Types of Gravel for Driveways

The main types of gravel for driveways do different jobs: angular crushed stone with fines makes a firm base, clean crushed stone makes a surface that drains, and rounded stone such as pea gravel suits paths better than drives. This guide compares crushed stone, Class 5 and road base, ballast, pea gravel, river rock, decomposed granite and crushed concrete, with the planning densities the calculators use for each.

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Crushed stone (#57): the usual surface layer

#57 is a common US size of clean, angular crushed stone, roughly an inch and smaller, with the dust screened out. The sharp edges lock together under traffic for grip, and the gaps between stones let water drain through. It is a typical choice for the top 2 to 3 inches of a drive. Planning density: 1.40 tons per cubic yard, the calculators’ default.

Class 5, road base and crusher run: the base layer

These are mixes of angular crushed rock with smaller pieces and stone dust. Names depend on the region: crusher run, dense grade aggregate (DGA), quarry process, road base, and Class 5 in some US states. When wetted and compacted, the fines fill the gaps between larger stones and the layer becomes firm, which is why it is used under the surface layer. Planning density: 1.50 tons per cubic yard. The driveway base gravel calculator uses it by default.

Large ballast rock

Larger crushed stone, sold under names such as #3 or #4, is sometimes laid first on soft or wet ground to bridge it before the base layer goes on. Whether you need it is a site-specific question for a local contractor. The calculators have no preset for it; enter your supplier’s density.

Pea gravel: paths, patios and borders

Pea gravel is small, smooth, rounded stone. It looks good and is comfortable underfoot, but the round stones roll rather than lock together, so on a drive it tends to shift under tyres and spread into lawns. It is usually chosen for paths, patios, play areas and borders rather than the main driving surface. Planning density: 1.35 tons per cubic yard. Size a project with the pea gravel calculator, which also counts bags.

River rock and round gravel

Rounded stones in larger sizes are mostly used for drainage areas, edging and decoration. Like pea gravel, they do not lock together well under vehicles. Planning density: 1.45 tons per cubic yard.

Decomposed granite

Decomposed granite is granite weathered down to fine particles and small grains. It packs into a firm, natural-looking surface and is popular for paths and some drives, especially in dry climates. Some products include a stabilizer to help it resist washing out. Planning density: 1.30 tons per cubic yard.

Crushed concrete (recycled aggregate)

Crushed concrete is old concrete broken and screened into aggregate. Graded with fines, it is used much like road base. Quality varies more than quarried stone: ask what it was made from, how it was screened, and whether metal and other debris have been removed.

How much does a yard of crushed concrete weigh? It depends on the source and grading. This site uses 1.30 tons (2,600 pounds) per cubic yard as a rough placeholder value until a better figure is available, so your supplier’s figure matters more than usual here. How much crushed concrete do I need? Work it out like any driveway layer: choose “Crushed concrete (recycled)” in the gravel driveway calculator or the tons to cubic yards calculator, then replace the density with your supplier’s.

Planning densities used by the calculators

Planning densities for common gravel types

Material	Tons per yd³	Pounds per yd³	Cubic yards per ton	Tonnes per m³	Cubic metres per tonne
Crushed stone (#57)	1.40	2,800	0.71	1.66	0.60
Class 5 / road base / crusher run	1.50	3,000	0.67	1.78	0.56
Pea gravel	1.35	2,700	0.74	1.60	0.62
River rock / round gravel	1.45	2,900	0.69	1.72	0.58
Decomposed granite	1.30	2,600	0.77	1.54	0.65
Crushed concrete (recycled) *	1.30	2,600	0.77	1.54	0.65

These are typical starting values to plan with, not measured or standard figures. The how many yards in a ton of gravel guide turns them into tons-to-yards tables.

Which gravel for which layer?

Driveway gravel compared

Material	Stone shape	Compacts firmly?	Drains?	Typical use
Crushed stone (#57)	Angular, no fines	Locks together	Well	Surface layer
Class 5 / road base / crusher run	Angular with fines	Yes	Less freely	Base layer
Large ballast	Large, angular	Bridges soft ground	Well	Bottom layer on soft ground
Pea gravel	Small, rounded	No, rolls	Well	Paths, patios, borders
River rock	Larger, rounded	No	Well	Drainage, edging, decoration
Decomposed granite	Fine grains	Yes	Moderately	Paths, rustic drives
Crushed concrete	Angular, varies	Yes, when graded with fines	Varies	Base layer

Related guides

• Gravel driveway depth: how thick each layer is usually planned.
• Gravel driveway cost: what to ask when you get quotes for these materials.