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Free Fall Calculator – Online Time, Speed, Distance

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Free Fall Calculator

Calculate time, speed, and distance for objects in free fall under gravity. Supports Earth, Moon, Mars & customizable gravity.

Gravity Acceleration
m/s²
= 32.1740 ft/s²
Height / Distance Calculated
Quick:
Time Calculated
seconds

Time is always in seconds

Velocity / Speed Calculated
Formulas Used (ideal free fall, no air resistance)
h = ½ g t² | v = g t | v² = 2 g h
Free Fall from 100 meters on Different Worlds
Celestial Body Gravity (m/s²) Fall Time Impact Speed
🌍 Earth9.8074.52 s44.3 m/s (159 km/h)
🌙 Moon1.6211.11 s18.0 m/s (64.8 km/h)
🔴 Mars3.7217.33 s27.3 m/s (98.2 km/h)
🪐 Jupiter24.792.84 s70.4 m/s (253 km/h)
☀️ Sun2740.85 s234 m/s (843 km/h)
Frequently Asked Questions

Free fall is the motion of an object where gravity is the only force acting upon it. In an ideal free fall (ignoring air resistance), all objects accelerate at the same rate regardless of mass — this is the equivalence principle famously demonstrated by Galileo at the Leaning Tower of Pisa. On Earth, this acceleration is approximately 9.80665 m/s² at sea level.

Use the formula t = √(2h/g), where h is the height in meters and g is the gravitational acceleration (9.80665 m/s² on Earth). For example, from 100 meters: t = √(2×100/9.80665) ≈ 4.52 seconds. This assumes no air resistance and zero initial velocity.

The impact velocity can be calculated using v = √(2gh) or v = g·t. Both formulas yield the same result in ideal conditions. For instance, an object falling from 100 meters on Earth hits the ground at approximately 44.3 m/s (about 159 km/h or 99 mph).

Yes, significantly in real-world scenarios. This calculator models ideal free fall without air resistance. In reality, air drag increases with speed until the object reaches terminal velocity — the maximum speed where drag equals gravity. For a human skydiver in a belly-to-earth position, terminal velocity is about 53–56 m/s (195–200 km/h). Our calculator would predict much higher speeds from extreme heights because it ignores this limiting factor.

Because gravitational acceleration varies by celestial body. The Moon's gravity is only about 1/6 of Earth's (1.62 vs 9.81 m/s²), so a fall from the same height takes longer and results in a lower impact speed. Jupiter's immense gravity (24.79 m/s²) would make objects fall over 2.5 times faster than on Earth. This calculator lets you explore these fascinating differences.

Terminal velocity is the constant maximum speed a falling object reaches when air resistance equals the gravitational force. It depends on the object's mass, cross-sectional area, and drag coefficient. A skydiver reaches ~53 m/s, a raindrop ~9 m/s, and a ping pong ball ~9.5 m/s. For falls under ~50 meters, air resistance has minimal impact, so this calculator's ideal model is quite accurate for short drops.

This calculator assumes zero initial velocity (object starts from rest). For objects thrown downward with an initial speed, use the more general kinematic equation: v² = v₀² + 2gh, where v₀ is the initial velocity. For objects thrown upward, the motion includes an ascent phase followed by free fall, which requires projectile motion equations beyond this tool's scope.

For short falls under ~30 meters (like construction safety calculations or physics demonstrations), the ideal free fall model is very accurate — within 1-3% of reality. For higher falls, air resistance becomes increasingly significant. The calculator uses the standard gravity value of 9.80665 m/s² (ISO 80000-3), which is accurate at sea level. Gravity decreases slightly with altitude (about 0.003% per 100 meters), but this effect is negligible for most practical purposes.
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