Measuring for Bulk Materials

If you’re thinking about landscaping your existing garden or starting a brand new garden project, you may wonder how much supply you’ll need to purchase to get the job done. To get the information you need to know before buying your landscaping materials, you’ll first need to calculate the volumes of the materials accurately you’ll need. Whether you’re an experienced gardener or landscaper or embarking on your first DIY gardening project, the guide below will teach you how to measure the area of the part of the yard you intend to put the material down on according to the project type.

What you’ll need to get started:

  • Measuring tape
  • Calculator (No need to go digging for your TI-84 calculator – the calculator on your smartphone is just fine.)

Step 1

Measure your yard or garden space by length and width. Then, multiply the length times the width, which will give you the square footage of the area.

Step 2

Determine how deep or thick you want your landscaping materials to be. Here is a simple breakdown of the depths we recommend for general projects and their corresponding materials:

  • General mulching: 3 inches
  • Mulching to reduce soil compaction: 6 inches
  • Installing or regrading a lawn with topsoil: 3-6 inches
  • Amending soil with topsoil: 2-3 inches
  • Drainage or decorating with gravel: 2-3 inches
  • New yard construction with fill dirt (subsoil): 12 inches

For your typical rectangular or square-shaped areas, multiply the length and width together, then multiply the total area calculation by the depth in inches, before converting to feet and dividing by twelve.

Step 3

After determining the depth of the material, multiply that number by the square footage of the space, which will give you the square footage of what your materials will need to cover.

Other things to consider before you order

  • The particular terrain of the space (Is it sloped, etc.?)
  • The quality of your topsoil (Color should be dark, smell should be sweet, texture should allow you to squeeze a handful into a ball and then easily crumble apart when you open your hand, and should be free of fragments, such as big stones, weeds, or any unwanted seeds.)
  • The quality of your mulch (Is it natural or man-made?)

If after completing the above steps, you’re still unsure about how much material you’ll need to purchase for your project, know that it’s always best to err on the side of buying more than less – You can always use any leftover material for your next project. You can also contact us for assistance with any questions you may have about measuring for bulk materials.

What about irregular-shaped areas?

When calculating the amount of materials needed for irregular areas, it’s best to divide them up into smaller shapes, measure each of them and assign them a letter. Then you can calculate the square feet for each shape and add them together to find the total amount needed. For example:


  1. Measure the length and width of 2 sides.
  2. Multiply the length by the width, and multiply by 0.5 to get the square footage.
  3. Divide the square footage by the square foot per yard to get the cubic yards needed (refer to conversion chart below).


  1. Find the radius, which is half the distance of the diameter, or the total distance across.
  2. Multiply the radius by itself, and then by 3.14 to get the square footage.
  3. Divide the square footage by the square foot per yard to find the cubic yards needed.

Square feet to cubic yards

[1 cubic yard of material will cover the following amounts of square feet at the given depth.]
  • ¼” deep = 1,296 square feet
  • 1” deep = 324 square feet
  • 2” deep = 162 square feet
  • 3” deep = 108 square feet
  • 4” deep = 81 square feet
  • 6” deep = 54 square feet
  • 12” deep = 27 square feet

Mulch vs. Topsoil – Which is better?

Actually, using a combination of both mulch and topsoil is most beneficial for your garden. Mulch reduces the amount of water that evaporates from your soil, while topsoil helps protect the roots of plants by locking in that moisture that has already drained into the soil. So, as mulch allows better water and air movement through the soil, providing nutrients and improving its ability to hold water, topsoil, by preventing evaporation, is key to giving your plants the moisture they need, even in periods of little rainfall.

While mulch will eventually break down and become topsoil, it should not be used alone or as a replacement for topsoil. This is because topsoil is sometimes composed of little to no organic matter or active soil microbes, and therefore, does not ensure soil performance. However, mulch, when applied to the soil surface, discourages weeds, provides shade, and reduces the amount of moisture loss through evaporation.

Pro-tip: Cover your topsoil with mulch to avoid erosion from rain and overheating from the sun.

Benefits of Mulch

  • Nourishes soil (Organic mulches break down and add nutrients to the soil.)
  • Suppresses weeds (by preventing germination or growth of weed seeds)
  • Regulates temperature (by providing insulation, keeping roots cooler in the summer and protecting them from freezing in the winter)
  • Conserves water, and;
  • Prevents erosion (from wind and water).

Benefits of Topsoil

  • Improved drought resistance (by locking in moisture that has already drained into the soil)
  • Improved plant health (by adding nutrients while also helping oxygen reach plant roots)
  • Improved drainage (Topsoil drains very well, so the more you add, the better.)
  • More nutrients (While topsoil already contains its own nutrients, it also helps to maintain any extra nutrients that are added to the soil.)

Now that you know the steps for calculating the amount of bulk landscaping materials you’ll need for your project, and that quality topsoil and mulch are the most essential factors that contribute to a healthy garden, this is a great time to start on your summer garden. If you’re looking for superior quality topsoil and mulch at competitive prices, conveniently delivered right to your driveway, contact the experts at Hawkins Landscape Supply by giving us a call today or placing an online order here.

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