APQ: Availability, Performance and Quality Explained

Definition: APQ stands for Availability, Performance, and Quality: the three components of Overall Equipment Effectiveness (OEE). Each component captures a different dimension of equipment and production loss: Availability measures losses caused by unplanned and planned downtime, Performance measures losses caused by speed reduction and minor stops, and Quality measures losses caused by defects and rework. Multiplied together, the three components produce an OEE score that reflects how effectively a piece of equipment is being used relative to its full productive potential.

The Three Components of APQ

Availability

Availability measures the proportion of planned production time during which the equipment was actually available to run. It is reduced by unplanned downtime (breakdowns, equipment failures) and planned downtime (scheduled maintenance, changeovers, planned stops).

Availability = Run Time / Planned Production Time

Where: Run Time = Planned Production Time minus Downtime (both planned and unplanned)

Example: If planned production time is 480 minutes and there were 60 minutes of downtime, Run Time = 420 minutes, and Availability = 420/480 = 87.5%.

Availability is the component most directly influenced by the maintenance program. Equipment failures, slow response to breakdowns, and unplanned stops all reduce availability.

Performance

Performance measures how fast the equipment ran during the time it was available. It is reduced by speed losses (running below the designed rate) and minor stoppages (brief interruptions that do not trigger a full downtime event).

Performance = (Ideal Cycle Time x Total Count) / Run Time

Or equivalently: Performance = Actual Output Rate / Ideal Output Rate

Example: If a machine's ideal cycle time is 1 minute per part and it produced 350 parts in 420 minutes of run time, Performance = (1 x 350) / 420 = 83.3%.

Performance losses are often caused by worn tooling, suboptimal machine settings, operator variation, or equipment running in a degraded state that has not yet triggered a full breakdown.

Quality

Quality measures the proportion of output that met specifications on the first pass. It is reduced by defects and rework.

Quality = Good Count / Total Count

Where: Good Count = Total Count minus defective, reworked, or off-spec parts

Example: Of 350 parts produced, 332 met quality specifications. Quality = 332/350 = 94.9%.

Quality losses are directly connected to equipment condition. Machines running out of tolerance, with worn tooling, or with unstable process parameters produce higher defect rates. Higher defect rates also increase production costs through scrap and rework.

How OEE Is Calculated from APQ

OEE = Availability x Performance x Quality

Using the examples above: OEE = 87.5% x 83.3% x 94.9% = 69.2%.

This means the equipment is producing at 69.2% of its theoretical maximum. The remaining 30.8% represents the combined losses from downtime, speed reduction, and defects.

A world-class OEE score is commonly cited as 85%, achieved through approximately 90% Availability, 95% Performance, and 99.9% Quality. Most facilities start well below this benchmark and improve incrementally by targeting the biggest loss category first.

What Each APQ Component Tells You About Your Maintenance Program

  • Low Availability: The primary maintenance signal. Frequent breakdowns, slow mean time to repair, excessive planned downtime, and unplanned stops all reduce availability. Improving availability requires reducing equipment failures and improving response times when failures occur.
  • Low Performance: Often a maintenance signal too. Equipment running in a degraded state frequently runs slower than its designed rate. A compressor with worn seals, a conveyor with a slipping belt, or a machine with misaligned components will all show performance losses before they show a full breakdown. Predictive maintenance programs are especially effective at catching these degraded-state conditions before they escalate.
  • Low Quality: Directly tied to equipment condition. Parts made by a machine running out of tolerance or with worn tooling will have higher defect rates. Equipment maintenance is a quality activity as much as a reliability activity.

APQ Loss Categories (Six Big Losses)

Each APQ component maps to two of the Six Big Losses framework, a structured way of categorizing all sources of production loss in manufacturing.

  • Availability losses: Equipment failures (breakdowns), Setup and adjustment losses (changeovers)
  • Performance losses: Idling and minor stoppages, Reduced speed
  • Quality losses: Process defects (scrap and rework during steady-state production), Reduced yield (startup losses and off-spec production during startup)
APQ Component Loss Category Example
Availability Equipment failures (breakdowns) A bearing failure shuts down a production line for 2 hours
Availability Setup and adjustment losses A product changeover takes 45 minutes instead of the target 20 minutes
Performance Idling and minor stoppages A conveyor jams briefly every 30 minutes, requiring an operator to clear it
Performance Reduced speed A packaging machine runs at 80% of its rated speed due to worn drive belts
Quality Process defects A CNC machine with a worn spindle produces parts that fail dimensional inspection
Quality Reduced yield The first 15 minutes of production after a startup produce off-spec parts until the process stabilizes

Protect your Availability score before breakdowns happen

Tractian's condition monitoring platform detects equipment degradation early, reducing unplanned downtime and keeping your Availability, Performance, and Quality scores on target.

See Tractian condition monitoring

Frequently Asked Questions

What does APQ stand for?

APQ stands for Availability, Performance, and Quality. These are the three components of OEE (Overall Equipment Effectiveness), the most widely used metric for measuring manufacturing equipment productivity. Each component captures a different category of production loss: downtime losses (Availability), speed losses (Performance), and defect losses (Quality).

How is APQ related to OEE?

OEE is calculated by multiplying the three APQ components together: OEE = Availability x Performance x Quality. Each component is expressed as a percentage, so a facility with 87% Availability, 90% Performance, and 95% Quality would have an OEE of 74.4%. OEE combines all three loss categories into a single score that reflects how effectively the equipment is being used relative to its full productive potential.

What is a good APQ score?

World-class benchmarks are approximately 90% Availability, 95% Performance, and 99.9% Quality, producing an OEE of around 85%. Most facilities starting a measurement program will find lower scores, and that is expected: the value of measuring APQ is not the score itself but understanding which component has the most room for improvement and targeting it.

How does maintenance affect APQ scores?

Maintenance directly drives the Availability component through its impact on equipment uptime and failure frequency. It also affects Performance (degraded equipment runs slower) and Quality (out-of-tolerance equipment produces more defects). A maintenance program focused on preventing failures through predictive and preventive maintenance strategies will improve all three APQ components, not just Availability.

The Bottom Line

APQ gives maintenance and operations teams a structured way to think about where production losses are coming from. When a facility's OEE score is below target, the APQ breakdown immediately shows whether the primary problem is downtime, speed, or quality, which points to very different root causes and solutions.

For maintenance teams, the most direct lever is Availability. Every hour of unplanned downtime is a direct reduction in Availability and a direct reduction in OEE. But the connection between maintenance quality and Performance and Quality scores means that the maintenance program's impact on production extends well beyond the breakdown log.

Related terms