Mulch Coverage Calculator

About this calculator

Mulch is sold and priced by volume, so covering a garden bed comes down to converting an area and a desired depth into cubic yards: cubic yards = (area in square feet × depth in inches) ÷ 324. A common landscaping bag holds 2 cubic feet, so dividing the cubic-yard total by that bag size (after converting) tells you how many bags to buy if you’re not ordering mulch in bulk.

Landscapers and home gardeners lean on this calculation because getting the depth right matters as much as getting the area right — a mulch layer that’s too thin (under 2 inches) does little to suppress weeds or retain soil moisture, while piling it too deep (over 4 inches) can smother plant roots and trap excess moisture against tree trunks and stems. Ordering the correct cubic yardage up front also avoids the two most common frustrations: running short mid-project and needing a second delivery, or over-ordering and having leftover mulch with nowhere to use it.

Enter your bed’s area and your target mulch depth, and this calculator returns the cubic yards needed and how many standard 2-cubic-foot bags that equals.