Updated on September 5th, 2025

Free Fall Calculator

Created By Jehan Wadia

🏢 Penny from Empire State Building
🪂 Felix Baumgartner's Jump
🗼 Galileo's Pisa Experiment
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Introduction

The Free Fall Calculator helps you understand how objects fall through space. When you drop something, gravity pulls it down faster and faster. This tool shows you exactly how fast, how long, and how much energy is involved when things fall.

Free fall happens when gravity is the only force acting on an object. In real life, air slows things down, but this calculator can handle both simple falls and falls with air resistance. You can calculate drops from any height, on Earth or other planets. The calculator also finds the speed at impact, the time to hit the ground, and the energy involved.

Whether you want to know how long a penny takes to fall from a tall building, or how fast a skydiver falls, this tool gives you the answers. It works for any object, from a feather to a bowling ball, and shows you step-by-step how to solve these problems yourself.

How to use our Free Fall Calculator

Enter the starting height and other values to find out how long an object takes to fall and how fast it hits the ground.

Initial Height: Type the height from where the object drops. Pick the unit you want (meters, feet, kilometers, miles, inches, or centimeters).

Time (optional): Leave this blank to find the fall time. Or type a time to see where the object is at that moment.

Mass (for energy): Type how heavy the object is. This helps calculate the energy when it hits the ground. Use our Kinetic Energy Calculator to explore energy in motion further.

Gravity: Pick a planet button or type your own gravity value. Earth's gravity is already set for you. For calculations involving gravitational forces between objects, try our Gravitational Force Calculator.

Initial Velocity (second tab): Type the starting speed if the object is thrown up or down. Use positive numbers for up and negative for down.

Drag Coefficient (air resistance tab): Type how much air slows down the object. Different shapes have different drag.

Cross-section Area (air resistance tab): Type how big the object looks from below as it falls through the air.

What is Free Fall?

Free fall happens when an object drops through the air with only gravity pulling it down. When you drop a ball, it falls faster and faster until it hits the ground. This is free fall in action. The only force working on the object is gravity, which pulls everything toward Earth. To calculate the forces involved in free fall, use our Force Calculator.

How Free Fall Works

When something falls, gravity makes it speed up. On Earth, gravity pulls objects down at about 9.8 meters per second squared. This means that every second, a falling object goes 9.8 meters per second faster than the second before. A ball dropped from a tall building starts at zero speed. After one second, it moves at 9.8 meters per second. After two seconds, it moves at 19.6 meters per second.

Free Fall on Other Planets

Different planets have different amounts of gravity. The Moon has weak gravity, so objects fall slowly there. Jupiter has strong gravity, so things fall much faster. An object that takes 10 seconds to fall on Earth would take about 25 seconds on the Moon but only 6 seconds on Jupiter.

Air Resistance Changes Things

In real life, air slows down falling objects. Light things like feathers fall slowly because air pushes against them. Heavy things like rocks fall fast because air doesn't affect them as much. In a place with no air, like space or the Moon, a feather and a hammer would fall at the same speed.

Terminal Velocity

When something falls for a long time, air resistance gets stronger as it goes faster. Eventually, the air pushes up as hard as gravity pulls down. The object stops speeding up and falls at a steady


Frequently Asked Questions

What is the difference between free fall and falling with air resistance?

Free fall means only gravity acts on the object - there's no air to slow it down. Objects speed up at the same rate no matter how heavy they are. With air resistance, the air pushes against falling objects and slows them down. Light objects like paper fall slower than heavy objects like rocks because air affects them more.

How do I calculate the time it takes for something to fall?

To find fall time, use the formula: time = square root of (2 × height ÷ gravity). For Earth, gravity is 9.8 m/s². So if you drop something from 100 meters, the time = square root of (2 × 100 ÷ 9.8) = about 4.5 seconds. The calculator does this math for you instantly.

Why do objects fall at different speeds on different planets?

Each planet has different gravity strength based on its size and mass. Earth's gravity is 9.8 m/s². The Moon's gravity is only 1.6 m/s² - about 6 times weaker. Mars has 3.7 m/s². This means the same object falls slower on the Moon and Mars than on Earth.

What is terminal velocity and how do I find it?

Terminal velocity is the fastest speed a falling object can reach when air resistance equals gravity's pull. The object stops speeding up and falls at a steady speed. Use the Air Resistance tab to calculate it. You need the object's mass, size, shape (drag coefficient), and the area facing the air.

Can I use this calculator for projectile motion?

Yes! Use the 'With Initial Velocity' tab. Enter a positive number if you throw the object upward, or negative if you throw it downward. The calculator will show the maximum height reached, total flight time, and impact speed.

How does mass affect falling speed without air?

Without air, mass doesn't change how fast things fall. A bowling ball and a tennis ball dropped from the same height hit the ground at the same time. This seems weird but it's true - gravity speeds up all objects equally when there's no air resistance.

What units can I use in the calculator?

The calculator accepts many units. For height: meters, feet, kilometers, miles, inches, and centimeters. For time: seconds, milliseconds, and minutes. For mass: kilograms, grams, pounds, and ounces. For speed: meters per second, km/h, mph, and feet per second. Pick whatever units you're comfortable with.

How accurate are the energy calculations?

The energy calculations are very accurate for ideal conditions (no air resistance). The calculator finds potential energy (energy from height) and kinetic energy (energy from speed). In real life with air resistance, some energy turns into heat from air friction, so actual values may be slightly lower.


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