How to calculate mulch
- Measure each bed. Length × width for rectangular beds; the diameter for rings around trees. For curved or irregular beds, estimate an average length and width.
- Choose a depth. 2–3 in is right for most beds; see the depth guide below.
- Pick bulk or bags. The calculator shows cubic yards for bulk delivery and the number of bags for your chosen bag size, so you can compare the cost of each.
Mulch formula
Bags = Cubic feet ÷ Bag size (cu ft), rounded up
Worked example
A border bed 30 ft long and 4 ft wide, mulched 3 in deep, needs 30 × 4 × 3 ÷ 12 = 30.00 cubic feet — that's 1.11 cubic yards, or 15 bags of the common 2 cu ft size.
How deep should mulch be?
- Flower and shrub beds: 2–3 in.
- Weed suppression: 3–4 in; deeper layers can keep water and air from reaching roots.
- Topping up existing mulch: 1–2 in is usually enough each year.
- Play areas and paths (wood chips, rubber mulch): often deeper — follow the product or safety guidance for playground surfacing.
Keep mulch a few inches away from tree trunks and plant stems. Piling it against bark holds moisture against the wood and invites rot and pests.
Mulch coverage chart
How much area each amount covers at different depths:
| Depth | 1 cubic yard covers | One 2 cu ft bag covers | One 3 cu ft bag covers |
|---|---|---|---|
| 1 in | 324 sq ft | 24 sq ft | 36 sq ft |
| 2 in | 162 sq ft | 12 sq ft | 18 sq ft |
| 3 in | 108 sq ft | 8 sq ft | 12 sq ft |
| 4 in | 81 sq ft | 6 sq ft | 9 sq ft |
| 6 in | 54 sq ft | 4 sq ft | 6 sq ft |
How many bags of mulch are in a yard?
A cubic yard holds 27 cubic feet, so:
| Bag size | Bags per cubic yard |
|---|---|
| 1 cu ft | 27 |
| 1.5 cu ft | 18 |
| 2 cu ft | 13.5 |
| 3 cu ft | 9 |
Bulk vs bagged mulch
Bags are clean, easy to carry and fine for a few small beds. Once you need more than about two or three cubic yards, bulk mulch from a landscape yard is usually much cheaper per yard — even after delivery. Enter both prices in the calculator to see the difference for your job.
Shredded hardwood stays in place well on slopes; bark nuggets are larger and last longer but can wash away in heavy rain; dyed mulch holds color for a season or so; and stone or rubber mulch doesn't decompose, so it won't feed the soil.
Frequently asked questions
How many bags of mulch do I need?
Multiply the bed's length × width (in feet) × depth (in inches), divide by 12 to get cubic feet, then divide by the bag size. For a 2 cu ft bag, a 10 × 10 ft bed at 3 in deep needs 25 cubic feet, or 13 bags.
How much does a yard of mulch cover?
One cubic yard covers about 162 sq ft at 2 in deep, 108 sq ft at 3 in, or 81 sq ft at 4 in.
How many 2 cubic foot bags of mulch equal a yard?
13.5 bags. A cubic yard is 27 cubic feet, and 27 ÷ 2 = 13.5, so buy 14 bags to be safe.
How deep should mulch be?
2–3 inches for most garden beds and 3–4 inches where weed control matters most. Deeper than about 4 inches can starve roots of air and water.
How much mulch do I need around a tree?
Measure the diameter of the ring. A 6 ft ring at 3 in deep is about 7.07 cubic feet — roughly 4 bags of 2 cu ft. Keep the mulch a few inches away from the trunk.
Is it cheaper to buy mulch in bulk?
Generally yes for larger jobs. Bagged mulch is convenient for small areas, but beyond two or three cubic yards bulk mulch is usually far cheaper per yard, even including delivery.