Tank Drain Time Calculator
Calculate time to drain a tank through an orifice using Torricelli's law
About this calculator
The Tank Drain Time Calculator determines how long it takes to completely empty a tank through an orifice using Torricelli's law, which describes fluid flow under gravity. This tool is essential for engineers, farmers, and facility managers who need to plan drainage operations, design tank systems, or calculate emptying schedules. Whether you're working with water storage tanks, fuel tanks, or industrial vessels, accurate drain time calculations help optimize operations, prevent overflow situations, and ensure proper system design for various applications.
How to use
Enter your tank's dimensions (height, cross-sectional area) and the orifice specifications (diameter or area) into the calculator. The tool applies Torricelli's law to compute the drain time, accounting for the changing flow rate as the water level drops. Click calculate to get your result in minutes or hours.
Frequently asked questions
What is Torricelli's law and why is it used?
Torricelli's law describes the speed of fluid flowing from an orifice under gravity. It's used because flow rate decreases as tank height drops, requiring integration for accurate total drain time.
What factors affect tank drain time?
Tank height, cross-sectional area, orifice size, fluid viscosity, and gravitational acceleration all influence drain time. Larger orifices and smaller tank volumes result in faster drainage.
Does this calculator work for all fluid types?
The calculator works best for low-viscosity fluids like water. For thick fluids like oil or syrup, viscosity effects may require additional corrections for accurate results.