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physics

Free Fall Calculator

Calculate the distance fallen, final velocity, and time of fall for an object in free fall under gravity, neglecting air resistance.

Reviewed by Christopher FloiedUpdated

This free online free fall calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Enter your values below and see results update in real time as you type. Perfect for everyday calculations, homework, or professional use.

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Free Fall Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.

3

Read the results

The Free Fall Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.

4

Explore parameter sensitivity

Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.

Formula Reference

Free Fall Calculator Formula

See calculator inputs for the governing equation

Variables: All variables and their units are labeled in the calculator interface above. Input fields accept values in multiple unit systems — select your preferred unit from the dropdown next to each field.

When to Use This Calculator

  • Use the Free Fall Calculator when you need accurate results quickly without the risk of manual computation errors or unit conversion mistakes.
  • Use it to verify calculations made by hand or in spreadsheets — an independent check can catch errors before they lead to costly decisions.
  • Use it to explore how changing input parameters affects the output — a quick way to develop intuition and identify the most influential variables.
  • Use it when collaborating with others to ensure everyone is working from the same numbers and applying the same assumptions.

About This Calculator

The Free Fall Calculator is a free, browser-based calculation tool for engineers, students, and technical professionals. Calculate the distance fallen, final velocity, and time of fall for an object in free fall under gravity, neglecting air resistance. It implements standard formulas and supports both metric (SI) and imperial unit systems with automatic unit conversion. All calculations are performed instantly in your browser with no data sent to a server. Use this calculator as a quick reference and sanity-check tool during design, analysis, and learning. Always verify results against primary engineering references and applicable standards for any safety-critical application.

About Free Fall Calculator

The Free Fall Calculator determines the distance fallen and velocity reached by an object falling under gravity alone, ignoring air resistance. Free fall is a fundamental concept in mechanics, describing the motion of any object influenced only by gravitational force. On Earth, all objects in free fall accelerate at approximately 9.81 m/s² toward the center of Earth, regardless of their mass — a surprising truth first demonstrated by Galileo. This calculator applies the kinematic equations for uniformly accelerated motion.

The Math Behind It

Free fall refers to motion under the influence of gravity alone, with no other forces acting on the object. On Earth's surface, gravitational acceleration g ≈ 9.81 m/s² (varies slightly with latitude and altitude). **Galileo's insight**: All objects fall at the same rate in a vacuum, regardless of mass. A feather and a bowling ball dropped simultaneously in a vacuum hit the ground at the same time. This is because gravitational force (F = mg) is proportional to mass, but acceleration (a = F/m = g) is independent of mass. **Kinematic equations**: - d = v₀t + ½gt² (distance) - v = v₀ + gt (final velocity) - v² = v₀² + 2gd (velocity from distance) **Air resistance**: In reality, air resistance limits falling objects' velocity. A skydiver reaches terminal velocity (~55 m/s) when drag equals gravitational force. **Other celestial bodies**: g varies enormously: Moon 1.62 m/s², Mars 3.71 m/s², Jupiter 24.8 m/s². An object falling for 3 seconds on the Moon covers only 7.3 m compared to 44 m on Earth.

Formula Reference

Distance

d = v₀t + ½gt²

Variables: v₀ = initial velocity, g = 9.81 m/s², t = time

Velocity

v = v₀ + gt

Variables: v = final velocity

Worked Examples

Example 1: Drop from Rest

Object dropped from rest, falls for 3 seconds

Step 1:d = 0(3) + 0.5(9.81)(3²)
Step 2:= 0 + 44.1 = 44.1 m
Step 3:v = 0 + 9.81(3) = 29.4 m/s

Falls 44.1 m and reaches 29.4 m/s after 3 seconds.

Example 2: Thrown Down

Ball thrown down at 5 m/s, falls for 2 s

Step 1:d = 5(2) + 0.5(9.81)(4) = 29.6 m
Step 2:v = 5 + 9.81(2) = 24.6 m/s

Falls 29.6 m and reaches 24.6 m/s.

Common Mistakes & Tips

  • !Forgetting that g is constant (9.81 m/s²) and doesn't depend on mass.
  • !Confusing 'free fall' with 'falling due to gravity.' Free fall means no other forces including no air resistance.
  • !Using g = 10 for rough estimates but expecting precise answers.

Related Concepts

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Frequently Asked Questions

Why does a feather fall slower than a bowling ball?

Air resistance. In a vacuum, both fall at the same rate. Apollo 15 astronaut David Scott famously demonstrated this on the Moon.

What is terminal velocity for a human?

About 55 m/s (200 km/h) in belly-down position. Head-down dives can reach 90+ m/s.