HesapHanem

Bark Chip Coverage Calculator

Enter your bed area, the depth you want and your bag size to see exactly how many bags to buy.

How it is calculated

Enter the bed area in square metres, the depth you want to spread in centimetres, and the bag size in litres. The tool converts the depth to metres and computes volume (m³) = area × depth / 100. Since 1 m³ is 1,000 litres, litres = volume × 1,000, and bags = litres / bag size, always rounded up to a whole bag. Output shows bags, volume in m³ and total litres. The calculation assumes a flat bed of even depth and does not add an allowance for uneven ground, settling or waste. Bag volumes are as printed on the bag; loose chips sold by the cubic metre can use the m³ figure directly.

Worked example

A 12 m² bed, mulched 7 cm deep, with 50-litre bags. Volume = 12 × 7 / 100 = 0.84 m³. In litres that is 0.84 × 1,000 = 840 L. Bags = 840 / 50 = 16.8, which rounds up to 17 bags. Buying 17 bags gives 850 L, a small margin over the 840 L needed.

Try this example →

Common mistakes

  • Typing the depth in metres or millimetres: the field is in centimetres, so 0.07 or 70 gives a result far from what you want.
  • Entering the area in square feet: the field is in square metres.
  • Using the bag's weight (kg) instead of its volume in litres.
  • Forgetting that mulch compacts and thins over time, so a bed topped up yearly needs fewer bags than a new one.
  • Spreading the full depth right up against stems or trunks: the quantity is for even cover, and mulch piled on stems can cause rot.

About this calculator

Bark chip mulch coverage is a simple volume calculation: the cubic volume needed to cover a bed is bed area × desired depth, and dividing that by the cubic volume in a single bag tells you how many bags to buy. Standard bags are typically sold as 2 cubic feet (about 56 litres), and most guides recommend a mulch depth of 2 to 4 inches (5–10 cm) for weed suppression and moisture retention without smothering plant roots.

Gardeners and landscapers run this calculation before a trip to the garden center because underestimating leaves a visibly thin, patchy bed and a second trip, while overestimating wastes money on bags that go unused — and depth matters more than most people expect, since doubling the depth doubles the volume and therefore the number of bags needed.

Bed area, the depth you want and the size of the bags on sale give the number of bags to buy, rounded up so you do not run out halfway through spreading.

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