In order to determine how much compost you will need, the following tools will be required: Tape measure, pen, paper, and a calculator. Once you have the necessary tools follow these two simple steps.

Step 1: Measuring you project area – Area is measured in a couple different ways depending on the shape of the project. Below are three common examples of how to measure different project areas.

Example 1: Square/rectangular project area

20’ length x 20’ width = 400 feet squared

Example 2: Circular project area

3.141 x 10’ Radius2 = 314.1 feet squared

Example 3: Triangular project area

.5 x 5’ Base x 10’ height = 25 feet squared

Step 2: How many cubic yards of compost – Now that you have determined the square footage of your project area you will have to determine how much compost you will need. Take the square footage (Project area square footage from step one) multiply by the depth of compost that you want to apply. After multiplying your square footage and depth of compost, multiply by .0031.

Example: Taking the square footage from step one, example one and applying 2” of compost to the overall area multiplied by .0031the formula will look like this.

400 ft2 x 2” compost depth x .0031 = 2.48 yards^3

This formula tells us, for an area 20’ x 20’ we will need 2.48 cubic yards of compost to give an overall compost depth of 2” over the entire project area.

You may ask yourself why it matters how much compost you put on your project area. The reason you need to be fairly accurate is because too little or too much compost is not good. Too little compost and the project area will not get enough good bacteria and nutrients. Too much and the nutrients will be wasted.

If you still need help determining how much compost that will be needed for your project, please call or email us with your measurements. A Compost King will respond to help you determine your compost needs.

Use the yardage calculator for rectangular shapes.