Gardening
Raised Bed Soil Calculator
Enter bed length, width and fill depth to see cubic metres, litres, bags and optional cost.
How much soil for a raised bed?
Raised beds are filled to a chosen depth rather than lightly top-dressing existing ground, so volume is simply length × width × fill depth. Convert that cubic volume to litres (1 m³ = 1,000 L) and divide by the bag size printed on the compost or topsoil you are buying, rounding up to whole bags. A settling allowance of around 10% helps after the first watering when fine mixes compact. Deeper beds for root crops need more soil than a shallow herb trough of the same footprint — that depth emphasis is what separates this tool from a general garden soil top-up. Pair planting density with the vegetable plant population calculator, and feed established beds with the fertilizer tool once soil is in place.
Worked example
A 2.4 × 1.2 m bed filled 30 cm deep is 0.864 m³ ≈ 864 L. With 10% extra ≈ 950 L. At 50 L per bag that is 19 bags.
Limits and assumptions
Does not model layered builds (drainage gravel under topsoil) separately — enter the fill depth you will actually buy as soil/compost. Bulk loose loads are often cheaper than bags above ~1 m³.
Frequently asked questions
How deep should a raised bed be?
Many vegetable beds run 20–40 cm of growing medium; deep-root crops and permanent beds often aim higher. Match depth to what you intend to grow.
Can I mix bag sizes?
Work in total litres needed, then buy a mix of bag sizes that sum to at least that volume.
Does timber bed volume include the walls?
Measure internal length and width only — the boards are not filled.
Why is this different from the garden soil tool?
Same volume maths, but this page is framed for raised-bed fill depth and settling when you are building or refilling a box.