What is MTBF & MTTR Formula Example Calculation

What is MTBF (Mean Time Between Failure)?

→ It indicates the expected time between two failures for a repairable machine or system.
→ MTBF=[(Total working time) - (Total Breakdown time)] / (No of Breakdowns)
     or        = (Total uptime) / (number of breakdowns)
→ It is very important for Total Productive Maintenance (TPM) implementation which is one of the most popular Lean Manufacturing Tool.
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MTBF Calculation:

→ Three similar_machines starting to function properly at 0 hours are working until all of them fail.
→ The first machine failed at 120 hours, the second failed at 140 hours and the third failed at 150 hours.
→ The MTBF=(Total uptime) / (number of breakdowns)
                       = [(120+140+150)]/3
                       = 136.667 hours.

→ The MTBF is the average of the three failures, which is 136.667 hrs.
→ It can be calculated as the arithmetic mean between the failures of equipment.
→ In other words, It is the average duration between the failure of equipment.
→ This value of 136.667 means that a failure in the system occurs every 136.667 hours and it generates losses for the company.
→ The opportunity is to increase the duration between two breakdowns.
→ In other words, the MTBF is the timing from one failure to another for repairable equipment.

MTBF MTTR MTTF MTTA Training Presentation

How can I improve my MTBF?

→ We can improve it by regular maintenance of machines.
→ By implementing small Kaizen activity for the equipment.
→ Make an equipment breakdown history book and take strong preventive action on it so this breakdown will not repeat in the future.

Benefits of MTBF:

→ It is a basic indicator to predict the reliability of a machine.
→ If the_MTBF has increased after a preventive maintenance activity then this indicates a clear improvement in the quality of your processes
→ It is very useful for implementing Lean Manufacturing culture in the factory.
→ The_MTBF increase will show that your maintenance or verification methods are going good.
→ It should be used to elaborate on the company’s knowledge about processes.
→ It reduces losses in productivity and also improves the quality of the product.

What is MTTR (Mean Time To Repair)?

→ It is the average time required to analyze and solve the problem and it tells us how well an organization can respond to machine failure and repair it.
→ In other words, failed equipment returns to normal operating conditions or the mean timing duration between the equipment failure and returns to operation.
→ It is a basic technical indicator related to the maintainability of the machine and repairable parts.
→ It represents the average duration required to repair a failed component.
→ In other words, how long the machine is out of production.
→ This includes notification timing, analysis timing, fixing timing, waiting, reassembly timing, alignment timing, calibration timing, testing timing, etc.
→ The formula of MTTR=Total maintenance time/number of repairs
→ It is also called as the meantime to recovery.

MTTR Calculation:

→ A machine should operate correctly for 20 hours. During this period, 6 failures occurred. The sum of all failure duration is 90 minutes.
→ The MTTR = Total maintenance time/number of repairs
                       = 90 / 6
                       = 15 minutes

Why MTTR is important?

→ It has a remarkable effect on the organization’s profit.
→ Long_MTTR means loss of productivity and sometimes, an organization can miss an order or it can impact business relationships.
→ To reduce the impact of MTTR, organizations should have their own maintenance teams and hold critical spare parts onsite or run parallel production lines.

How can I improve my MTTR?

→ We can improve it by Team Work.
→ Implement and follow the troubleshooting manual concept or breakdown history concept
→ By providing training on quick repair and motivating people
Maintaining 5S
→ Follow the standardized operation procedure.
→ Keep the critical spare in stock

Benefits of MTTR:

→ It indicates the efficiency and productivity of the equipment and it has reduced after the preventative maintenance of the machine.
→ By reducing Mean Time To Repair we can improve the efficiency and productivity of the machine.
→ Lower_MTTR indicates that your company has an immediate action plan to overcome failure.
→ It should be used to elaborate on the company’s knowledge about how strong the action plan against the machine failure.
→ It reduces losses and also improves productivity and Quality of the Product.
→ It is very useful for implementing a Lean Manufacturing culture in the factory.

👉 See Also:


  1. Great Job done with all the articles Mr. Nikuj. Thank you so much for all the information you have provided. Hope to use same in industry. i have also joined your telegram & whatsapp groups. thanks a lot again.

  2. What is important for an organization is it MTBF or MTTR?

    1. Both are very much important for the organization.

  3. There will be any available case study
    MTBF sustainable development
    Please share with us

  4. Thank you sir... Very good information

  5. Short and sweet, nice information shared, would be appropriated if you post like information, can you make on maintenance Planning and scheduling basics.

    1. Sure we will work on that. Thanks for your feedback!!

  6. how do i extract that in report in form of excel

  7. Very good summarised information and subject matter in various key areas; expertly done ; relevant overall good value adding !.

    1. Thank you very much for your kind comment and feedback

  8. Mr. Nikunj
    Thats simple and neat explanation with presenting data, thanks for posting
    I have some doubt say I have 1000 machines today i have failure of machines ABC then subsequently i will arrive at some no. of MTBF, suppose i have failure of machines XBZ then subsequently i will arrive at some no. of MTBF
    so this holds good for specific days and the same will be populated across the period then how do we infer which MTBF no. is good value ? or ideal ?
    further i would like to discuss may be by zoom call also fine for me will it be ok?
    Please advise

  9. Sir, I have received link of industrial knowledge for the implementation in process and there's so many resources but isn't downloaded....so can we download or not ??

    1. Yes you can definitely download. If you are facing any difficulty then you can reach us at contact@nikunjbhoraniya.com

  10. very good information.


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