Mulch Calculator
Cubic yards and bags of mulch for garden beds at any depth
2–4 in is the usual range for beds
2 and 3 cu ft bags are common; check the bag
Optional; 0 to skip
Optional; 0 to skip
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Quick summary
Mulch volume is bed area × depth: a 20 × 10 ft bed at 3 inches deep is 200 sq ft × 3/12 ft = 50 cu ft, or 1.85 cubic yards (27 cu ft per yard). In 2 cu ft bags that is 25 bags; in 3 cu ft bags, 17. Enter a bulk price per yard and a price per bag to see which way is cheaper for your bed.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Choose the Area Input: enter length and width, or enter square footage directly.
- Enter Length (ft) and Width (ft), or Area (sq ft) for the total of several beds.
- Set Depth (in) — 2 to 4 inches is the usual range for beds.
- Enter the Bag Size (cu ft) printed on the bags you plan to buy.
- Optionally enter Bulk Price per Cubic Yard ($) and Price per Bag ($) to compare costs.
- Read the cubic yards needed, the number of bags, and the cost of each option.
Mulch Formulas
Mulch Volume
- A
- Bed area in square feet (length × width)
- D
- Depth in inches (divided by 12 to convert to feet)
- 27
- Cubic feet in one cubic yard
Worked example
A 20 × 10 ft bed, 3 inches deep
- Given
- A = 200 sq ftD = 3 in
- Calculation
- Result
- V ≈ 1.85 cubic yards
Bags Needed
- V (cu ft)
- Volume in cubic feet (area × depth ÷ 12)
- Bag size
- Cubic feet per bag, printed on the bag (2 and 3 are common)
Worked example
50 cu ft using 2 cu ft bags
- Given
- V (cu ft) = 50Bag size = 2 cu ft
- Calculation
- Result
- 25 bags
Frequently asked questions
How deep should mulch be?
About 2–4 inches is the common recommendation for garden beds. Thinner layers do less to hold moisture and block weeds, while very deep layers can keep soil too wet and starve roots of air. Keep mulch pulled back a little from plant stems and tree trunks.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 bags of 2 cu ft or 9 bags of 3 cu ft. Check the bag size printed on the package, since sizes vary.
Is bulk or bagged mulch cheaper?
It depends on local prices and how much you need. Bulk mulch is often cheaper per cubic yard for large areas, but delivery fees can outweigh the savings on small jobs. Bags are convenient for small beds and easy to carry. Enter both prices to compare for your bed.
How much area does a cubic yard of mulch cover?
One cubic yard covers about 108 sq ft at 3 inches deep, 162 sq ft at 2 inches, or 81 sq ft at 4 inches. The rule is 324 divided by the depth in inches.
How do I measure an irregular bed?
Break the bed into rough rectangles, multiply length by width for each, and add the results. Then switch the area input to square footage and enter the total. For a round bed, area is about 3.14 × radius².
Key terms
- Cubic Yard
- 27 cubic feet — the usual unit for buying bulk mulch.
- Bag Size
- The volume of mulch in a bag, printed on the package in cubic feet (2 and 3 are common).
- Bulk Mulch
- Loose mulch sold by the cubic yard, picked up or delivered by truck.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.