Mulch Calculator
Estimate mulch in bags or bulk cubic yards at any depth.
Result
Enter your bed size and depth to see how many bags of mulch you need.
A 20 × 4 ft garden bed, 3 in deep needs about 10 × 2 cu ft bags of mulch (0.74 cu yd).
You need10× 2 cu ft bags
- 3 in deep
- 108 sq ft/yd at this depth
- bulk cheaper past ~14 bags
What you’ll need
- 2 cu ft bagged mulch10 bags3 in deepShop bagged mulch on Amazon (opens in a new tab)
- Landscape fabricweed barrierShop landscape fabric weed barrier on Amazon (opens in a new tab)
- Bed edgingclean, defined edgesShop landscape bed edging on Amazon (opens in a new tab)
- Wheelbarrow & steel rakeShop wheelbarrow and steel garden rake on Amazon (opens in a new tab)
- Garden glovesShop garden gloves on Amazon (opens in a new tab)
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Estimated cost
See the full breakdown
- Volume
- 20.00 cu ft (0.74 cu yd)
- 2 cu ft bags
- 10
- Bulk order
- 0.74 cu yd
- Bags vs bulk
- 10 bags — bagging is fine; bulk (13.5 bags = 1 cu yd) usually wins past ~14 bags.
- Coverage
- 1 cu yd covers 108 sq ft at this depth
How this is calculated
- Area = length × width; volume = area × depth (all in feet), ÷ 27 for cubic yards.
- Bags: ⌈ volume ÷ 2 cu ft ⌉. There are 13.5 bags in a cubic yard of this size.
- No waste factor applied — mulch is forgiving, so we don’t silently over-order.
- Bulk (cubic yards) is usually cheaper than bags above ~1 cu yd.
How much mulch do I need?
To figure out how much mulch you need, multiply the bed’s length × width × depth (in feet) to get cubic feet, then divide by 2 for the number of standard 2 cu ft bags (or by 27 for bulk cubic yards). For example, a 20 ft × 4 ft bed at 3 inches deep needs 20 cubic feet — exactly 10 bags, or about 0.74 cubic yards in bulk. There are 13.5 bags in a cubic yard. Enter your bed above for an instant estimate you can save or share.
How to use this calculator
- Pick a shape. Choose a rectangular or circular bed.
- Enter dimensions. Type length and width (or diameter) and set the depth — 3 in is the default.
- Choose a bag size. Keep the standard 2 cu ft bag or switch to 1.5 or 3 cu ft.
- Read your estimate. See the number of bags and the bulk cubic yards, then save or share it.
Tips & real-world notes
- Keep mulch 2–3 inches off trunks and stems — avoid “mulch volcanoes” that rot bark.
- Above about 1 cubic yard, bulk mulch is much cheaper than bags — compare the two.
- Bulk delivery usually has a minimum load and a delivery fee, so for a small bed bagged mulch can win once you add haulage.
- Fine or double-shredded mulch settles faster; coarse bark holds its depth longer.
- Dyed hardwood keeps its color longest; natural hardwood and pine bark fade but feed the soil as they break down; rubber/playground mulch doesn’t decompose but doesn’t enrich soil either.
- 3 inches is the sweet spot for weed suppression and moisture retention in most beds.
Frequently asked questions
How much mulch do I need?
Multiply length × width × depth in feet to get cubic feet, then divide by 2 for standard 2 cu ft bags or by 27 for bulk cubic yards. A 20 ft × 4 ft bed at 3 inches needs 10 bags (0.74 cu yd).
How many bags of mulch are in a cubic yard?
There are 13.5 standard 2 cu ft bags in one cubic yard of mulch.
How deep should mulch be?
Use about 2 inches to refresh an existing bed and 3 inches for weed suppression and moisture retention, up to 4 inches for heavy weed control.
How much does a 2 cu ft bag of mulch cover?
A 2 cu ft bag covers about 8 square feet at 3 inches deep, 12 square feet at 2 inches, or 6 square feet at 4 inches.
Is bagged or bulk mulch cheaper?
Bagged mulch is convenient for small beds, but bulk mulch by the cubic yard is usually cheaper once you need more than about one cubic yard (13.5 standard 2 cu ft bags). Factor in that bulk deliveries often carry a minimum load and a delivery fee, so for a small job bagged can still come out ahead.
What type of mulch should I use?
Volume is the same whatever you pick, so the number of bags won’t change — choose by look and longevity. Dyed hardwood holds its color the longest. Natural hardwood and pine bark fade over a season but break down to feed the soil. Cedar resists insects and smells great. Rubber or playground mulch lasts for years and cushions falls but never enriches the soil, so it’s best under play sets rather than in planting beds.
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