Enter the aspect ratio of the wing into the Oswald Efficiency Factor Calculator. The calculator will evaluate the Oswald Efficiency Factor.

## Oswald Efficiency Factor Formula

The following two example problems outline the steps and information needed to calculate the Oswald Efficiency Factor.

**e = 1.78*(1-.045*AR^.68)-.64**

Variables:

- e is the Oswald Efficiency Factor ( )
- AR is the aspect ratio of the wing

## How to Calculate Oswald Efficiency Factor?

The following steps outline how to calculate the Oswald Efficiency Factor.

- First, determine the aspect ratio of the wing.
- Next, gather the formula from above = e = 1.78*(1-.045*AR^.68)-.64.
- Finally, calculate the Oswald Efficiency Factor.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

aspect ratio of the wing = 13

e = 1.78*(1-.045*AR^.68)-.64** **= ?