Short answer
Multiply bed length × width in feet, multiply by the depth in inches, then divide by 324. That number is cubic yards. One cubic yard of mulch covers about 100 square feet at 3 inches deep.
The formula
Square footage × depth in inches ÷ 324 = cubic yards. The 324 comes from a cubic yard being 27 cubic feet, spread one inch deep across 324 square feet.
For odd-shaped beds, break the area into rectangles and circles, calculate each, and add them together. Round up — coming up half a yard short means a second trip.
- 100 sq ft at 3 inches ≈ 1 cubic yard
- 500 sq ft at 3 inches ≈ 4.6 cubic yards
- 1,000 sq ft at 2 inches ≈ 6.2 cubic yards
- 13.5 bags of 2 cu ft mulch = 1 cubic yard
How deep should it go?
Two to three inches is the target on established beds. Any deeper and you restrict oxygen to the roots and invite fungal problems.
If last year's mulch is still 2 inches thick, rake it to break the crust and add only an inch of fresh material for color.
Bulk or bagged?
Bags make sense under about 8–10 bags. Beyond that, bulk is cheaper per cubic foot, faster to spread, and leaves no plastic behind.
A standard pickup bed holds roughly 2 cubic yards of mulch; a 6-foot bed holds about 1.5.
Frequently asked
- How many bags of mulch are in a yard?
- 13.5 bags at 2 cubic feet each, or 27 bags at 1 cubic foot.
- How much mulch fits in a pickup truck?
- About 2 cubic yards in a full-size 8-foot bed, roughly 1.5 in a 6-foot bed.
- When should mulch be refreshed?
- Once a year, typically mid-to-late spring on Long Island, after the soil has warmed.