Mulch calculator
Calculator
The calculator needs JavaScript. The tables below give the same numbers for common cases.
How it is worked out
- Volume = area × depth = 80 sq ft × 0.25 ft = 20 cubic feet.
- 27 cubic feet = 1 cubic yard. Compare bag sizes on the label.
| Inputs | Answer |
|---|---|
| Units: Feet, depth in inches; Length of the bed: 20; Width of the bed: 4; Depth: 3; Bag size: 2 | To cover 80 sq ft at 3 in deep you need about 0.74 cubic yards (20 cubic feet). |
| Units: Feet, depth in inches; Length of the bed: 30; Width of the bed: 10; Depth: 2; Bag size: 2 | To cover 300 sq ft at 2 in deep you need about 1.85 cubic yards (50 cubic feet). |
| Units: Metres, depth in cm; Length of the bed: 6; Width of the bed: 1.2; Depth: 7; Bag size: 2 | To cover 77.5 sq ft at 2.8 in deep you need about 0.66 cubic yards (17.8 cubic feet). |
How to use it
Mulch volume is area × depth. A 20 × 4 foot bed covered 3 inches deep needs 20 cubic feet, about 0.74 cubic yards. Bagged mulch is usually sold in 2 cubic foot bags, and bulk mulch by the cubic yard.
A depth of 2 to 3 inches is commonly recommended around plants; keep mulch away from trunks and stems.
Frequently asked questions
How much mulch do I need?
Multiply the bed area by the depth: 20 × 4 ft × 3 in = 20 cubic feet.
How many bags is a cubic yard?
At 2 cubic feet a bag, 13.5 bags.
How deep should mulch be?
Commonly 2 to 3 inches.
Method: standard arithmetic shown step by step; no outside data is used. Checked 2026-11-12.
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General information only. Results are plain arithmetic on the numbers you enter; check anything important (money, health, school work) against your own records or the official source.