Mulch calculator
Cubic yards, cubic metres and bags of mulch or bark
Type the size of the bed and how deep you want the mulch. The example is a 20 ft by 10 ft bed, 3 inches deep, in 2 cu ft bags.
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- Same volume, other units
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- Bags
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- Before the extra
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An estimate of quantity from the sizes you typed, not an order list or a price. Check structural work, and anything covered by a building code, with your local code or a qualified person.
How the amount is worked out
Volume is the area of the bed x the depth of mulch. Inches and millimetres are turned into feet and metres first: 3 inches is 0.25 ft and 75 mm is 0.075 m. The extra allowance is added, then the total is shown in cubic yards (US bulk), cubic metres (bulk elsewhere) and bags.
Bags
Bagged mulch is sold by volume: 2 or 3 cubic feet in the US, and 50, 60 or 70 litres in the UK and Australia. The number of bags is the total divided by one bag, rounded up. If your bag is a different size, choose Other and type it.
Worked example
A 20 ft x 10 ft bed, 3 in deep: 20 x 10 x 0.25 = 50 cu ft, which is 1.85 cu yd. Add 5%: 52.5 cu ft (1.94 cu yd). In 2 cu ft bags that is 26.25, so 27 bags.
Round beds and odd shapes
Choose Circle for a round bed and type its diameter. For other shapes, use the square footage calculator to add up the area, then type a length equal to that area and a width of 1.
What it leaves to you
It does not choose a depth for you. Garden advice on depth varies with the plant, the climate and the mulch, so follow the advice for your plants. Bulk mulch can also be fluffier or more packed than bags, so suppliers' cubic yards are not always exactly equal.
Defaults and where they come from
Every default is only a starting point. Change any box to match what you are buying or building.
| Default | Value | Source |
|---|---|---|
| US bag sizes | 2 cu ft (also 1.5 and 3 cu ft) | Sizes printed on US bagged mulch. Choose Other for any other size. |
| UK and Australian bag sizes | 50 litres (also 60 and 70 litres) | Sizes printed on UK and Australian bagged bark and mulch. Choose Other for any other size. |
| Extra allowance | 5% (usual 0 to 10%) | Common practice for settling and uneven beds. No standard sets a figure. |
| Conversions | 1 cu yd = 27 cu ft; 1 m³ = 1,000 litres; 1 cu ft = 28.3168 litres | Exact definitions. |