Mulch Calculator
Calculate how many cubic yards or bags of mulch you need for a garden bed. Enter the bed size and mulch depth to get cubic yards, 2 cu ft bags and 3 cu ft bags.
By CalcBuilt Editorial TeamUpdated September 11, 2026Formulas checked against manufacturer specs, see how we calculate.
Results
- Mulch needed
- 0.93 cu yd
- 25 cu ft; under about 2 yards, bags cost less once the bulk delivery fee is counted
- 2 cu ft (56 L) bags
- 13 bags
- Bagged runs about twice the bulk price per yard; a store pallet is 60 to 65 bags
- 3 cu ft (85 L) bags
- 9 bags
- A store pallet is 40 to 50 bags; ask for the pallet price
- Area covered
- 100 sq ft
- At 3 in deep
Mulch formula
Cubic feet = Length (ft) x Width (ft) x Depth (in) / 12
Cubic yards = Cubic feet / 27
Bags = Cubic feet / bag size (2 or 3 cu ft per bag)Worked example
Three beds each 15 x 4 ft mulched 3 in deep: 15 x 4 x 0.25 x 3 = 45 cubic feet, or 1.67 cubic yards. That is 23 bags of 2 cu ft or 15 bags of 3 cu ft. At $40 per yard in bulk, about $67 of mulch plus delivery.
Quick reference
| Depth | Sq ft covered per cubic yard | Cubic yards per 1,000 sq ft |
|---|---|---|
| 1 in | 324 | 3.1 |
| 2 in | 162 | 6.2 |
| 3 in | 108 | 9.3 |
| 4 in | 81 | 12.3 |
| 6 in | 54 | 18.5 |
How to calculate mulch
Multiply the bed length by width in feet, then by the depth in feet (inches divided by 12). That gives cubic feet. Divide by 27 for cubic yards. A 20 by 5 foot bed at 3 inches deep needs 25 cubic feet, or just under one cubic yard.
One cubic yard of mulch covers 108 square feet at 3 inches deep, 162 square feet at 2 inches, and 81 square feet at 4 inches.
Bags or bulk?
Under about 2 cubic yards, bags win: no delivery fee, no pile in the driveway, and a store pallet of 40 to 65 bags is often discounted. Past 2 yards, bulk at typically $30 to $60 per yard plus a $50 to $100 delivery fee is about half the price per yard. A bulk load dumps in one pile, so clear the spot and lay a tarp; 5 yards is about 25 heaped wheelbarrow loads.
On an established bed, rake the old layer and add 1 to 2 inches; the total should stay under 4 inches or roots suffocate. Keep mulch 3 to 6 inches off tree flares and stems; a volcano against the trunk rots the bark and grows girdling roots. Dyed mulch is usually ground recycled pallet wood with colorant: it holds color a season, bleeds onto concrete in the first rains, and does not belong around vegetables. Shredded hardwood knits on slopes; bark nuggets float and wash out.
What this calculator leaves out
The delivery fee, edging, pre-emergent, and hauling off old mulch that has built up past 4 inches. Skip landscape fabric under organic mulch; it mats, sheds water and starves the soil. Bulk is loose measure and settles 10 to 20 percent over a season, which the yearly top-up covers.
Mistakes that cost money
- Volcano mulching: mulch piled against a trunk holds moisture on the bark and invites rot and girdling roots; keep it 6 in off the flare.
- Buying bags for a 4 yard job costs about twice bulk; past about 2 yards one delivered bulk load is cheaper even with the fee.
- A bulk load dumps in one pile; 5 yards is a car-sized heap that moves by wheelbarrow, so pick the spot first.
- Dyed mulch bleeds in the first rain and stains concrete and pavers; keep it off the walk and out of vegetable beds.
- Piling 6 in of fresh mulch on last year's bed smothers roots and holds water; rake old mulch and top up 1 to 2 in.
- Mulch piled against siding hides the inspection gap and bridges termites into the sill; keep it 6 in below the siding.
Key facts
- One cubic yard of mulch covers 108 sq ft at 3 in deep, 162 sq ft at 2 in, and 81 sq ft at 4 in.
- A cubic yard equals 13.5 bags of 2 cu ft or 9 bags of 3 cu ft.
- Keep mulch 2 to 3 in deep and 3 to 6 in back from trunks and stems; a mulch volcano against a trunk rots the bark and girdles the tree.
- In 2026 US retail bulk hardwood mulch is typically $30 to $60 per cubic yard plus delivery; bagged runs roughly twice that per yard.
Frequently asked questions
How many bags of mulch are in a cubic yard?
13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet.
Is bulk or bagged mulch cheaper?
Bulk is typically $30 to $60 per yard in 2026 plus a $50 to $100 delivery fee; bags run about twice that per yard. Under 2 yards the delivery fee wipes out the saving, so buy bags. Past 2 yards order bulk and pick the drop spot before the truck comes.
How deep should mulch be?
2 to 3 inches for most garden beds, up to 4 inches over bare soil for weed control, and 1 to 2 inches to top up an existing bed. Keep it 3 to 6 inches off stems and tree trunks; a mulch volcano rots the bark.
Sources and references
- Mulch factsheet HGIC 1604: types and recommended depth (Clemson Cooperative Extension)
- Mulching Landscape Trees: 2 to 4 inch depth guidance (Penn State Extension)
- Edging and Mulching Landscape Beds (University of Illinois Extension)
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The usual order for a landscaping & outdoor project. See all landscaping & outdoor calculators.
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Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.