Free Fall Calculator
Calculate fall time and impact velocity for an object dropped from a height.
Assumptions used in this calculation
- No air resistance, dropped from rest: Assumes no air resistance and an initial velocity of zero (a simple drop, not a throw).
About this calculator
How long a dropped object takes to hit the ground, and how fast it's moving when it does, isn't something most people can estimate accurately, gravity accelerates falling objects continuously, so the relationship between height, time and speed isn't linear. This calculator applies the standard free-fall kinematic equations to an object dropped from rest: fall time is computed as t = √(2h ÷ g), and impact velocity as v = √(2gh), using Earth's standard gravitational acceleration of 9.80665 m/s². Enter just the drop height and it returns both values directly, without you needing to rearrange either formula or handle the square root by hand. Because both equations assume the object starts at rest and falls straight down under gravity alone, with no air resistance, the results are exact only in a vacuum; for compact, dense objects falling over a few dozen meters, air resistance has a negligible effect, but for light or large-surface-area objects like paper or feathers, actual fall time will be longer than this idealized calculation predicts.
Worked example
Dropped from 20m
Result: 2.02s fall time, 19.8 m/s impact velocity
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