Freefall Time/Distance/Speed Calculator

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This page allows you to do various calculations regarding the speed, acceleration and distance travelled by an object falling under gravity. Gravitational figures are provided for various bodies in the solar system, as well as here on earth, or you can enter your own specific choice.
Click on any of the links at the top of the page to reveal (or hide) more information about this calculator.


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At this point in time the calculators on this site are entirely dependent on JavaScript. Given enough time and money it is hoped to develop a version in the future which will be able to operate independently. Since JavaScript runs on your own computer, rather than on this server, it has been possible to set up this site much more quickly than if a server-side language was used, and it is possible to serve far more pages with the available bandwidth.
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Current vertical speed, technically known as Velocity.
Initial vertical speed relative to the particular reference point, usually ground level or sea level.
Rate of Acceleration, in freefall this will be equal to 'g' the acceleration due to Gravity, and is therefore the same as 'g' below.
This calculator assumes theoretical conditions, ie zero friction, and that the effect of gravity does not change. In reality, the force of gravity decreases slightly with height, particularly if approaching another stellar body, such as either the sun or the moon.
Time before or after a specific starting point.
Vertical displacement - distance / height above or below a reference point.
Acceleration due to gravity, usually measured in metres per second (m/s).


v = u + at
y = 0.5 g t2


  1. Enter each known quantity into the relevant text-boxes.
  2. Hit the ENTER or RETURN key on your keyboard, or press the 'CalcResult' button below the input fields.
  3. A results area will appear at the bottom of the page, showing the missing values.
  4. Click the spanner icon next to any entry to Edit, Remove or annotate that item.
  5. Press the 'Clear Results' button if you wish to discard the current results list, otherwise further calculations will be added to the bottom of the current results list.
Enter Data Here


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