Basic Equation

Dynamic_Pressure = 0.5 x Air_Pressure x Velocity²

In Standard (US) Units

Dynamic Pressure (lb/ft²) (also known as PSF)
Air Pressure (slugs/ft³)
Velocity (ft/sec)

In Metric (SI) Units

Dynamic Pressure (Pascals)
Air Pressure (kg/m³)
Velocity (m/sec)