Driveway Gravel Calculator

The sub-base carries the load, not the gravel.

The sub-base carries the load, not the gravel. Gravel for a driveway by volume and weight, at the depth and density you specify.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Area to cover

m²

Depth

Waste and settlement

Density of gravel

kg/m³

Varies a great deal with moisture and grade — check the supplier's figure

Bag size

Cost per bag

Gravel required

2.1 m³

3.15 tonnes · 2.75 cubic yards

Volume2 m³

With 5% allowance2.1 m³

Weight3.15 tonnes

In cubic yards2.747

Bulk bags (about 0.6 m³ each)3.5

One cubic metre covers, at 100 mm10 m²

Gravel needs a depth that holds together under load, and a sub-base under it that carries the load rather than the gravel doing so. A single deep layer of loose gravel rutted by tyres is the usual failure — a compacted sub-base with a shallower wearing layer performs far better and uses less material overall.

How the Driveway Gravel Calculator works

Gravel for a driveway by volume and weight, at the depth and density you specify. Depth matters, and so does what is underneath it — a deep loose layer over soft ground ruts rather than holding.

Also known as: how much gravel for a driveway · driveway stone tonnage calculator · gravel depth for a drive · chippings quantity calculator

The sub-base carries the load

A driveway's strength comes from a compacted layer of graded crushed stone spreading the load over the subsoil. The gravel on top is a wearing surface, not a structure — a deep loose layer with nothing beneath it simply ruts.

Typical construction is 100 to 150 mm of compacted sub-base for cars, more over soft ground, with a 50 to 100 mm wearing layer above. It should be laid and compacted in layers rather than in one lift, because a thick lift does not compact through its depth.

That means the total material is more than the visible depth suggests, and the two layers are different products. Ordering the whole depth as decorative gravel produces a driveway that looks right for a month.

Stone shape, edges and migration

Angular 10 to 20 mm aggregate locks together under load and stays put. Rounded pea gravel of the same size rolls, migrates under tyres, and ends up in ridges at the edges and on the lawn.

Edge restraint is the other half. A driveway with nothing containing its sides loses material outwards continuously, no matter how much is added, which is why some drives seem to need topping up every year and others do not.

A geotextile membrane between sub-base and subsoil stops the two mixing. Without it the stone gradually works down into soft ground and the ground works up into the stone, which is what makes a drive sink progressively rather than suddenly.

Drainage and permission

Gravel drains through itself provided the sub-base does, which is its main advantage over a sealed surface. Where the subsoil is impermeable, the water has to go somewhere and a channel or soakaway becomes necessary.

That permeability has a regulatory dimension in several jurisdictions, where a permeable surface is permitted development and an impermeable one over a threshold area is not. It is worth checking locally before choosing a surface.

The maintenance trade is real. Gravel is far cheaper in materials than paving and needs occasional topping up, raking and weed control. Over a decade the gap narrows, particularly where the sub-base was skimped and eventually needs redoing.

Where to go next

The Driveway Gravel question rarely arrives on its own. These are the ones that usually come with it:

Paver Calculator — Bedding sand is screeded, never used to fix levels.
Sand Calculator — Wet sand weighs 20% more than dry for the same volume.
Concrete Slab Calculator — Dry materials occupy 54% more than the wet mix.
Ring Size Calculator — Finger measurement to US, UK, EU and Japanese sizes.

Frequently asked questions

How deep should a gravel driveway be?

The wearing layer is typically 50 to 100 mm over a compacted sub-base of 100 to 150 mm. A single deep layer of loose gravel with no sub-base is the usual failure, because the load goes straight into the soil.

How much gravel do I need per square metre?

One cubic metre covers 20 m² at 50 mm depth or 10 m² at 100 mm. Multiply by the density (around 1,500 kg/m³ for most aggregate) to get the tonnage suppliers quote.

What gravel size is best for a driveway?

Angular 10 to 20 mm aggregate locks together and stays put. Rounded pea gravel of the same size migrates under tyres and ends up in ridges and on the lawn.

Do I need a membrane?

A geotextile between sub-base and subsoil stops the two mixing, which is what causes gradual sinking. It is inexpensive and it is the difference between a driveway that lasts and one that needs topping up annually.

Why does my gravel keep migrating?

Usually rounded stone, insufficient depth, or no edge restraint. A driveway with nothing containing the sides loses material outwards no matter how much is added.

Is gravel cheaper than paving?

Substantially in materials, and it needs ongoing topping up and weeding. Over ten years the gap narrows considerably, particularly if the sub-base was skimped and needs redoing.

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