TL;DR
A 320 sq ft bed at 3" deep needs 3 cubic yards of mulch = 40 bags of the standard 2 cu ft size. Bulk delivered runs $105–$135; bagged runs $140–$200. Use the mulch calculator for exact figures.
The unit trap
Bags are labeled in cubic feet. Bulk mulch is sold in cubic yards (27 cu ft = one yard). A "2 cu ft" bag of mulch is 1/13.5 of a yard, and there are 13.5 bags per yard — the number every landscaper has burned into memory.
What our data shows
Across recent MaterialCalc mulch jobs, the median bed area is 320 sq ft and users consistently pick 3-inch depth. About one in eight users come back and re-run the calc after ordering — usually because they measured only the visible bed area and forgot the strip along the driveway.
The formulas
cubic yards = (sq_ft × depth_in ÷ 12) ÷ 27
bags = cubic_yards × 13.5 (assuming 2 cu ft bags)
Coverage table
| Depth | Sq ft per cubic yard | Sq ft per 2 cu ft bag |
|---|---|---|
| 1" | 324 | 24 |
| 2" | 162 | 12 |
| 3" | 108 | 8 |
| 4" | 81 | 6 |
Worked example
Front-yard bed: 12' × 25' plus a 2' × 40' strip along the walk = 300 + 80 = 380 sq ft at 3":
- 380 × (3 ÷ 12) = 95 cu ft
- 95 ÷ 27 = 3.52 cu yd → order 3.5 yards bulk or ~48 bags
Common mistakes
- Mulch volcanoes. Piling mulch against the trunk rots bark and invites voles. Keep a 2–3" bare ring around each trunk.
- Too deep. 6" of mulch suffocates fine roots and holds water against stems — cap at 4".
- Skipping edging. Mulch migrates onto lawns and driveways without a defined edge; a $30 spade cut lasts a full season.
- Cheap dyed mulch on food gardens. Use natural hardwood or leaf mulch around anything edible — dyed mulches sometimes hide CCA-treated pallet wood.
Bulk vs bags (2026 pricing)
| Format | Typical price | Break-even |
|---|---|---|
| 2 cu ft bag (hardwood) | $3.50–$4.99 | — |
| Bulk cubic yard (hardwood) | $35–$55 delivered | Bulk wins above ~3 yd |
| Dyed mulch (bag) | $4.00–$5.50 | — |
| Bulk delivery fee | $65–$120 flat | Amortizes fast at 5+ yd |
Get exact numbers
The mulch calculator accepts multiple bed shapes, converts between bags and yards, and factors in the depth you actually want to install.