GUIDE · 2026-07-23
How to use the Mulch Calculator
Mulch is ordered as a shallow volume, not just an area. The tool converts inch depth to feet, calculates cubic feet and yards, then divides by bag size and rounds up.
How it works
Volume (ft³) = area (ft²)×depth (in)÷12
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Step-by-step
- 01Measure bed length and width in feet.
- 02Enter desired depth in inches, an allowance and bag volume in ft³.
- 03Compare bulk yd³ with whole bags, purchased volume and optional cost.
Worked example
INPUT20×6 ft bed; 3 in depth; 2 ft³ bags
RESULT30 ft³ = about 1.11 yd³ → 15 bags at 0% extra
For a top-up over existing mulch, enter only the additional depth needed.Limits and checks
- Avoid piling mulch against plant stems and tree trunks.
- Settling and actual bag volume vary with material and moisture.
Useful examples
- Count bags for a garden bed
- Compare bulk cubic yards with bags
- Budget a seasonal top-up
Frequently asked questions
How deep should mulch be?
It depends on the use and existing layer. New applications often consider 2–4 inches, but plant and product guidance comes first.
How do I compare bulk and bagged mulch?
Compare the calculated cubic yards and bag count with quotes from local suppliers.
Does this account for settling?
You can enter an extra allowance, but long-term settling varies by material and moisture.