Free Fall Calculator
Drop something from a height and find how long it falls and how fast it lands, or work back from the fall time to the height. Air resistance ignored.
0 if dropped
t
Fall time
s
h
Height fallen
m
v
Impact speed
m/s
71.31 km/h
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0/1500
Distance fallen each second (from rest, g = 9.81 m/s²)
| Time (s) | Distance (m) | Speed (m/s) |
|---|---|---|
| 1 | 4.9 | 9.8 |
| 2 | 19.6 | 19.6 |
| 3 | 44.1 | 29.4 |
| 4 | 78.5 | 39.2 |
| 5 | 122.6 | 49.1 |
Distance grows with the square of time: in 2 s an object falls four times as far as in 1 s. The distances covered in successive seconds go 1 : 3 : 5 : 7, the odd-number pattern Galileo found with balls rolling down ramps.
Frequently asked questions
What is the free fall formula?
Starting from rest: h = ½gt², v = gt and v = √(2gh). So fall time is t = √(2h ÷ g). With g = 9.81 m/s², a 20 m drop takes √(40 ÷ 9.81) = 2.02 s and lands at 19.8 m/s.
Do heavier objects fall faster?
Not in a vacuum. Galileo’s insight, confirmed by astronaut David Scott dropping a hammer and a feather on the Moon in 1971 (Apollo 15): all objects accelerate at g. In air, drag slows light, wide objects more.
What value of g should I use?
Standard gravity is 9.80665 m/s²; most courses use 9.81 or 9.8. It varies from about 9.78 at the equator to 9.83 at the poles. Use your textbook’s value to match the answer key.
What is terminal velocity?
The speed where air resistance equals weight, so acceleration stops. A skydiver belly-down reaches about 55 m/s (200 km/h). This calculator ignores drag, so for long falls it overestimates the speed.