Mulch Calculator
Estimate bulk mulch or bags from the area and depth of your new layer.
Free calculator. Mixed units and fractions welcome.1 yd³ = 27 ft³
At a glance
Mulch Calculator
Mulch volume in cubic yards equals bed area in square feet × new layer depth in inches ÷ 324. One cubic yard covers 108 square feet at 3 inches deep.
Materials
Calculate the new mulch layer
Measure the bed and decide how much new material to add. Consider the mulch already present; the new layer is not necessarily the full final depth. Split winding beds into measured shapes without overlapping the sections.
Mulch (yd³) = area (ft²) × new layer depth (in) ÷ 324
A 20 ft by 10 ft bed with a 3 inch new layer needs 50 cubic feet, or about 1.852 cubic yards. The same bed at 2 inches needs about 1.235 cubic yards.
University of Minnesota Extension describes a general mulch depth of 2 to 4 inches and advises keeping it clear of trunks and stems. Use guidance suited to your plants, material, drainage, and existing mulch. The calculator does not require a particular depth.
Materials
Bulk mulch coverage
| Delivered volume | At 2 inches | At 3 inches | At 4 inches |
|---|---|---|---|
| 1 yd³ | 162 ft² | 108 ft² | 81 ft² |
| 10 yd³ | 1,620 ft² | 1,080 ft² | 810 ft² |
| 15 yd³ | 2,430 ft² | 1,620 ft² | 1,215 ft² |
| 20 yd³ | 3,240 ft² | 2,160 ft² | 1,620 ft² |
These are geometric coverage values for a uniform layer. Irregular ground, settling, and handling losses can affect how much material you choose to order. The coverage tool accepts any delivered quantity and depth.
Materials
How many bags of mulch?
Convert cubic yards to cubic feet, then divide by the volume printed on one bag and round the purchase up to whole bags. For 50 ft³, a 2 ft³ bag gives 25 bags. A 1.5 ft³ bag gives 33.333 portions, so you need 34 whole bags.
Whole bags = required cubic feet ÷ bag volume, rounded up
One cubic yard is 13.5 bags at 2 ft³ each, or 18 bags at 1.5 ft³ each. Whole bag purchasing and supplier bulk order increments are separate rounding decisions.
Materials
Compare a bag price with a bulk quote
Compare the same finished quantity. Convert each bag’s price into a price per cubic foot, or multiply that rate by 27 for a price per cubic yard. Add any bulk delivery charge and account for unused portions of whole bags. The calculator’s optional material price is your entered quote, not a local market price.
Common questions
Mulch questions, answered.
How many square feet does a yard of mulch cover?
At a uniform depth, one cubic yard covers 162 square feet at 2 inches, 108 square feet at 3 inches, and 81 square feet at 4 inches. You must specify depth to get coverage.
What does 10, 15, or 20 yards of mulch mean?
If the supplier means cubic yards, these are 270, 405, and 540 cubic feet. At 3 inches deep they cover 1,080, 1,620, and 2,160 square feet respectively.
Do I need to remove old mulch first?
Measure and assess the existing layer before choosing how much to add. Material condition and plant needs matter. Quantity arithmetic alone cannot decide whether existing mulch should remain.
Are bags calculated before or after an extra allowance?
The bag count uses the planned quantity, including any extra material or order increment you selected. It then rounds up to whole bags. Leaving the options blank uses the measured volume.
Check the basis