THE MULCH CALCULATOR
How much mulch do you need?
Get the cubic yards, bag count, and cost for your garden.
THE QUICK ANSWER
A yard goes further than you think.
One cubic yard of mulch covers 108 square feet at 3 inches deep. For a 20 × 10 ft bed at that depth, you need 50 cubic feet: about 1.85 cubic yards or 25 two-cubic-foot bags.
Cubic yards = square feet × depth in inches ÷ 324Measure just the area you will cover, choose the depth you need to add, and round up when ordering. The calculator keeps the volume calculation separate from whole bags and your supplier’s bulk increments.
Mulch coverage, at a glance.
Cubic yards needed · no extra allowance
| Garden area | 2 in deep | 3 in deep | 4 in deep |
|---|---|---|---|
| 100 sq ft | 0.62 yd³ | 0.93 yd³ | 1.23 yd³ |
| 200 sq ft | 1.23 yd³ | 1.85 yd³ | 2.47 yd³ |
| 300 sq ft | 1.85 yd³ | 2.78 yd³ | 3.70 yd³ |
| 500 sq ft | 3.09 yd³ | 4.63 yd³ | 6.17 yd³ |
| 1,000 sq ft | 6.17 yd³ | 9.26 yd³ | 12.35 yd³ |
Rounded to 2 decimal places. These are calculated volumes; order quantities may need to be rounded up.
Before you buy.
Two useful reads for a better estimate.
GOOD QUESTIONS
A few things worth knowing.
How many bags are in a cubic yard?
A cubic yard is 27 cubic feet. That equals 13.5 two-cubic-foot bags, so you would buy 14 whole bags to cover at least one cubic yard. For three-cubic-foot bags, it is exactly 9 bags.
How much area does a 2-cubic-foot bag cover?
At 3 inches deep, a 2-cubic-foot bag covers 8 square feet. At 2 inches, it covers 12 square feet; at 4 inches, it covers 6 square feet. These figures assume even spreading and no extra allowance.
What if my garden bed is an odd shape?
Split it into rectangles or circles, add their areas, and subtract any areas that will stay uncovered. Enter that total using “Known area.” For a ring, subtract the inner circle’s area from the outer circle’s area before entering the total.
Does this include existing mulch?
No. Enter only the thickness of the layer you want to add. If you want a 3-inch total layer and already have 1 inch in place, calculate for 2 inches. See the depth guide for a worked example.