Enter the height of an object and the angle of the source of light measure from the ground to calculate the shadow length. This calculator can also evaluate the height or angle given the other variables are known.

Shadow Length Formula

The following formula is used to calculate the length of a shadow cast by an object.

L = H / tan (a) 
  • Where L is the length of the shadow
  • H is the height of the object
  • a is the angle to the source of light (typically the sun)

To calculate the length of a shadow, divide the height of the object by the tangent of the angle from the object to the light source.

What is the length of my shadow?

The length of your shadow depends on how tall you are and where the sun or source of light behind you is in relation to the ground. The lower the angle of the sun the longer the length of the shadow. Also the taller you are the longer the shadow.


How to calculate shadow length?

  1. First, determine the height.

    Measure or calculate the height of the person or object.

  2. Next, determine the angle of the light.

    Measure the angle from the surface of the shadow to the source of light.

  3. Finally, calculate the shadow length.

    Calculate the length of the shadow using the equation above.


What is a shadow?

A shadow is a darker reflection of an object caused by the blocking of a light source from the reflection surface.