Gravel Density and Weight per Cubic Yard Explained
Core Metric & Standard Rule
Standard crushed stone aggregate has an industry benchmark bulk density of 105 pounds per cubic foot (1,680 kg/m³), which equals 2,832 pounds per cubic yard or 1.416 US short tons per cubic yard. Because dry aggregate contains 30% to 40% void space between angular stone particles, loose bulk density is substantially lower than solid rock density.
1. Bulk Density vs. Solid Specific Gravity
One of the most frequent misconceptions in landscape math is confusing the solid mineral density of rock with its loose bulk density. Solid limestone rock has a specific gravity of roughly 2.65, meaning a solid cubic foot without any air gaps weighs over 165 pounds.
However, when aggregate is blasted, crushed, and screened into standard stone sizes, the fragments tumble together loosely in a truck bed or stockpile. The air gaps between individual pieces are known as the void fraction. Under standard test specifications in ASTM C29 / C29M, loose aggregate typically has a void ratio between 32% and 42%.
Consequently, loose crushed gravel weighs only 100 to 115 pounds per cubic foot, depending on grading, stone mineralogy, and particle shape.
2. Material Density Comparison Chart
Different aggregate classifications have varying particle size distributions. Dense-graded aggregates (which combine stone fragments with fine stone dust) pack more tightly than clean, washed round gravel.
| Aggregate Type | Typical Particle Size | Bulk Density (lbs/cu ft) | Weight per Yard (lbs) | Tons per Cubic Yard |
|---|---|---|---|---|
| Clean Pea Gravel (#8) | 3/8 in rounded | 100 lbs/ft³ | 2,700 lbs | 1.350 tons |
| Standard Crushed Stone (#57) | 1/2 in to 1 in angular | 105 lbs/ft³ | 2,832 lbs | 1.416 tons |
| Dense Grader Crusher Run (ABC) | 3/4 in down to fines | 115 lbs/ft³ | 3,105 lbs | 1.553 tons |
| River Rock / Oversized Cobble | 1-1/2 in to 3 in rounded | 98 lbs/ft³ | 2,646 lbs | 1.323 tons |
| Heavy Basalt / Trap Rock | 1/2 in to 1 in angular | 110 lbs/ft³ | 2,970 lbs | 1.485 tons |
Density ranges derived from aggregate testing data published by the USGS National Minerals Information Center and standard state DOT material specification books.
3. Worked Example: French Drain Trench
Consider a residential foundation French drain requiring clean #57 crushed granite for subsurface water drainage around a basement wall.
Trench Specs: 40 feet length × 2 feet width × 18 inches depth
- Trench Cross-Section: 2 ft wide × 1.5 ft deep (18 in / 12) = 3 sq ft
- Total Trench Volume: 40 ft × 3 sq ft = 120 cubic feet
- Base Cubic Yards: 120 / 27 = 4.44 cubic yards
- Theoretical Base Weight: 4.44 cu yd × 1.416 tons/yd³ = 6.29 US short tons (12,580 lbs)
Applying the standard 10% safety buffer for trench irregularities:
- Buffered Volume = 120 × 1.10 = 132 cu ft = 4.89 cubic yards
- Buffered Delivery Weight = 4.89 × 1.416 = 6.92 short tons (13,840 lbs)
Verified in One Calculator vitest engine: 132 cu ft, 4.89 cu yd, 6.92 tons.
4. How Moisture Content Distorts Scale Tickets
Commercial quarries weigh outgoing haul trucks on platform vehicle scales certified under NIST Handbook 44. You pay for the gross weight of the truck minus the empty tare weight.
When gravel sits uncovered in a quarry stockpile during sustained heavy rain, porous aggregates (such as sandstone or vesicular volcanic rock) absorb water into internal pores, while all aggregates hold surface tension water in capillary voids. Surface moisture can add 3% to 7% extra weight to a load without adding any usable rock volume. If you purchase aggregate immediately following a storm, expect a slightly smaller volumetric yield per purchased ton.
5. Pitfalls in Quarry Weigh-Ins
Short Tons vs. Metric Tonnes Confusion
In US markets, a ton is 2,000 lbs (short ton). In Canada and international markets, aggregate is sold in metric tonnes (2,204.6 lbs / 1,000 kg). A metric tonne yields approximately 10% more volume than a US ton. Make sure your price quote specifies the exact unit.
Assuming Rounded Stones Pack Like Angular Stones
Smooth river gravel does not compact into void spaces the way angular crushed stone does. Angular stone has interlocking faces that create shear resistance under compaction. For a complete comparison, see our article on pea gravel vs. crushed stone differences.
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Sources & References
- ASTM International — ASTM C29 / C29M-17a: Standard Test Method for Bulk Density ("Unit Weight") and Voids in Aggregate. West Conshohocken, PA. Accessed October 11, 2026.
- US Geological Survey (USGS) — Crushed Stone Statistics and Information. National Minerals Information Center. Accessed October 11, 2026.
- National Institute of Standards and Technology (NIST) — Handbook 44: Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices. Accessed October 11, 2026.