About

Converting crushed stone from weight to volume involves more than just the density of the rock itself; it requires the bulk density, which accounts for the voids (air gaps) between the stones. A cubic meter of solid granite weighs significantly more than a cubic meter of crushed granite due to these spaces. This tool calculates the required volume for road base, drainage, or concrete mixing by applying bulk density factors for specific rock types (Granite, Limestone, Gravel). Accurate conversion prevents under-ordering when truckloads are sold by the ton but site requirements are measured in cubic meters.

Formulas

Volume is derived by dividing total mass by the bulk density of the aggregate.

V_bulk = Mρ_bulk

Note: ρ_bulk is typically 40-50% lower than the density of the solid rock due to air packing.

Reference Data

Material	Bulk Density kg/m³	Solid Density kg/m³	Void Ratio
Granite Crushed	1400	2700	~48%
Limestone Crushed	1275	2600	~51%
Gravel (Dry)	1450	2650	~45%
Basalt	1600	2900	~45%
Sandstone	1300	2400	~46%
Recycled Concrete	1100	2300	~52%
Slag	1750	2800	~38%
Clean Ballast	1500	2600	~42%

Frequently Asked Questions

Yes, but less than expected. While larger stones have larger individual voids, they also have less surface friction. However, "well-graded" aggregates (a mix of small and large sizes) pack much tighter, increasing density to ~1800 kg/m³ or more.

Granite is generally denser and harder than limestone. For the same volume, granite will weigh roughly 10-15% more. If you order 10 tons of each, you will get a smaller pile of granite compared to the limestone.

When stone is dumped from a truck, it is "loose". After you run a plate compactor over it for a driveway base, the volume decreases by 15-20% as voids collapse. Always order 15-20% extra volume if you plan to compact the material.

Yes, standard "Gravel" density (1450 kg/m³) is a close enough approximation for most rounded decorative river stones.