Preventive Maintenance Compliance (PMC) is a metric that measures the percentage of scheduled preventive maintenance work orders completed on time within a defined period. PMC is the primary indicator of whether a PM program is being executed as designed — not whether the program exists on paper, but whether the work is actually getting done at the intervals and standards required to prevent equipment failures.
A PM program that exists in the CMMS but is not executed consistently does not prevent failures. It creates the appearance of a maintenance program while delivering none of its reliability benefits. PMC makes that gap visible. A facility with 500 scheduled PMs per month and a 60 percent PMC rate has 200 missed maintenance events every month — each one a potential failure that the PM was designed to prevent.
PMC is most meaningful when paired with the right definition of compliance. Counting a PM as complete regardless of when it was finished overstates program performance. The 10% rule — which counts a PM as compliant only if completed within 10 percent of its scheduled interval — produces a more accurate measure of whether the program is delivering its intended reliability benefit.
Why PMC Matters
PM programs represent a significant investment of maintenance labor, parts, and downtime. PMC measures the return on that investment. A high PMC rate indicates that scheduled maintenance work is being executed consistently and that the program’s reliability benefits — reduced unplanned failures, extended component life, predictable maintenance costs — are being realized. A low PMC rate indicates that the investment is being made without the return.
PMC also serves as an early warning system for maintenance program problems. When PMC declines, the cause is usually one of four things: insufficient technician capacity to execute the scheduled work volume, a PM schedule that is too dense relative to available resources, a parts or materials problem that prevents work orders from being completed, or a prioritization problem where reactive work is consistently displacing planned work. Each cause requires a different management response — and PMC is what makes the problem visible before it produces a pattern of unplanned failures.
For regulated industries, PMC is an audit metric. Inspectors examining a maintenance program look at whether scheduled PMs are being completed on time as evidence of program effectiveness. Consistently low PMC on safety-critical or regulatory-required maintenance tasks creates compliance exposure that goes beyond operational risk.
How PMC Is Calculated
The PMC Formula
PMC is calculated as:
PMC = (Completed PMs / Scheduled PMs) x 100
For a given period, count the number of preventive maintenance work orders scheduled and the number completed. Divide completed by scheduled and multiply by 100 to get the compliance percentage. Only PM work orders are included — corrective and reactive work orders do not count regardless of whether they were planned in advance.
Example: A facility schedules 120 PM work orders in a month. The maintenance team completes 96. PMC = (96 / 120) x 100 = 80%.
The 10% Rule
A PM counted as complete regardless of when it was finished overstates compliance. A work order scheduled for day 1 and completed on day 28 of a 30-day interval was late by nearly the full cycle — yet a simple completion count treats it identically to a work order completed on time.
The 10% rule addresses this by counting a PM as compliant only if completed within 10 percent of its scheduled interval. A PM on a 30-day cycle is compliant if completed within 3 days of its due date. A PM on a 90-day cycle is compliant if completed within 9 days. Work orders completed outside that window are counted as non-compliant even if eventually finished.
The 10% rule produces a more accurate PMC measure because it reflects whether the maintenance interval is actually being honored — which is what determines whether the PM delivers its intended reliability benefit. A bearing lubrication task on a 30-day interval that consistently runs 25 days late is not providing 30-day lubrication protection regardless of what the completion record shows.
PMC Benchmarks
Industry benchmarks for PMC:
- 90% and above: World-class. The PM program is being executed consistently and is delivering its reliability benefit.
- 85 to 90%: Good. Some improvement opportunity exists but the program is fundamentally sound.
- Below 85%: Systemic issues exist. Capacity, scheduling, parts availability, or prioritization problems are preventing consistent PM execution and should be investigated.
PMC below 85 percent sustained over multiple months typically indicates that the PM schedule volume exceeds available maintenance capacity — a scheduling problem, not an execution problem. Reducing PM schedule density on lower-criticality assets to protect execution quality on Tier 1 critical assets is often more effective than attempting to improve execution across the board with insufficient resources.
PMC by Industry
Manufacturing: PMC is a standard KPI in manufacturing maintenance departments, often reported weekly to operations leadership alongside OEE. In TPM environments, PM compliance rates are tracked at the asset level — low PMC on a specific asset or asset class points directly to where unplanned failures are most likely to originate. High-volume production facilities target 90 percent or above PMC on production-critical equipment as a prerequisite for reliable throughput.
Mining: Mobile equipment in mining operates on strict service intervals tied to operating hours rather than calendar time. PMC in mining is typically measured against hour-based PM triggers — haul truck engine services, hydraulic system inspections, conveyor drive overhauls. Deferred PMs on high-utilization equipment in demanding conditions accumulate failure risk rapidly, making PMC tracking on mobile equipment a production continuity issue as much as a maintenance metric.
Oil and Gas: Regulatory frameworks in oil and gas require documented completion of safety-critical maintenance tasks — pressure relief valve testing, emergency shutdown system checks, rotating equipment inspections. PMC on safety-critical work orders is a compliance metric with regulatory consequence. Incomplete safety-critical PMs identified during an audit can result in regulatory action regardless of whether a failure has occurred.
