Created By : Naaz Fatima

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 10, 2023

Drag Equation Calculator will help you determine the force exrted on a moving object immersed in a fluid. Simply enter the inputs such as fluid density, drag coefficient, velocity and cross sectional area to know the drag force in no time.

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Drag Coefficient:
Drag force:

What is Drag Force?

If an object moves through a fluid it experiences a force namely drag force. However, the fore value depends on the size and shape of the object, relative velocity of the fluid and object, density of fluid, etc. Drag Force Formula is given by d = 1/2 * ρ * u² * A * Cd

  • Where Fd is the drag force.
  • ╧ü is the density of the liquid.
  • u is the relative velocity
  • A is the Reference Area
  • Cd is the drag coefficient

The reference area A of an object of a simple shape is the cross sectional area orthogonal to the direction of motion. For a complicated shape it is difficult to specify the reference area.


A car travels with a speed of 60 km.h-1 with a drag coefficient of 0.5. If the cross-sectional area is 8 m┬▓, density of fluid is 1.2 kg/m┬│ calculate the drag force?


Given that

Velocity u = 60 km/h

Drag Coefficient Cd = 0.5

Cross Sectional Area A = 8 m┬▓

Density of fluid ρ = 1.2 kg/m³

Formula to calculate Drag Force is given by d = 1/2 * ρ * u² * A * Cd

Substituting the input values we get the drag force equation as under

d = 1/2*1.2*(60)┬▓*8*0.5

d = 666.7 N

Therefore, drag force acting on the car is 666.7 N

Drag Coefficient

Drag Force Equation depends on the drag coefficient. Drag Coefficient is a dimensionless number and depends on the shape of the object. If an object has smooth shape then Cd would be small and is the Drag Force as well. Drag Coefficient also depends on the Reynolds Number. If Reynolds Number is small the dependance is quite small and the drag coefficient is almost constant.

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FAQs on Drag Equation Calculator

1. What is C in Drag Equation?

C is the Constant of Proportionality and varies from object to object.

2. What is Drag Force Equation?

Drag Force Equation is written as Fd = 1/2 * ρ * u² * A * Cd

3. What is Drag Force?

Drag Force is defined as the force that resists the motion of a body with fluid. It always acts opposite to the direction of fluid flow.

4. How is Force of Drag Calculated?

You can Calculate the Drag Force by simply multiplying the fluid density, square of velocity, drag coefficient and cross sectional area.