Mulch Calculator: Bags or Cubic Yards?
Bagged mulch is sold by volume (usually 2 cu ft), while bulk mulch is sold by the cubic yard (27 cu ft). Enter your bed size and depth to see both, plus which costs less.
Formula
Cu ft = area (sq ft) × depth (in) ÷ 12. Cubic yards = cu ft ÷ 27. Bags = cu ft ÷ bag size, rounded up. One cubic yard is 13.5 two-cubic-foot bags.
Coverage by depth
| Depth | 1 cu yd covers | One 2 cu ft bag | One 3 cu ft bag | 2 cu ft bags per 100 sq ft |
|---|---|---|---|---|
| 1 in | 324 sq ft | 24 sq ft | 36 sq ft | 4.2 |
| 2 in | 162 sq ft | 12 sq ft | 18 sq ft | 8.3 |
| 3 in | 108 sq ft | 8 sq ft | 12 sq ft | 12.5 |
| 4 in | 81 sq ft | 6 sq ft | 9 sq ft | 16.7 |
How deep should mulch be?
- 2–3 in for most beds. That's enough to suppress weeds and hold moisture.
- 3–4 in for bare ground, new beds and paths.
- 1 in top-up each year over old mulch that's still in place.
- Keep mulch 2–3 in away from tree trunks and stems. "Volcano" mulching causes rot.
Bulk usually costs less once you pass 2–3 yards, but add the delivery fee. For standard bed sizes, see mulch bags for 10x10, 10x20 and 20x20 beds.
Frequently asked questions
How many bags of mulch in a yard?
13.5 bags of 2 cu ft, or 9 bags of 3 cu ft (27 cu ft per yard).
How much area does a yard of mulch cover?
324 sq ft at 1 in, 162 sq ft at 2 in, 108 sq ft at 3 in, and 81 sq ft at 4 in.
Is bagged or bulk mulch cheaper?
Bulk is usually cheaper per yard once you need 2–3+ yards, but delivery fees ($40–$90 is common) can tip small jobs toward bags.
Last reviewed October 2026 by Jim Frith. These are planning estimates; confirm quantities with your supplier and follow local codes.