How to Calculate Failure Rates

Manufacturers of computer cables will know the failure rates of their products.

Calculating failure rates is important in everything from manufacturing car parts to shooting baskets in a game of basketball. A failure rate is usually expressed as the percentage of times that something didn't work, or failed, as compared to the number of times it was tested. You can calculate the failure rate of your basketball shooting to give you a sense of how good of a shooter you are. On the other hand, a company that manufactures parking brakes for cars needs to know the failure rate of the parts it makes. The company will then make it its goal to reduce the failure rate to near zero.

Things You'll Need

• Calculator

Instructions

1. Conduct the trials or analyze the data that will tell you how many times something fails in a given number of tests. As an easy example, suppose you shoot 20 baskets and miss, or fail, seven times. What is your failure rate?

2. Divide the number of failures by the total number of trials. In the example, there were seven failures in a total of 20 trials, 7 / 20 = 0.35.

3. Multiply your answer from the previous step by 100 percent to calculate the failure rate. For the example, the calculation would look like this:

   Failure rate of basketball shots = 0.35 x 100 percent = 35 percent

   You can then say that your failure rate for shooting baskets is 35 percent.

References

• Oklahoma State University: Restaurant Failure Rates