Free Fall Calculator
Calculate how long an object takes to fall from a height and how fast it hits the ground.
About the Free Fall Calculator
Enter the drop height and gravity. The calculator gives the fall time and the impact speed in m/s, km/h and mph, ignoring air resistance.
In free fall without air resistance, distance = ½ g t², so t = √(2h ÷ g) and impact speed v = g t = √(2 g h). Air resistance limits real falling objects to a terminal velocity (about 55 m/s for a skydiver belly-down).
The formula
t = √(2h ÷ g); v = √(2 g h)
Worked example
Dropping from 20 m
- t = √(2 × 20 ÷ 9.807) = 2.02 s
- v = 9.807 × 2.02 = 19.8 m/s
- About 71 km/h (44 mph)
Questions people ask
Do heavy things fall faster?
Not in a vacuum; in air, drag affects light, broad objects more.
What is terminal velocity?
The speed where drag equals weight, so acceleration stops.