Crane and Rigging: ASME B30 standards and OSHA regulations require periodic inspection of cranes and lifting equipment at defined intervals. PMC on regulatory inspection work orders is a legal compliance requirement — a crane operated past its required inspection interval creates liability exposure regardless of apparent condition. PMC tracking in crane operations must distinguish between regulatory inspection tasks, where non-compliance has legal consequence, and routine maintenance tasks, where non-compliance has operational consequence.
Common PMC Program Failures
Counting completions without applying the 10% rule: Completion-based PMC that does not account for lateness overstates program performance and masks chronic schedule slippage. A team consistently finishing PMs two weeks late on monthly intervals has a 100 percent completion rate and a reliability program that is not delivering its intended benefit.
PM schedule volume exceeds available capacity: The most common cause of chronic low PMC is a PM schedule that was built without accounting for realistic technician capacity. When planned work volume consistently exceeds available hours, reactive work displaces PM work every week. The solution is schedule rationalization — reducing PM density on lower-criticality assets to protect execution quality on critical equipment — not simply pushing harder on the same schedule.
PMC measured but not acted on: Tracking PMC without investigating the cause of non-compliance produces a metric without improvement. When PMC falls below target, the response should be a structured analysis: which assets, which task types, which time periods are driving non-compliance, and what resource, scheduling, or process change would address the root cause.
No distinction between asset criticality tiers: A single facility-wide PMC number obscures which assets are receiving consistent maintenance and which are not. A 90 percent facility PMC that includes 70 percent compliance on Tier 1 critical assets and 100 percent compliance on Tier 3 non-critical assets represents a worse reliability outcome than an 85 percent overall PMC with uniform compliance across tiers. PMC should be tracked and reported by asset criticality tier.
Reactive work not tracked separately: When reactive and corrective work orders are mixed into the PM compliance calculation, the metric loses meaning. PMC measures planned maintenance execution. Reactive work is a separate category that should be tracked as a ratio to planned work — the planned-to-reactive maintenance ratio — as a complementary indicator of program health.
PMC vs. Related Metrics
- Preventive Maintenance Compliance (PMC): Percentage of scheduled PM work orders completed on time. Measures PM program execution quality.
- Planned Maintenance Percentage (PMP): The ratio of planned maintenance hours to total maintenance hours. Measures how much of the total maintenance workload is planned versus reactive. PMC measures whether the planned work gets done; PMP measures how much of total work is planned.
- Wrench Time: The percentage of a technician’s available time spent performing actual maintenance work. Low wrench time reduces PMC capacity. See: Wrench Time.
- Mean Time Between Failures (MTBF): Measures asset reliability over time. Sustained high PMC should produce improving MTBF on maintained assets — the relationship between these metrics validates whether the PM program is correctly designed. See: Mean Time Between Failures (MTBF).
- Overall Equipment Effectiveness (OEE): Production performance metric that captures availability, performance, and quality losses. Sustained high PMC on production-critical assets should improve OEE Availability over time. See: Overall Equipment Effectiveness (OEE).
Frequently Asked Questions
What is a good PMC rate?
90 percent or above is the world-class benchmark for PMC — meaning 90 percent of scheduled PM work orders are completed within the 10% rule window. Rates below 85 percent indicate systemic execution problems that should be investigated and addressed. The benchmark is most meaningful when applied to Tier 1 critical assets specifically — a facility with 95 percent overall PMC but 75 percent PMC on its most critical equipment has a reliability problem that the aggregate number conceals.
How do you improve PMC?
Start by identifying whether the PMC problem is a capacity problem or an execution problem. If scheduled PM volume consistently exceeds available technician hours, the schedule needs to be rationalized — reducing density on lower-criticality assets to protect execution on critical equipment. If capacity is adequate but compliance is still low, investigate parts availability, work order clarity, and whether reactive work is systematically displacing planned work. PMC improvement requires diagnosing the specific constraint, not simply setting a higher target.
Why use the 10% rule for PMC?
The 10% rule counts a PM as compliant only if completed within 10 percent of its scheduled interval — 3 days for a 30-day PM, 9 days for a 90-day PM. Without this rule, a simple completion count treats a PM finished the day before the next cycle is due identically to one finished on schedule. The 10% rule ensures that PMC reflects whether the maintenance interval is actually being honored, which determines whether the PM is delivering its intended failure prevention benefit. A lubrication task completed 25 days late on a 30-day cycle is not providing 30-day lubrication protection.
How does a CMMS track PMC?
A CMMS tracks PMC by recording the scheduled due date and actual completion date for every PM work order, then calculating compliance based on whether completion fell within the defined tolerance window. PMC reports can be generated by asset, asset class, technician, time period, or criticality tier. The CMMS also identifies which specific work orders are overdue at any point in time, enabling proactive management of schedule slippage before it accumulates into a compliance problem. Without a CMMS, PMC calculation requires manual data aggregation from paper records or spreadsheets — a process that is too slow to support timely management response.
Related Terms
- Preventive Maintenance (PM)
- Overall Equipment Effectiveness (OEE)
- Mean Time Between Failures (MTBF)
- Wrench Time
- Asset Criticality Ranking (ACR)
- Maintenance SOP (Standard Operating Procedure)
- Computerized Maintenance Management System (CMMS)
Track and Improve PM Compliance With Redlist
Redlist generates real-time PMC reporting by asset, criticality tier, and time period — so maintenance teams can identify schedule slippage before it becomes a pattern of unplanned failures.
