Measure only the mulch you are adding
Measure between the edges of each border. For a curved bed, divide the outline into rectangles, circles or triangles that do not overlap. Leave planted gaps out of those shapes, or subtract their area with “Leave out an area.”
Check the mulch already on the ground before choosing a depth. If you want a total layer of 3 inches and 1 inch remains, enter 2 inches. The University of Minnesota Extension gives 2 to 4 inches for mulch, and a 6-inch bare ring around tree trunks. Penn State Extension adds: use less where the soil drains poorly.
Mulch for common areas
Cubic yards and 2 cubic foot bags at three depths. Bags are rounded up.
| Area | 2 in deep | 3 in deep | 4 in deep |
|---|---|---|---|
| 50 sq ft | 0.31 yd³ · 5 bags | 0.46 yd³ · 7 bags | 0.62 yd³ · 9 bags |
| 100 sq ft | 0.62 yd³ · 9 bags | 0.93 yd³ · 13 bags | 1.23 yd³ · 17 bags |
| 200 sq ft | 1.23 yd³ · 17 bags | 1.85 yd³ · 25 bags | 2.47 yd³ · 34 bags |
| 300 sq ft | 1.85 yd³ · 25 bags | 2.78 yd³ · 38 bags | 3.7 yd³ · 50 bags |
| 500 sq ft | 3.09 yd³ · 42 bags | 4.63 yd³ · 63 bags | 6.17 yd³ · 84 bags |
| 1,000 sq ft | 6.17 yd³ · 84 bags | 9.26 yd³ · 125 bags | 12.35 yd³ · 167 bags |
Bags or a bulk delivery?
Use the cubic-foot volume on your bag. The bag count rounds up; the cubic-yard figure is the calculated volume before any supplier minimum or loading increment. Extra material is your choice and starts at zero.
A bulk price alone does not settle which order costs less. Compare the bag total with the delivered bulk quote, including the minimum load, using the same questions in the bags or bulk guide. One supplier, Sands and Soils, says a standard pickup or a single-axle 5 × 8 trailer holds two yards of its hardwood mulch.
How much extra to order
The result is what the area and depth take, and the extra field starts at zero. None of the extension services we cite gives a percentage to add for mulch. If you want a margin for uneven ground, enter it as a percentage; the order shows it on its own line. The mulch depth guide lists the allowances public bodies and makers give for other jobs.
Soil goes underneath; mulch goes on top
If the bed still needs filling, work out that separate layer with the raised bed soil calculator. For a stone path beside the bed, use the gravel calculator, where weight depends on the stone.