Gravel Calculator

How this calculator works

Volume = area x depth. Purchase volume = volume x (1 + waste / 100). Tonnes = purchase volume x density / 1000. Bags = round up(purchase volume x density / bag weight).

Worked example

A 5 m x 3 m driveway edge at 5 cm deep needs 0.75 m3, or 0.825 m3 with 10% waste - about 1.32 tonnes, or 53 bags at 25 kg each.

Assumptions to check

The area is a flat rectangle at a uniform depth.
Default density (1600 kg/m3) is a commonly quoted figure for compacted gravel; loose, coarse, or decorative aggregate density varies - use the supplier figure when known.
For bulk-bag or tonne-priced delivery, use the tonnes output directly instead of the bag count.

Read the calculation and QA methodology →

FAQ

How deep should a gravel driveway or path be?

A sub-base layer is often 50-100 mm and a decorative top dressing 25-50 mm - depth depends on use, traffic, and any sub-base already in place; check local guidance for your project.

Bags or bulk/tonne delivery - which is cheaper?

Bulk or bulk-bag delivery is usually cheaper per tonne for larger areas; small top-ups are often more practical by the bag. Use the tonnes output to compare bulk pricing.

Does density really vary that much?

Yes - loose gravel, crushed stone, and compacted sub-base materials can range roughly 1400-1800 kg/m3. Use the supplier-quoted density for the most accurate order.