Horsepower & Aerodynamic Drag Calculator
By AssassinRacing.com

Calculate the theoretical Horsepower required to move a vehicle at a certain speed based on the Vehicle Drag Coefficient (Cd), Vehicle Frontal Area (sq. ft.), Vehicle Weight (in pounds), and desired Vehicle Speed (MPH).

Assumptions: The vehicle is a car driven on concrete with tire pressures set to 30 psi. Ambient temperature is around 25º Celsius (77º Fahrenheit), no wind.

Drag figures are usually calculated from wind tunnel models without side mirrors, gaps in the windows and body panels, and smooth wheel covers. These all contribute to Drag Coefficient (Cd) and can increase the vehicle's frontal area. Most of the drag on a car is aerodynamic drag rather than rolling resistance (from tires and vehicle weight).

Top speeds are either gear limited or drag limited. Use the Gear Ratio Speed Calculator to determine which is the case for your particular scenario.

Use the Drag Performance Calculator to calculate the theoretical 1/8 Mile ET, 1/4 Mile ET, 1/4 Mile Top End Speed, and Ideal 1/4 Mile Gear Ratio and the 0-60 MPH Time Calculator to calculate the theoretical 0-60 Time for a given application.