Enter a drop height to get the fall time and impact velocity, or enter a time to find how far something fell. Add a starting speed, switch to feet or choose gravity on the Moon or Mars.
| Time (s) | Distance fallen | Height above ground | Speed |
|---|
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Check answers to kinematics problems with every value shown.
Estimate impact speed for packaging and drop tests.
How long would a stone take to reach the bottom of a well?
In free fall the only force is gravity, so speed increases by g every second: about 9.8 m/s each second on Earth. The distance fallen grows with the square of time, so in 2 seconds an object falls four times as far as in 1 second.
Real falls are slowed by air resistance. A skydiver stops accelerating at a terminal velocity of about 55 m/s (200 km/h) belly-down, which this drag-free calculator flags when the impact speed goes above it.
h = v0*t + g*t^2 / 2
v = v0 + g*t
t = sqrt(2h/g) from rest
Dropped from rest: t = sqrt(2h / g). With an initial downward speed v0: t = (-v0 + sqrt(v0^2 + 2gh)) / g.
v = sqrt(v0^2 + 2gh). Dropped from 20 m on Earth with no air resistance, that is about 19.8 m/s or 71 km/h.
About 4.5 seconds on Earth if air resistance is ignored.
Not without air. In a vacuum all objects fall with the same acceleration. In air, light or wide objects are slowed much more by drag.
A negative value means the object was thrown upward first. It rises, stops and then falls past its starting point, so the total time is longer.
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