Calculate mulch volume in cubic yards and bags for any bed size and depth.
Mulch volume in cubic yards equals (area in sq ft × depth in inches) ÷ 324. The constant 324 comes from 27 cubic feet per cubic yard × 12 inches per foot. Bags are rounded up to ensure you have enough. Recommended mulch depth is 2–4 inches; less won't suppress weeds, more can rot plant crowns.
Volume
Cubic yards = (area sq ft × depth inches) ÷ 324
2–3 inches for most garden beds. 3–4 inches for weed suppression and moisture retention. Never more than 4 inches around tree bases — 'mulch volcanos' cause root rot and bark decay.
A standard full-size pickup can hold about 1–2 cubic yards of mulch. A full-size pickup with a high-side extension can hold up to 3 cubic yards. Check the truck's payload rating before loading.
There are 27 cubic feet in a cubic yard. To convert sq ft × inches to cubic feet you divide by 12; to then convert to cubic yards you divide by 27. Combined: ÷ 12 ÷ 27 = ÷ 324.
Bulk delivery (by the cubic yard) is usually more economical above 3 cubic yards. Below that, bagged mulch avoids delivery fees and is easier to handle.