Mulch Calculator
Free and simple, type the size of your garden bed and how deep you want the mulch, and get cubic yards and the number of bags right away. No sign-up, no email.
Calculate Mulch
How to Use: 3 Easy Steps
Step 1: Measure your bed: length and width in feet. For a round bed, measure straight across the middle, that is the diameter.
Step 2: Pick how deep the mulch should be. 3 inches is right for most new beds; 2 inches is enough to refresh old mulch.
Step 3: Press Calculate. You get the amount in cubic yards (for bulk delivery) and in bags (for store-bought mulch).
Mulch Formula: How to Calculate Cubic Yards and Bags
Mulch (cubic feet) = Length (ft) × Width (ft) × Depth (ft)
Depth is in inches, so divide it by 12 first. Example: 3 inches ÷ 12 = 0.25 feet.
Example: a 10 × 10 bed, 3 inches deep.
10 × 10 × 0.25 = 25 cubic feet = 0.93 cubic yards (divide cubic feet by 27) = 13 bags of 2 cubic feet (25 ÷ 2 = 12.5, round up to 13).
For a round bed: Area = 3.1416 × (Diameter ÷ 2) × (Diameter ÷ 2), then multiply by the depth in feet, the same as above.
How Much Does 1 Cubic Yard Cover?
| Mulch Depth | 1 Cubic Yard Covers | One 2 cu ft Bag Covers |
|---|---|---|
| 2 inches | 162 sq ft | 12 sq ft |
| 3 inches | 108 sq ft | 8 sq ft |
| 4 inches | 81 sq ft | 6 sq ft |
Ready Answers for Common Beds (3 inches deep)
| Bed Size | Cubic Yards | 2 cu ft Bags | Common Use |
|---|---|---|---|
| 5 × 10 ft | 0.46 yd³ | 7 bags | Small flower bed |
| 10 × 10 ft | 0.93 yd³ | 13 bags | Front-yard bed |
| 10 × 20 ft | 1.85 yd³ | 25 bags | Long side bed |
| 20 × 20 ft | 3.70 yd³ | 50 bags | Big garden area |
Small job (under about 1 cubic yard)? Bags are usually easier to carry and spread. Bigger job? Bulk delivery by the cubic yard is usually much cheaper per amount, one delivery, no plastic bags to open.
Common Mistakes to Avoid
1. Making the mulch too deep. More is not better. Over 4 inches, water and air cannot reach the plant roots well. 2–3 inches is right for most beds.
2. Piling mulch against tree trunks and stems. This is called a “mulch volcano” and it rots the bark. Keep mulch a few inches away from trunks and plant stems.
3. Forgetting that bags are sold in cubic feet, not yards. One cubic yard is 27 cubic feet, and one bag is 2 cubic feet: 27 ÷ 2 = 13.5, so about 14 bags to equal one cubic yard. This calculator does that math for you.
4. Measuring only the easy side. Beds are rarely perfect rectangles. Measure the longest length and the widest width, a little extra mulch is far better than running short halfway.
Questions People Ask
How much mulch do I need for a 10×10 bed?
At 3 inches deep: 25 cubic feet, which is 0.93 cubic yards, or 13 bags of 2 cubic feet.
How many bags of mulch make one cubic yard?
About 14 bags of the common 2 cubic feet size. One cubic yard is 27 cubic feet: 27 ÷ 2 = 13.5, so you buy 14 bags.
How deep should mulch be?
2–3 inches for most beds. Use 2 inches to refresh old mulch and 3–4 inches on a brand-new bed. Keep it away from tree trunks and plant stems.
Is it cheaper to buy bags or bulk mulch?
For small beds, bags are simple and cheap enough. For 1 cubic yard or more, bulk delivery is usually much cheaper for the same amount, and there is no plastic waste.
How much does a bag of mulch cover?
One 2 cubic feet bag covers about 8 square feet at 3 inches deep, 12 square feet at 2 inches, or 6 square feet at 4 inches.
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