Free Fall Calculator
Free fall calculator — fall time, impact velocity, and speed from any drop height and gravity, with an animated drop.
Everyday Uses
Physics homework
Find fall time and impact speed from any drop height, with an animated drop.
Skydiving & drops
Estimate how long a fall takes and how fast an object is going when it lands.
Depth from time
Time a stone dropping down a well or off a bridge to estimate the height.
Other planets
Change gravity to the Moon or Mars and watch the fall slow right down.
Frequently Asked Questions
How do you calculate free fall time?
For an object dropped from rest, fall time is t = √(2h ÷ g), where h is the drop height and g = 9.81 m/s². An object dropped from 20 m takes t = √(2 × 20 ÷ 9.81) ≈ 2.02 s to hit the ground. Fall time grows with the square root of height, so a drop four times as high takes only twice as long.
What is the impact velocity in free fall?
Impact velocity is v = g × t = √(2gh) for an object dropped from rest. From 20 m, v = √(2 × 9.81 × 20) ≈ 19.8 m/s (about 71 km/h). If it starts with a downward speed v₀, then v = √(v₀² + 2gh).
Do heavier objects fall faster?
No — ignoring air resistance, all objects fall at the same rate regardless of mass, because gravity accelerates everything equally at g = 9.81 m/s². A feather and a hammer hit the ground together in a vacuum. In real air, drag slows lighter, larger objects, which is why a feather flutters down slowly.