Mean Time Between Failure (MTBF) Calculation, Explained

Every minute of downtime costs more than money — it drains momentum. One motor seizes, one conveyor stops, and suddenly your schedule is chaos. Most teams react too late because they’re guessing when parts will fail instead of knowing. That’s where mean time between failure (MTBF) comes into play. It turns equipment reliability from a mystery into a metric. By tracking how long assets actually last between breakdowns, you can forecast failures before they happen, plan maintenance without panic and budget for replacements that make sense.

We tested MTBF modeling across multiple maintenance systems, and the payoff is real: fewer surprises, fewer midnight calls. In this guide, you’ll learn how to calculate MTBF accurately — and how to use it to design a maintenance strategy that keeps production steady.

What Is MTBF?

MTBF is a maintenance metric used for calculating the average time between system breakdowns. Used correctly, it is an effective measure for determining how reliable an asset is. A high MTBF indicates that an asset can operate for longer periods of time without failure; whereas, a low MTBF signals that equipment will need frequent maintenance and cause unexpected system breakdowns.

MTBF does not account for scheduled maintenance but rather only unplanned maintenance. MTBF is one half of the mean time to repair (MTTR) formula used for measuring the average amount of time required to repair an asset that failed. 

MTTF vs. MTBF vs. MTTR

There are a variety of maintenance calculations needed to accurately calculate important metrics about your equipment and systems, including mean time between failure (MTBF), mean time to repair (MTTR) and mean time to failure (MTTF). As mentioned, MTBF is a formula for measuring the reliability of an asset and how often that asset has unplanned failures, but let’s discuss the importance of each and how they differ.

What’s the Difference Between MTBF & MTTR?

MTTR measures the average time it takes to repair a system or piece of equipment after it failed; while MTBF speaks to system reliability, MTTR shows its maintainability. 

What’s the Difference Between MTBF & MTTF?

Mean time to failure calculates how long a piece of equipment has before complete failure. Unlike MTBF, you can’t repair this type of equipment failure.

How Do You Calculate MTBF?

Calculating the average time between unplanned system breakdowns is integral to mitigating risk and understanding when failures may arise. The MTBF formula is simple. It’s calculated by dividing the number of operational hours (between failures) by the number of failures during that given period.

Let’s demonstrate this calculation with a simple example. Suppose you have an HVAC system that was operational for 1,200 hours in a year, and it broke down 10 times during that specific period of time. 

Using the formula, you divide total operational hours (1,200) by total number of failures (10). By calculating 1,200/10, the MTBF value is then 120 hours.

Why Should You Calculate MTBF?

Calculating MTBF is integral to effective asset management by determining the likelihood and frequency of an asset failure occurring. Here are the core ways performing MTBF can support a maintenance team’s asset management strategy:

• Set a baseline for preventive maintenance: By understanding the types of failures that are likeliest to occur and when, you can build a preventive maintenance plan for enhancing asset dependability and preventing the failure from even occurring in the first place. 
• Planning for specific types of failures: Understanding which failures happen most frequently allows you to plan accordingly to ensure costly delays or safety hazards don’t arise. 
• Better parts inventory management: If you know when an asset is likely to fail, you can pre-order replacement parts so that they’re in stock as needed for repairable items.
• Knowing when to replace an asset: If a piece of equipment has a worsening MTBF and a frequent failure rate, using this key performance indicator (KPI) can make it easy to dictate when replacing equipment is more worthwhile than repairing it. 

How to Improve MTBF

Investing in your infrastructure can help extend the total operating time between failures for core business systems. As such, here are the best ways to improve MTBF for your equipment and systems:

Invest in Better Quality Parts & Systems

Being cheap when it comes to equipment and parts come at a cost. Failures are likely to happen more frequently, requiring expensive repairs and causing unplanned downtime and outages. Consider a proactive approach by purchasing high-quality equipment at a higher cost to save money and to increase the total uptime for your assets in the long-term. 

Follow Manufacturer Recommendations 

Ensure your equipment is operated and maintained with optimal conditions. Manufacturers perform extensive testing to dictate the best ways to use and maintain their equipment, and proper usage ensures there is no misuse that can cause more frequent failures.

Create a Preventative Maintenance Plan

Proactively maintaining your equipment by checking on core components that commonly fail can ensure you catch potential issues before they turn into serious and costly system failures. Schedule maintenance tasks to regularly check on your equipment, especially on infrastructure with a low MTBF. 

Key Benefits to Improving MTBF 

By focusing on improving MTBF, businesses can reduce downtime, optimize maintenance costs and enhance overall operational efficiency. Here are major benefits that come with focusing on MTBF:

Increases Asset Reliability & Lifespan

Improving MTBF means less part failures and more reliable system operations. When equipment components operate functionally for longer periods, they deal with less stress and wear, leading to fewer repairs and longer useful life.

Reduces Maintenance Costs

By reducing the total number of equipment failures, you won’t have to pay for costly emergency maintenance as frequently. Additionally, longer time frames between failures means you can optimize your recurring maintenance schedule to be more efficient and organized to prevent downtime and lower costs.

Enhances Quality 

When breakdowns and disruptions occur less frequently, machines will maintain optimal performance levels longer, leading to a consistent production output, less manufacturing process errors and stability across business procedures.

Creates Workplace Safety

By reducing the likelihood of unanticipated equipment failures, there is a risk reduction of accidents caused by malfunctioning equipment. And with less emergency maintenance needs, you’re limiting the total time maintenance workers need to spend in potentially dangerous work environments repairing broken parts. 

Makes Purchasing Decisions Easier

Having metrics on the reliability and functionality of equipment can help in making informed decisions across particular systems. By calculating MTBF when acquiring new equipment, business owners can determine the lifecycle costs of equipment beyond the initial purchase price, leading to more informed purchases of machinery that will function longer without frequent failures and costly repair needs. 

Using a CMMS for MTBF Calculations

Using a computerized maintenance management system (CMMS) like Coast can make calculating MTBF and managing your equipment substantially easier because it helps you automatically track data on equipment run times, failure occurrences and historical repairs. With access to this data in an easy-to-understand maintenance report, your MTBF calculation will be simple to calculate and much more accurate.

Beyond the calculation, once you understand how frequently recurring maintenance is needed to maintain your equipment and prevent failures and downtimes, you can use automations to schedule maintenance work orders as needed to check on important equipment and maintain optimal operating conditions. 

Don’t wait to collect the maintenance data your business requires to calculate mean time before failure accurately. Get started with Coast today to organize all your maintenance needs in one simplified digital platform.