Garden Bed Soil Volume Calculator

Work out garden bed soil volume instantly with clear inputs, formula shown and shareable results.

About Garden Bed Soil Volume Calculator

Bed volume is length times width times depth, plus a settling allowance because fresh compost and topsoil compact by 10-20% after watering. Buying by the cubic metre in bulk is typically a third the cost of the same volume in 50 litre bags.

Formula

Soil volume

volume = length x width x depth x (1 + settling allowance)

Worked example

With the default values below, Garden Bed Soil Volume Calculator returns Soil required of 0.99. Change any input above and every figure here is recalculated in your browser.

Inputs used

Bed length: 2.4 m
Bed width: 1.2 m
Soil depth: 30 cm
Settling allowance: 15 %

Results

Soil required: 0.99 m³
Soil required: 994 L
50 litre bags: 20 bags
Approximate weight: 1.19 t

Step by step

1Values used
2Soil volume
3Soil required= 0.99 m³
4Soil required= 994 L
550 litre bags= 20 bags
6Approximate weight= 1.19 t

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How deep should a raised bed be?

20 cm for salads and herbs, 30 cm for most vegetables, and 45 cm or more for root crops and permanent planting.

Why does soil settle so much?

Bagged compost is aerated and dry. Watering collapses the air voids, and organic matter continues to decompose, so topping up each season is normal.