The Mulching Calculator includes equations and data for approximating the volume (cubic units or bags) of mulch needed to cover areas and an approximate cost based on the volume and type of mulch.  This includes:

• Mulch to Cover Area: Enter an area size (e.g. 45 square feet or 0.75 acres) and depth of mulch wanted, and see estimated amount of mulch needed.
• Mulch to Cover Circular Area:  Enter the diameter (D) of the circle and depth of mulch wanted, and see estimated amount of mulch needed.
• Mulch to Cover Rectangular Area: Enter the length (L) and width (W) of the area and depth of mulch wanted, and see estimated amount of mulch needed.
• Mulch to Cover Irregular Area: Enter the length of the four sides (a,b,c,d) and the diagonal (D) of an irregular area (see diagram) and the depth of mulch wanted, and see estimated amount of mulch needed.
• Mulch Cost Estimate: Enter the amount of mulch needed, choose a type of mulch and it will provide an estimate of the cost.
• Mulching With Straw (Irregular Area): Enter the length (L) and width (W) of the rectangular area and it will estimate the number of bales of straw needed to mulch the area with straw.
• Mulching With Straw (Area): Enter the area (acres, square feet) to see an estimate of the number of bales of straw needed to mulch the area with straw.
• Bulk vs Bag Price Comparison: Enter the bulk mulch and bag prices and volumes, and it tells you which is cheaper and by how much.
• Landscape Fabric:  Computes the amount of landscape fabric needed for an area.        Autumn Garden on Black Mulch Bed

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Mulching Information

Mulching is an excellent way to help your garden, plants, shrubs or trees in your yard.  Mulch slows the growth of weeds, while allowing water and air to get to your plants; it also provides a pleasing visual boundary to highlight your plants. 

To help you know how much mulch you need for a job, the vCalc mulch calculator helps calculate the volume of mulch needed.  The volume equations, mulch cover (area), mulch cover (circular)  and  mulch cover (rectangle) both use the dimensions of the area to be covered and the desired depth of mulch in order to calculate the volume.  The volume is returned in cubic units (system units such as cubic feet) or in standard bags.  Bags of mulch in the U.S. typically come in units of 2 cubic feet.  Note: most experts recommend a depth(d) of 1" to 2" of fine mulch or 3" to 4" of coarse mulch.

The mulch cost equation allows you to enter the cubic measurement (ft³ or m³) and then lets you enter the unit price for a cubic foot of mulch.  vCalc uses the volume and unit price to compute the total cost.  Local pricing should always be used.  However, for the convenience of the user, a periodic Internet survey is made of mulch prices. The most recent observations are as follows:

• Date: 12/27/21
• Store: Lowes
  • Red Mulch: 1.84 USD/ft³
  • Pine Mulch: 2.44 USD/ft³
  • Common Hardwood Mulch: 1.84 USD/ft³
  • Cedar Mulch: 1.83 USD/ft³
  • Rubber Mulch: 8.725 USD/ft³

Mulcher's Advice

Bulk Mulch

My family buys mulch in two ways, bags and loose.  The bags are as described above.  They are typically 2.0 cubic feet plastic bags, are easy to transport in the trunk of our car (boot for our British friends) or in the back of our hatchback without causing too much of a mess.  However, we more often use our truck to get bulk mulch from a local garden center.  That usually turns out to be much cheaper, but we have to get it ourselves using a trailer or truck.  In this case, we typically buy a scoop or two, which fits in the back of our truck, and costs $40 -$60 per scoop.  However, the cheapest mulch that we've bought has come from our local landfill.  At the landfill, they take common yard debris and processes it into mulch.  This is arguably lower quality mulch and not always available, but still is very useful and much cheaper.  We've seen it for free or up to $20/cubic yard.  Word of caution: make sure you cover your load of loose mulch before you leave the garden center or landfill.  Many local law enforcement officers won't hesitate to pull you over and give you a ticket for an uncovered load; it does tend to blow away a little as you drive down the road.   Calculate: Mulch for Circular Area

Make Your Own Mulch

 At some point, we want to rent a chipper to make our own mulch out of our own yard debris,  but that is noisy and potentially dangerous.  (But still in the plan).  It kills two birds with one stone (cleaning up the yard and mulching).  Home Depot will rent a chipper in some of their stores.

Mulching Tools

 The most useful tool for mulching (particularly loose bulk) is a pitchfork.  You will find it much easier to "shovel" mulch using a pitchfork than any shovel, because you'll be able to dive into the middle of the pile and not start on the bottom.  However, a grain shovel or even snow-shovel is useful when getting the last bits of mulch out of your truck or off your driveway.  And unless you don't mind stained hands, use ruberized gloves.  Most mulches are dyed and the dye comes off when spreading it.

Garden Fabric

 Speaking of my wife, she is the queen of mulching.  She goes through 10 cubic yards of mulch almost every year.  However, she likes to put garden fabric down first and then apply the mulch.  She'll only put the fabric down once and then refresh the mulch in subsequent years.  Lawn or garden fabric is terrific at weed prevention.  There's nothing like it for eliminating a large area of weeds and the mulch lasts much longer.  The only hazard is losing your scissors while cutting and laying the fabric; they are easily hidden under the fabric or mulch.  If our yard is excavated by an archaeologist in millennia to come, they will call us the Scissor People for all of the scissors they will find. 

Related Calculators

vCalc has a library of equations and calculator for planters and green houses at the following links:

• Soil and Planter Calculator: This calculator helps compute soil volumes and watering needs for raised planters.
• Greenhouse Calculator:   This calculator computes greenhouse factors such as surface areas and volumes of Quonset huts, and soil volumes, of planters.
• Square Footage Calculator:  This calculator helps compute the area (square feet, meters and acres) of an area based on its shapes and simple measurements.