How the mulch calculator works
Enter the garden bed length, width, and mulch depth. The calculator estimates cubic feet, adds 10% for planning, and converts the result to cubic yards.
Formula
Volume = length × width × depth in feet
Order volume = volume × 1.10
Cubic yards = order volume ÷ 27
Example
A 20 ft × 8 ft bed at 3 inches deep is about 40 cubic feet before the allowance, or about 1.63 cubic yards with the 10% planning allowance.
Assumptions and material notes
Mulch settles over time, and actual coverage depends on material, moisture, and application method. Bagged mulch should be checked against the manufacturer's stated coverage.
Frequently asked questions
Why add 10%?
It is a general planning allowance for settling and small measurement variation.
How many cubic feet are in a cubic yard?
One cubic yard equals 27 cubic feet.
Does this calculate bags?
No. Use the cubic-foot or cubic-yard result with the coverage printed on your mulch bag.
Can I use decimal depths?
Yes.
How should I handle irregular beds?
Break an irregular bed into simple measurable sections, calculate each section, and add the volumes together.
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Disclaimer: Estimates are for planning purposes only. Actual material requirements may vary based on site conditions, material specifications, installation methods, waste, and local requirements. Always verify quantities with your supplier or qualified professional before purchasing materials.