Mulch Calculator
Calculate how much mulch you need for garden beds, around trees or along borders – in cubic yards and in bags – and see whether bulk delivery saves money.
Formulas shown on this page · Last reviewed October 2026
Mulch formula
cubic feet = area (sq ft) × depth (in) ÷ 12
cubic yards = cubic feet ÷ 27 · bags = cubic feet ÷ bag size
Mulch coverage chart (per cubic yard)
| Depth | Coverage per yard | 2 cu ft bags per 100 sq ft |
|---|---|---|
| 1 in | 324 sq ft | 4.2 |
| 2 in | 162 sq ft | 8.4 |
| 3 in | 108 sq ft | 12.5 |
| 4 in | 81 sq ft | 16.7 |
Measuring irregular beds
Break curved or odd-shaped beds into rectangles and circles, calculate each one and add them up. For a ring around a tree, calculate the outer circle and subtract the bare area near the trunk.
Frequently asked questions
How many bags of mulch are in a yard?
A cubic yard is 27 cubic feet: about 13.5 bags of 2 cu ft mulch, 9 bags of 3 cu ft, or 18 bags of 1.5 cu ft.
How much area does a yard of mulch cover?
One cubic yard covers about 162 sq ft at 2 inches deep, 108 sq ft at 3 inches, and 81 sq ft at 4 inches.
How deep should mulch be?
Spread 2–3 inches in flower beds and 3–4 inches where you want to suppress weeds. Keep mulch a few inches away from tree trunks and plant stems.
Is bulk mulch cheaper than bags?
Usually yes. Bulk mulch costs about $30–$50 per cubic yard plus delivery, while the same volume in 2 cu ft bags at $4 each costs about $54. Bags make sense for small beds.