How much mulch do I need?
Multiply the bed's area by the depth you want, then convert to cubic yards (bulk) or bags:
cubic yards = length (ft) × width (ft) × depth (in) ÷ 324
The 324 comes from 27 cubic feet per yard × 12 inches per foot. For a 12 × 20 ft bed at 3 inches: 12 × 20 × 3 ÷ 324 = 2.22 cubic yards, or 60 cubic feet = 30 bags of 2 cu ft.
- Measure each bed. Split L-shapes into rectangles and use the "How many" box for repeated beds.
- For round tree rings, measure the diameter and choose Circle. Leave the trunk area out if it's large.
- Pick a depth (see below) and read the yards, bags and cost.
How deep should mulch be?
- 2–3 inches for most flower and shrub beds — enough to block weeds and hold moisture.
- 1–2 inches to top up an existing layer each spring.
- 3–4 inches for paths and play areas (wood chips), or very weedy ground.
- Keep mulch a few inches away from tree trunks and stems — "volcano" mulching invites rot and rodents.
Mulch coverage chart
How far one cubic yard and one 2 cu ft bag go at each depth:
| Depth | 1 cubic yard covers | One 2 cu ft bag covers | Bags per 100 sq ft |
|---|---|---|---|
| 1" | 324 sq ft | 24 sq ft | 5 |
| 2" | 162 sq ft | 12 sq ft | 9 |
| 3" | 108 sq ft | 8 sq ft | 13 |
| 4" | 81 sq ft | 6 sq ft | 17 |
| 6" | 54 sq ft | 4 sq ft | 25 |
Bags vs. bulk: which is cheaper?
One cubic yard equals 13.5 bags of 2 cu ft (or 9 bags of 3 cu ft). Bagged mulch typically runs $3–$6 per 2 cu ft bag, so a yard's worth costs about $40–$80. Bulk mulch is usually $20–$50 per yard plus a delivery fee (often $50–$100), so bulk wins once you need more than about 2–3 yards. For a few small beds, bags are easier to haul and store.
FAQ
How many bags of mulch are in a yard?
13.5 bags of 2 cubic feet, 9 bags of 3 cubic feet, or 18 bags of 1.5 cubic feet.
How many square feet does a yard of mulch cover?
324 sq ft at 1 inch, 162 sq ft at 2 inches, 108 sq ft at 3 inches and 81 sq ft at 4 inches.
How much does a yard of mulch weigh?
Wood and bark mulch usually weighs 400–800 lb per cubic yard, depending on moisture. Compost is heavier, around 800–1,600 lb.
Should I remove old mulch first?
Not usually. Rake it to loosen any crust and top up to a total of 2–3 inches. Remove it only if it's matted, moldy or piled against stems.