Free Fall Calculator
This free fall calculator finds the fall time and impact velocity of an object dropped from a height under gravity. Enter the drop height and the free fall calculator returns the time to fall and the speed at impact. It applies the free fall equation, h = ½ g t², with no air resistance.
Results
The Free Fall Calculator is part of our Motion & Force collection. Browse more motion & force to size, convert, and check your work alongside this tool.
What the free fall calculator shows
When an object falls with only gravity acting on it, its motion is set by one acceleration, g. This free fall calculator uses the drop height to find how long the fall takes and how fast the object is moving when it lands. It applies the free fall equation for an object that starts from rest, ignoring air resistance.
The free fall equation
The free fall equation relates the drop height to the fall time and the impact speed:
Rearranged for time, t = √(2h ÷ g), and the impact velocity is v = g × t, which equals √(2gh). g is the acceleration due to gravity, 9.81 m/s² on Earth. The free fall calculator solves these together, so one height gives both the time and the speed.
Free fall formula example
An object dropped from 10 m on Earth. The free fall formula gives:
So the object lands after 1.43 seconds at 14 m/s. Change the height and the free fall calculator updates the time and speed at once.
How to use the free fall calculator
Enter the drop height in metres and the gravity value, then the free fall calculator returns the fall time in seconds and the impact velocity in metres per second and kilometres per hour. Use 9.81 m/s² for Earth, or change it for the Moon or another body. The object is assumed to start from rest, which is the usual free fall case.
Reading the free fall calculator result
The fall time tells you how long the drop takes; the impact velocity tells you how fast the object is going when it lands. Because the height sits under a square root for time, doubling the height does not double the time, it multiplies it by about 1.4. The impact speed grows the same way. These results ignore air resistance, so a light or wide object such as a feather or a parachute falls more slowly than the free fall calculator shows.
When to use the free fall calculator
- Solving physics problems with the free fall calculator
- Finding the fall time and impact speed from a height
- Working as a free fall distance calculator when you rearrange for height
- Comparing gravity on the Moon or other bodies
Common free fall calculator mistakes
- Expecting mass to matter. Without air resistance, all objects fall at the same rate.
- Forgetting the square root. Time grows with the square root of height, so double the height is not double the time.
- Ignoring air resistance. A feather or parachute falls far slower than the ideal formula shows.
Tips for free fall problems
- Use 9.81 m/s² for Earth and change g for other bodies.
- Assume the object starts from rest for standard free fall.
- Remember the results ignore air resistance.
The free fall formula in physics
The free fall formula physics uses is a direct result of constant acceleration. Starting from rest, the distance fallen grows with the square of the time, h = ½ g t², because the object keeps speeding up as it falls. The free fall equation physics students learn is the same relation rearranged: solve for t to get the fall time, or combine the two to get v = √(2gh) for the impact speed without needing the time first. The free fall motion formula ignores air resistance, so it is exact for dense objects over short drops and a good approximation for many everyday cases. Over long drops a real object reaches terminal velocity, where drag balances gravity and the speed stops rising, which the ideal formula does not capture.
Free fall distance calculator and time
The same equation works in every direction. As a free fall distance calculator you rearrange for height, h = ½ g t², to find how far an object falls in a given time; after 2 seconds on Earth that is about 19.6 m. As a free fall time calculator you solve for t from the height. And the impact speed follows from either. For motion that is not free fall, where the object has a starting speed or a different acceleration, the speed distance time calculator handles the general case. Free fall is the clean version where gravity does all the work.
Free fall equation values by height
Fall time and impact velocity by drop height on Earth, from the free fall equation:
| Drop height | Fall time | Impact velocity |
|---|---|---|
| 5 m | 1.01 s | 9.9 m/s |
| 10 m | 1.43 s | 14.0 m/s |
| 20 m | 2.02 s | 19.8 m/s |
| 50 m | 3.19 s | 31.3 m/s |
| 100 m | 4.52 s | 44.3 m/s |
Free Fall Calculator FAQ
What is the free fall equation?
The free fall equation is h = half g t squared, which rearranges to t = square root of (2h / g). The free fall calculator solves it for the time and the impact speed.
What is the free fall formula for impact velocity?
The impact velocity is v = g times t, which also equals the square root of 2gh. For a 10 m drop that is about 14 m/s.
Does the mass affect free fall?
No. In the free fall formula physics without air resistance, all objects fall at the same rate, so a heavy and a light object hit the ground together from the same height.
Does this include air resistance?
No. This is ideal free fall. A light or wide object such as a feather or a parachute falls more slowly than the free fall calculator shows.