Free Fall Calculator
Calculate the fall time, drop height and impact velocity of an object falling freely under gravity.
How it works
From height: t = √(2h/g), v = √(2gh) · From time: h = ½·g·t², v = g·t
In free fall the only force is gravity, so an object starting from rest speeds up by g every second regardless of its mass. Enter the drop height to find how long the fall takes and how fast it lands, or enter the time to find the distance dropped. Impact velocity grows with the square root of height but linearly with time.
Worked example
Dropped from 45 m with g = 9.81: t = √(2 × 45 ÷ 9.81) ≈ 3.03 s and v = √(2 × 9.81 × 45) ≈ 29.7 m/s (about 107 km/h).
Sources: Free fall — Wikipedia
Frequently asked questions
Does a heavier object fall faster?
No. Ignoring air resistance, all objects accelerate at the same g and fall together, as Galileo showed. Mass cancels out of the free-fall equations entirely.
Why is air resistance ignored?
These equations describe ideal free fall in a vacuum. In air, drag eventually balances gravity and the object stops accelerating at its terminal velocity, so real falls from great heights are slower.
What gravity value should I use?
Standard Earth gravity is about 9.81 m/s². Use 1.62 for the Moon or 3.71 for Mars to model a fall on another body.
Related calculators
Educational estimate. Check the formula and units for your exact case.