Mulch Calculator

Bags or cubic yards of mulch for beds, trees and borders.

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 )

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.

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Mulching like a pro

How to use this calculator

Measure each bed's length and width (odd shapes: split into rectangles and add).
Choose depth: 2 inches to top up, 3 inches for new beds.
Decide bags vs bulk: over about 3 cubic yards, bulk delivery usually wins on price and hauling.
Add 5–10% for uneven depths and settling.
Keep mulch an inch off trunks, stems and house siding.

Quick reference

Depth	Coverage per cubic yard	2-cu-ft bags per yard
1 in (top-up)	~324 sq ft	13.5 + overage
2 in (standard)	~162 sq ft	13.5 + overage
3 in (new beds)	~108 sq ft	13.5 + overage
4 in (paths)	~81 sq ft	13.5 + overage

Pro tips

Dyed mulch needs 24–48 dry hours to set its color; spread it before rain if you can pick the day.
Old mulch thinner than an inch can stay — count only the depth you are adding, not the total.
Shredded hardwood knits together and stays put on slopes; bark chips float away in heavy rain.

Frequently asked questions

Does mulch attract termites?

Mulch against the foundation raises moisture that termites like, but it is not a food draw the way people fear. Keep mulch a foot off wooden siding and trim, and the practical risk stays low.

How often should I replace mulch?

Shredded mulch breaks down in a season or two and feeds the soil as it does. Top up an inch each spring rather than stripping and replacing — cheaper and better for the soil.

Rubber mulch or wood mulch?

Rubber lasts but adds nothing to soil, heats up in sun, and is not recommended for vegetable beds. Wood mulch feeds soil life as it breaks down — the better default for gardens.