Mulch Calculator
Find out how much mulch you need for flower beds, tree rings and garden paths. Enter the size of the area and the depth you want, and get the amount in cubic yards, cubic feet and bags.
- In cubic feet
- 26.3 cu ft
- Bags (2 cu ft)
- 14 bags
- Area covered
- 100 sq ft
How this calculator works
The calculator multiplies the area of your bed by the depth. Depth is entered in inches, so it is divided by 12 to convert it to feet before multiplying.
For round beds and tree rings, the area is π × radius², where the radius is half the diameter.
The volume in cubic feet is divided by 27 to get cubic yards, which is how bulk mulch is sold. Bag counts are rounded up to whole bags.
Example: a 10 × 10 ft flower bed, 3 inches deep
- Area: 10 × 10 = 100 sq ft.
- Depth in feet: 3 ÷ 12 = 0.25 ft.
- Volume: 100 × 0.25 = 25 cu ft.
- In cubic yards: 25 ÷ 27 = 0.93 cu yd.
- In 2 cu ft bags: 25 ÷ 2 = 12.5, so buy 13 bags.
Quick reference
| Depth | Area covered |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
Tips before you buy
- Bulk mulch by the cubic yard is usually cheaper than bags once you need more than about 1.5 cubic yards.
- Keep mulch a few inches away from tree trunks and plant stems to prevent rot.
- If you are topping up an existing layer, only calculate the extra depth you are adding.
Common sizes
Frequently asked questions
How many bags of mulch are in a cubic yard?
One cubic yard is 27 cubic feet, so it equals 13.5 bags of 2 cu ft mulch or 9 bags of 3 cu ft mulch.
How deep should mulch be?
A layer of 2 to 3 inches is enough for most flower beds. Use 3 to 4 inches where you want to suppress weeds. More than 4 inches can stop water and air reaching the soil.
How much area does a bag of mulch cover?
A 2 cubic foot bag covers about 12 square feet at 2 inches deep, or 8 square feet at 3 inches deep.
Should I add extra mulch for waste?
Mulch settles and compacts after it is spread, so adding about 5 percent is sensible. The calculator includes this by default.
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- Gravel CalculatorEstimate how much gravel or crushed stone you need for a driveway, path, patio base or drainage area.
- Square Footage CalculatorCalculate the square footage of a room, a yard or any area.
Last updated October 25, 2026