# Mulch Calculator

> Work out how much mulch or bark to buy for a garden bed from its length, width and depth, in cubic metres, litres, cubic yards and bags.

Category: Everyday tools · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/mulch-calculator

Mulch volume is simply the bed’s area times the depth you want. Convert that to the units your supplier sells in: bulk cubic yards or metres, or bags.

Also called: Bark calculator, Garden mulch calculator.

## Inputs
- Units (options: Metric (m, cm), Imperial (ft, in); default metric)
- Bed length (default 5)
- Bed width (default 4)
- Depth (default 7.5)
- Bag size (default 50)
- Bag size in (options: Litres, Cubic feet; default l)

## Results
- Mulch needed
- Mulch needed
- Mulch needed
- Mulch needed
- Bags

## Formula

```
Volume = Length × Width × Depth;  Bags = Volume ÷ Bag size, rounded up;  1 yd³ = 27 ft³ = 0.7646 m³
```

Where:
- Depth: thickness of the mulch layer (converted from cm or inches)
- Bag size: volume printed on the bag

## Worked example
1. Area = 5 × 4 = 20 m². Depth 7.5 cm = 0.075 m.
2. Volume = 20 × 0.075 = 1.5 m³ = 1,500 litres.
3. 1,500 ÷ 50 L per bag = 30 bags.

**Result:** A 5 × 4 m bed mulched 7.5 cm deep needs 1.5 m³ (about 1.96 yd³), or 30 bags of 50 litres.

## What the result means

For larger beds, bulk delivery by the cubic metre or yard is usually cheaper than bags. Fresh mulch settles, so some gardeners add a little extra.

## Assumptions and limits
- A rectangular bed of even depth. For irregular beds, measure the area another way and use length = area and width = 1.
- Mulch compacts and settles over time; the volume is for the loose material at the depth entered.

## Questions

### How deep should mulch be?

Garden guidance commonly suggests about 5–8 cm (2–3 in) for beds. Keep mulch pulled back from plant stems and tree trunks.

### How many 2 cubic foot bags make a cubic yard?

A cubic yard is 27 ft³, so 13.5 bags; in practice buy 14.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/mulch-calculator