How deep should gravel be?
Last reviewed 1 July 2026
Short answer
40–50 mm (about 2 in) for decorative areas and paths, and 50–75 mm (2–3 in) of surface gravel for a driveway laid over a properly compacted 100–150 mm sub-base. Deeper is not better on a footpath — beyond about 75 mm loose gravel becomes hard work to walk on and starts behaving like dry sand.
Work it out for your project with the gravel calculator →
Depth by use
| Use | Metric | Imperial | What goes underneath |
|---|---|---|---|
| Decorative border | 30–40 mm | 1¼–1½ in | Weed membrane over firm soil |
| Garden path, foot traffic | 40–50 mm | 1½–2 in | Weed membrane, or 50 mm sub-base on soft ground |
| Path over soft or wet ground | 50 mm | 2 in | 75–100 mm compacted sub-base |
| Car driveway surface | 50–75 mm | 2–3 in | 150 mm compacted sub-base |
| Driveway with heavy vehicles | 75 mm | 3 in | 200 mm compacted sub-base |
| Shed or bin-store base | 50 mm | 2 in | 100 mm compacted sub-base |
Why deeper is worse for walking
Loose gravel supports you because the particles below the surface are confined by the ones around them. The thicker the loose layer, the less confinement there is near the surface, and the more your foot sinks.
Above about 75 mm you get the beach effect: every step displaces material, pushing gravel to the edges and leaving ruts. On a driveway that shows up as tyre tracks within weeks.
The answer to a soft gravel surface is almost never more gravel. It is a properly compacted sub-base, angular rather than rounded stone, and edge restraint.
What the sub-base is for
The sub-base spreads load and stops the surface gravel being pushed into the subsoil. Without it, a driveway's gravel gradually disappears into the ground — it has not washed away, it has been pumped into the clay beneath.
MOT Type 1 in the UK, or dense graded base in the US, laid and compacted in layers of no more than 100 mm. It is the layer that does the structural work; the gravel on top is largely cosmetic and for drainage.
Important: Order 30% more sub-base than the finished depth
Choosing the stone itself
- Angular chippings interlock and stay put. The right choice for anything trafficked.
- Rounded pea gravel is comfortable underfoot and looks softer, but it rolls. Avoid it on slopes and driveways.
- Size. 10–20 mm is the practical range. Smaller gets carried indoors on shoes; larger is uncomfortable to walk on.
- Edging. Whatever you choose, restrain the edges. Gravel without edging is a maintenance commitment.
Safety notice: Material planning only