Mean Time to Repair: MTTR Meaning & Formula [With Calculator!]

Benjamin Franklin once said “nothing is certain except death and taxes.” If you work in maintenance, you know that equipment failure is also on that list.

As inevitable as equipment failures are, by paying close attention to mean time to recovery (MTTR), you can make sure failures and outages are resolved efficiently, with the smallest possible impact on your organization’s bottom line.  

In this article you will learn what MTTR is, why it is important, and how to calculate and – most importantly – reduce it. 

Mean time incident metrics overview

Managing system failure well means minimizing its negative impact. To help you effectively manage losses, several critical metrics should be monitored.

What are the key metrics your maintenance data can give you? 

In this post, we will be discussing MTTR. You will find, however, that knowing how to use the three together will provide you with the most useful data and KPIs (key performance indicators). 

That being said, make sure you read our posts on MTBF and MTTF to get a complete understanding of their value and how to utilize them in tandem with MTTR to your advantage.

What is MTTR, or mean time to repair?

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. The MTTR clock starts ticking when the repair begins and continues until operations are restored.

It includes:

  • Time to troubleshoot and diagnose the problem
  • Repair time
  • Testing period
  • Time to assemble and start up the asset

Why MTTR is important

Lengthy downtime periods have a huge effect on 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.

But MTTR can be an important tool for any organization.  Lengthy repairs can indicate many inefficiencies that have easy fixes such as: 

  • Lack of training, technical knowledge, or maintenance records 
  • Insufficient availability of tools or spare parts needed to complete a repair
  • Communication delays 

What your MTTR means for your organization

MTTR is a measure, but it’s not magic. It is the number you’ll use as a guidepost but you must use it to take action and drive change in order to see meaningful improvement. 

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. If you have a single incident with vastly different incident response or repair than others, your data may be skewed. 
  • MTTR is not time-bound. It cannot calculate for on or off-peak usage times, meaning that it cannot accurately report back on overuse or quiet periods impacting repair times.

Here is an example: 

When a water heater in your building breaks, it is usually an easy and inexpensive fix. But one makes strange noises, has mineral buildup, and needs to be drained and repaired before a costly leak or explosion occurs. It takes a lot longer to fix that thermostat which will skew your results. If you have many data points to work with, you may consider removing the highest and lowest repair times in your calculation in order to get the most accurate MTTR.

When you combine MTTR with a well-trained team, the systems to manage data, and the right set of supplementary metrics to find the root causes of inefficiency, you will have the complete picture you are looking for. 

When to measure your mean time to repair

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

Mean Time Metrics Calculator

Just getting started with maintenance metrics? Use this helpful calculator with formulas and calculations.

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. We will walk you through every step of the calculation process. 

The data needed to find your MTTR

Data is important. And high-level failure statistics require a large amount of it. As we’ll show in the calculations below, the following measurements must be collected in your maintenance history.

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

Accuracy is also important. If data is wrong, so will any learnings you take away from the incident metrics you calculate from it. Worse still, if you don’t know that the information is unreliable, you might make operational decisions that could slow production or shorten the equipment lifecycle.

There is no need to worry, however, as long as you’ve tracked the total amount of time you’ve spent on maintenance and the total number of repairs, you have everything you need. 

A simple MTTR formula

How to calculate MTTR

Imagine a pump that 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

The average time for performing repairs on that pump is 20 minutes.

Each failure will have a different severity level, so while some may require days to diagnose and repair, others could take mere minutes. MTTR can give you a big-picture average of what to expect. 

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 makes calculating MTTR easy as long as you are making note of the correct data. But a CMMS software basically does all the work for you.

With a CMMS like Limble, 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 calculator. Download it, and see how nice it is to have the work done for you!

How to reduce MTTR and improve productivity

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

  1. 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. 
  2. 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 arrange a repair.
  3. Implement CMMS software. Mobile CMMS solutions like Limble allow technicians quick access to maintenance history which can speed up the repair process, reducing both planned and unplanned downtime. 
  4. Streamline the repair process. Create clear standard operating procedures and maintenance checklists for repairs that are performed regularly. House these in Limble so that they can be accessed by technicians on the job.
  5. Proper training. If you want a job done properly and in the shortest time 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 has A LOT of different meanings. The two most relevant to maintenance definitions are “mean time to repair” and “mean time to recovery.” The two are very similar, but with one specific distinction.

Mean Time To Recovery | MTTR meaning

While mean time to repair measures the troubleshooting and repair time only, mean time to recovery also includes the failure notification time. The latter comprises the entire time failure 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 that all parties agree on exactly what is being measured. 

Take the guesswork out of metrics

Now that you know what MTTR is and how and when to use it, you can get started on increasing your productivity. Remember, however, to consider outliers, off-peak period of time usage, as well as additional metrics like MTTF and MTTR. 

Additionally, using a powerful CMMS like Limble takes the guesswork out of calculating these metrics. Limble makes it quick and easy to log accurate data in real-time while you are performing maintenance tasks and uses that information to automatically calculate MTTR and other metrics for you. 

Let Limble CMMS take the guesswork out of metrics measurement and automate the process for you. Learn how we can make your life easier by placing your maintenance management in the palm of your hand. 

To learn more, schedule a quick product demo or start a free trial.

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