How much mulch do I need?

Multiply the garden area by the depth of mulch to get the volume in cubic metres, then divide by the bag size if you are buying bags. The calculator does both. Bagged mulch is often sold in 40 to 60 litre bags.

How deep should mulch be?

A layer of about 50 to 75 mm is usual for suppressing weeds and holding moisture, kept clear of plant stems. Thinner layers break down and need topping up sooner. Enter your chosen depth in millimetres.

How many litres in a cubic metre?

There are 1,000 litres in a cubic metre. So a 50 litre bag is 0.05 of a cubic metre, and it takes 20 of those bags to make one cubic metre. Bulk mulch by the cubic metre is usually cheaper for large areas.

Mulch Calculator

Work out how much mulch or bark to buy for your garden. Enter the area to cover and the depth, and the calculator shows the volume in cubic metres and how many bags that is. Bulk mulch by the cubic metre is usually cheaper for larger beds.

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Garden area (m²)

Depth (mm)

Bag size (litres)

0 m³

mulch needed

Bags0

Litres0 L

How it works

The volume is the area times the depth in metres. There are 1,000 litres in a cubic metre, so the calculator converts the volume to litres and divides by the bag size to get the number of bags, rounded up.

Worked example

For 15 square metres at 60 mm deep, the volume is 0.9 cubic metres, which is 900 litres. In 50 litre bags that is 18 bags, or you could order just under a cubic metre in bulk.

Related calculators

Topsoil Calculator: soil for a garden.
Gravel Calculator: gravel and aggregate.
Cubic Metre Calculator: work out a volume.
Square Metre Calculator: work out an area.

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