Mulch Calculator
Give the area as length and width or as a total, then the depth, in feet and inches or in meters and centimeters. Press Calculate. You get the volume in cubic yards, cubic feet and cubic meters, the number of 2 cu ft bags and a weight estimate. The same calculator covers gravel, topsoil and sand, so check that Mulch is selected.
How to use the Mulch Calculator
- Enter your numbers in the Mulch Calculator above.
- Press the Calculate button to see the result.
- To try other numbers, change any value and press the button again.
The mulch volume formula
Cubic yards = (Area ft² × Depth inches) / 324
324 turns square feet times inches into cubic yards, because 1 yd³ = 27 ft³ and a foot is 12 inches, so 27 × 12 = 324. In metric, cubic meters = area in m² × depth in m. The calculator converts metric input with the exact definitions of the units and shows all three volumes either way. For the weight it counts 400 lb per cubic yard of mulch.
Worked example
300 sq ft of garden bed mulched 3 inches deep: (300 × 3) / 324 = 2.78 cubic yards, or 75 cubic feet. In 2 cu ft bags that is 37.5, so the calculator says 38 bags. It puts the weight at about 1,111 lb.
Frequently asked questions
How deep should mulch be?
Gary Bachman of Mississippi State University Extension finds a 2- to 3-inch layer enough for most beds, and warns against piling mulch around trees and shrubs so that it looks like a volcano. Enter the depth you choose and the calculator works out the volume.
Bagged vs. bulk mulch?
Bulk mulch is sold by volume, often by the cubic yard, and bagged mulch by the bag. The calculator shows both: the cubic yards to order and the number of 2 cu ft bags. It does not compare prices.
Does the type of mulch change the result?
Only the weight. The volume and the bag count are the same for any mulch. The weight estimate uses 400 lb per cubic yard for every kind, so treat it as a rough guide.