How the mulch estimate works
Mulch is a volume job: bed area times depth, converted to cubic yards (1 yard = 27 cubic feet = 13.5 bags at 2 cu ft, or 9 bags at 3 cu ft). Most bagged mulch is sold in 2-cubic-foot bags; bulk delivery arrives by the cubic yard.
Cu ft = area x (depth / 12)
Bags (2 cu ft) = ceil( cu ft x 1.1 / 2 )
Bags (2 cu ft) = ceil( cu ft x 1.1 / 2 )
Depth: the number that matters
Two to three inches is the sweet spot for most beds. At 2 inches a cubic yard covers about 160 sq ft; at 3 inches about 108. Deeper is not better — mulch piled past 4 inches can shed water before it soaks in, and mulch volcanoes against tree trunks invite rot and rodents. Keep an inch of breathing room around trunks and stems.
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Use cases
- Annual top-up - 1 inch over existing mulch refreshes color without burying perennials.
- New beds - 3 inches over landscape fabric or bare soil.
- Tree rings - 2–3 inches, tapered away from the trunk.
- Play areas - engineered wood fiber follows depth rules from playground safety standards, not garden rules.
Frequently asked questions
How many 2 cu ft bags are in a cubic yard?
Exactly 13.5 bags (27 cu ft per yard). In practice, buy 14–15 bags per yard — depths are never perfectly even.
Is bulk mulch cheaper than bags?
By a wide margin for big jobs: a cubic yard of bulk mulch typically costs about the same as 4–6 bags. Bags make sense under a couple of yards, or where carrying bags beats wheeling a pile.
Estimates only. Settling and compaction vary by material; hardwood mulch settles more than bark chips.