Enter the static pressure, total pressure, and density of fluid into the calculator to determine the velocity through a pitot tube.

Pitot Tube Formula

The following formula is used to calculate the velocity of flow through a pitot tube.

V = SQRT ( 2*(pt-ps) / d ) 
  • Where V is the velocity
  • pt is the total pressure
  • ps is the static pressure
  • d is the density

To calculate velocity from a pitot tube, multiply the difference between the total pressure and static pressure by 2, divide by the density of the air, then finally, take the square root of this result.

Pitot Tube Definition

What is a pitot tube?

A pitot tube is a right-angled tube that points into the flow of fluid to measure the pressure. This pressure can then be used to calculate the speed or velocity of the fluid or object moving through the fluid.

These tubes are most often used on aircraft to help determine the speed of the aircraft. Although, in current times, GPS can also be used to confirm aircraft speed.

Example Problem

How to calculate velocity from a pitot tube?

The following example outlines the steps and information required to calculate the velocity of fluid from a pitot tube.

First, determine the total pressure reading of the tube. In this example, the total pressure is measured as 50 N/m^2.

Next, determine the static pressure measured by the pitot tube. The static pressure reads 25 N/m^2 for this example.

Next, determine the density of the fluid. In this case, we are looking at room temperature air which has a density of 1.225 kg/m^3.

Finally, calculate the velocity using the formula above:

V = SQRT ( 2*(pt-ps) / d )

V = SQRT ( 2*(50-25) / 1.225 )

V = 6.388 m/s