Build & renovate
Gravel & Aggregate Calculator
Area times depth gives volume; density turns it into the tonnes and bulk bags the merchant actually sells.
Calculator
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How it works
Typical densities: gravel 1.6 t/m3, sand 1.5, topsoil 1.2, bark 0.35. Paths want 40-50 mm of gravel; driveways 100-150 mm over a compacted sub-base. A "bulk bag" holds roughly 850 kg.
Frequently asked questions
How much gravel for a 20 m2 path?
At 50 mm deep: 1 m3, about 1.6 tonnes - two bulk bags with a little left over for topping up.
How deep should driveway gravel be?
100-150 mm of angular gravel over a compacted MOT Type 1 sub-base. Rounded pea gravel migrates - keep it to paths and borders.