Calculating MTTR & MTBF with Zero Failure Metrics

Article Written by:

Ganesh Veerappan

Created On:

December 16, 2022

Calculating MTTR & MTBF with Zero Failure Metrics

Table of Contents:

Reliability is one of the few things that determines the difference between profitability and loss in the industrial sector.

The long-term objective of the maintenance managers and plant operators is the so-called Zero Failures, which implies the continuous operation of equipment with no unexpected failures. Although it is difficult to have zero failures, the highway leading to zero failures is data-driven. Particularly, two important reliability indicators are Mean Time Between Failures (MTBF) and Mean Time to Repair (MTTR).

These measures are not simple figures in a spreadsheet; these are the heartbeat of your maintenance strategy. The industry professionals state that it is expensive to operate equipment until it fails by up to 10 times as compared to running a proactive preventive maintenance program. With the control of MTBF and MTTR, you will be able to switch from fighting fires with the prediction of the same and save much time and money. This guide is going to deconstruct these metrics, the calculation, and how you can use them to propel your organization into a Zero Failure mindset.  

What Is Mean Time Between Failures (MTBF)?

Mean Time Between Failures (MTBF) is a reliability metric that measures the average time a piece of equipment operates without interruption between inherent failures. It is a critical indicator of asset health and design quality.
 

Crucially, MTBF tracks the time passed during normal operation—it excludes the time spent repairing the asset.  

Real-World Example

Consider the case of an operations manager in a steel plant. They are looking at substituting a huge industrial electric arc furnace with an expensive capital cost. Nevertheless, after considering the data of the MTBF, the manager finds that the machine is not a problem, but certain parts are breaking down regularly. They also do not substitute the whole machine; instead, they substitute only the worn parts.  

The Result: The company saves thousands of dollars in capital expenditure and extends the asset's life, all driven by MTBF insights.  

How to Calculate MTBF

Calculating MTBF is straightforward but requires accurate data logging. The formula is:  

MTBF = Total Operational Time / Number of Failures  

  • Total Operational Time: The total time the system was running and productive.  
  • Number of Failures: The count of unexpected breakdowns during that period.  

Note: MTBF focuses purely on availability. It does not include the time taken to fix the issue (that’s where MTTR comes in).  

Why It Matters

Having a high score in the MTBF shows a sound system. This measure is used to determine when a machine is most likely to fail, and hence, manufacturers can schedule preventive maintenance right before it fails and not after the production process has ceased.  

Strategies to Improve MTBF

When your MTBF is out of industry standards, then it is an indicator that your assets are wearing out or you need to modify your maintenance plan. Here is how to improve it:  

  1. Standardize Training & Best Practices. Human error is one of the most common causes of premature equipment failure. Make sure that your technicians are qualified and trained in the make and model of your machinery. When employees adhere to Standard Operating Procedures (SOPs), equipment is utilized appropriately, and this minimizes wear and tear.  

  1. Use High-Quality Replacement Parts. Poor quality replacement parts translate to high expense repair. Sparing with poor quality may reduce costs in the short term, but in many cases will result in increased repair rates, and your MTBF will be reduced by a significant amount. Use high-grade or OEM-recommended ones.  

  1. Adhere to Preventive Maintenance Schedules. Shift from reactive to proactive. You can avoid that by simply adhering to a preventive maintenance plan (lubrication, calibration, inspections), and you will solve minor problems before they lead to a complete system failure.  

What Is Mean Time to Repair (MTTR)?

While MTBF measures reliability, Mean Time to Repair (MTTR) measures maintainability.  

MTTR is the mean time to troubleshoot, repair, and bring up a failed piece of equipment. The clock commences as soon as the failure is realized and ends when the piece of equipment is completely tested and is in production once more.

Real-World Example

An example of a thermal heater is an injection molding company that installs a new thermal heater. Surprisingly, the time taken to repair begins to go out of proportion. The manager gets into the data of MTTR and discovers that the technicians have not been exposed to the new model, hence the long delayed diagnostic time. The manager decreases the MTTR by offering specific training that will allow the machine to be put on the line sooner.  

How to Calculate MTTR

In order to determine the MTTR, you have to count the actual duration of time that your group has to spend fixing.

MTTR = Total Maintenance Time / Total Number of Repairs  

  • Total Maintenance Time: The sum of all downtime caused by repairs (including diagnosis, fixing, and testing).  
  • Total Number of Repairs: The count of repair incidents.  

Insight: Since MTTR is a mean, it is prone to being distorted due to outliers (e.g., waiting weeks to get a part). Nevertheless, it is the most effective measure of detecting inefficiency in your repair process.  

How to Reduce MTTR

The lower the MTTR, the higher the availability. The way to reduce this number is as follows:  

  1. Optimize the Repair Process: Evaluate your processes. Do you squander time trying to find the tools or manuals? Make the process lean by making sure that technicians can access the resources they require instantly.  

  1. Implement Smart Inventory Management. Waiting is one of the biggest causes of high MTTR. Employ inventory monitoring to have the critical spares available at all times.  

  1. CMMS Tools Current Maintenance and Reliability programs (such as Cryotos) serve as a command center. They automatically inform the technicians about failures, give access to electronic manuals, and monitor the history of repair, which greatly accelerates the detect-to-repair cycle.  

MTBF vs. MTTR: What is the Difference?

Although they may be said to measure opposite halves of the maintenance coin, they are frequently used interchangeably:  

  • MTBF (Reliability): Measures how long you run without problems.
    •  Example: An HVAC unit runs for 40 days straight before needing service.
       
  • MTTR (Resilience): The rate at which you come back after something has gone wrong.
    • Example: A technician fixes a packaging machine in 34 minutes

Both are essential. You desire high (rare failures) and low (fast fixes) values of MTBF and MTTR, respectively. The combination of these two is what will get the desired metrics of Zero Failure.  

Managing MTBF and MTTR with Cryotos

Monitoring these measures in a spreadsheet can easily be erroneous and slow. In order to actually be heading in the right direction, towards a Zero Failure environment, you must have real-time information.  

Cryotos CMMS is made to automate this intelligence. Being a mobile-first maintenance app, Cryotos enables your company to:  

  • Log start and stop times for repairs instantly from the field.  
  • Automatically calculate MTBF and MTTR in real-time dashboards.  
  • Integrate with IoT sensors to trigger work orders the moment a machine deviates from normal parameters.  

By digitizing your maintenance management, you don't just calculate these metrics—you use them to drive decisions that extend asset life and improve the bottom line.  

Conclusion

Achieving "Zero Failure" isn't about luck—it's about intelligence. MTBF and MTTR are the critical metrics that allow you to predict failures and streamline repairs. However, relying on manual spreadsheets often leads to outdated data and costly delays. To truly optimize asset uptime and reduce costs, you need real-time automation.  

Ready to Automate Your Reliability Strategy? Cryotos CMMS tracks your maintenance metrics instantly, turning complex data into clear, actionable decisions. Stop guessing and start optimizing today.  

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