Calculator

Tank Volume Calculator

Estimate rectangular tank capacity in US liquid gallons.

Tank Details

Uses the same dimension unit.
Uses the same dimension unit.
Optional. Leave blank if wall thickness should not be subtracted.
Assumptions
  • The result is based on US liquid gallons.
  • The tank is treated as square or rectangular.
  • When material thickness is provided, twice the converted thickness is subtracted from both length and width, matching the calculator specification.
  • The final result is rounded to the nearest whole gallon.
Disclaimer

This calculator provides an estimate for educational purposes only. It does not replace advice from specialists in tank design, installation, construction, or engineering.