What does MTBF measure?

What does MTBF measure?

• A. The total uptime of a system
• B. The average length of time between failures of a product or component
• C. The time to repair a failed component
• D. The time to replace a system

Answer: (B)

MTBF measures the average time a system operates before a failure occurs. It’s calculated by taking the total operating time and dividing it by the number of observed failures. This reflects how reliable a repairable system is over time, not how long repairs take or how long the system stays up in a single stretch. For example, if a machine runs for 8,400 hours and experiences 14 failures, the MTBF would be 8,400 ÷ 14 = 600 hours. A higher MTBF indicates longer intervals between failures, while MTBF is distinct from the time to repair (MTTR) or the total uptime.

MTBF measures the average time a system operates before a failure occurs. It’s calculated by taking the total operating time and dividing it by the number of observed failures. This reflects how reliable a repairable system is over time, not how long repairs take or how long the system stays up in a single stretch.

For example, if a machine runs for 8,400 hours and experiences 14 failures, the MTBF would be 8,400 ÷ 14 = 600 hours. A higher MTBF indicates longer intervals between failures, while MTBF is distinct from the time to repair (MTTR) or the total uptime.