Formula
Cubic feet = length x width x depth in feet. Cubic yards = cubic feet / 27. Bags needed = cubic feet / bag size, rounded up.
Landscape bed material estimator
Mulch Calculator
Use this mulch calculator to estimate how much mulch you need for flower beds, garden paths, tree rings, borders, and landscape projects. It calculates cubic feet, cubic yards, bag count, and estimated cost from your bed dimensions and bag size.
Best for
Beds, borders, tree rings
Main output
Cubic yards and bags
Planning tip
Add waste margin
Calculate mulch amount
Enter project dimensions and unit costs. Results update instantly and can be used for rough ordering and budget planning.
Cubic yards
0
Cubic feet
0
Bags needed
0
Estimated cost
0
Example
An 18 ft by 6 ft bed at 3 inches deep needs about 27 cubic feet, or 1 cubic yard, before rounding bags.
Ordering advice
When buying bags, round up to a whole bag. For bulk mulch delivery, round up to the supplier minimum and consider a small touch-up buffer.
How to estimate mulch material
Mulch depth should match the purpose of the bed. New beds often need a thicker layer, while refreshing an existing bed may only require a lighter top-up.
Measure the landscape bed in feet. For curved beds, estimate average width, or divide the bed into simple sections and add the volumes together.
If you buy bagged mulch, check the bag size. Two cubic foot bags are common, but some products are sold in 1.5, 2, or 3 cubic foot bags.
- Keep mulch away from direct contact with trunks and stems.
- Use a thinner refresh layer over existing mulch.
- Use landscape edging to reduce spreading and loss.
- Bulk mulch is often more efficient for large beds.
Common reference values
| Refresh existing mulch | 1-2 inches |
| New flower bed | 2-3 inches |
| Weed suppression | 3-4 inches |
| Common bag size | 2 cu ft |
Local supplier values can vary by product, moisture, compaction, and regional measurement practices.
Important estimate note
Mulch settles over time. Organic mulch also breaks down, so annual refresh quantities may be lower than the first installation amount.
FAQ
How deep should mulch be?
Many beds use 2-3 inches of mulch. Weed suppression may require more, while refresh layers over existing mulch can be thinner.
How many bags of mulch are in a cubic yard?
One cubic yard is 27 cubic feet. If bags are 2 cubic feet each, one cubic yard is about 14 bags after rounding up.
Should I buy bulk mulch or bagged mulch?
Bulk mulch is often better for large projects. Bagged mulch is easier for small beds, storage, and jobs without delivery access.
Can too much mulch be a problem?
Yes. Excess mulch can hold too much moisture and harm plants, especially when piled against tree trunks or plant stems.