Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 15, 2023

The Drag Equation Calculator can be used to calculate the force exerted on a moving object in a fluid. To calculate the drag force, simply enter the fluid density, drag coefficient, velocity, and cross-sectional area.

Choose a Calculation
Drag Coefficient:
Drag force:

What is Drag Force?

When an object moves through a fluid, it is subjected to a force known as drag. On the other hand, the fore value is dependent on the item's size and shape, relative fluid and object velocity, fluid density, and so on.

The drag force formula is given by d = 1/2 * ρ * u² * A * Cd

  • Where, Fd = drag force
  • ρ = density of the liquid
  • u = relative velocity
  • A= Reference Area
  • Cd = drag coefficient

The cross-sectional area orthogonal to the direction of motion is the reference area A of a basic form object. It's tough to identify the reference area for a complicated shape.

Drag Coefficient

The drag coefficient Cd is used in the drag force equation. What exactly is this? The drag coefficient is a dimensionless quantity that is affected by the object's form. Cd is a small quantity when an object has a smooth shape, and the accompanying drag force is also minimal. For example, a streamlined body has a value of 0.04 whereas a cube has a value of 1.05.

The Reynolds number Re determines the drag coefficient. When the Reynolds number is low enough (on the order of a few thousands or less), the dependence is minimal, and the drag coefficient is nearly constant. To understand more about different types of flows and their classification using the Reynolds number, use the Reynolds number calculator.

How do I use the Drag Coefficient Calculator?

The process for using the drag coefficient calculator is as follows

  • Step 1: Input the unknown's fluid density, drag coefficient, velocity, and cross-sectional area, and x in the appropriate input fields.
  • Step 2: Select the "Calculate unknown" option to calculate the drag force.
  • Step 3: Finally, the drag force of the object will be displayed in the output field.

You may also compute the mass flow rate by multiplying the volumetric flow rate and the fluid density i.e. m = q * ρ

Drag Coefficient Examples

Question 1: With a drag coefficient of 0.45, a car drives at a speed of 80 km.h^-1. Calculate the drag force if the cross-sectional area is 7.5 m^2 and the fluid density is 1.4 kg/m^3.



Velocity u = 80 km/h

Drag Coefficient Cd = 0.45

Cross-Sectional Area A = 7.5 m^2

Density of fluid ρ = 1.4 kg/m^3

Drag Force d = 1/2 x ρ x u^2 x A x Cd

d = 1/2 x 1.4 x (80)^2 x 7.5 x 0.45

d = 15120 N

Hence, the drag force acting on the car is 15120 N

For more concepts check out to get quick answers by using this free tool.

FAQs on Drag Coefficient

1. In physics, what is drag force?

The aerodynamic force opposing an aircraft's motion through the air is known as drag. The differential in velocity between the solid item and the fluid causes drag. Between the item and the fluid, there must be movement.

2. What is the purpose of a drag coefficient calculator?

The drag coefficient calculator determines how much an object drags as it passes through a fluid medium like water or air. The drag coefficient is a dimensionless (i.e., without units) unit that is used to measure an object's drag or resistance in a fluid environment.

3. What is C in Drag Equation?

C is the Proportionality Constant, which changes from item to item.

4. What is an example of a drag force?

The drag force, which is the force that objects feel when moving through a fluid, is an example of air resistance (liquid or gas).

5. How do you calculate drag if you don't have a drag coefficient?

To create a non-dimensional drag coefficient, the measured drag is divided by the dynamic pressure as well as the reference area.