Mulch Calculator

324 square feet at 1 inch deep — the number every other figure derives from. At the standard 3-inch depth for new beds, that's 108 square feet per yard; at a 2-inch refresh, 162. A yard is also 27 cubic feet, i.e. 13.5 of the common 2-cubic-foot bags — the conversion that makes bulk-vs-bag price comparisons possible.

2–3 inches is the horticultural consensus: enough to suppress weeds and slow evaporation, not so deep that water and air can't reach roots. More is not better — 4+ inches can suffocate shallow roots and harbor pests. And keep it a few inches clear of trunks and stems; the 'mulch volcano' piled against a tree traps moisture on bark and invites rot and rodents.

Price crosses over around 1.5 cubic yards — beyond that, bulk is meaningfully cheaper per yard even with a delivery fee. Bags win below it, and whenever access matters (a wheelbarrow path to a backyard, a driveway you can't dump on) or leftovers need dry storage. One yard bulk dumped on a tarp is very manageable; three yards is a weekend.

Break curved and L-shaped beds into rough rectangles, run each, and add the yardage. For circular beds around trees, length × width of the bounding square overshoots by ~21%, which conveniently covers settling and the inevitable this-spot-looks-thin top-up. Mulch keeps if stored dry, so rounding up beats a second delivery fee.