Topsoil Quantity

Free Topsoil Quantity calculator with clear step-by-step results.

About Topsoil Quantity

Bed volume is length by width by depth, multiplied by the number of beds, with a settlement allowance because loose-delivered topsoil consolidates by 10-20% once watered and walked on. Mass is derived from bulk density since suppliers often sell by the tonne rather than by volume.

Formulas

Volume to order

m3 = length x width x depth x beds x (1 + settlement allowance)

Mass

Tonnes = volume m3 x bulk density t/m3

Worked example

With the default values below, Topsoil Quantity returns Topsoil to order of 4.968. Change any input above and every figure here is recalculated in your browser.

Inputs used

Bed lengthminimum 0.1 m: 6 m
Bed widthminimum 0.1 m: 1.2 m
Topsoil depthminimum 10 mm: 200 mm
Number of bedsaccepts 1–100: 3
Topsoil bulk densityaccepts 0.8–2 t/m3: 1.35 t/m3
Settlement allowanceaccepts 0–40 %: 15 %

Results

Topsoil to order: 4.968 m3
Equivalent mass: 6.71 t
Net volume of the beds: 4.320 m3
Bulk bags (0.6 m3 each): 9 bags

Step by step

1Values used
2Volume to order
3Mass
4Topsoil to order= 4.968 m3
5Equivalent mass= 6.71 t
6Net volume of the beds= 4.320 m3
7Bulk bags (0.6 m3 each)= 9 bags

Assumptions and limits

The result is derived only from the 6 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 3 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 topsoil be?

At least 150 mm for lawn, 200-300 mm for vegetable beds and 400 mm or more for deep-rooted shrubs. Raised beds over hard standing need the full rooting depth.

Why does bulk density vary?

Moisture and organic content. A wet mineral topsoil can exceed 1.6 t/m3 while a dry, peat-rich blend may be under 1.0, so ordering by tonne without knowing the density is risky.