Kalkulo / Garden & Outdoor / Mulch Calculator

Mulch Calculator

Calculate how many bags of wood chips or bark mulch you need for flower beds and planting areas, based on area and layer thickness.

Mulch volume
0.50 m³
6 × 1.2 m, 7 cm thickness
Area
7.2 m²
Bags (60 L)
9

How to use the mulch calculator

  1. Enter the length and width of the bed or planting area.
  2. Enter the desired layer thickness — 5-8 cm is common for effective weed suppression.
  3. The calculator shows volume in cubic meters and roughly how many 60-liter bags you need.

How the mulch amount is calculated

The volume is area times thickness, once the thickness is converted from centimeters to meters:

Volume (m³) = Length × Width × (Thickness ÷ 100)

Wood chips and bark mulch are often sold in bags of around 50-70 liters. This calculator uses 60 liters (0.06 m³) as a typical average — check the bag size of the product you're buying for a more exact count.

Note: To suppress weeds effectively, the mulch layer should be at least 5-7 cm thick. Thinner layers give weaker weed suppression and break down faster.

Frequently asked questions

What's the difference between wood chips and bark mulch?

Wood chips are made from ground-up wood, while bark mulch is a byproduct of debarking timber. Both work well as ground cover in beds, but can differ somewhat in how fast they break down and in appearance.

How often do I need to refill?

Depending on material and exposure, the mulch layer gradually breaks down, and most need refilling every 1-3 years to maintain the desired thickness and weed suppression.

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