Dynamic Pressure
Aerodynamics / Flow Properties
Table of Contents
About this calculator
Dynamic Pressure converts air density and air-relative speed into the aerodynamic loading term used in lift, drag, and air-data work.
Use manual mode when local density is already known, altitude mode when you want ISA density from height, and Mach + altitude mode when flight condition is defined by compressible-flow inputs.
Integrated mode computes ISA temperature, local speed of sound, velocity, density, and dynamic pressure in one engineering workflow.
Inputs
Enter the required values used in the formula for Dynamic Pressure.
Calculation mode
Altitude mode computes density from ISA. Mach + altitude mode computes ISA temperature, local speed of sound, velocity, density, and then dynamic pressure.
Required inputs for calculation
- Density (rho) (kg/m^3) - Local air density
- Velocity (V) (m/s) - Flow or aircraft speed relative to air
Results
Results are hidden until you click Calculate.
Formula used for calculations
q = 0.5 * rho * V^2
Manual engineering inputs
Density rho is the local air density in kg/m^3.
Velocity V is the flow or aircraft speed relative to the surrounding air in m/s.
Optional altitude mode
Input altitude h and velocity V.
Density rho is computed automatically from ISA.
Optional Mach + altitude mode
T = T_ISA(h)
a = sqrt(gamma * R * T)
V = M * a
rho = rho_ISA(h)
q = 0.5 * rho * V^2
Dynamic pressure is the aerodynamic loading term used in lift, drag, and air-data workflows. Keep SI units consistent: rho in kg/m^3 and V in m/s. In integrated mode the calculator derives temperature, speed of sound, velocity, and density from altitude and Mach number.
Assumptions
- Velocity is relative to the surrounding air and all inputs use SI units.
- Altitude-based modes assume ISA conditions up to 86 km.
- Mach + altitude mode assumes standard air with gamma = 1.4 and R = 287.05 J/kg.K.
Recommendations
- Use local measured density in manual mode when atmospheric conditions deviate from ISA.
- Use Mach + altitude mode when your flight condition is defined in terms of compressible-flow variables.
- For loads and performance calculations, make sure velocity is true airspeed or another air-relative speed consistent with the density used.
FAQs
What velocity should I use for dynamic pressure?
Use air-relative velocity. In most aircraft workflows that means true airspeed or another speed quantity that is consistent with the density being used.
What does Mach + altitude mode compute?
It computes ISA temperature from altitude, local speed of sound, velocity from Mach number, ISA density, and then dynamic pressure.
Is this suitable for engineering use?
Yes for real engineering workflows such as performance checks, loads estimates, and air-data calculations, provided the ISA assumption matches the atmosphere you want to model.