Mulch Coverage Calculator
Mulch is sold by the cubic yard in bulk or in 2- or 3-cubic-foot bags. This calculator converts your bed area and desired depth into cubic yards: Volume (yd3) = Area (sq ft) x Depth (in) / 324, where 324 = 27 (ft3/yd3) x 12 (in/ft). It then calculates how many standard bags you need as an alternative to ordering bulk delivery. A 3-inch depth of mulch is the most commonly recommended for weed suppression and moisture retention in landscape beds.
Mulch quantity formula
Volume (yd3) = Area (sq ft) x Depth (in) / 324
Bags = ceil(Volume (yd3) x 27 / Bag size (cu ft))
One cubic yard = 27 cubic feet. Dividing by bag size in cubic feet and rounding up gives the number of bags to purchase. For large areas, bulk delivery by the cubic yard is usually more economical than bags.
Mulch coverage reference
- 1 cubic yard at 2 inches deep covers approximately 162 square feet.
- 1 cubic yard at 3 inches deep covers approximately 108 square feet.
- 1 cubic yard at 4 inches deep covers approximately 81 square feet.
- 1 cubic yard of bulk mulch equals approximately 13.5 standard 2-cubic-foot bags.
- Mulch compresses approximately 10 to 15 percent after settling; order accordingly.
Mulch coverage calculator: frequently asked questions
How do I calculate cubic yards of mulch needed?
Multiply area (sq ft) by depth (inches) and divide by 324. For example, 500 sq ft at 3 inches deep = 500 x 3 / 324 = 4.63 cubic yards.
What depth of mulch should I apply?
Apply 2 to 4 inches of mulch for established plant beds. Too little (less than 2 inches) does not suppress weeds; too much (more than 4 inches) can cause root rot and crown rot. Keep mulch 2 to 3 inches away from plant stems and tree trunks.
How many square feet does a cubic yard of mulch cover?
At 3 inches deep, one cubic yard covers 108 square feet. At 2 inches deep, one cubic yard covers 162 square feet. At 4 inches deep, one cubic yard covers 81 square feet.
How many bags of mulch equal a cubic yard?
A standard 2-cubic-foot bag of mulch: 13.5 bags per cubic yard. A standard 3-cubic-foot bag: 9 bags per cubic yard. Most bulk mulch suppliers quote by the cubic yard; bags are more economical for small areas.
What type of mulch is best?
Shredded hardwood mulch is most popular for landscape beds; it decomposes slowly and adds organic matter. Pine bark nuggets are good for slopes. Cedar mulch resists insects. Keep any mulch material at least 3 inches from house foundations to prevent moisture and pest issues.
Official sources
- USDA Natural Resources Conservation Service: Soil Quality Institute - Mulches and Their Use.
- US Forest Service: Tree Care Best Management Practices.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.