How Our Gravel Calculations Work

Every figure on this site comes from these formulas and assumptions. Nothing is hidden.

Volume

  • Rectangle area = length × width
  • Circle area = π × radius²
  • Direct entry = the square footage you enter
  • Depth in feet = depth in inches ÷ 12
  • Cubic feet = area × depth in feet
  • Cubic yards = cubic feet ÷ 27

When you add multiple areas, each area's volume is calculated and then summed before any density conversion.

Weight

Tons = cubic yards × material density (tons per cubic yard).

Extra material

  • Recommended cubic yards = cubic yards × (1 + extra% ÷ 100)
  • Recommended tons = tons × (1 + extra% ÷ 100)

The default allowance is 10% and is editable. Both the calculated and recommended amounts are always displayed.

Bag calculations

  • Volume-based bags: bags = recommended cubic feet ÷ bag cubic feet, rounded up
  • Weight-based bags: pounds = recommended tons × 2,000; bags = pounds ÷ bag weight, rounded up

The default standard bag is 0.5 cu. ft. Bag counts are always rounded up to the next whole bag. For large quantities the calculator leads with bulk delivery and keeps the bag equivalent as secondary information.

Rounding

  • Cubic yards and tons: 2 decimal places
  • Cubic feet: nearest whole cubic foot
  • Bags: always rounded up
  • Recommended tons are not rounded up to a full ton

Default densities

MaterialTons per cubic yard
General Gravel1.50
Crushed Stone1.50
Pea Gravel1.35
River Rock1.20
Limestone Gravel1.50
Custom densityWhatever you enter

Unit conversions

  • 1 m = 3.2808 ft; 1 m² = 10.7639 sq ft; 1 cm = 0.3937 in.
  • 1 cubic yard = 0.7646 cubic metres
  • 1 US ton = 0.9072 metric tonnes

Limitations

Actual gravel weight and required quantity can vary based on stone type, particle size, moisture, compaction, supplier, and site conditions:

  • stone size and gradation
  • material composition
  • moisture content
  • compaction
  • supplier-specific material
  • local site conditions

For purchasing, use your supplier's published density when available. These calculators provide estimates and are not engineering or construction-design advice.

Use the calculators

Apply these formulas with the main gravel calculator, the driveway gravel calculator, the gravel cost calculator, the gravel coverage calculator, or the tons to cubic yards converter.