How to use this mulch calculator
- Measure each bed and add the areas, or calculate them one at a time.
- Use 2 inches for fine mulch, 3 inches for bark and wood chips, 4 inches to suppress weeds.
- A cubic yard equals 13.5 bags of 2 cu ft: bulk is cheaper for large areas.
Example
A 30 ft long, 4 ft wide flower bed with 3 inches of mulch needs 1.11 cu yd. In bags that is 16 bags of 2 cu ft or 11 bags of 3 cu ft.
What to know before you buy
Types of mulch
Shredded hardwood bark is the most common landscape mulch and knits together well on slopes. Pine bark nuggets last longer but can float away in heavy rain. Dyed mulches keep their color longer. Rubber and stone mulches do not decompose, which means they do not feed the soil either.
When to mulch
Spring, after the soil warms, is the classic time to mulch beds. A fall layer helps protect roots through winter. Pull weeds and water the soil before spreading new mulch.
Mulch coverage per cubic yard
| Area and depth | Mulch needed | 2 cu ft bags |
|---|---|---|
| 100 sq ft at 2 in | 0.62 cu yd | 9 |
| 100 sq ft at 3 in | 0.93 cu yd | 13 |
| 200 sq ft at 3 in | 1.85 cu yd | 26 |
| 500 sq ft at 3 in | 4.63 cu yd | 63 |
| 1,000 sq ft at 3 in | 9.26 cu yd | 126 |
Formula
Volume = length × width × depth. One cubic yard = 27 cubic feet = about 765 liters.
Tips from the pros
- Top up existing mulch with 1 inch per year instead of adding a full new layer.
- Keep mulch a few inches away from tree trunks and house siding.
- Bulk mulch is usually much cheaper than bags above about 1 cubic yard.
Common mistakes to avoid
- Piling mulch against trees ("volcano mulching"), which invites rot and pests.
- Laying more than 4 inches, which can suffocate roots.
Frequently asked questions
How many bags of mulch in a yard?
13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet.
How deep should mulch be?
2–3 inches for most beds. Keep it a few inches away from tree trunks and plant stems.
How many bags of mulch do I need for 100 square feet?
At 3 inches deep, 100 sq ft needs 25 cubic feet: about 13 bags of 2 cu ft.
How much does a yard of mulch cover?
About 108 sq ft at 3 inches deep, 162 sq ft at 2 inches deep.