Measure & Make
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Garden projects

The right amount of gravel.

Turn an area and depth into cubic metres, estimated tonnes and bags. Change the density and bag sizes to match your supplier.

For a level gravel layer. Density is an estimate until confirmed for the product you will order.

1. Your measurements

Where should I measure?
Area measurements are in metres and the gravel layer depth is entered in millimetres.Length × width = areaDepth (mm)Volume = area × depth ÷ 1,000
Area measurements are in metres and the gravel layer depth is entered in millimetres.

Read the gravel measurement guide ↗

m
m
mm
Measure the gravel layer only, excluding any sub-base.
Allowances & stock sizes
kg/m³
Example only. Replace with your supplier’s density.
kg
kg
%

2. Your plan

Example estimate

Estimate

Project layout

Layout sketch · not an installation drawing

Your materials

    A look at the numbers

    What’s behind your estimate?

    How the weight is estimated

    For a rectangle, area = length × width. For a circle, area = π × (diameter ÷ 2)². Volume = area × depth in metres. We add your extra percentage to the volume, then multiply by your entered bulk density to estimate kilograms.

    Bulk density includes the spaces between pieces. It differs from the solid-rock density and varies by material, grading and moisture.

    Bulk bags or small bags?

    Each count is a separate way to buy the full quantity, rounded up. For example, 1,320 kg needs either two 850 kg bulk bags or fifty-three 25 kg bags. It does not mean buying both.

    Worked example

    A 5 × 3 m area at 50 mm depth needs 0.75 m³. With 10% extra, the volume is 0.825 m³. At the example density of 1,600 kg/m³, that is 1,320 kg or 1.32 tonnes: two 850 kg bags, or fifty-three 25 kg bags.

    Check the product listing

    Example supplier bag sizes — a supplier reference, not a product endorsement.

    Bag weights and coverage vary. Confirm the product’s density, intended depth and actual bag weight before ordering.