What is MTBF and how to calculate this index
Monitoring USA

What is MTBF and how to calculate this index

Abraão Almeida
Abraão Almeida

Tabela de conteúdos

If you've heard about MTTR, you've probably wondered what MTBF is. Right? If you have this doubt, our article will help you to better understand what this index consists of and how to calculate it.

What is MTBF?

If your company depends on machines for its operation, if these equipments are essential for the production of your final product, you need to know what MTBF is.

MTBF is another very important maintenance indicator for companies that deal with different machines and equipment.

This acronym, in English, means Mean Time Between Failures. In Portuguese, its translation would be “mean time between failures”.

In other words, we can say that the MTBF is an indicator that indicates the reliability of a given product or operating system that is repairable.

MTBF is responsible for measuring the rate of random failures that occurred during the operation of a machine or equipment.

Unlike many other indicators, that the smaller the better, the MTBF will be better used by the company when it is larger.

This is because this indicator will show, usually in hours, the time elapsed between one failure and the next. Therefore, the longer this time, the smaller the repetitions of failures that should not occur.

Was it possible to understand what MTBF is?

As we mentioned, this indicator goes hand in hand with the MTTR. In order for you to understand even better what MTBF is and its importance, let's remember the concept of MTTR and the difference that exists between these two indicators.

Know the difference between MTBF and MTTR

MTBF, Mean Time Between Failures, will measure the time that distances one failure from another. The MTTR, Mean Time to Repair, will be responsible for measuring the time it takes to repair any failure.

The MTBF indicates the reliability of a system, while the MTTR shows the effectiveness that the repair actions have. And, as can be seen, these performance indicators go hand in hand.

Understanding the concept of these two indicators is not a complicated task. However, it is important to understand that the two must be calculated together, considering that their results can provide complementary analysis for the company.

This way, in moments of decision making, it will be much easier to take the correct and necessary measures in face of the situation, whatever it may be. This is because you will have much more information at hand when using both indicators, not just one.

Now, you might be wondering how it's possible, then, to measure MTBF, isn't it? This is what we will see shortly afterwards. Read on!

How to measure MTBF?

Now that you know what MTBF is, it's important to know how to calculate this index. The math part of this index is not complicated:

MTBF = (Total available time - Lost time) / Number of stops

To make this formula easier to understand in practice, let's imagine an everyday situation within a company.

For this, let's assume that your company is an enterprise that produces plastic packaging.

Its production takes place for 16 hours a day. Therefore, 16 hours is the total time available.

One of their machines, however, had 4 failures during its operating period.

Each one of these failures took 1 hour, 2 hours, 1 hour, and the last one, 30 minutes (0.5 hour).

Thus, the total time lost was 4.5 hours.

The MTBF calculation would then look like this:

MTBF = (16 - 4.5) / 4 = 2.875 hours.

This means that, on average, every 2,875 hours your machine should experience a failure.

Obviously, the higher this number, the better. Because that will mean it will take longer for your machine to fail again.

What to do from MTBF?

Knowing what MTBF is and how to calculate this index, you need to know what to do with the number obtained as a result of the indicator.


Considering that this final number indicates the time that the machine in question will take to present a failure, we can say that based on this indicator, several decisions can be taken.

The MTBF can show, for example, that it's time to do some heavy maintenance on the equipment. Or, still, that it is time to replace this machine with another one that is in better condition.

Review of procedures

In addition, it is also possible to make changes in its procedures, if this indicator does not show a pleasant number. That's because maybe the machine doesn't have any problems in itself, maybe it just isn't being used correctly.

Finally: from MTBF, it is possible to carry out different analyzes of your machine and then make decisions based on facts and not on guesswork.

Corrective action implementation

Furthermore, as with any indicator, making use of MTBF, you will know if the corrective actions implemented are, in fact, bringing results or not.

If you observe an increase in MTBF, for example, after implementing some corrective action, you will know that this action was a correct choice.

If this does not happen, or even the opposite occurs - the decrease of this indicator -, you will know that the action being implemented is not bringing good results and, therefore, it must be changed.

Indicator monitoring

Therefore, another very important point to be highlighted is: monitor these indicators! It won't do any good to implement the use of this metric if no monitoring is done.

Only then, with the proper monitoring of the indicator, you will know the real performance of your machines and the result presented by the decisions that are taken along the way.

The use of metrics is extremely important for the management of any project, no matter what market segment it is inserted in.

Through the use of indicators, you can direct resources and efforts to areas that really need attention.

As a result, you will see your business achieving even better results.

Was our content on what is MTBF helpful to you? Do you still have any doubts? If so, get in touch with us and our team can help you with whatever you need.

Junte-se à conversa.