Enter the total number of failures and the total amount of time into the calculator to determine the failure rate. This calculate can also determine the number of failures or time when provided the other variables.

Failure Rate Formula

The following formula is used to calculate a failure rate.

fr = TF / TT
• Where fr is the failure rate (failures/time)
• TF is the total amount of failures
• TT is the total amount of time

To calculate a failure rate, divide the total mount of failures by the total amount of time.

Failure Rate Definition

What is a failure rate? A failure rate is a measure of the total number of failures that occur in a given amount of time. Most often this metric is used in industries such as manufacturing to describe failures in equipment or produced goods.

Example Problem

How to calculate failure rate?

1. First, determine the total number of failures.

For this example, there were found to be 20 equipment failures through an entire manufacturing plant.

2. Next, determine the total time.

The total time that elapsed during the time period was 40 hours.

3. Finally, calculate the failure rate.

Using the formula above the failure rate is found to be .5 failures per hour.