Mulch Calculator
Calculate how many cubic yards of mulch you need to cover a garden bed to a desired depth.
Formula
Volume (cu yd) = Area (sq ft) × Depth (in) ÷ 324
- 324 = 12 in/ft × 27 cu ft/cu yd.
- 1 cubic yard covers 108 sq ft at 3 inches depth.
- Typical bag sizes: 2 cu ft (~13.5 bags/cu yd) or 3 cu ft (~9 bags/cu yd).
100 sq ft at 3 inch depth
Inputs
- Total Area: 100 sq ft
- Mulch Depth: 3 in
100 × 3 / 324 = 0.93 cubic yards.
Frequently asked questions
How deep should mulch be?
2–4 inches for most plants. Deeper can prevent water penetration and promote disease.
Should I buy more than calculated?
Order 10–15% extra to account for settling and irregular areas.