Worked example: 3 inches deep
| Step | Math | Result |
|---|---|---|
| Area | 10 ft × 20 ft | 200 sq ft |
| Volume at 3 in | 200 × 3 ÷ 12 | 50.0 ft³ |
| Add 5% extra | 50.0 × 1.05 | 52.5 ft³ |
| Cubic yards | 52.5 ÷ 27 | 1.94 yd³ |
| 2 ft³ bags | 52.5 ÷ 2, rounded up | 27 bags |
| 3 ft³ bags | 52.5 ÷ 3, rounded up | 18 bags |
Mulch by depth
| Depth | Cubic feet | Cubic yards (+5%) | 2 ft³ bags | Bag cost | Bulk order (yd³) | Bulk delivered | Cheaper |
|---|---|---|---|---|---|---|---|
| 2 in | 33.3 | 1.30 | 18 | $72 | 1.5 | $135 | Bags |
| 3 in | 50.0 | 1.94 | 27 | $108 | 2.0 | $155 | Bags |
| 4 in | 66.7 | 2.59 | 35 | $140 | 3.0 | $195 | Bags |
At 3 inches, bags win: 27 bags cost about $108 versus $155 for a delivered 2.0 yd³ (which includes a $75 delivery fee).
Prices used: 2 ft³ bag $4, 3 ft³ bag $6; bulk mulch $40/yd³ plus $75 delivery (1 yd³ minimum). Spring sales change the crossover.
Top-ups and depth
If the bed already has mulch, a 1 inch refresh takes only 0.65 yd³ or 9 bags of 2 ft³. Keep mulch 2–3 inches away from trunks and stems.
Nearby sizes
Also see 10×10 bed , 12×12 bed , 8×8 bed, or the mulch by bed size chart. Use the mulch calculator for other sizes.