Mulch, topsoil, gravel and sand calculator

How to estimate mulch, topsoil, gravel or sand in five steps

1. Pick the material and the shape. Choose mulch, topsoil, gravel or sand, then the shape of the area: a rectangle, a circle or a triangle. A curved bed can be split into a few of these shapes.
2. Type the size and the depth. Enter the dimensions in feet and the depth in inches. The calculator shows the area in square feet and the volume in cubic feet and cubic yards. It also shows how many square feet one cubic yard covers at that depth.
3. Set the waste and the bag size. The waste starts at 10 percent. Pick 20 percent if you are laying a compacted gravel base. Choose a bag of 2 or 3 cubic feet, and read the number of bags, always rounded up to a whole bag.
4. Read the order. See the amount to order with waste in cubic yards. For gravel and sand you also get the weight in tons as a low, middle and high figure.
5. Add your prices and print. Type the prices you were quoted to see a cost range, or compare two or more bids per cubic yard. Then download a one-page sheet in English, Spanish or both to take to the yard.

What this calculator does, and what it does not

Landscape material is sold by volume, but most people start from a yard. This page turns a shape, a few measurements and a depth into an order you can say out loud at the supplier: so many cubic yards, or so many bags.

It gives an estimate. Real ground is uneven and piles settle, so use the result as a starting point with your supplier. We never invent a price. If you want a cost, you type the prices you were quoted.

How the volume is worked out

First comes the area. A rectangle is length times width. A circle is pi times the radius squared, where the radius is half the width across. A triangle is half the base times the height. All of it is in feet, so the area is in square feet.

Then the depth, which you type in inches, is divided by 12 to turn it into feet. Area times depth in feet gives cubic feet. Suppliers sell by the cubic yard, and one cubic yard is 27 cubic feet, so you divide by 27 for the last step.

One cubic yard covers about 324 divided by the depth in inches, in square feet. At 3 inches that is 108 square feet. At 4 inches it is 81 square feet. The calculator shows this number for your depth.

Worked example: a mulch bed

Say a bed covers 400 square feet and you want mulch 3 inches deep. Three inches is 0.25 feet, so the volume is 400 times 0.25, which is 100 cubic feet. With 10 percent waste you order 110 cubic feet. Divided by 27, that is about 4.0741 cubic yards.

If you buy bags of 2 cubic feet, 110 divided by 2 is 55 bags. If you buy in bulk, you would ask for a little over 4 cubic yards. Check your bag label, because bag sizes vary and the volume printed on it is the number that counts.

How deep should it go, and a gravel base

Depth is a choice about your plants and your site, and this page does not make it for you; your supplier or the plant's care information can say what suits. Topsoil depth depends on whether you are leveling, topping a lawn or filling a raised bed.

For a depth you are unsure about, check with a landscaper, a garden center or your local extension office. Type their number into the calculator and see what it means in cubic yards before you order.

How deep a gravel base should be, what stone to use and how it is compacted depend on the ground, the load and local rules. That is a contractor's call. The page turns the depth you were given into a volume and a weight, and makes no claim about what a base will carry or how it will drain.

Measuring an odd-shaped bed

Few beds are perfect rectangles. The easiest way to measure a curved or irregular one is to split it into pieces you can calculate, then add the volumes together.

• Sketch the bed on paper and draw lines that cut it into rectangles, circles and triangles.
• Measure each piece in feet and run it through the calculator on its own.
• Add up the cubic yards from each piece, then order from the total.
• For a gentle curve, a rectangle that lands slightly outside the curve is a fair simplification, and the waste covers the difference.
• If the depth is not the same everywhere, treat each depth as its own piece.

Waste and rounding up

The waste percentage covers material that settles, spills, sits in low spots or gets spread a little deeper than planned. It starts at 10 percent, a common allowance. A compacted gravel base loses more volume when it is packed down, so 20 percent is offered for that case.

Bags are rounded up. If the math says 54.2 bags, you cannot buy a fifth of a bag, so the answer is 55. A bulk order is rounded in whatever steps your supplier sells, so ask your supplier.

Bags or bulk by the cubic yard

Bags are handy for small jobs. They fit in a car, you can carry them one at a time, and you can stop whenever the bed looks done. The cost is that a cubic yard is 27 cubic feet, which is 13.5 bags of 2 cubic feet, so the count climbs fast on a big bed.

Bulk material is sold by the cubic yard and dropped from a truck or loaded in a trailer. Ask your supplier about delivery rules, minimums and how they measure a yard.

Why weight changes with the material

Gravel and sand are often sold by the ton, and a truck has a weight limit, so the calculator shows tons as a low, middle and high figure. It uses a range because density varies: gravel and crushed stone run about 1.4 to 1.7 tons per cubic yard, dry sand about 1.3 to 1.5, and loose soil about 1.0 to 1.3.

Moisture matters too. Wet sand and wet soil weigh noticeably more than dry. For mulch the weight varies so much with the type and how wet it is that the page does not give a figure. Ask your supplier.

Example: a gravel area of 20 by 12 feet at 4 inches deep is 80 cubic feet. With 10 percent waste that is about 3.2593 cubic yards. At 1.4, 1.55 and 1.7 tons per cubic yard, the weight is about 4.5630, 5.0519 and 5.5407 tons.

Comparing prices and bids

If you type prices, the page shows a cost range from your own numbers and marks each one as typed by you. Nothing is filled in for you.

The bid check compares suppliers per cubic yard, so a delivered load and a bulk pickup can be set side by side. Ask each one whether the price includes delivery, how a yard is measured and whether there is a minimum.

Your answers and your privacy

The calculator runs in your browser. It asks for no phone number, email or address, nothing you enter is sent to a server, and nothing is kept when you close the page.

Frequently asked questions