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Free Fall Calculator

Physics

Calculate free fall time and final velocity from a drop height under gravity. Enter a height in meters to instantly get fall time and impact velocity, ignoring air resistance.

01,000,000

Fall Time

2.02
Final Velocity
19.799

This calculator computes your Fall Time, Final Velocity from the values you enter.

Inputs
Drop Height
Outputs
Fall TimeFinal Velocity

What is a Free Fall?

The Free Fall Calculator computes how long an object takes to fall from a given height and how fast it's moving when it hits the ground, using standard kinematics equations under gravity alone. Enter a drop height in meters, and the calculator instantly returns both the fall time and the final (impact) velocity, assuming no air resistance — the standard idealization used in introductory physics.

Free fall is one of the simplest and most fundamental motion scenarios in physics, involving only gravity as the acting force. This calculator makes it easy to see how fall time and impact velocity scale with height, both following a square-root relationship rather than a linear one.

If the object was launched at an angle rather than simply dropped, use the Projectile Motion Calculator instead, which accounts for horizontal motion as well.

How to use this Free Fall calculator

  1. Enter the drop height — the vertical height the object falls from, in meters.

  2. Read the fall time result — the highlighted result shows how long the fall takes, in seconds.

  3. Check the final velocity — the secondary result shows the impact velocity in meters per second.

  4. Adjust the height to explore scaling — try doubling or quadrupling the height to see the square-root relationship in action.

  5. Feed the result into further calculations — use the final velocity with the Kinetic Energy Calculator to find impact energy, or compare with the Potential Energy Calculator to verify energy conservation.

Formula & Methodology

Fall time formula:
t = √(2h ÷ g)

Final velocity formula:
v = g × t

Variable definitions:
- h — drop height (meters)
- g — gravitational acceleration, fixed at 9.8 m/s²
- t — fall time (seconds)
- v — final (impact) velocity (meters per second)

Worked example:

An object is dropped from a height of 45 meters.

Step 1 — Fall time: t = √(2 × 45 ÷ 9.8) = √9.18 ≈ 3.03 s

Step 2 — Final velocity: v = 9.8 × 3.03 ≈ 29.7 m/s

This means the object takes about 3 seconds to fall and hits the ground at roughly 29.7 m/s (about 107 km/h) — a speed that can be used with the Kinetic Energy Calculator to find its impact energy.

Note: This calculator ignores air resistance, which becomes significant for lightweight or oddly-shaped objects and long falls where terminal velocity is reached. Real-world impact speeds for such objects will be lower than these idealized results.

Frequently Asked Questions

This calculator uses t = √(2h ÷ g) to find fall time from a drop height, and v = g × t to find the final (impact) velocity, where h is height in meters, g is gravitational acceleration (9.8 m/s²), t is fall time in seconds, and v is final velocity in meters per second.
No — this calculator assumes free fall in a vacuum or an idealized scenario with no air resistance, which is the standard simplification used in introductory physics. Real-world falling objects, especially lightweight or irregularly shaped ones, experience air resistance that slows their fall compared to these idealized results.
This calculator uses 9.8 m/s², the standard approximation for Earth's gravitational acceleration at sea level. This value is fixed in the calculation and represents the typical value used in most introductory physics problems.
Fall time increases with the square root of height, not linearly — quadrupling the drop height only doubles the fall time, because t = √(2h/g) involves a square root. This means very tall drops take proportionally less additional time than shorter ones might suggest.
Final velocity (also called impact velocity) is calculated as v = g × t, or equivalently v = √(2gh) directly from height. It represents the speed at which the object hits the ground, ignoring air resistance, and increases with the square root of height.
This calculator handles purely vertical motion starting from rest (an object simply dropped, with no horizontal velocity), while the [Projectile Motion Calculator](/projectile-motion-calculator/) handles motion launched at an angle with both horizontal and vertical velocity components, computing range in addition to fall time and height-related values.
Take the final velocity result from this calculator and enter it, along with the object's mass, into the [Kinetic Energy Calculator](/kinetic-energy-calculator/) to find its kinetic energy just before hitting the ground — which should closely match the potential energy it started with at the drop height.
An object dropped from a 20-meter height (about a 6-story building) takes roughly 2 seconds to fall and hits the ground at about 19.8 m/s (around 71 km/h) — illustrating how quickly falling objects reach significant speeds even from modest heights.
No — this calculator assumes the object starts from rest (zero initial velocity) at the given height, which is the standard definition of free fall. An object thrown downward with an initial speed would reach the ground faster and with a higher final velocity than this calculator's results.
The potential energy an object has at the drop height converts almost entirely into kinetic energy by the time it reaches the ground (ignoring air resistance). Use the [Potential Energy Calculator](/potential-energy-calculator/) to compute the starting potential energy, which should match the kinetic energy calculated from this calculator's final velocity result.
In the idealized case with no air resistance, all objects fall at the same rate regardless of their mass — a heavier object experiences more gravitational force, but also more inertia resisting acceleration, and the two effects exactly cancel out. This is why a feather and a hammer fall at the same rate in a vacuum, as famously demonstrated on the Moon.
Free fall calculations underpin drop testing for packaging and electronics (estimating impact velocity and force), skydiving and parachute design (before terminal velocity from air resistance takes over), and safety standards for fall protection in construction and industrial settings.
Also known as
free fall time calculatordrop height calculatorgravity fall calculatorimpact velocity calculatorfalling object calculator