How the mulch calculation works
Mulch volume (m³) = length × width × depth in metres. Depth in centimetres is divided by 100.
Worked example
A 5 m × 2 m bed is 10 m². At 7.5 cm deep, the volume is 0.75 m³, or about 750 litres.
Guide: using this calculator accurately
For the full explanation, worked examples, measurement tips and FAQs, read the Mulch Guide →.
How deep should mulch be?
Choose a depth based on the mulch product, the garden use and local horticultural guidance. The calculator lets you enter the depth you actually plan to install.
Measure garden beds
For a simple rectangular bed, measure length and width. For irregular beds, divide the shape into smaller rectangles or estimate each section separately.
Cubic metres versus litres
Bulk mulch is commonly sold by cubic metre while bagged products are often labelled in litres. One cubic metre equals 1,000 litres.
Why mulch depth matters
Doubling the depth doubles the volume required if the area stays the same. A small change in depth can therefore change the order substantially.
Common mulch mistakes
Do not enter a depth in centimetres as if it were metres. Also remember that loose mulch can settle after installation.
Frequently asked questions
How many bags of mulch do I need?
Divide the total litre requirement by the litres in each bag and round up. The bag size is product-specific, so check the label.
Does this include settling?
No. It calculates the installed geometric volume. Loose organic mulch can settle, so consider the product and supplier guidance.
Can I use this for irregular beds?
Yes, by splitting the bed into rectangular sections and adding the calculated volumes.