Mulch Calculator
Cubic yards or bags of mulch for garden beds and borders.
3 in for new beds, 1 to 2 in for a refresh.
You need
0.74 cubic yards
Bulk delivery is usually cheaper above about 2 cubic yards.
- 2 cu ft bags
- 10 bags
- 3 cu ft bags
- 7 bags
- Bed area
- 80 sq ft
Estimates only. Verify quantities before ordering.
How this is calculated
Volume = length (ft) x width (ft) x depth (in) / 12, then divided by 27 for cubic yards. One cubic yard equals 13.5 bags at 2 cu ft or 9 bags at 3 cu ft.
Measure the bed's length and width in feet, pick a depth, and this calculator gives you the volume in cubic yards for bulk orders plus the equivalent number of bags. For irregular beds, break the shape into rough rectangles, run each one, and add the results together.
Depth is the main decision. A fresh bed benefits from a full 3 inches, which suppresses weeds and holds moisture well. An annual refresh over existing mulch usually only needs 1 to 2 inches. More than 4 inches is counterproductive, since thick mulch can suffocate roots and hold too much moisture against stems.
Mulch for common bed sizes
Rows use a full 3 inch depth for new beds except where noted. One cubic yard equals 13.5 of the common 2 cu ft bags.
| Bed size | Cubic yards | 2 cu ft bags |
|---|---|---|
| 4 x 10 ft, 3 in | 0.37 cubic yards | 5 bags |
| 4 x 25 ft, 3 in (long border) | 0.93 cubic yards | 13 bags |
| 10 x 10 ft, 3 in | 0.93 cubic yards | 13 bags |
| 20 x 4 ft, 2 in (refresh) | 0.49 cubic yards | 7 bags |
| 20 x 10 ft, 3 in | 1.85 cubic yards | 25 bags |
| 30 x 15 ft, 3 in (full yard) | 4.17 cubic yards | 57 bags |
Common questions
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 of the common 2 cu ft bags or 9 of the 3 cu ft bags. If you need more than about 25 bags, price out a bulk delivery: it is almost always cheaper per yard and saves a lot of lifting.
How deep should mulch be?
2 to 3 inches is the sweet spot for most beds: enough to block light from weed seeds and slow evaporation without smothering plant roots. Coarse mulches like bark nuggets can go slightly deeper, and fine mulches like shredded leaves should stay closer to 2 inches.
Should mulch touch tree trunks and plant stems?
No. Pull mulch 2 to 3 inches back from trunks and stems. Piling mulch against bark (the so-called mulch volcano) traps moisture, invites rot and pests, and encourages girdling roots. The mulch ring should look like a donut, not a volcano.
How often does mulch need to be replaced?
Organic mulches break down over one to two seasons. Most beds do well with a 1 to 2 inch top-up each spring. Rake and fluff the old layer first, and only remove it if it has compacted into a water-shedding mat.