Pitot Tube Velocity Calculator Formula

Understand the math behind the pitot tube velocity calculator. Each variable explained with a worked example.

Use the Pitot Tube Velocity Calculator

Formulas Used

Flow Velocity

velocity = sqrt(2 * (total_pressure - static_pressure) / density)

Dynamic Pressure

dynamic_pressure = total_pressure - static_pressure

Variables

VariableDescriptionDefault
total_pressureTotal (Stagnation) Pressure(Pa)102000
static_pressureStatic Pressure(Pa)101325
densityFluid Density(kg/m3)1.225

How It Works

Pitot Tube

A pitot tube measures airspeed by comparing stagnation (total) and static pressure.

Formula

v = sqrt(2 (P_total - P_static) / rho)

where the difference (P_total - P_static) is the dynamic pressure q = 0.5 rho v^2.

Pitot tubes are standard instruments on aircraft for measuring airspeed.

Worked Example

Aircraft: P_total = 102 000 Pa, P_static = 101 325 Pa, rho = 1.225 kg/m3.

total_pressure = 102000static_pressure = 101325density = 1.225
  1. 01dP = 102000 - 101325 = 675 Pa
  2. 02v = sqrt(2 * 675 / 1.225)
  3. 03v = sqrt(1102)
  4. 04v = 33.2 m/s = 119.5 km/h

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Open Pitot Tube Velocity Calculator