# Free Fall Calculator

Calculate free fall time, impact velocity, and distance for objects falling under gravity. Supports custom gravity for Moon, Mars, and more.

## What this calculates

Free fall describes the motion of an object falling solely under the influence of gravity, with no air resistance. This calculator determines how long it takes an object to fall a given height, what velocity it reaches at impact, and the average velocity during the fall. You can adjust the gravitational acceleration for different planets.

## Inputs

- **Drop Height** (m) — min 0
- **Initial Velocity (downward)** (m/s) — min 0
- **Gravitational Acceleration** (m/s²) — min 0 — Earth: 9.81, Moon: 1.62, Mars: 3.72

## Outputs

- **Fall Time** (s) — Time to reach the ground
- **Final Velocity** (m/s) — Velocity at impact
- **Impact Speed** (km/h) — Impact velocity expressed as a speed
- **Average Velocity** (m/s) — Mean velocity during the fall

## Frequently Asked Questions

**Q: What is free fall?**

A: Free fall is the motion of an object where gravity is the only force acting on it. In true free fall, air resistance is ignored. All objects in free fall near Earth's surface accelerate at approximately 9.81 m/s², regardless of their mass (as Galileo demonstrated).

**Q: Do heavier objects fall faster?**

A: No. In a vacuum, all objects fall at the same rate regardless of mass. This was famously demonstrated by Apollo 15 astronaut David Scott, who dropped a hammer and a feather on the Moon and they hit the ground at the same time. In air, however, air resistance affects lighter or less aerodynamic objects more.

**Q: What is terminal velocity?**

A: Terminal velocity is the maximum speed a falling object reaches when the drag force from air resistance equals the gravitational force. For a skydiver, terminal velocity is roughly 55 m/s (200 km/h) in a spread-eagle position. This calculator ignores air resistance and shows theoretical free-fall velocities.

**Q: How do I calculate fall time from a given height?**

A: For an object dropped from rest, fall time is t = √(2h/g), where h is the height and g is gravitational acceleration. For Earth, dropping from 10 meters gives t = √(20/9.81) ≈ 1.43 seconds.

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Source: https://vastcalc.com/calculators/physics/free-fall
Category: Physics
Last updated: 2026-04-21