Physics formula
How free-fall calculations work
Free fall describes vertical motion when gravity is the only significant force acting on an object. Near Earth, gravitational acceleration is commonly approximated as 9.81 metres per second squared.
For an object released from rest, distance can be calculated with h = ½gt² and final velocity with v = gt. The correct equation depends on the value being solved.
Worked example
Free-fall distance after three seconds
Suppose an object is released from rest and falls for 3 seconds near Earth, where gravitational acceleration is 9.81 m/s².
h = ½gt²
h = ½ × 9.81 × 3² = 44.145 m
The object falls approximately 44.1 metres. Its final velocity is v = gt = 9.81 × 3, or about 29.4 m/s downward.
Model limitations
Assumptions and limitations
The calculator assumes constant gravitational acceleration, negligible air resistance, and straight vertical motion. These assumptions work well for short falls near Earth’s surface.
Results may differ for objects with substantial drag, very high-altitude falls, changing gravity, powered motion, or situations where another force is significant.
Related gravity calculators
Calculate the local gravitational field with the Acceleration Due to Gravity Calculator.
Analyze launched objects with the Projectile Motion Calculator.
Common questions
Free fall calculator FAQs
What is free fall?
Free fall is vertical motion in which gravity is the only significant force acting on an object.
What value of gravity should I use near Earth?
A standard value of 9.81 metres per second squared is commonly used for calculations near Earth’s surface.
Does the free fall calculator include air resistance?
No. It uses an idealized model that ignores air resistance and assumes constant gravitational acceleration.
Can I solve for falling time or final velocity?
Yes. The calculator can solve for time, falling distance, final velocity, or gravitational acceleration when enough values are provided.