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Mulch Calculator

Measure your bed, pick a depth, and get cubic yards for bulk delivery or a bag count for the store. The same maths works for topsoil, compost and bark chips.

How the mulch calculation works

  1. Measure each bed’s length and width in feet. Split L-shaped beds into rectangles.
  2. Choose a depth — 2 to 3 inches suppresses weeds and holds moisture without smothering roots.
  3. Convert inches to feet by dividing by 12.
  4. Multiply length × width × depth for cubic feet.
  5. Divide by 27 for cubic yards if you are ordering bulk, or by 2 and 3 for bag counts.

The formula

Volume (ft³) = Length (ft) × Width (ft) × Depth (in) ÷ 12. Divide by 27 for cubic yards.

Buying materials?

Compare prices before you order:

Common questions

How deep should mulch be?

Two to three inches. Less lets weeds through, more starves roots of oxygen and pushes moisture into the stems, which causes rot. Keep it a few inches clear of trunks and stems.

How many bags of mulch are in a cubic yard?

Either 13.5 bags at 2 ft³ or 9 bags at 3 ft³. A cubic yard is 27 ft³, so budget for 14 of the 2 ft³ bags to be safe.

Is bulk mulch cheaper than bags?

Usually yes once you pass about 3 cubic yards, though delivery fees can erase the saving. Below that, bags are often the better deal and you can carry them yourself.

Can I use this calculator for soil and compost?

Yes. The volume maths is identical. Just check the bag labels — potting mix is often sold by quarts or litres rather than cubic feet.

How often should I remulch?

Once a year for organic mulch, since it decomposes and feeds the soil. Top up to the 2 to 3 inch depth rather than piling more on — adding to an already thick layer causes problems.

Sizes people search for

Jump straight to a worked example:

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