Mean Time to Repair (MTTR)

GM of Operations

Published 20 August 2026

MTTR (mean time to repair) is the average time taken to diagnose a failure, complete the repair and return an asset to full operation, calculated by dividing total repair time by the number of failures.

Mean Time to Repair (MTTR) measures the average time required to diagnose and fix a failed asset and return it to operational status. It includes diagnosis, sourcing parts, performing the repair, testing, and return to service, and is calculated by dividing the total repair time across all failures by the number of failure events in a given period. MTTR is a key input to availability calculations and is often tracked alongside Mean Time Between Failures (MTBF) to give a complete picture of asset reliability and maintainability. Some organisations distinguish between Mean Time to Repair (active repair time only) and Mean Time to Restore, also called Mean Time to Recover (the full elapsed time including waiting for parts, travel and administrative delays), as the broader measure often reveals improvement opportunities beyond wrench-time efficiency.

Why it matters

A high MTTR indicates inefficiencies in the repair process, such as difficulty diagnosing faults, slow parts procurement, or inadequate technician skills. Reducing MTTR directly increases asset availability and reduces the operational impact of each failure. Tracking MTTR at the asset, asset-class and site level helps maintenance managers identify bottlenecks, justify investments in training or spare parts inventory, and set meaningful targets for continuous improvement.

How MapTrack helps

MapTrack captures repair start and completion times on every work order, providing accurate MTTR data that helps teams identify bottlenecks and improve repair turnaround times.

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Frequently asked questions

How is MTTR calculated?

MTTR is calculated by dividing the total maintenance downtime by the number of repair events in the same period. For example, if an asset was down for repairs three times in a month with total repair time of 12 hours, the MTTR is 12 divided by 3, which equals 4 hours. It is important to define clearly what "repair time" includes, as some organisations measure only wrench time while others include the full elapsed time from failure detection to return to service.

What is the difference between MTTR and MTBF?

MTTR measures how long it takes to repair a failed asset (maintainability), while MTBF measures the average operating time between failures (reliability). Together they determine asset availability: Availability equals MTBF divided by the sum of MTBF and MTTR. Improving either metric, either by extending the time between failures or by reducing repair time, increases overall availability.

What factors increase MTTR?

Common factors that inflate MTTR include lack of diagnostic information, unavailable spare parts, insufficient technician training, poor access to service history, and administrative delays in work order approval. Geographic remoteness on mining or civil sites can also significantly increase repair times due to parts and specialist travel logistics.

How can teams reduce MTTR?

Effective strategies include maintaining accurate service histories so technicians can diagnose faults faster, stocking critical spare parts on-site, providing mobile access to manuals and procedures, and ensuring work orders contain all necessary information before a technician is dispatched. Standardising repair procedures for common failure modes also helps.

How is MTTR different from mean time to recover?

Mean Time to Repair measures the time to fix the faulty component, while Mean Time to Recover includes the full duration from failure detection through diagnosis, repair, testing and return to normal operation. Recovery time is always equal to or greater than repair time because it accounts for logistics, administrative approvals and post-repair validation. Both metrics are useful but measure different aspects of the response process.

Related terms

Mean Time Between Failures (MTBF)

Mean Time Between Failures (MTBF) is a reliability metric that measures the average elapsed time between inherent failures of a repairable system during normal operation. It is calculated by dividing the total operational time by the number of failures over a given period. MTBF is typically expressed in hours and is used to compare the reliability of assets, components, or equipment models.

Downtime

Downtime is any period during which an asset is unavailable for its intended function. It can be planned (scheduled maintenance, shutdowns, inspections) or unplanned (breakdowns, failures, waiting for parts). Downtime is typically measured in hours and expressed as a percentage of total available time, providing a key indicator of asset availability.

Corrective Maintenance

Corrective maintenance refers to repair or restoration work carried out after a fault, defect, or failure has been identified in an asset. It may be triggered by an operator report, a failed inspection, or an unexpected breakdown. Corrective tasks range from minor adjustments to major overhauls, depending on the severity of the issue.

Work Order

A work order is a formal document or digital record that authorises and tracks a specific maintenance task. It typically includes the asset identification, description of work required, priority, assigned technician, parts needed, safety requirements, and completion details. Work orders provide a structured workflow from request through approval, execution, and closeout.

Spare Parts Management

Spare parts management is the process of planning, procuring, storing, and issuing replacement components and consumables needed to maintain and repair assets. It involves determining which parts to stock, setting minimum and reorder quantities, managing supplier relationships, and ensuring parts are available when needed without carrying excessive inventory. Effective spare parts management balances availability against holding costs.

MTTR vs MTBF

MTBF and MTTR are the two headline metrics for equipment reliability, and they answer different questions. MTBF (mean time between failures) is how long an asset runs, on average, before it fails again - a measure of reliability. MTTR (mean time to repair) is how long it takes, on average, to get a failed asset running again - a measure of maintainability. MTBF is total operating time divided by the number of failures; MTTR is total repair time divided by the number of repairs. You want MTBF high and MTTR low, and the two combine into availability, the share of time an asset is ready to work: Availability = MTBF / (MTBF + MTTR).

Cite this definition

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Mean Time to Repair (MTTR) measures the average time required to diagnose and fix a failed asset and return it to operational status.

Short attribution: MapTrack Glossary: Mean Time to Repair (MTTR), https://www.maptrack.com/glossary/mttr
Reference list: MapTrack. (2026). Mean Time to Repair (MTTR) [Glossary definition]. Retrieved from https://www.maptrack.com/glossary/mttr

Free to reuse with credit under a Creative Commons Attribution 4.0 licence. If you’d rather link straight to it, the page is https://www.maptrack.com/glossary/mttr.