How to calculate cubic feet for mulch

Whether you're buying bagged bark mulch or purchasing a truckload, you'll need to determine how much you'll need to get the job done. Our calculator can help. In general, bark mulch should be spread in a 2" to 4" deep layer — any deeper and you risk smothering roots. See other tips below. This calculator is also handy for determining how much pea stone you'll need for a path.

Mulch Calculator

1

Measure the length and width, or the diameter, of the area to be mulched. Tip: For irregularly shaped beds, break them into rough rectangles and circles. Then calculate the mulch needed for each section and add them for the total mulch needed.

2

Select the shape:

3

Enter the measurements:

Length of area (in feet)

Width of area (in feet)

Depth of mulch (in inches; we recommend 2-4")

Reset Calculator

Calculate

Here's what you need:

 cubic yards of mulch (  cubic feet)

Note that one cubic yard of mulch (often just called "a yard") is 27 cubic feet. Most bags of mulch hold 2 cubic feet. So there are 13-1/2 bags of mulch in a yard.

An organic mulch, such as bark mulch and pine straw, offers many benefits to plants and soil. It helps hold in moisture, minimizes soil temperature fluctuations, keeps weeds at bay, and adds a decorative final touch. All types of gardens can be mulched — perennial gardens, raised beds, vegetable gardens, even planters!

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FAQs for Proper Mulching

Q. Should I mulch under my trees?

A. Yes. But no mulch volcanoes! Grass growing under trees will intercept much of the water and fertilizer you apply, keeping it from reaching the trees' roots. Keep a large (3' plus), turf-free circle around the trunk. Extend it out as the tree grows. (Grass often struggles to grow in the shade anyway.) A 2" to 4" layer of organic mulch, such as shredded bark, bark chips, or pine straw, helps conserve moisture and keeps weeds at bay. To prevent rot, keep mulch at least 6" away from the trunk, and definitely don't pile it against the trunk.

Q. What is used to dye red and black mulches?

A. The dyes are generally made from a base of either iron oxide or carbon. Both materials are used in many other applications and are considered safe. The only concern with dyed mulches is that they may be made from recycled wood, as opposed to bark. The source of the wood can be just about anything, such as old pallets, which is a concern for some people. Also, note that light-colored concrete and stone can be stained by dyed mulch.

Q. Is it better to buy mulch in bulk or by the bag?

A It depends on how much you need, among other factors. Bulk mulch is usually less expensive by volume. For example, at a recent visit to a garden center, bagged cedar mulch was $5.99 for a 2 cubic foot bag. Bulk mulch was $46 per cubic yard. A cubic yard (often just called "a yard") is 27 cubic feet. So the price per cubic foot was bulk, $1.70; bagged, $3.00. Note that this did NOT take into account any delivery charge.

A layer of mulch can tie your garden together, giving your beds a clean, uniform appearance. Mulch also benefits your garden by reducing water loss from the soil through evaporation and providing a barrier to sprouting weeds. As degradable mulches, such as straw or bark dust, decompose, they improve the soil by adding organic matter and nutrients. Other mulches, such as gravel, don't break down, but need to be replaced less often than degradable mulches. Regardless of which type of mulch you choose, though, you'll first need to determine how much mulch you need.

Calculating Cubic Yards

1. 1.

   Measure the length and width of the area in feet. Multiply these figures together to find the area in square feet. Do this for all areas where you want to lay mulch and then add the square footage together to get the total square footage of the areas you need to cover.

2. 2.

   Determine how deeply you want to layer your mulch. In most flowerbeds and vegetable gardens, 2 to 3 inches is a good depth. For heavy weed or grass suppression, put down a 6-inch layer.

   Tip

   To allow for oxygen movement to and from your garden soil, don't exceed a 2- to 3-inch depth for fine mulches; for coarser mulches, such as bark chips, lay a maximum of 6 inches.

3. 3.

   Multiply your total area in feet by how deep you want your mulch in inches. For example, if your square footage is 648 and you want a 2-inch depth, multiply 648 by 2 to get 1296 (648 x 2 = 1296).

4. 4.

   Divide your answer by 324 (1 cubic yard of mulch will cover 324 square feet 1 inch deep). Round the result to the nearest whole number to find out how many cubic yards of mulch you need to purchase. In this example, we need to purchase 4 cubic yards of mulch (1296/324 = 4).

Circular Bed Square Footage

1. 1.

   Measure the diameter of the bed in feet. Divide this by half to get the radius. For example, if the bed measures 6 feet across, the radius is 3 feet (6/2 = 3).

2. 2.

   Square the radius (multiply it by itself). In this example, multiplying 3 by 3 equals 9 (3 x 3 = 9).

3. 3.

   Multiply the radius squared by 3.14 (pi) to get the area in square feet. In this example, multiply 9 by 3.14 to get 28.26 square feet (9 x 3.14 = 28.26).

4. 4.

   Multiply the area in square feet by the desired depth in inches, for example, 2 inches (28.26 x 2 = 56.52). Divide this figure by 324 (56.52/324 = 0.2). For a 2-inch layer of mulch on this 6-foot circle, you will need 0.2 cubic yards of mulch. Because this bed is so small, the number is rounded to the nearest tenth rather than the nearest whole number.

   Things You Will Need

   • Measuring tape

   • Pencil and paper

   • Calculator

   Tip

   Garden beds are rarely perfectly square, and it's OK to take rough measurements. It's better to estimate too large than too small when taking such a measurement. Remember that you're calculating for cubic yards, not cubic feet. Loose mulch is sold in cubic yards, but bags of mulch sold in garden centers are often sold in cubic feet. To convert your answer from cubic yards to cubic feet, multiply it by 27.

   How do I calculate how much mulch I need?

   To calculate mulch in yards, it is essential to note that one cubic yard of material will cover an area of 324 square feet at a depth of an inch. To determine the total amount of mulch needed, the formula is: Square footage x desired depth (in inches)/ 324.

   How many square feet does a 2 cubic foot bag of mulch cover?

   One 2 Cubic Foot Bag Covers covers 8 sq feet.

   How much does a cubic foot of mulch cover?

   A 1 cubic feet bag of straw mulch covers approximately 200 square feet and weighs around 20 pounds.

   How many 2 cubic feet bags of mulch in a yard?

   Most bagged mulch is sold in 2 cubic foot bags. So, for every 13.5 bags, you need one cubic yard.