Free tool
Mulch Calculator
Enter the size of each bed and how deep you want the mulch, and get how much to buy in cubic yards for bulk delivery or in bags.
How we calculate it
- Bed area = length × width (or 3.1416 × (diameter ÷ 2)² for a circle)
- Cubic feet = area × depth in inches ÷ 12, plus your extra allowance
- Cubic yards = cubic feet ÷ 27
- Bags = cubic feet ÷ the cubic feet printed on your bag, rounded up
One cubic yard covers 324 ft² at 1 inch, 162 ft² at 2 inches, 108 ft² at 3 inches and 81 ft² at 4 inches (27 ft³ × 12 ÷ depth).
How to use this tool
- Measure your bedsMeasure each bed in feet. Use a circle for tree rings.
- Pick a depthEnter the depth you want. Compare a couple of depths to see the difference.
- Choose bulk or bagsRead cubic yards for a delivery, or enter the bag size printed on your bag to get a bag count.
Frequently asked questions
How do I calculate how much mulch I need?
Multiply the bed's length by its width to get square feet, then multiply by the depth in inches divided by 12 to get cubic feet. Divide cubic feet by 27 for cubic yards. A 10 by 10 foot bed at 3 inches deep needs 25 cubic feet, about 0.93 cubic yards.
How much area does a cubic yard of mulch cover?
A cubic yard is 27 cubic feet. Spread 1 inch deep it covers 324 square feet, at 2 inches 162 square feet, at 3 inches 108 square feet and at 4 inches 81 square feet. That is pure geometry; settling and uneven ground can change how much you actually need.
How deep should mulch be?
The right depth depends on the mulch, your plants and your climate, so this calculator does not pick one for you; the depth shown is only an example. Ask your local cooperative extension office or your supplier what they recommend, enter it, and compare a few depths to see how the amount changes.
How many bags of mulch make a cubic yard?
It depends on the bag, so check the volume printed on the bag you plan to buy and enter it. A cubic yard is 27 cubic feet, so the number of bags is 27 divided by the cubic feet in one bag, rounded up. The calculator does that division for your beds.