Mulch and soil calculator: how much you need
Works out the volume of mulch or soil for a garden bed, and how many 30 L bags that is.
Calculator · Updated 15 October 2026
Enter the size of your garden bed and how deep you want the layer to see how many cubic metres, litres and 30 L bags you need.
The calculator
Your result
Volume needed: 0.90 m³
Volume needed
0.90 m³
- Volume
- 0.90 m³
- Litres
- 900 L
- Bags of 30 L
- 30
- Volume = length × width × depth. This is geometry only, so it doesn't allow for settling, uneven ground or waste.
- Bags are rounded up to whole 30 L bags. Check the bag size on the product, as some suppliers sell different sizes.
How this is worked out
- Volume in cubic metres = length (m) × width (m) × depth (mm ÷ 1000).
- Litres = cubic metres × 1,000.
- Bags = litres ÷ 30, rounded up to a whole bag.
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Find a providerFrequently asked questions
How deep should mulch be?
Most garden beds get a layer of about 50 to 75 mm. Keep it a little clear of plant stems and tree trunks so they don't stay damp.
Does the calculator allow for settling or waste?
No. It only multiplies length, width and depth. Mulch and soil can settle after you spread them and some is lost at the edges, so many people order a little extra. Your supplier can advise on how much.
How many cubic metres is a bag of mulch?
A 30 L bag is 0.03 cubic metres, so 33 bags make roughly one cubic metre. Check the size printed on the bag, as products differ.
Should I buy bags or bulk?
For small beds, bags are easier to carry and store. For larger areas, bulk delivery by the cubic metre is usually cheaper per litre, but you need somewhere to tip it. Compare quotes from garden suppliers or landscaping providers.
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Find a providerRelated
Updated 15 October 2026. An estimate is a starting point — compare quotes for the same scope.
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