1. What is Failure Rate?

Failure Rate is a reliability metric that measures the frequency of failures per unit of exposure (time or units). It quantifies how often a system, component, or process fails during operation.

2. How Does the Calculator Work?

The calculator uses the Failure Rate formula:

Where:

• \( \text{Number of Failures} \) — Total count of failures observed (unitless)
• \( \text{Total Exposure} \) — Total operating time or number of units exposed (time or units)

Explanation: The formula calculates the failure rate as the ratio of failures to the total exposure period, providing a standardized measure of reliability performance.

3. Importance of Failure Rate Calculation

Details: Failure rate calculation is essential for reliability engineering, maintenance planning, quality control, and risk assessment. It helps organizations predict system performance, schedule preventive maintenance, and improve product design.

4. Using the Calculator

Tips: Enter the number of failures observed and the total exposure (operating time or number of units). Both values must be valid (failures ≥ 0, exposure > 0). The result is expressed as failures per unit time or per unit.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between failure rate and failure probability?
A: Failure rate measures failures per unit time/unit, while failure probability represents the likelihood of failure over a specific period or usage.

Q2: How is failure rate used in reliability engineering?
A: It's used to predict system reliability, determine mean time between failures (MTBF), and establish maintenance schedules for optimal system performance.

Q3: What are typical units for failure rate?
A: Common units include failures per hour, failures per million hours (FPMH), or failures per operating cycle, depending on the application.

Q4: Can failure rate change over time?
A: Yes, failure rates often follow a "bathtub curve" - high initially (infant mortality), then stable (useful life), then increasing again (wear-out phase).

Q5: How does failure rate relate to MTBF?
A: For constant failure rates, MTBF (Mean Time Between Failures) is the reciprocal of the failure rate: MTBF = 1 / Failure Rate.