How to Calculate Mulch
To determine how much mulch you need, you first measure the length and width of the area you want to cover, and decide on the depth of the mulch layer (usually 2 to 4 inches for general landscaping).
Formula:
Area (sq ft) = Length (ft) × Width (ft)
Volume (cubic feet) = Area (sq ft) × (Depth in inches ÷ 12)
Volume (cubic yards) = Volume (cubic feet) ÷ 27
Example Calculation
A garden bed is 20 ft long and 10 ft wide, and you want 3 inches of mulch.
- Area: 20 × 10 = 200 sq ft
- Depth in feet: 3 / 12 = 0.25 ft
- Volume in cubic feet: 200 × 0.25 = 50 cubic ft
- Cubic yards: 50 / 27 = 1.85 cubic yards
Therefore, a user would typically purchase approximately 2 cubic yards, with additional material depending on settling and project conditions.
How Much Should I Buy?
Always round your purchasing quantity up. Mulch compacts and settles over time, and bag coverage varies by actual bag volume. Having a little extra on hand is much better than running out right at the end of your project.
Frequently Asked Questions
How much mulch do I need?
The amount of mulch you need depends on the square footage of the area and the desired depth. Use our mulch calculator above by entering your dimensions to find out exactly how many bags or cubic yards to purchase.
How many cubic yards of mulch do I need?
Divide your total required cubic feet by 27 to find the number of cubic yards. Bulk mulch is typically sold by the cubic yard.
How many bags of mulch are in a cubic yard?
It depends on the bag size. A standard 2 cubic foot bag means there are 13.5 bags in one cubic yard (27 / 2 = 13.5). If you buy 3 cubic foot bags, there are 9 bags in a cubic yard.
How deep should mulch be?
For most garden beds and landscaping, a depth of 2 to 4 inches is recommended. Too little will not suppress weeds or retain moisture effectively, while too much can suffocate plant roots.
How do I calculate mulch for an irregular area?
Break the irregular area down into smaller rectangular or circular sections, calculate the volume for each, and then add them together. Our calculator allows you to add multiple areas easily.