1. What is Failure Rate?

Failure rate (λ) is a fundamental reliability metric that represents the frequency at which an engineered system or component fails, expressed as failures per unit time. It is a key parameter in reliability engineering and maintenance planning.

2. How Does the Calculator Work?

The calculator uses the failure rate formula:

Where:

• \( \lambda \) — Failure rate (failures per hour)
• Number of Failures — Total count of failures observed
• Total Time — Cumulative operating time in hours

Example: If 5 failures occur in 1000 hours of operation, λ = 5/1000 = 0.005 failures/hour.

3. Importance of Failure Rate Calculation

Details: Failure rate calculation is essential for predicting system reliability, planning maintenance schedules, determining warranty costs, and making informed decisions about system design and improvement.

4. Using the Calculator

Tips: Enter the total number of failures observed and the total operating time in hours. Both values must be positive numbers, with total time greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between failure rate and failure probability?
A: Failure rate is the frequency of failures per unit time, while failure probability is the likelihood that a component will fail by a specific time.

Q2: How is failure rate related to MTBF?
A: Mean Time Between Failures (MTBF) is the reciprocal of failure rate: MTBF = 1/λ for repairable systems.

Q3: What are typical failure rate units?
A: Common units include failures per hour, failures per million hours (FPMH), or FIT (failures in time - failures per billion hours).

Q4: Does failure rate change over time?
A: Yes, most systems follow the "bathtub curve" with high initial failure rates (infant mortality), low constant rates (useful life), and increasing rates (wear-out phase).

Q5: How can failure rate data be used practically?
A: It helps in reliability prediction, maintenance planning, spare parts inventory management, and system design improvements.