How It Is Calculated
This calculator determines the volume, weight, and cost of gravel needed to cover a rectangular area. The calculation follows these steps:
- Compute the area in square feet: L × W, where L is length and W is width.
- Compute the volume in cubic feet: area × (D / 12), where D is depth in inches.
- Apply the waste factor: volumewaste = volume × (1 + F / 100), where F is the waste factor in percent.
- Convert to cubic yards: V = volumewaste / 27.
- Compute weight in tons: Wt = V × (ρ × 27 / 2000), where ρ is the density of the selected gravel type in lb/ft³.
- Compute material cost: C = Wt × P, where P is the price per ton.
V = L × W × (D / 12) × (1 + F / 100) / 27
Wt = V × (ρ × 27 / 2000)
C = Wt × P
Assumptions
- The area is rectangular and flat.
- Depth is uniform across the area.
- Gravel density values are typical averages for loose gravel; actual density may vary by moisture and compaction.
- Waste factor of 5% is typical for small projects; adjust as needed.
- Price per ton is for the gravel material only; delivery and taxes may be extra.
Worked Example
Suppose you have a patio that is 10 ft long and 10 ft wide, and you want a 3-inch layer of crushed stone (density 110 lb/ft³). You include a 5% waste factor, and the gravel costs $50 per ton.
- Area = 10 ft × 10 ft = 100 ft².
- Volume = 100 ft² × (3 in / 12) = 25 ft³.
- Volume with waste = 25 ft³ × (1 + 5/100) = 26.25 ft³.
- Cubic yards = 26.25 ft³ / 27 = 0.9722 yd³ ≈ 0.97 yd³.
- Weight = 0.9722 yd³ × (110 lb/ft³ × 27 / 2000) = 0.9722 × 1.485 = 1.443 tons ≈ 1.44 tons.
- Cost = 1.443 tons × $50/ton = $72.15 ≈ $72.
The results match the example: Gravel needed = 0.97 yd³, Weight = 1.44 tons, Material cost = $72.
Practical Tips
- Always measure the area carefully and add a waste factor to account for spillage and compaction.
- For irregular shapes, divide the area into rectangles and sum the volumes.
- If you need to order gravel for a large project, consider using the Stockpile volume and tonnage calculator to estimate stockpile quantities.
- For bulk material handling, the Bulk material weight and volume calculator can help convert between weight and volume for different materials.
- When planning a conveyor system for gravel, the Conveyor belt capacity calculator may be useful.
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