Gravity and motion tool

Free Fall Calculator

Calculate falling distance, final velocity, or fall time for an object released from rest under constant gravity.

Enter one starting value

Calculate free-fall motion

Free tool

Enter height to calculate fall time and final velocity.

Enter time to calculate fallen distance and final velocity.

Standard Earth gravity is 9.80665 m/s².

Try an example:

Your result will appear here

Enter either height or time, confirm gravity, then select calculate.

Calculator guide

How this calculator works

Free Fall Calculator determines the motion of objects falling under the influence of gravity. It helps physics students, engineers, researchers, and laboratory users calculate fall time, distance, velocity, and acceleration using classical kinematics equations.

Formula explanation

Free fall calculations determine motion under gravitational acceleration without considering air resistance.

Formula

Distance = ½ × Gravity × Time², Velocity = Gravity × Time, Time = √(2 × Distance ÷ Gravity)

Worked example

Example: Falling distance can be calculated using gravity and time.

Assumptions

  • Gravity is considered constant during the calculation.
  • Air resistance and external forces are ignored in the ideal model.
  • Input measurements use compatible scientific units.
  • The object is assumed to move vertically under gravitational acceleration.

Examples

  • Example: Calculate the final velocity of an object dropped from a known height.
  • Example: Researchers estimate gravitational acceleration by measuring fall time in laboratory experiments.

Common mistakes

  • Using incorrect gravity values.
  • Ignoring initial velocity.
  • Mixing distance and displacement.

Variables

  • Initial velocity
  • Final velocity
  • Height or displacement
  • Fall time
  • Gravitational acceleration
  • Free fall distance
  • Measurement units

Limitations

  • Results assume ideal free fall without air resistance.
  • Large distances or changing gravitational fields require advanced physics models.

Scientific references

  • OpenStax University Physics: Free Fall and Motion
  • NIST physical constants and measurements
  • Classical mechanics principles

Content review

Reviewed by: ScienceCalcHub Physics Review Team | Last reviewed: 2026-08-30

Applications

  • Physics education
  • Kinematics analysis
  • Gravity experiments
  • Engineering motion studies
  • Drop testing and safety analysis
  • Laboratory measurement experiments

Frequently asked questions

How is free fall velocity calculated?

Free fall velocity is calculated using gravitational acceleration and fall time with the equation v = gt when the object starts from rest.

What is free fall in physics?

Free fall is the motion of an object when gravity is the only significant force acting on it.

What gravity value is used in free fall calculations?

The standard gravitational acceleration near Earth's surface is approximately 9.8 m/s² and is commonly used for physics calculations.

Does air resistance affect free fall?

Yes. Real objects experience air resistance, but ideal free fall calculations ignore drag to simplify motion analysis.

Accuracy and transparency

Created and maintained by our editorial team

This physics calculator is maintained by the ScienceCalcHub Editorial Team. Its calculation logic is tested with representative inputs, while the supporting guidance is checked for formula clarity, units, assumptions, and common mistakes.

Written by
ScienceCalcHub Editorial Team
Reviewed by
ScienceCalcHub Scientific Review Team
Review standard
Formula accuracy, units, examples, and educational clarity

Learn more about our formula-review and correction process, explore our calculation methodology, or view our scientific references.

  • Calculation logic tested
  • Variables and units explained
  • Assumptions stated clearly
  • Corrections handled transparently

Physics overview

What is free fall?

Free fall is motion in which gravity is the only significant force acting on an object. The object accelerates downward whether it is moving downward, moving upward, or momentarily at rest.

This calculator models an object released from rest. Its initial velocity is therefore zero, and gravitational acceleration is treated as constant throughout the fall.

Equations

Free-fall formulas from rest

Distance from timeh = ½gt²

Velocity from timev = gt

Time from heightt = √(2h ÷ g)

Velocity from heightv = √(2gh)

  • h is vertical falling distance in metres.
  • t is elapsed time in seconds.
  • v is final speed in metres per second.
  • g is positive gravitational acceleration in metres per second squared.

Worked example

Fall time and velocity from a 20 m height

Suppose an object is released from rest 20 metres above the ground using standard gravity of 9.80665 m/s².

  1. Calculate time: t = √((2 × 20) ÷ 9.80665).
  2. The fall time is approximately 2.019 seconds.
  3. Calculate final velocity: v = √(2 × 9.80665 × 20).
  4. The final speed is approximately 19.806 m/s.

Second worked example

Distance and velocity after 2 seconds

  1. Calculate distance: h = ½ × 9.80665 × 2².
  2. The object falls approximately 19.613 m.
  3. Calculate final velocity: v = 9.80665 × 2.
  4. The final speed is approximately 19.613 m/s.

Standard gravity

Which gravity value should you use?

Standard acceleration of gravity is exactly 9.80665 m/s². Many classroom problems round this value to 9.81 m/s² or 9.8 m/s².

Use the value specified by your assignment or experiment. For another world, enter an appropriate local gravity value; for example, lunar surface gravity is commonly approximated as 1.62 m/s².

Units

Use consistent SI units

  • Enter height in metres.
  • Enter fall time in seconds.
  • Enter gravity in metres per second squared.
  • Read final velocity in metres per second.
  • Convert centimetres, feet, or other units before calculating.

Assumptions and limitations

When these free-fall equations apply

  • The object is released from rest, so its initial velocity is zero.
  • Gravity is constant over the falling distance.
  • Air resistance, buoyancy, wind, and other forces are ignored.
  • Height and time inputs must be positive.
  • The result is an ideal model and may not match a real atmospheric fall.

Air resistance becomes important for objects with a large area, low mass, or long falling distance. A drag model is required when those effects cannot be neglected.

Scientific references

Sources and further reading

Related tools

Estimate local gravity with the Acceleration Due to Gravity Calculator.

Solve broader constant-acceleration problems with the Kinematic Equations Calculator.

Analyze horizontal and vertical launch motion with the Projectile Motion Calculator.

Questions and answers

Calculator FAQ

How is free fall velocity calculated?

Free fall velocity is calculated using gravitational acceleration and fall time with the equation v = gt when the object starts from rest.

What is free fall in physics?

Free fall is the motion of an object when gravity is the only significant force acting on it.

What gravity value is used in free fall calculations?

The standard gravitational acceleration near Earth's surface is approximately 9.8 m/s² and is commonly used for physics calculations.

Does air resistance affect free fall?

Yes. Real objects experience air resistance, but ideal free fall calculations ignore drag to simplify motion analysis.