Number 2 stone: roughly 2 to 2.5 inches, large and coarse, used as a first layer over soft ground.
• Crusher run, sometimes sold as number 411 or road base: crushed stone with the fines left in, which is what allows it to compact solid.

Limestone, granite, and basalt are the three rock types you are most likely to be offered, and the size numbers apply the same way to all of them. Limestone is the most common and usually the cheapest, granite is harder and holds its edges longer under traffic, and basalt is darker and often sold as decorative stone.

For estimating purposes the size barely matters. Crushed stone of any grade runs close to 1.4 tons per cubic yard, so the tool above works as a stone calculator for number 57, 3/4 inch, base rock, or limestone without changing the material setting. Select crushed stone, enter your dimensions, and the tonnage will be accurate enough to order from. It is the same gravel calculator underneath, only the density changes.

Landscape Rock Calculator: Decorative Stone Depths

Decorative stone is ordered exactly like driveway aggregate, but the depths are shallower and the priority is coverage rather than load bearing. Used as a rock calculator for landscaping, the tool above gives you the same two figures, cubic yards and tons, from the area you are covering.

• Planting beds and borders: 2 to 3 inches, deep enough to suppress weeds and hold moisture.
• Pathways: 2 to 3 inches over a compacted base, using smaller sizes that stay comfortable underfoot.
• Dry creek beds and drainage features: 3 to 4 inches, usually river rock in mixed sizes.
• Around foundations and downspouts: 3 to 4 inches of angular stone, which drains freely and does not wash away.

River rock is the one that catches people out. It is the lightest material in the dropdown at about 1.3 tons per cubic yard, and because the stones are large and rounded they need more depth than a fine gravel to cover the ground properly. Select river rock rather than leaving the gravel calculator on general gravel, or you will order roughly 8% more weight than you need.

Whichever material you pick, run the landscape rock calculator at your chosen depth before ordering, and lay landscape fabric underneath any decorative stone bed. Without it the stone gradually works down into the soil and you end up topping the bed up every two or three years, which costs far more over time than the fabric ever would.

How Much Does a Yard of Rock Weigh?

The gravel calculator handles rock and stone on the same densities. A cubic yard of rock weighs between 1.3 and 1.5 tons depending on the type, which is 2,600 to 3,000 pounds. Crushed stone and limestone sit around 1.4 tons, river rock is lighter at about 1.3, and crusher run is heaviest at about 1.5 because the fines fill the gaps between the stones.

The rock calculator above converts in both directions, so you can work from an area or check a supplier’s quote. Working the other way, a ton of rock is about 0.71 cubic yards, and it covers roughly 115 square feet spread 2 inches deep, 77 square feet at 3 inches, or 58 square feet at 4 inches. Those coverage figures hold for crushed stone, limestone, and landscape rock alike, since their densities are close enough that the difference disappears into the rounding when you order.

How Much Does Gravel Cost?

The price of gravel depends more on fuel and transportation costs than on the rock itself; therefore, a national average is not very useful when planning a specific project. However, the cost breakdown is usually consistent:

• The material: price per ton at the quarry, or per cubic yard at the supply yard.
• Delivery: generally a flat rate per trip, depending more on distance than on quantity.
• Minimum delivery quantity: most suppliers will not dispatch a truck to transport just a fraction of a ton.
• Spreading: if the material needs to be spread directly at the site rather than simply dumped in a pile on the driveway.

Delivery charges account for the high cost per ton when dealing with small quantities. If the same flat transport rate applies to one ton instead of ten, the material appears much more expensive than it actually is. If the desired quantity is close to a round number, it is usually more economical to order that amount upfront rather than scheduling a second delivery later.

The gravel calculator provides fields for entering both types of pricing. Request a quote from a local supplier, either per ton or per cubic yard, and enter the corresponding value; this will give you a total cost reflecting current local prices. If you enter both values, the price per ton takes precedence, since that is how the load is normally billed.

Sand, Topsoil, and Mulch

The same volume calculation applies to all other materials sold in bulk by volume, and for this reason these products appear in the gravel calculator’s material menu.

When used as a base layer beneath paved surfaces or patios, sand is typically spread to a thickness of one inch over a compacted gravel base. For a new lawn, the standard practice is to apply a layer of topsoil between 4 and 6 inches thick, which is a surprisingly large amount when calculating requirements for an entire garden. Mulch is usually spread in a layer 2 to 3 inches thick, sufficient to retain moisture and block light without suffocating the roots.

It is important to pay close attention to weight, especially with mulch. At approximately 0.5 tons per cubic yard, this material is light enough to be sold almost exclusively by volume in cubic yards; therefore, the order is determined by the volume in cubic yards rather than the weight in tons.

Gravel is entirely unsuitable for surfaces that need to be firm and level, such as garage floors or stair treads. In these cases, a poured concrete slab is the ideal solution, and our concrete calculator allows you to determine the necessary quantity in cubic yards as well as the number of bags required. For everything that is spread rather than poured, the gravel calculator above will give you the tonnage to order.

For the other materials in a build, see all our construction calculators.

Frequently Asked Questions