Loose material compacts down — over-order a little so you don't run short.
Decorative gravels and shingles (typically 10mm and 20mm) are used for driveways, paths, borders and drainage. A 50mm topping is normal over a prepared base. Enter the area and depth to get the tonnage and number of bulk bags.
How to use this calculator
- Measure the area in square metres.
- Use 40–50mm depth for a decorative topping over a firm base.
- Little wastage is needed for clean decorative gravel.
- Get delivered quotes for the tonnes or bulk bags.
How we work this out
We take your area and finished depth, work out the volume in cubic metres, then convert to weight using a loose delivered density of 1.75 tonnes per cubic metre for Gravel / shingle 10-20mm — the figure used across the UK trade. The compaction and wastage allowance is added on top so you don’t run short. Bulk-bag counts assume a standard 850 kg dumpy bag.
Delivered densities and coverage vary with grade, moisture and how hard the material is compacted, so these figures are a working estimate to size your order — always confirm the exact quantity and price with your supplier before buying. Our team reviews the density figures and guidance periodically; this page was last reviewed on 12 July 2026.
Frequently asked
How deep should decorative gravel be?
A 40–50mm topping over a compacted, weed-membraned base gives good coverage without stones scattering.
How much gravel per square metre?
At 50mm depth, roughly 0.09 tonnes (about 90kg) of gravel per square metre.