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Bryan Christiansen


Mean Time to Repair

MTTR meaning and formula (with calculator!)

Published: Wednesday, May 17, 2023 - 12:02

Benjamin Franklin said, “... in this world nothing can be said to be 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 affect on your organization’s bottom line.

In this article you’ll learn what MTTR is, why it’s important, and how to calculate and—most important—reduce it.

Mean time incident metrics overview

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

What are the key metrics your maintenance data can give you?
• MTTR (mean time to repair)
MTBF (mean time between failures)
MTTF (mean time to failure)

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

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

What is MTTR, or mean time to repair?

Mean time to repair 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’s 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 can’t calculate for on- or off-peak use times, meaning that it can’t accurately report back on overuse or quiet periods affecting repair times.

Here’s an example: When a water heater in your building breaks, it’s usually an easy and inexpensive fix. It might make strange noises, have mineral buildup, and need to be drained and repaired before a costly leak or explosion occurs. But it takes a lot longer to fix the thermostat that 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 to get the most accurate MTTR.

When you combine MTTR with a well-trained team, along with the systems to manage data and the right set of supplementary metrics to find the root causes of inefficiency, you’ll have the complete picture you’re 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’re planning resources appropriately
• Increase uptime in areas of the business that seem 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 be calculated automatically within your computerized maintenance management system (CMMS), or even with simple tools you probably already have, like Microsoft Excel or Google Sheets. We’ll walk you through every step of the calculation process.

The data needed to find your MTTR

Data are important, and high-level failure statistics require a large amount of them. 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 are wrong, so will any information be that you take away from the incident metrics you calculate from them.

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 life cycle.

There is no need to worry, however. If 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

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

Although it’s useful to know how to measure MTTR by hand, it’s impractical to do it that way every time. A simple spreadsheet makes calculating MTTR easy as long as you’re 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 a dashboard of useful KPIs.

However, if you aren’t quite ready to take the CMMS plunge, we’ve 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.

Optimize spare parts management and asset inventory management processes. This ensures that your technicians have quick access to the right tools and spare parts when they need them.

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.

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.

Streamline the repair process. Create clear standard operating procedures and maintenance checklists for repairs that are performed regularly. House these in the CMMS so they can be accessed by technicians on the job.

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 enables 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 vs. 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 similar, but with one specific distinction.

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 use, as well as additional metrics like MTTF and MTTR.

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

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

First published on April 6, 2023, by Limble.


About The Author

Bryan Christiansen’s picture

Bryan Christiansen

Bryan Christiansen is the founder and CEO of Limble CMMS. Limble is a modern, easy-to-use mobile CMMS software that takes the stress and chaos out of maintenance by helping managers organize, automate, and streamline their maintenance operations.