A Garden Mulch Calculator

While working on the list of things I need to complete my 48 Hour Blog Project I was trying to figure out how many bags of mulch I’ll need for the planting areas and I came up with this little calculator. All you have to do is input the dimensions of the area followed by how deep you want the mulch and it will tell you the amount in cubic feet. Please keep in mind this is just an estimate!

function MultiplyMulch(Atext, Btext, Ctext, form){var A = parseFloat(Atext);var B = parseFloat(Btext);var C = parseFloat(Ctext);form.Answer.value = A * B * C/12;}/* ClearForm: this function has 1 argument: form. It clears the input and answer fields on the form. It needs to know the names of the INPUT elements in order to do this. */function ClearForm(form){form.input_A.value = “”;form.input_B.value = “”;form.input_C.value = “”;form.Answer.value = “”;}// end of JavaScript functions –>

How Much Mulch Do I Need?

Enter the area length (in feet):

Enter the area width (in feet):

Enter the mulch depth (in inches):

Mulch in Cubic Feet=

Mulch Don’ts

  • Don’t mulch right up to the base of trees, leave a gap. Voles love the cover of mulch to get to the bark of trees.
  • Don’t mulch more than 2-3 inches high around trees and shrubs.
  • Don’t volcano the mulch around trees. It look silly and will suffocate the roots systems. Mt. Saint Helen’s never spewed out Bradford Pears!

Since I am definitely not a talented html coder I adapted a script from: Science Buddies.

10 thoughts on “A Garden Mulch Calculator”

  1. Now Dave, I think you are one of the most tech savvy bloggers on here! Good job inputting this calculator into your site. I like these calculators. I often use them for bricks and sand too.
    Can’t wait to see your project!

  2. Dave-
    I tried to plug in some numbers to see if the amounts we use at work would equal what the calculator says. Unfortunately, the calculator didn’t work.

    The way we figure mulch for a 2″ depth is:
    Length x Width= X
    X divided by 160= Number of cubic yards needed.
    For a 3″ depth you would divide X by 120.

    Our customers seem to be happy with the amounts that are delivered when we use that method.

    It is amazing, however, how many adults cannot do this type of math so the calculator would come in handy!

  3. Tina,

    I’ll be seeing some progress soon. Hopefully the rain will hold off for a couple days so I can get going!


    There were some blogger and scripting disagreements. Hopefully it’s fixed now. I basically used the old formula for volume with an added conversion so that the height could be put in inches.

  4. Just tried it again using 40x4x2 and it came out to 26.66 which is close enough to 1 cubic yard for me! Or as my husband would say, “Close enough for government work!”

  5. Now could you please come up with a “Companion Gardening Calculator”? You know one where you could check the plants you want to grow from an alphabetized list of plants. Then enter if you will have a standard garden and the size or if you will have raised beds and the # and sizes. Then it would spit out the hand dandy recommendation. It would be so AWESOME!!!!!
    I guess if there is already one out there that someone knows of just let me know where to go for it.

  6. IdahoTomboy,

    That is a very good idea. I think my html skills may be lacking for that but I can get a chart together. I’ll target next week for that!

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