Mulch Calculator
Calculate how much mulch you need in cubic yards and bags for garden beds and landscaping.
A mulch calculator estimates the volume of mulch in cubic yards and the number of bags needed to cover a garden bed at your desired depth.
Examples
20x10 ft bed, 3 inches deep
Frequently Asked Questions
How deep should mulch be?
Should I buy bags or bulk?
Quick Tips
- •Always round up when ordering materials -- running short means an extra trip to the store.
- •Apply mulch 2-4 inches deep for best weed suppression, but keep it several inches away from plant stems and tree trunks.
- •Refresh mulch annually, as organic mulch decomposes and loses depth over time.
A mulch calculator estimates the volume of mulch in cubic yards and the number of bags needed to cover a garden bed at your desired depth.
How to Use This Calculator
Enter the length and width of the area in feet, the desired mulch depth in inches, and select the bag size. The calculator determines how many cubic yards and bags of mulch you need.
Understanding the Formula
Volume = Length x Width x (Depth / 12) in cubic feet. Cubic Yards = Cubic Feet / 27. Bags = Cubic Feet / Bag Size.
Examples
20x10 ft bed, 3 inches deep
Volume: 20 x 10 x 0.25 = 50 cu ft = 1.85 cu yd. At 2 cu ft/bag: 25 bags.
Frequently Asked Questions
How deep should mulch be?
Most landscaping applications call for 2-4 inches of mulch. Use 2 inches around shallow-rooted plants and up to 4 inches in beds for maximum weed suppression. Avoid piling mulch against tree trunks.
Should I buy bags or bulk?
For areas needing less than 3 cubic yards, bags are usually practical. For larger areas, bulk delivery (sold by the cubic yard) is more cost-effective, often 40-50% cheaper per cubic yard.
Assumptions & Limitations
- Assumes standard material densities; actual weights vary by product, moisture content, and mulch type.
- Depth is uniform across the entire area; uneven terrain may require more material in low spots.
- Weight estimate uses an average of 400 lbs per cubic yard, which varies between wood mulch, rubber mulch, and stone.