Mulch & Soil Calculator
How much mulch or topsoil for your bed — in cubic yards and the exact number of bags at your chosen depth.
Your project
Total area: 0 sq ft
Material estimate only — confirm quantities against your own measurements and the product packaging before you buy. Round up and keep a little extra for cuts, waste, and mistakes.
What you need
What to buy
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Volume
— cu yd
Bags to buy
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Est. cost
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Shopping list
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How we calculate it
volume (cu ft) = area × (depth / 12) • cubic yards = volume / 27 • bags = round up( volume / bag size )
Assumptions & sources
- Mulch and topsoil are sold by volume, so no material density is needed
- Bagged mulch is most commonly 2 cubic feet (some brands 3 cu ft); topsoil often comes in smaller 0.75–1.0 cu ft bags
- 27 cubic feet = 1 cubic yard (exact); bulk delivery is usually cheaper past ~1 cubic yard
- Typical mulch depth is 2–3 inches; deeper for weed suppression, shallower around shallow-rooted plants
Formulas reviewed against manufacturer spec sheets and industry standards. Last verified 2026.
How to estimate mulch and topsoil
Both are volume products: bed area times depth (in feet) gives cubic feet, and dividing by 27 gives cubic yards. A standard bag of mulch holds 2 cubic feet, so it takes 13.5 bags to equal a cubic yard.
Depth matters most
- Pick the right depth: 2–3 inches of mulch suppresses weeds and holds moisture; much deeper can smother roots. Topsoil depth depends on whether you’re top-dressing or filling a bed.
- Bags vs. bulk: Bags are easy for small beds; for a big project, bulk mulch by the cubic yard (often delivered) is cheaper per unit.
- Odd-shaped beds: For curved or irregular beds, estimate the area as a rectangle that roughly bounds it, then trust the waste in your rounding.
Common questions
How many bags of mulch in a cubic yard?
13.5 bags of the standard 2 cubic-foot size, or 9 bags of the 3 cubic-foot size (27 ÷ bag size).
How much mulch for 200 square feet?
At 3 inches deep, 50 cubic feet — about 1.85 cubic yards, or 25 × 2 cu ft bags.
How deep should mulch be?
Two to three inches is ideal for most beds. Too shallow won’t suppress weeds; too deep can suffocate roots and cause rot near stems.