Mulch Calculator
Garden Bed Inputs
RESULT
Mulch Layer Cross-Section
100 sq ft × 3 in deep
Illustrative cross-section • keep mulch clear of stems
Volume & Purchase Summary
| Option | Quantity | Notes |
|---|
Formula & Worked Example
Volume (cu yd) = area (sq ft) × depth (in) ÷ 324
Bags = round up(volume ÷ bag volume)
100 × 3 ÷ 324 = 0.93 cu yd
Shape and unit formulas
Rectangle: area = length × width. Circle: area = π × radius². Metric volume: m³ = m² × depth in cm ÷ 100. 1 cu yd = 27 cu ft. Bag sizes remain 2 or 3 cu ft when switching input units.
Frequently Asked Questions
How deep should mulch be?
A 2–3 inch layer is commonly recommended for landscape mulching, but material, plants and existing mulch change the appropriate depth. Enter the additional depth you intend to add, and keep mulch away from plant stems and trunks.
Why are bags rounded up?
You normally buy whole bags. The calculator rounds up using the full-precision volume, so the displayed rounded yard figure cannot make you buy too little.
Can I calculate a circular garden bed?
Yes. Select Circular Bed and enter its radius, not its diameter. For rings or irregular areas, subtract the unmulched area and use Custom Area.
Should I buy more than calculated?
The estimate assumes a uniform layer and no waste. Uneven ground, settling or handling can change actual needs. Choose any allowance based on site conditions; this tool does not add one automatically.
How is the estimated cost calculated?
For bag purchases, cost equals the whole bag count multiplied by the entered price per bag. For bulk, cost uses the calculated volume and the selected supplier unit. Delivery, tax, labor and minimum-order charges are excluded.
Mulch Calculator Calculate how many cubic yards of mulch you need to cover a garden bed to a desired depth. — free online calculator.