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Mihsaba›Torricelli’s Law Calculator

Torricelli’s Law Calculator

Calculate ideal efflux velocity from liquid head and volumetric flow rate from the opening area using Torricelli’s law.

Ideal model: contraction, viscosity and losses are ignored, so real discharge is often lower.

How to use

Torricelli’s law links liquid head above an opening to ideal exit speed. Adding opening area converts that speed into volumetric flow.

  1. Enter vertical liquid head h.
  2. Enter gravity or keep Earth gravity.
  3. Enter opening area.
  4. Review exit speed and flow rate.

How it is calculated

v=√(2gh); Q=Av

Example

At h=2 m under Earth gravity, ideal exit speed is about 6.26 m/s. A 0.001 m² opening gives about 6.26 L/s ideal flow.

Important notes

Real discharge depends on discharge coefficient, opening geometry, viscosity and changing tank level.

Frequently asked questions

What exactly is h?

Approximately the vertical difference between the free surface and opening center.

Is real flow exactly Av?

Usually not; a discharge coefficient is commonly needed.

Does this apply to gases?

This simple form is intended for essentially incompressible liquids.