Formulas and calculation methodology

Geometric tank volume is computed using standard stereometric formulas:

  • Rectangular & Cube: Volume = (Length × Width × Height) ÷ 231 (in inches to US Gallons) or ÷ 1000 (in cm to Liters).
  • Cylinder: Volume = (π × Radius² × Height) ÷ 231 (gallons).
  • Bowfront: Volume = [Length × (Width Side + Width Center) / 2 × Height] ÷ 231.
  • Substrate Displacement: Substrate grains have an average packing porosity of 35–40%, meaning 60–65% of the substrate layer volume physically displaces water.

Explore our other free tools: check biological safety ranges with the Water Parameter Safety Checker, calculate maintenance needs with the Water Change Calculator, or browse the Species Care Guides.