Terminal Velocity Calculator

This terminal velocity calculator will help you estimate the speed of a free-falling object through a gaseous or liquid medium. The most common idea to connect this concept of terminal velocity is skydiving, i.e., humans falling through the air as a medium. This terminal velocity of say, a baseball would depend on factors like properties of object like mass, shape), and size as well as the density of the medium and gravitational acceleration.

So if you throw a penny in the air or fire a gun, what is the terminal velocity of the bullet or penny? Read on to understand the definition of terminal velocity and how to find terminal velocity.

If you are interested in velocity of a free falling object, check out our free fall calculator and free fall with air resistance calculator.

As an object falls through the air, the velocity increases until a point where the gravitational pull is equal to the drag force on the object. At this point, the object's velocity is known as terminal velocity. Consider an object having mass, $m$, the total force, $F$ acting on the object is:

where:

• $g$ — Gravitational acceleration;
• $ρ$ — Density of fluid;
• $v$ — Velocity of object;
• $A$ — Cross-sectional area (see cross sectional area calculator); and
• $C_d$ — Coefficient of drag

Under the equilibrium conditions, the net force becomes zero and the velocity becomes terminal velocity. Upon rearranging the terms, the terminal velocity equation is:

There are two types of factors that affect the terminal velocity:

• Depending on an object — area, mass, and drag coefficient; and
• Depending on the environment — density and gravitational acceleration.

Let's first look at each object dependant factor:

• Drag coefficient: This parameter depends on the object's shape. Such that a more streamlined body would have a lower drag compared to a blunt body. Refer to our drag equation calculator for more.

• Area: The larger the area of the object, the lower the terminal velocity of the object. For instance, the terminal velocity of a skydiver in a belly-to-earth direction will be lower than in the case where he pulls his limbs in.

• Mass: A heavier object would have a higher terminal velocity than the lighter one. The terminal velocity of a penny would be less than that of a bullet.

And the two environmental dependant factors:

• Density: As the density of the fluid medium reduces, the terminal velocity increases. These different mediums or density variations could also come from different planetary environments.

• Acceleration due to gravity: This parameter is most applicable for different planets. The variation in gravitational acceleration is directly proportional to terminal velocity.

To calculate terminal velocity calculator:

1. Select the shape of the object (this fills in the drag coefficient for that shape).

2. Enter the mass of the object.

3. Fill in the cross-sectional area.

4. Enter the density of the fluid medium (default value is for air).

5. Fill in the gravitational acceleration (default value is for Earth's gravity).

6. The calculator will return the terminal velocity.

If you need to insert your own value for the coefficient of drag, first select Enter a custom drag coefficient from the list of shapes. Then, you will be able to enter a value.

What is the terminal velocity of a human skydiver having a mass of 75 kg and a cross-sectional area 0.18 m²? Take the drag coefficient as 0.7.

To calculate terminal velocity calculator:

1. Enter the mass, $m = 75 \text{ kg}$.

2. Fill in the cross-sectional area, $A = 0.18 \text{ m}^2$.

3. Select Enter a custom drag coefficient as the shape and then insert the coefficient of drag, $\text{C}_d = 0.7$.

4. The density of the fluid medium at $20\ °\text{C}$ is prefilled.

5. The gravitational acceleration, $\text{g}$ is prefilled for you.

6. Using the terminal velocity formula: