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Crushed Stone Calculator

Calculate cubic yards and tons of #57 crushed stone and angular aggregate for French drain trenches, concrete slab bases, shed foundations, and retaining wall backfill.

Engineering Principles of Crushed Stone

Unlike rounded gravel, crushed stone is produced by mining solid rock ledges (such as limestone, dolomite, or granite) and feeding it through industrial jaw crushers. The resulting stones have fractured, razor-sharp facets that interlock with exceptional friction.

The most widely specified size in construction is ASTM #57 crushed stone (approximately 1/2" to 1" angular stone). Because #57 stone is screened and washed to eliminate powdery stone dust, it leaves approximately 40% open void space between stones. This gives it the highest water permeability of any structural aggregate.

Crushed Stone Volume & Weight Formula: 1. Area (sq ft) = Trench/Pad Length (ft) × Width (ft)
2. Depth in Feet = Depth (inches) ÷ 12
3. Volume (cu ft) = Area × Depth in Feet
4. Cubic Yards = Volume (cu ft) ÷ 27
5. Weight (Tons) = Cubic Yards × 1.35 tons/yd³

Worked Example: 60-Foot French Drain Trench

Project: 60 ft Long Trench × 1.5 ft Wide × 18 Inches Deep (1.5 ft)
  1. Calculate Trench Cross-Section: 1.5 ft wide × 1.5 ft deep = 2.25 sq ft.
  2. Multiply by Length: 2.25 sq ft × 60 ft = 135 cubic feet.
  3. Convert to Cubic Yards: 135 cu ft ÷ 27 = 5.00 cubic yards.
  4. Apply 10% Ordering Adjustment: 5.00 yd³ × 1.10 = 5.50 recommended cubic yards (+0.50 yd³ allowance for trench sidewall irregularities and interlock).
  5. Calculate Tonnage (#57 Stone @ 1.35 tons/yd³): 5.50 yd³ × 1.35 tons = 7.43 tons (14,850 lbs).

Top Applications for Clean Angular Stone

  • Concrete Slab Sub-Bases: Poured concrete needs a stable, non-yielding base that will not retain ground moisture. A 4-inch layer of clean crushed stone acts as a capillary break, stopping moisture from wicking up through the concrete.
  • Retaining Wall Drainage Backfill: Retaining walls collapse when soil behind them becomes waterlogged, creating massive hydrostatic pressure. Filling a 12" to 24" vertical chimney behind the wall with clean #57 stone directs water harmlessly down to base weep holes.
  • French Drains and Swales: Clean stone surrounds perforated collection pipes without clogging them with mud. Always wrap the entire stone trench in non-woven drainage filter fabric (an envelope style) before backfilling with topsoil.
French drain cross-section diagram showing perforated pipe, clean washed stone, and geotextile filter fabric wrap
French drain engineering cross-section: perforated pipe encased in washed #57 stone and wrapped in filter fabric.

Frequently Asked Questions About Crushed Stone

#57 stone is an ASTM standard aggregate size ranging from 1/2 inch to 1 inch (averaging approximately 3/4 inch). It is mechanically crushed angular limestone, granite, or trap rock that has been washed to remove fine dust, allowing rapid water drainage and strong inter-particle friction.

A cubic yard of clean #57 crushed stone weighs approximately 2,700 pounds, or 1.35 US short tons. One ton equals approximately 0.74 cubic yards.

Gravel is naturally rounded stone shaped by river currents and glacial weathering. Crushed stone is produced in a quarry by mechanically blasting and crushing solid ledge rock, giving every piece sharp, angular edges that lock together under load.

French drains require high void ratios so water can enter the perforated pipe quickly. Clean #57 stone has no stone dust or dirt fines, leaving clear channels for water flow. Dense-grade gravel contains fines that would clog the drainage pipe and filter fabric.

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