Mulch Calculator
Estimate how much mulch you need for garden beds, landscaping, trees, flower beds, walkways, and yard projects.
Project dimensions
Enter your bed size, mulch depth, waste, and bag size.
How to Use the Mulch Calculator
Enter the length, width, and depth of the area you want to cover with mulch. The calculator estimates the total mulch volume, applies your selected waste percentage, and converts the result into cubic yards or bags depending on your selected bag size.
Common Mulch Depths
| Project Type | Common Mulch Depth |
|---|---|
| Refreshing existing beds | 1–2 inches |
| New garden beds | 3–4 inches |
| Around trees | 2–3 inches |
| Weed suppression | 3–4 inches |
| Decorative landscaping | 2–3 inches |
Example Mulch Estimate
For a 20 ft by 8 ft garden bed at 3 inches deep, the volume is about 40 cubic feet. Dividing by 27 gives about 1.48 cubic yards. With 5% waste, that becomes about 1.56 cubic yards. If using 2 cubic foot bags, you would need about 21 bags.
Should You Add Extra Mulch?
Yes. A small waste allowance helps account for spreading variation, uneven beds, settling, and irregular shapes. For simple rectangular beds, 5% is usually enough. For curved or uneven beds, 10% may be safer.
Frequently Asked Questions
How do I calculate how much mulch I need?
Multiply length by width by depth to get volume. In US units, convert depth from inches to feet first, then divide cubic feet by 27 to get cubic yards.
How many bags of mulch are in a cubic yard?
One cubic yard equals 27 cubic feet. If each bag contains 2 cubic feet, one cubic yard requires about 14 bags.
How deep should mulch be?
Mulch is commonly applied 2–4 inches deep. Use 1–2 inches to refresh existing beds and 3–4 inches for new coverage or weed suppression.
Can too much mulch hurt plants?
Yes. Mulch that is too deep or piled against plant stems and tree trunks can trap moisture and cause rot. Keep mulch away from trunks and crowns.