Free Fall Distance Calculator
Calculate how far an object falls in a given time under gravity. Distance-time tables, planetary comparisons, height equivalents bar chart, and energy analysis.
Free Fall Calculator
Calculate free fall distance, time, and velocity. Solve for any variable with optional initial velocity, planetary gravity comparison, and distance-time tables.
m
m/s
m/s²
Distance Fallen⧉
20.000 m
65.62 ft
Fall Time⧉
2.0193 s
Time for the object to fall the specified distance
Final Velocity⧉
19.809 m/s
71.3 km/h = 44.3 mph
Average Velocity⧉
9.905 m/s
v̄ = d / t — average speed during the fall
Impact Energy⧉
196.20 J/kg
Specific kinetic energy: E/m = g × d (per unit mass)
Impact Force Estimate⧉
19,620 N/kg
Rough impact force assuming 1 cm deformation (F = E / Δd)
Distance-Time Table
| Time (s) | Distance (m) | Velocity (m/s) | Velocity (km/h) |
|---|---|---|---|
| 0.5 | 1.23 | 4.91 | 17.7 |
| 1.0 | 4.91 | 9.81 | 35.3 |
| 1.5 | 11.04 | 14.72 | 53.0 |
| 2.0 | 19.62 | 19.62 | 70.6 |
| 3.0 | 44.14 | 29.43 | 105.9 |
| 4.0 | 78.48 | 39.24 | 141.3 |
| 5.0 | 122.63 | 49.05 | 176.6 |
| 7.0 | 240.35 | 68.67 | 247.2 |
| 10.0 | 490.50 | 98.10 | 353.2 |
Same Fall on Different Bodies
| Body | g (m/s²) | Fall Time (s) | Final Velocity (m/s) |
|---|---|---|---|
| Mercury | 3.70 | 3.288 | 12.17 |
| Venus | 8.87 | 2.124 | 18.84 |
| Earth | 9.81 | 2.019 | 19.81 |
| Moon | 1.62 | 4.969 | 8.05 |
| Mars | 3.72 | 3.279 | 12.20 |
| Jupiter | 24.79 | 1.270 | 31.49 |
| Saturn | 10.44 | 1.957 | 20.44 |
| Pluto | 0.62 | 8.032 | 4.98 |
Fall Progress
Objects fall slowly at first and accelerate: in the first half of time, less than 25% of distance is covered.
Planning notes, formulas, and examples
About the Free Fall Calculator
Free fall describes motion under the sole influence of gravity, with no air resistance. Starting from rest, an object near Earth's surface accelerates at about g = 9.81 m/s², gaining roughly 35 km/h of speed every second.
The core equations d = ½gt², v = gt, and v² = 2gd are the basic tools for relating distance, time, and velocity in the ideal case. They are useful whenever you want to solve one part of the motion from the other two.
This calculator solves for any unknown distance, time, or velocity, supports an initial downward velocity, allows custom gravitational acceleration, and compares results across different celestial bodies.
When This Page Helps
Free-fall problems often come down to choosing the right equation for the known quantity. This calculator keeps the distance, time, and velocity forms together so the same setup can be checked from multiple angles without redoing the algebra each time.
How to Use the Inputs
- Choose what to solve for: time, distance, or final velocity.
- Enter the known value (distance, time, or final velocity).
- Optionally enter initial downward velocity (0 for drop from rest).
- Adjust gravitational acceleration for non-Earth scenarios (default 9.81 m/s²).
- Read the complete results including impact energy and force estimates.
- Review the distance-time table to see how speed builds exponentially.
- Compare fall times across planets and moons in the solar system table.
Formula used
Free Fall Equations (from rest):
d = v₀t + ½gt²
v = v₀ + gt
v² = v₀² + 2gd
Solving for time from distance:
t = (−v₀ + √(v₀² + 2gd)) / g
Specific impact energy: E/m = gd
Where:
d = distance (m), t = time (s)
v₀ = initial velocity (m/s), v = final velocity (m/s)
g = gravitational acceleration (9.81 m/s² on Earth)Example Calculation
Result: t = 2.019 s, v = 19.81 m/s (71.3 km/h)
Dropping from 20 m on Earth: t = √(2 × 20 / 9.81) = 2.019 s. Final velocity: v = 9.81 × 2.019 = 19.81 m/s = 71.3 km/h.
Tips & Best Practices
- Quick estimate: an object falls about 5 meters in the first second (d = ½ × 9.8 × 1² ≈ 4.9 m).
- Double the height → √2 × the fall time (time scales with the square root of distance).
- Terminal velocity for a skydiver is about 55 m/s (200 km/h) belly-down, 90 m/s (320 km/h) head-down.
- On the Moon (g = 1.62 m/s²), a ball dropped from 2 m takes 1.57 s to fall vs. 0.64 s on Earth.
- Impact force depends on deformation distance — a hard surface means higher force than a soft one.
- The kinematic equations assume constant acceleration; they break down for very high altitudes where g varies.
The Physics of Free Fall
Free fall is the simplest gravitational motion: constant downward acceleration with no other forces. The resulting parabolic distance-time relationship (d ∝ t²) means an object covers progressively more distance each second. After 1 s it has fallen 4.9 m; after 2 s, 19.6 m (not 9.8); after 3 s, 44.1 m.
The velocity increases linearly: about 9.81 m/s added per second. After 4 seconds, a dropped object on Earth is moving at ≈ 39 m/s (141 km/h). This relentless acceleration is why even moderate heights can produce dangerous impact speeds.
Free Fall in the Real World
In practice, air resistance always exists and grows with speed. For a compact, heavy object (bowling ball, rock), free fall equations are accurate for drops of a few meters. For lighter objects or higher drops, air resistance becomes significant. A skydiver reaches terminal velocity (where drag equals gravity) after about 12 seconds of free fall.
Historical Significance
Galileo's insight that all objects fall at the same rate was revolutionary. It contradicted Aristotle's claim that heavier objects fall faster, which had been accepted for nearly two millennia. This principle — along with the parabolic trajectory of projectiles — laid the foundation for Newton's laws of motion and the entire field of classical mechanics.
Sources & Methodology
Last updated:
Frequently Asked Questions
No. In a vacuum, all objects fall at the same rate regardless of mass. This was demonstrated dramatically on the Moon by Apollo 15 astronaut David Scott, who dropped a hammer and feather simultaneously — they hit the ground together.
Free fall by definition assumes no air resistance. For real-world scenarios with drag (skydiving, parachutes), see the free-fall-air-resistance calculator. Free fall equations work well for dense objects over short distances.
Felix Baumgartner jumped from 39 km altitude in 2012, reaching 1,357 km/h (Mach 1.25) during his free fall phase. Alan Eustace later broke the altitude record at 41.4 km in 2014.
Earth's surface gravity varies from about 9.78 m/s² at the equator to 9.83 m/s² at the poles due to Earth's rotation and equatorial bulge. The standard value is g = 9.80665 m/s².
Yes, for downward throws. Set the initial velocity to the throw speed. For objects thrown upward, the equations still work but you need to handle the upward phase separately (this calculator assumes downward motion).
Because objects accelerate during free fall. In the first half of the fall time, the object covers only 25% of the total distance. The remaining 75% is covered in the second half of the time, when the object is moving faster.
More in this topic
Free Fall Time Calculator
Calculate how long an object takes to fall a given distance or reach a given velocity. Includes planetary comparison, distance-time tables, and timing visualization.
Free Fall Velocity Calculator
Calculate the velocity of a falling object from time or distance. Speed context chart, velocity build-up tables, Mach number, kinetic energy, and momentum analysis.