Mean Time To Repair (MTTR)

What is Mean Time To Repair (MTTR)?

Mean Time To Repair (MTTR) is the average amount of time it takes to repair a system or piece of equipment and restore it to full functionality after a breakdown. For this measurement, the clock starts ticking when the repair begins and continues until operations are restored.

It includes:

• Diagnostic and troubleshooting
• Repair
• Testing period
• Reassembly and restart

Table of Contents

Why MTTR and incident metrics are important
What your MTTR means
How to calculate MTTR
5 ways to use MTTR to improve productivity
Take the guesswork out of metrics

Why MTTR and incident metrics are important

Lengthy periods of downtime can have a huge impact on your organization’s productivity. In a manufacturing environment, long mean time to repair leads to missed production deadlines, increased labor costs, loss of revenue, and various operational issues.

Regularly measuring MTTR is also critical. It is a standard measure of maintenance productivity and can indicate inefficiencies that have easy fixes such as: 

• Lack of maintenance training, technical knowledge, or work records 
• Insufficient availability of tools or spare parts
• Communication delays

What your MTTR means

MTTR is helpful, but it is not magic. It is a number you can use as a starting point for taking action to drive change toward meaningful improvement. 

But because there are so many ways to interpret MTTR, success will only come when you dig deep into the data to explore patterns and outliers. It is important to keep a few things in mind.

MTTR can easily be distorted by outliers 

It is inevitable that you will experience incidents here and there with vastly different repair times than usual. This may be the result of factors such as: 

• Repairs that are delayed to avoid peak usage times
• Unusually long shipping times for necessary parts
• Specialized or outsourced expertise needed to complete a repair

These incidents are especially important ones to explore. Identifying their root causes will often expose valuable learnings and opportunities to improve and plan for similar situations. 

However, if outliers are included in your MTTR calculation, they will skew your results. Make sure to remove these one-offs when measuring your average or “mean” time to repair. 

Measure MTTR for the right reasons

There are many different metrics that can be used as key performance indicators for your maintenance team. MTTR is common because it is such a simple yet useful representation of your response times and incident response process.  

However, MTTR provides just one piece of the puzzle when solving for system failures and outages. So how do you know when to use MTTR and when to rely on other measures? Use MTTR when you want to: 

• Measure and improve the average time your team takes to repair assets
• Understand how much time you should be scheduling for repairs so that you are planning resources appropriately
• Increase uptime in areas of the business that seems to be constantly on hold due to repairs
• Pick out anomalies in incident management

How to calculate MTTR

Calculating MTTR doesn’t have to be hard. MTTR can even be calculated automatically within your CMMS, or even with simple tools you probably already have access to like Microsoft Excel or Google Sheets. They key is to make sure you have the right data on hand, and that it is accurate.

The data needed to find your MTTR

Data is important. And high-level failure statistics are only valuable if you collect accurate data consistently. If your data is wrong or incomplete, so too will be any reports, averages, or learnings to try to find from it.

For MTTR, you will need:

• Labor hours spent on maintenance 
• Number of breakdowns and repairs
• Operational time

A simple MTTR formula

MTTR is simply the ratio of maintenance time to the number of repairs.

For example, if a pump fails three times throughout a workday. The first repair lasted for 30 minutes, while the other two repairs lasted only 15 minutes. In this case:

MTTR = (30 + 15 +15) / 3

MTTR = 60 / 3

MTTR = 20 minutes

So in this example, repairs to that particular pump on that particular day took 20 minutes on average. You can now assume that most repairs on that pump will also take about 20 minutes per failure and you can plan your maintenance time and resources to accommodate that. 

While this example may feel small in scale (becuase it is), it can easily include as many pumps or assets over whatever period of time you would like. Ultimately, you can calculate your organization’s overall MTTR and set global goals for improvement. 

How to calculate MTTR using Excel and other reporting tools

While it is good to know how to measure MTTR by hand, it is impractical to plan to do it that way every time. A simple spreadsheet using formulas makes calculating MTTR easy as long as you have the correct data. But a CMMS software does all the work for you.

With a CMMS, equipment failures are logged through the work request process, tracking downtime and operational time automatically. As a result, your mean time metrics begin calculating the second you begin using the system, building you a dashboard of useful KPIs. 

However, if you aren’t quite ready to take the CMMS plunge, we have created a handy mean time metrics calculator. Download it, and see how nice it is to have the work done for you!

5 ways to use MTTR to improve productivity

Efficient maintenance teams are always looking for opportunities to improve and reduce MTTR. That can be done in many different ways:

1. Segment MTTR calculations to find areas with the biggest opportunity to improve. Calculate your MTTR for specific locations, asset types, and time periods. This will help you set baselines and find areas where small changes can have the biggest impact on your global MTTR.
2. Optimize spare parts management and asset inventory management processes. This ensures your technicians have quick access to the right tools and spare parts when they need them, minimizing repair time. 
3. Use condition-monitoring sensors to track machine health and performance. Sensors are typically used to prevent unexpected failures, but sensor data can also speed up the diagnosis and troubleshooting process, giving your team more time to perform a repair.
4. Implement CMMS software. Mobile CMMS solutions allow technicians quick access to maintenance history which can speed up the repair process, reducing both planned and unplanned downtime. 
5. Streamline the repair process. Create clear standard operating procedures and maintenance checklists for repairs that are performed regularly. Make them accessible and interactive in your CMMS so technicians can use them on the job.
6. Proper training. If you want a job done properly and in the shortest time frame possible, your technicians need to know what they are doing. Limble allows you to track the productivity of each technician and identify those who need additional training, ensuring you give the best quality service every day. 

Mean time to repair versus mean time to recovery

MTTR can stand for many similar but slightly different maintenance metrics. The two most common are “mean time to repair” and “mean time to recovery” (also referred to as “mean time to restore”). The two are very similar, but with one specific distinction.

In contrast to mean time to repair, mean time to recovery or restore also includes the failure notification time, totaling the entire time from occurrence, to resolution.

Although these terms are often used interchangeably, they  must be clearly defined within your team and also in Service Level Agreements (SLAs) and maintenance contracts. This ensures all parties agree on exactly what is being measured.