How to use this calculator
- Choose US customary or metric measurements.
- Enter a garden bed’s length, width, and desired mulch depth.
- Add each separate bed.
- Calculate volume and compare bulk and bag results.
How the calculation works
The calculator multiplies length, width, and depth for each rectangular bed, then combines the volumes. It converts the result to cubic yards, cubic feet, and cubic meters and rounds bag counts up.
Formula
Bed volume = length × width × depth Cubic yards = cubic feet ÷ 27 Bags = cubic feet ÷ bag volume, rounded up
Worked example
A 12 ft × 6 ft bed covered 3 in deep needs 18 cubic feet, or about 0.67 cubic yards. That equals nine 2-cubic-foot bags or six 3-cubic-foot bags.
Project considerations
- Measure only the area to be covered.
- Existing mulch and settlement can change the needed depth.
- Bag volumes are nominal; check the label.
Frequently asked questions
How many bags equal one cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 two-cubic-foot bags or nine three-cubic-foot bags. Whole-bag purchases should be rounded up.
Does the calculator add extra mulch?
No. It calculates the entered dimensions only. Increase the depth or quantity separately if conditions warrant an allowance.