20 × 20 ft bed: the short answer
At 3 inches deep, a 20 × 20 ft bed needs about 100.0 cubic feet of mulch — roughly 50 bags of 2 cu ft, or about 3.70 cubic yards in bulk.
Bed size
Mulch for a 20 × 20 ft bed
A 20 × 20 ft bed at 3 inches deep needs about 100.0 cubic feet of mulch — about 50 bags of 2 cu ft, or 3.70 cubic yards in bulk. Adjust depth and bag size below.
Mulch needed
—Enter bed size and depth to estimate mulch.
| Total volume | — |
|---|---|
| Bulk (cubic yards) | — |
| Bags to buy | — |
| Coverage per bag | — |
| Estimated cost | — |
Estimate only.
Mulch is typically applied 2–3 inches deep (3–4 inches for weed suppression). Bag counts are
rounded up; coverage varies with how finely the mulch is shredded and how much it settles.
Before you buy
Mulch settles and breaks down, so topping up to 3 inches each year is normal rather than piling it deeper. For more than 8–10 bags, compare bulk delivery by the cubic yard.
Standard volume math at 3″ depth; 1 cu yd = 27 cu ft. Estimates only.
FAQ
How much mulch for a 20 × 20 ft bed?
At 3 inches deep, a 20 × 20 ft bed needs about 100.0 cubic feet (3.70 cubic yards) of mulch — roughly 50 bags of 2 cu ft. Deeper mulch scales directly: 4 inches needs about a third more than 3 inches.
How many bags of mulch for a 20 × 20 ft bed?
About 50 bags of 2 cu ft at 3 inches deep. If that's more than 8–10 bags, price out bulk mulch by the cubic yard (3.70 cu yd here) — it's usually cheaper.
Estimate only, based on standard volume math at 3″ depth. Coverage varies with mulch type and settling; bag counts are rounded up. Confirm against your supplier before buying.