How the planner works
A gravel driveway is built in layers. A compacted sub-base carries the weight of cars. A membrane stops the layers mixing with the soil and slows weeds. The top gravel is the surface you see. Edging keeps the gravel in place. The planner works out each layer separately, because each is a different stone, depth and price.
stone volume = length × width × depth × (1 + compaction %) × (1 + waste %)
weight = volume × density (low to high for the stone you chose)
membrane strips = 1 + ⌈(width − roll width) ÷ (roll width − overlap)⌉; fabric = strips × length
edging = 2 × length (+ width if you edge the far end)
Worked examples
UK drive, 10 × 3 m: 150 mm of MOT Type 1 plus 10% compaction = 4.95 m³, which weighs 7.9–9.9 tonnes, or about 12 bulk bags of 850 kg. Then 50 mm of crushed stone with 10% compaction and 5% waste = 1.73 m³, which weighs 2.8–3.1 tonnes (4 bulk bags). Membrane with 2.25 m rolls and 300 mm overlaps: 2 strips × 10 m = 20 m, so 1 roll. Edging both sides: 20 m.
US driveway, 50 × 10 ft: 6 in of road base + 10% = 10.2 yd³ (13.7–17.2 US tons), and 2 in of #57 crushed stone + 15% = 3.6 yd³ (4.8–5.3 US tons). Edging both sides: 100 ft.
The assumptions, in plain words
- Depths are finished, compacted depths. The compaction allowance turns them into the loose stone you order.
- Weights are ranges, from published densities for each stone type. Buying by weight? Order the top figure. Wet stone weighs about 6% more.
- Bulk bags are 850 kg, the common UK size. Some suppliers sell 1-tonne bags, so check yours.
- Membrane strips run along the length and overlap side by side. We don't add extra for turning the fabric up at the edges. Add a little if you plan to.
- A rectangular drive. For L-shapes or curves, plan each straight section separately and add each one to your project.
Common mistakes to avoid
- Ordering only the top gravel. The sub-base is usually two to three times as much stone.
- Forgetting compaction. Rolled stone ends up thinner than it was delivered, so keep the allowance.
- Butting membrane strips together. Strips must overlap, or the stone and weeds get through the gaps.
- Mixing up tonnes and US tons. A US ton is 0.907 tonnes.
Measuring an awkward shape? See how to measure an irregular area.
Frequently asked questions
How deep should a gravel driveway be?
UK guides suggest a compacted sub-base of MOT Type 1 at least 100 mm deep (150 mm is preferred for cars), with about 50 mm of gravel on top: roughly 200 mm in total. US guides commonly suggest 4–6 inches of compacted base (crusher run or road base) under 2–3 inches of #57 crushed stone. Soft or clay ground may need a deeper base. Ask a local contractor if you are unsure.
Do I need a membrane under a gravel driveway?
Most guides recommend one. A geotextile membrane stops the stone sinking into the soil and slows weeds. Lay it in strips that overlap. Sources suggest 150–300 mm, and we use 300 mm by default so you buy enough.
Why is the sub-base more than the depth × area?
Loose stone compacts when it is rolled or plate-compacted, so you need more loose material than the finished depth. We add 10% for compaction by default. You can change it.
Should I buy bags or a bulk delivery?
For a whole driveway, bulk is usually cheaper. But that depends on your local prices and delivery charge, so open "Bags or bulk?" and type in the prices you've been quoted. We never guess prices. In the UK, loose stone is often sold in bulk bags of about 850 kg.
What edging do I need?
Edging stops gravel spreading onto lawns and borders. The planner gives you the length to buy. Choose a product (timber, steel, plastic or kerb) and check how long each piece is.
Sources
- Mainland Aggregates: Driveway construction guide (sub-base 100 mm minimum, 150 mm preferred)
- Homebuilding & Renovating: How to lay a gravel driveway
- GCL Products: How to lay a gravel driveway
- Hellogravel: Best gravel for driveways (base and top layers, US)
- Vertigraph: Gravel tonnage (crushed stone, road base densities)
- Calcforlife: MOT Type 1 calculator UK (loose density)
- Materials Market: 2.25 m × 50 m geotextile membrane
- Drainage Superstore: Landscaping fabrics buyer’s guide (overlaps)
Last updated 11 November 2026. Found a mistake? Tell us.