Production and OEE
What is Machine downtime?
Machine downtime is time a machine is not producing when it should be. Planned versus unplanned downtime, common causes, and a free downtime cost calculator.
Quick answer
Machine downtime is any period when a machine is not producing while it is scheduled to. Unplanned downtime comes from breakdowns, material shortages or missing operators; planned downtime covers changeovers and scheduled maintenance. Its cost is the margin on parts not made plus idle labour, expediting and overtime to catch up.
Updated 30 October 2026. Written by the Ajinkya Technologies engineering team, reviewed by Amey Kadle.
How to estimate the cost of downtime
Monthly downtime cost ≈ downtime hours × good parts per hour × margin per part + downtime hours × idle labour cost per hour
Worked example: 1,200 minutes (20 hours) of unplanned downtime a month on a machine making 120 good parts an hour at ₹150 margin per part loses 2,400 parts, or ₹3,60,000 of margin. With ₹2,000 an hour of idle crew cost, the total is about ₹4,00,000 a month.
Downtime cost calculator
Free and instant. Nothing is stored or sent.
- Good parts not made
- 2,400 per month
- Lost margin
- ₹3,60,000
- Idle labour
- ₹40,000
- Total downtime cost
- ₹4,00,000 per month
Machine downtime explained
Downtime is the largest and most visible OEE loss, but the reported figure is usually smaller than the real one. Long breakdowns get written down; the many short stops of one to five minutes rarely do, and neither does time lost waiting for material, inspection approval or a forklift.
Causes fall into a few families: equipment failure (mechanical, electrical, hydraulic), process problems (jams, tooling, quality holds), supply (material, utilities, upstream starvation), people (no operator, skills, breaks not covered) and planning (changeovers, trials). Each family has a different owner, which is why downtime needs a reason code that maps to who can fix it.
The practical sequence is to measure automatically first, so the totals are true; ask for reasons only for stops above a threshold; rank losses by minutes or cost; and fix the top loss before chasing the rest. Predictive maintenance reduces failure downtime, changeover reduction cuts planned downtime, and line level visibility shows when a stop on one machine starves or blocks the next.
Key concepts
- Planned versus unplanned downtime
- Short stops are the most underreported
- Reason codes mapped to an owner
- Cost = lost margin plus idle labour and catch up
- Starving and blocking spread one stop down the line
Questions
What is the difference between planned and unplanned downtime?
Planned downtime is scheduled in advance, such as changeovers or preventive maintenance. Unplanned downtime is unexpected, such as breakdowns, jams or material shortages.
How do you calculate the cost of downtime?
Multiply downtime hours by the good parts you would have made per hour and by the contribution margin per part, then add idle labour, overtime and expediting costs. The calculator above does the first two.
Why is our downtime higher when measured automatically?
Manual logs miss short stops and round long ones. Automatic capture from machine signals records every stop, so the total usually rises before it starts to fall.
What is the fastest way to reduce downtime?
Rank stops by total minutes for a few weeks, then fix the single largest cause. Broad programmes without that ranking spread effort too thin.
References
How we help with downtime
Our downtime tracking takes run and stop signals straight from machines, classifies every stop, and shows the cost of each loss per line and shift; one connected line is usually the first step.
Interactive 3D demo with simulated data: watch OEE, counts and the plan react to a stop.
Go deeper
Related terms
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