Planning
Gravel Depth Guide: How Deep Should Gravel Be?
Gravel depth is the single biggest factor in how much material you need — and whether the surface holds up. Here are recommended depths for every common project, from a 2-inch garden bed to a 12-inch driveway base.
Recommended gravel depth by project
| Project | Recommended depth | Notes |
|---|---|---|
| Garden / planting bed | 2–3 in (5–7.5 cm) | Decorative mulch layer over soil or fabric |
| Walkway / path | 2–4 in (5–10 cm) | Deeper if it carries a wheelbarrow or cart |
| Patio base (under pavers) | 4–6 in (10–15 cm) | Compacted crushed stone, plus bedding sand |
| Driveway top layer | 2–3 in (5–7.5 cm) | Driving surface over the base |
| Driveway total base | 8–12 in (20–30 cm) | All layers combined; deeper on soft soil |
| Shed / building base | 4–6 in (10–15 cm) | Compacted 3/4 in crushed stone in a frame |
| French drain | Fills the trench | Depends on trench size around the pipe |
Why depth matters
Too shallow and the gravel shifts, scatters and lets weeds or mud through. Too deep and you've spent money on stone that does nothing. The right depth gives enough material to spread the load, drain water and stay put without waste. Heavier traffic and softer ground both call for more depth.
Don't forget compaction
Crushed stone loses 15–20% of its loose depth once compacted. If you want a finished 4-inch base, spread closer to 5 inches loose and compact it down. Order about 5–10% extra material to cover compaction and settling.
Build deep layers in lifts
For anything thicker than about 4 inches — like a driveway or shed base — add and compact the gravel in lifts of 3–4 inches at a time. Compacting one thick layer won't firm up the bottom, and the surface will settle unevenly later.
Estimate any depth instantly with the main Gravel Calculator, or use the project-specific driveway, patio and French drain calculators.
Frequently asked questions
How deep should gravel be?
It depends on the job: 2–3 inches for garden beds, 2–4 inches for walkways, 4–6 inches for a patio or shed base, and 8–12 inches total for a driveway. Deeper is needed for heavier traffic or soft ground.
How deep should gravel be for a driveway?
Plan on 8–12 inches (20–30 cm) of total gravel built in layers, with a 2–3 inch top driving layer over a compacted base. Use the deeper end for heavy vehicles or clay soils.
How deep should gravel be under pavers?
A paver patio or path needs about 4–6 inches of compacted crushed-stone base, plus roughly 1 inch of bedding sand on top before the pavers.
How much extra gravel should I order for compaction?
Add about 5–10%. Crushed stone loses roughly 15–20% of its loose depth when compacted, so spreading a little extra ensures you hit your finished depth.
Disclaimer: This guide gives general estimates for planning. Actual gravel quantities, weights and prices vary with material type, particle size, moisture, compaction, supplier and your province. Costs are material-only ballparks in Canadian dollars and exclude labour, delivery and taxes unless stated. Always confirm quantities and prices with your local supplier.