Gravel Calculator
Estimate volume, weight, and cost. Mass↔Volume price auto-convert via density.
  Gravel Specification
    
    
    
    
      Using density: —
    
    How much gravel do I need?
    Enter the dimensions of the rectangular area you want to fill with gravel.
    
    Area auto-calculates from Length×Width, or you can enter it directly.
    How much will the gravel cost me?
    —
      Edit either price; the other updates automatically using the current density & units.
  Step-by-step derivation
    —
  References
    - Area: A = length × width
- Volume: V = A × depth
- Weight: W = ρ × V
- Price coupling: (Currency/vol) = (Currency/mass) × ρ, with proper unit conversions
