Mulch Calculator
Enter the size of your garden bed and the depth of mulch to see the cubic yards, bags and cost you need.
Free, no sign-upRuns in your browserHow we calculate
2–3 inches is typical for beds; 1–2 inches to refresh old mulch.
Cubic feet per bag, printed on the bag.
5–10% is a common allowance.
- Bed area
- 200 ft²
- Cubic feet (exact)
- 50
- Cubic yards (exact)
- 1.852
- Cubic meters
- 1.416
- Bags of 2 cu ft
- 28
| Depth | 1 cubic yard covers | 1 bag (2 cu ft) covers | 1 bag (3 cu ft) covers |
|---|---|---|---|
| 1 in | 324 ft² | 24 ft² | 36 ft² |
| 2 in | 162 ft² | 12 ft² | 18 ft² |
| 3 in | 108 ft² | 8 ft² | 12 ft² |
| 4 in | 81 ft² | 6 ft² | 9 ft² |
How this was calculated
- Convert to feet: 20 ft × 10 ft × 0.25 ft = 50 cubic feet.
- Divide by 27 cubic feet per cubic yard: 50 ÷ 27 = 1.8519 cubic yards.
- Add 10% extra: 1.8519 × 1.1 = 2.037 cubic yards.
- Bags: 55 cubic feet ÷ 2 cubic feet per bag = 27.5, rounded up to 28 bags.
How this mulch calculator works
The mulch you need is the volume of the bed: length × width × depth. This mulch calculator converts everything to feet, multiplies to get cubic feet, and divides by 27 to give cubic yards, the unit that bulk suppliers sell by. It then adds an allowance for settling and spillage and rounds the bagged amount up to whole bags, because you cannot buy a fraction of a bag.
Worked example
A bed 20 ft long and 10 ft wide, mulched 3 inches (0.25 ft) deep, is 20 × 10 × 0.25 = 50 cubic feet, or 50 ÷ 27 = 1.85 cubic yards. With 10% extra that becomes 55 cubic feet, or 2.04 cubic yards. In 2-cubic-foot bags that is 27.5, so 28 bags; in 3-cubic-foot bags it is 18.3, so 19 bags. For a bulk delivery you would order 2 cubic yards or, to be safe, 2.5.
How deep should mulch be?
Two to three inches is the usual depth for flower beds and around shrubs: deep enough to block most weeds and hold moisture, shallow enough that water and air still reach the soil. To refresh mulch that is already down, one to two inches on top is enough. One cubic yard covers 324 square feet at 1 inch, 162 at 2 inches, 108 at 3 inches and 81 at 4 inches. A 2-cubic-foot bag covers 8 square feet at 3 inches, and a 3-cubic-foot bag covers 12.
Bags or bulk?
Bags are easier to carry and cheaper to buy in small amounts, but the price per cubic foot is almost always higher. One cubic yard equals 13.5 bags of 2 cubic feet, so once a job needs about a cubic yard or more it is worth pricing a bulk delivery. Enter both prices in the optional fields to compare them. Delivery fees and minimum loads are not included.
Common mistakes
- Mixing units. Bed sizes are in feet but depth is in inches. Dividing the inches by 12 first, or using the depth unit box here, avoids a 12-fold error.
- Forgetting irregular shapes. For a curved bed, split it into rectangles, calculate each and add them up, or measure the area in square feet and multiply by the depth in feet.
- Piling mulch against trunks. Keep it a few inches away from tree trunks and plant stems; deep mulch against bark holds moisture and invites rot and pests.
The same math works for compost, topsoil, gravel and bark: only the depth changes. For other materials or concrete, use the cubic yard calculator.
Frequently asked questions
How do you calculate how much mulch you need?
Multiply the bed length × width × depth in feet to get cubic feet, then divide by 27 for cubic yards. A 20 ft × 10 ft bed at 3 inches (0.25 ft) is 50 cubic feet, or 1.85 cubic yards.
How many bags of mulch are in a cubic yard?
13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet, because a cubic yard is 27 cubic feet.
How deep should mulch be?
Two to three inches for most beds, and one to two inches to top up existing mulch. Keep it a few inches clear of tree trunks and plant stems.
How much does one cubic yard of mulch cover?
324 square feet at 1 inch deep, 162 at 2 inches, 108 at 3 inches and 81 at 4 inches.
Should I add extra for waste?
Yes, 5% to 10% covers settling, uneven ground and spillage. The calculator adds the percentage you choose before it rounds up to whole bags.