Mulch Calculator
Calculate cubic yards and bags of mulch for any bed size and depth.
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Currency: Amounts are calculated in the currency you select; this site does not convert between currencies and does not use live exchange rates.
What this tool does
The Mulch Calculator turns bed length, width and depth into cubic yards of mulch for bulk delivery and the number of bags to buy, so you buy enough to suppress weeds without wasting money.
How to use the Mulch Calculator
- Measure the bed length and width.
- Enter the mulch depth you want.
- Choose the bag size you plan to buy.
- Enter the bulk price per cubic yard to compare.
- Buy the bags shown or order the bulk yards.
Formula
cu ft = L × W × (D ÷ 12); yd³ = cu ft ÷ 27; bags = ⌈cu ft ÷ bag size⌉
- L, W
- Length and width (ft)
- D
- Depth (in)
- bag size
- Bag volume in cu ft
Worked example
A 20 × 10 ft bed at 3 in deep using 2 cu ft bags.
Inputs
- Length20 ft
- Width10 ft
- Depth3 in
- Bag size2 cu ft
- Price per cubic yard (bulk)$38
Result
- Mulch needed1.85 cu yd
- Bags (2 cu ft)25
- Volume50 cu ft
- Bulk cost estimate$70.37
Mulch coverage by depth
| Depth | Coverage of 1 cu yd | Coverage of a 2 cu ft bag |
|---|---|---|
| 1 in | 324 sq ft | 24.0 sq ft |
| 2 in | 162 sq ft | 12.0 sq ft |
| 3 in | 108 sq ft | 8.0 sq ft |
| 4 in | 81 sq ft | 6.0 sq ft |
| 6 in | 54 sq ft | 4.0 sq ft |
Results explained
- Mulch needed
- Cubic yards for a bulk delivery.
- Bags
- Bags to buy, rounded up to whole bags.
- Volume
- Total cubic feet.
- Bulk cost
- Yards × price per yard, excluding delivery.
Frequently asked questions
Multiply length × width in feet by depth in inches ÷ 12, then divide by 27 for cubic yards. A 20 × 10 ft bed at 3 in needs 1.85 cu yd.
2–3 inches for most beds; 3–4 inches for weed control. Over 4 inches can suffocate roots.
13.5 bags of 2 cu ft, 9 bags of 3 cu ft, or 18 bags of 1.5 cu ft.
About 108 sq ft at 3 in deep and 162 sq ft at 2 in deep.
Usually once you need more than 2–3 cubic yards, even after delivery fees.