How Much Mulch Do I Need?

One cubic yard of mulch covers about 108 square feet at the standard 3-inch depth, and equals roughly 13.5 bags of 2-cubic-foot bagged mulch.

Those two numbers are the same fact stated twice: a cubic yard is 27 cubic feet, a standard bag holds 2 cubic feet, and 27 ÷ 2 is 13.5 — a conversion that holds regardless of how deep you spread it. Everything past that is either a depth adjustment or a bulk-vs-bagged cost comparison built on top of it.

Depth is the variable that changes everything

The same bed can need anywhere from half as much to nearly twice as much mulch depending on depth alone, so pick the depth before doing any other math.

• 2 inches — topping up an established bed. If last year’s mulch has broken down but hasn’t disappeared, a 2-inch refresh restores the look and weed suppression without burying groundcover or shrub crowns.
• 3 inches — the default for a new bed. This is the standard depth for suppressing weeds and holding soil moisture without smothering roots, and it’s what most nurseries and landscapers quote unless a project calls for something else.
• 4 inches — heavy weed pressure or slopes. Erosion-prone slopes and beds fighting persistent weeds justify the extra inch. Don’t go past 4 inches — deeper mulch holds enough moisture against roots and stems to encourage rot and fungal disease instead of preventing it.

Keep mulch a few inches back from tree trunks and shrub stems at any depth — piling it directly against bark traps moisture there and invites rot and pests, the classic “mulch volcano” mistake. Run your bed’s square footage through the mulch calculator to get cubic yards and bag counts for whichever depth applies.

How many bags of mulch are in a cubic yard

Bag coverage is pure volume conversion — divide 27 cubic feet by the bag size:

Bag size	Bags per cubic yard
1 cu ft	27
2 cu ft (most common)	13.5
3 cu ft	9

Check the bag label before assuming 2 cubic feet — some brands sell 1.5 or 3 cubic foot bags, and using the wrong figure throws off the count by 25% or more. Since bags don’t split, round any fractional total up rather than down.

Calculating your own coverage

The full formula is area in square feet times depth in inches, divided by 324 (the product of 12 inches per foot and 27 cubic feet per yard):

cubic yards = (area × depth) ÷ 324

A 200-square-foot bed at the standard 3-inch depth works out to 200 × 3 ÷ 324 ≈ 1.85 cubic yards — call it 25 bags of 2-cubic-foot mulch after rounding up. The mulch calculator runs this same formula and rounds to a shoppable bag count automatically, so there’s no need to do it by hand.

Bulk vs. bagged: the honest breakeven

Bagged mulch runs roughly $3–7 per 2-cubic-foot bag as of 2026-07, depending on grade — dyed hardwood mulch sits at the low end, cedar and cypress at the high end. That’s about $40–95 per cubic-yard equivalent once you scale it up. Bulk mulch delivered by the yard is cheaper per unit, typically $25–50 per cubic yard, but almost every supplier adds a flat delivery fee — commonly $50–100 — and many set a minimum order of 2 to 3 cubic yards.

That delivery fee is what decides the breakeven. For a small bed needing a yard or less, bagged mulch is often the cheaper option once the flat fee is factored in, and there’s no leftover pile to store or dispose of. Past roughly 2 to 3 cubic yards, bulk pricing pulls ahead even after the delivery fee, and the gap widens the more you order. Get your volume from the calculator first, then price both routes for that specific number — the breakeven point moves with local delivery fees and mulch grade.

Prep before you mulch

A new bed usually needs grading before mulch goes down. If the bed is low, uneven, or short on organic matter, add and level topsoil first — mulch sits on top of soil, it doesn’t fix drainage or grade problems underneath it. For weed control, landscape fabric under mulch blocks weeds more effectively than mulch depth alone, though it comes with a tradeoff: it also blocks organic matter from breaking down into the soil, and over time fabric can work its way toward the surface as mulch shifts. Where that tradeoff is worth it — heavy weed pressure, gravel paths, low-maintenance beds — the landscape fabric calculator sizes the roll to the same bed footprint you already measured for mulch.

Updated: 2026-07-15