Mulch Calculator
Calculate how much mulch you need from the bed area and the depth you want.
Mulch volume1.500m³
In cubic yards1.96yd³
50 L bags to buy30bags
Mulch volume = area × depth, with depth converted from cm to metres (÷ 100). For a 20 m² bed at 7.5 cm deep: 20 × 0.075 = 1.5 m³. That is ≈ 1.96 cubic yards, or — since 1 m³ = 1,000 L — about 30 bags of 50 L. A 5–8 cm layer suits most beds; round bags up.
Questions
How much mulch do I need?
Multiply the bed area by the depth in metres. A 20 m² bed at 7.5 cm (0.075 m) deep needs 20 × 0.075 = 1.5 cubic metres of mulch.
How deep should mulch be?
A layer of about 5–8 cm suppresses weeds and holds moisture without smothering plants. Top up each year as the old mulch breaks down.