Mulch Calculator

Calculate how much mulch you need by entering the size of the landscaping area and the depth of fill. Get results in cubic feet, cubic yards, and the number of bags of mulch needed.

How to Calculate Mulch

Adding mulch is a great way to refresh a landscaping bed and prevent weed growth. Adding mulch is a pretty easy project, but as you begin, you might be wondering how much mulch you need.

You’re in luck! Follow along, and we’ll show you how to calculate how much mulch you need for your landscaping project.

Fresh mulch being added to a landscaping bed

The easiest way to calculate mulch coverage is to use the calculator above since it takes all the math and guesswork out of the process.

If you want to do the calculations yourself, you can estimate material in a few easy steps.

Step One: Measure the Landscaping Space

The first step to calculating how much mulch you need is to measure the space you want to cover. Use a tape measure to measure the length and width of the space.

Next, measure the depth of the mulch bed. We recommend a 3″ depth for an average mulch bed, but 2″ or 4″ would be just fine as well.

Ensure all measurements are in the same unit of measure; the calculations will be easiest if all measurements are in feet.

Step Two: Calculate the Volume of the Landscaping Space

Once you have measured the space, it’s time to calculate the volume.

Multiply the length times the width to find the area of the space. If the landscape bed is complex, then split it up into manageable sections and measure each separately.

For landscape beds with portions that aren’t a simple rectangle, you can use an area calculator to estimate the area of more complex shapes.

Then, multiply the area by the depth. Remember to keep all measurements in the same unit of measure, so if the width and length are in feet, then multiply the area by the depth in feet.

Volume Formula

For an area that is a standard rectangle, you can use the following formula to calculate the volume.

volume = length × width × depth

Step Three: Convert the Volume to the Unit Needed

The final step to calculating how much mulch you need is to convert the volume measurement to the unit of measure that the mulch is sold by if it isn’t already in the same unit of measure.

Mulch sold by the bag is usually measured by the cubic foot. You can also purchase in bulk by the cubic yard.

When calculating volume, if all the measurements used are in feet, then the volume is in cubic feet. If the measurements were in inches, then the volume is cubic inches.

To convert to the desired volume measurement, you can use our cubic inches to cubic feet or cubic feet to cubic yards calculators.

To convert manually, divide a cubic inches measurement by 1,728 to get cubic feet. Convert cubic feet to cubic yards by dividing by 27.

Mulch Formulas

cubic feet = cubic inches ÷ 1,728

cubic yards = cubic feet ÷ 27

What Type of Mulch Should You Use?

Before purchasing mulch, do some research on the best type for your project. Backyard Boss explains that there are several types available, including standard garden, rubber, bark, hardwood, hemlock, and leaf mulch.[1]

Each type has a different look, so spend some time to find the right variety to complement your home and landscaping. Different types also cost more than others, which may be an important factor in your decision.

Check out our soil calculator to calculate soil for a garden bed and use our cubic yardage calculator to estimate other landscaping materials.


  1. Backyard Boss, Everything You Ever Needed to Know About Mulch,