About

Ordering crushed stone without precise volume-to-weight conversion leads to two outcomes: costly surplus sitting unused on site, or project delays from shortages requiring emergency deliveries at premium rates. This calculator converts geometric dimensions of your fill area into compacted volume, then applies material-specific bulk density (ρ) to produce tonnage. It accounts for the compaction factor (K_c), typically 1.20 - 1.30, because loose crushed stone occupies 20 - 30% more volume than its compacted state. The tool references density values per GOST 8267-93 and ASTM C33 standards for 15 aggregate types across common fraction sizes from 5 - 20mm to 40 - 70mm.

Approximation assumes uniform depth and homogeneous material. Real-world variance of ±5 - 10% is normal due to moisture content, irregular sub-grade, and fraction inconsistency. Always order 5 - 10% extra to absorb these tolerances. Pro tip: confirm the supplier quotes bulk density for the specific fraction you need. A 5 - 20mm granite fraction at 1.36t/m³ differs significantly from 40 - 70mm at 1.32t/m³.

Formulas

The loose volume of the fill area is computed from geometry. For a rectangular area:

V = L × W × D

For a cylindrical area:

V = π × r² × D

For a trapezoidal cross-section:

V = 12 × (a + b) × h × L

The compacted volume accounts for settlement and void reduction under load:

V_comp = V × K_c

Total weight required from the supplier:

W = V_comp × ρ

Number of truck deliveries:

N_trucks = ⌈ WC_truck ⌉

Where: L = length m, W = width m, D = depth m, r = radius m, a and b = parallel sides m, h = perpendicular height m, K_c = compaction factor (dimensionless, typically 1.0 - 1.30), ρ = bulk density t/m³, C_truck = truck payload capacity t.

Reference Data

Stone Type	Fraction Size	Bulk Density	Compaction Factor	Typical Use
Granite	5 - 20mm	1.36t/m³	1.26	Concrete mix, drainage
Granite	20 - 40mm	1.38t/m³	1.25	Foundation base, roads
Granite	40 - 70mm	1.32t/m³	1.22	Railroad ballast, embankments
Limestone	5 - 20mm	1.30t/m³	1.28	Landscape, light fills
Limestone	20 - 40mm	1.32t/m³	1.27	Driveway base, parking
Limestone	40 - 70mm	1.26t/m³	1.24	Erosion control, rip-rap
Gravel (natural)	5 - 20mm	1.60t/m³	1.20	Concrete aggregate
Gravel (natural)	20 - 40mm	1.55t/m³	1.18	Backfill, sub-base
Gabbro-Diabase	5 - 20mm	1.45t/m³	1.25	Asphalt mix, high-load roads
Gabbro-Diabase	20 - 40mm	1.43t/m³	1.24	Heavy foundation base
Dolomite	5 - 20mm	1.40t/m³	1.26	Decorative, garden paths
Dolomite	20 - 40mm	1.42t/m³	1.25	Drainage layers
Sandstone	5 - 20mm	1.30t/m³	1.30	Decorative fill, paths
Basalt	5 - 20mm	1.50t/m³	1.25	Road base, high-strength concrete
Basalt	20 - 40mm	1.48t/m³	1.23	Railway ballast, industrial paving
Slag (GBFS)	5 - 20mm	0.80t/m³	1.30	Lightweight fill, insulation base
Recycled Concrete	20 - 40mm	1.30t/m³	1.28	Temporary roads, eco-backfill
Marble Chips	5 - 10mm	1.50t/m³	1.20	Decorative landscaping
Quartzite	20 - 40mm	1.55t/m³	1.22	High-abrasion surfaces
Porphyry	5 - 20mm	1.45t/m³	1.24	Premium paving, plazas

Frequently Asked Questions

The compaction factor (K_c) multiplies the geometric volume to account for the stone settling when compacted by a plate compactor or roller. A K_c of 1.25 means you need 25% more loose material than the finished volume. Skipping this adjustment results in a layer thinner than designed, compromising load-bearing capacity. For foundation sub-bases under structures, GOST 8267-93 recommends K_c values of 1.25-1.30 for granite fractions 20-40 mm.

Smaller fractions (5-20 mm) pack more tightly, leaving fewer air voids between particles, which increases bulk density. Larger fractions (40-70 mm) create more inter-particle voids, reducing bulk density. For example, granite 5-20 mm has a bulk density of approximately 1.36 t/m³, while granite 40-70 mm drops to 1.32 t/m³. This 3% difference scales significantly on large orders - a 100 m³ project would see a 4-tonne difference.

Yes. Suppliers typically quote density for air-dry material (3-5% moisture). After rain or from wet stockpiles, moisture content can reach 7-10%, adding 5-8% to the delivered weight per truckload. This means you may receive fewer cubic meters per truck than expected. Confirm with the supplier whether they sell by weight (scale ticket) or by volume (bucket count). Weight-based purchasing is more accurate.

Granite has a Mohs hardness of 6-7 and compressive strength of 120-250 MPa, making it suitable for structural foundations, heavy-traffic roads, and concrete aggregate (M300+). Limestone (Mohs 3-4, 20-60 MPa) is adequate for light-duty paths, landscaping, drainage layers, and concrete up to M200. Granite costs 30-50% more but lasts significantly longer under cyclic loading. For driveways with vehicle traffic, granite 20-40 mm is the standard recommendation.

Standard dump trucks carry 10-15 tonnes. A KAMAZ-65115 carries 15 t, a small Isuzu/Hino carries 5-8 t, and articulated trailers carry 20-25 t. The calculator defaults to 15 t. Always confirm with your hauler - overloading beyond axle limits incurs fines and road damage liability. For large projects (100+ tonnes), negotiate bulk rates with the quarry for full trailer loads at 20-25 t.

Yes. Natural gravel (river-rounded) has a higher bulk density (1.55-1.60 t/m³) than crushed stone because rounded particles pack more efficiently. Select "Gravel (natural)" from the material dropdown. Note that natural gravel has a lower compaction factor (1.18-1.20) since it already packs well without as much settlement. The calculator adjusts both density and default compaction factor per material.

Add 5-10% for waste and spillage on any project. For irregular terrain (uneven sub-grade), add 10-15% because low spots consume more fill than average depth suggests. The calculator includes a surplus percentage input. A 5% surplus on a 50-tonne order adds 2.5 tonnes - roughly $50-75 in material cost - but avoids a $200+ emergency delivery charge for a shortfall.