Garden guide
What Depth of Gravel Does a Driveway Need?
The short version
On a driveway carrying cars, loose gravel needs to be about 10cm deep over a compacted sub-base. Laid over gravel grids, 3–4cm is enough — the grids do the structural work. Footpaths and decorative areas only need 4–5cm.
The full build-up
A lasting gravel driveway is a sandwich: dig out, compact 10cm of MOT type 1 sub-base, lay a heavy-duty weed membrane, then add your gravel. Skip the sub-base and the stones simply sink into soft ground within a season or two.
Why the depth matters
Too thin and the sub-base shows through in bald patches while tyres carve straight down to it. Too deep and it's like driving on a shingle beach — wheels spin, stones fly, and walking across it becomes hard work. The 10cm figure is the sweet spot for loose gravel under cars.
Size and shape count too
Choose 10–20mm angular chippings for driveways — 20mm stays put best under tyres. Avoid rounded pea gravel for trafficked areas: the stones roll against each other and migrate to the edges no matter how deep you lay them.
Working out what to order
Area (m²) × depth (cm) × 10 = litres needed. A bulk bag (about 730L, roughly 850kg) covers around 7m² at 10cm deep. Our gravel calculator does the maths, prices bulk against handy bags, and can add stabilising grids and membrane to your list in one click.