Free Fall Calculator

No air resistance • Downward is treated as positive

Mode

Use height to solve for time and impact velocity, or use time to solve for displacement and velocity.

Quick summary

Select a mode, enter the required values, then click Calculate.

Initial vertical speed (v₀)

Leave blank for 0. Use positive for downward throw and negative for upward throw.

Height / drop distance (h)

Height must be 0 or greater in height mode.

Time (t)

Time must be 0 or greater in time mode.

Gravity (g)

Custom gravity must be greater than 0.

Results

Time

— s

Vertical displacement

— m

Final vertical velocity

— m/s

Average vertical velocity

— m/s

Downward-positive sign convention is used throughout the calculation.

Use this Free Fall Calculator to estimate fall time, vertical displacement, final velocity, and average velocity under constant gravity.

Calculation Method

The calculator uses constant-acceleration equations:

s = v₀t + ½gt²

v = v₀ + gt

v² = v₀² + 2gs

If an object is dropped from rest:

t = √(2h ÷ g)

Example

An object dropped from rest from a height of 20 m on Earth uses g = 9.80665 m/s²:

t = √(40 ÷ 9.80665) ≈ 2.02 s

Final velocity:

v = 9.80665 × 2.02 ≈ 19.8 m/s

Important Note

The calculator models ideal vertical motion with constant gravity and ignores air resistance. In real conditions, drag can significantly affect falling objects depending on their shape, size, mass, and speed.

Final velocity is not the same as impact force. Impact force also depends on stopping time, stopping distance, deformation, and other factors.

Source

OpenStax University Physics — Free Fall

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