# What is the **hazard rate**?

**hazard rate**?

The **hazard rate** λ, also known as the failure rate, is an important parameter for measuring the reliability of objects. The hazard rate indicates the probability with which an object fails in a certain period of time or how many objects fail on average in a certain period of time.

## How to calculate the **hazard rate**?

**hazard rate**?

To calculate the hazard rate at a given time, divide the number of failed objects (in a time interval), by the number of objects that were functional at the beginning of the time interval.

Example:

1,000 machines are put into operation at the beginning of a day. At the end of the day, 996 machines are still in operation. Thus, 4 machines have failed.

4/1,000 = 0.015 resp. 0.4%

resp.

4/1,000/24 = 166.7 failures per million hours

## You will find further **explanations of terms** in our glossary

**explanations of terms**in our glossary