What Is Downtime? Meaning, Formula and a Worked Shop Floor Example
For plant heads, maintenance engineers and production planners: understand what counts as downtime, measure it the same way every shift, and act on the biggest causes.
What is downtime? It is the time a machine, line or workstation that is meant to be producing is not producing. A press waiting for a die, a CNC stopped for a broken tool and a line idle because material has not arrived are all downtime, whatever the reason.
Most Indian plants know downtime exists. Fewer can say how many minutes they lost last week, on which machine, and why. The stoppage is fixed, the shift carries on, and the lost time never reaches a register.
This page gives the plain meaning, the common formulas with worked numbers, an illustrative example, and how Apragya records each stoppage against the workstation.
Downtime meaning, types and formula
Downtime is any period when equipment that is scheduled to run is stopped. Planned downtime is agreed in advance: preventive maintenance, a changeover or a trial. Unplanned downtime is everything else: breakdowns, tool failure, power cuts, waiting for material, waiting for an operator, or a quality hold.
Availability shows the share of planned time a machine actually ran: availability = (planned production time minus unplanned downtime) divided by planned production time. Mean time to repair (MTTR) is total repair time divided by the number of breakdowns.
A worked example: an 8 hour shift is 480 minutes. Take out 30 minutes of planned breaks and planned production time is 450 minutes. If the machine stops for 45 minutes, it runs for 405 minutes, and availability is 405 divided by 450, or 90%. If those 45 minutes came from three breakdowns, MTTR is 15 minutes.
- Decide what counts as planned time.
- Record every unplanned stop with a start, an end and a reason.
- Add up the minutes by machine and by reason.
- Work out availability and MTTR for each machine.
- Compare the same figures month on month.
An example: a Rajkot pump casting unit
Take an illustrative foundry and machining unit making pump bodies. The plant head felt the VMC line was slow, but the daily report only showed pieces made. For two weeks, every stoppage was recorded with a start time, an end time and a reason.
One eight hour shift on one VMC
6:00 start
Shift begins; 30 minutes of breaks are planned.7:40 tool change
Insert worn out; 20 minutes stopped.10:15 no castings
Waiting for fettled castings; 25 minutes.12:50 power trip
Machine reset and re-zeroed; 15 minutes.14:00 shift end
60 minutes of unplanned downtime recorded.
Over the fortnight, waiting for castings was the largest reason by minutes, ahead of breakdowns. The plant moved fettling earlier in the day and kept a small buffer of castings beside the line. Availability on the VMC line rose, without buying a new machine.
What unrecorded downtime costs
Lost capacity
Minutes lost every shift add up to days of output over a year.
Late orders
Plans assume machines run; stoppages push dispatch dates out.
Overtime and rework
Lost hours are recovered with overtime, often at a higher cost.
Causes stay hidden
Without reasons on record, the same failure repeats every month.
How downtime in manufacturing is recorded in Apragya
Step 1 of 5
Against a workstation
Each downtime entry names the workstation that stopped.
- Against a workstation: Each downtime entry names the workstation that stopped.
- Start and end time: The entry stays open while the machine is down and closes with an end time.
- Duration worked out: Minutes lost are calculated when the entry is closed.
- Reason and notes: A reason and notes are recorded, with an optional link to the job card.
- Downtime analysis: Minutes by reason and by workstation, with the mean time to repair.
Choosing a way to track machine downtime
A whiteboard or a register shows today's stoppages. It rarely adds them up by reason across a month, and it cannot link a stoppage to the job that was running. Those links are what make downtime data useful in a production meeting.
A downtime register, against Apragya
| Feature | Paper register | Apragya Manufacturing |
|---|---|---|
| Start and end | Written if remembered | Recorded on the entry |
| Duration | Worked out later | Calculated on close |
| Reason | Free text, varies by shift | Recorded on every entry |
| Link to job | None | Optional link to the job card |
| Monthly view | Totalled by hand | Downtime analysis by reason and machine |
Checked against public information on 16 September 2026.
What sets Apragya apart for downtime
One production record
Workstations, job cards and work orders share one record.
AI you can put to work
An agent bound to downtime entries can summarise the week's top causes.
Mean time to repair
See how long repairs take, not just how often machines stop.
Access by role
Operators record stops; managers see the analysis.
Phone-friendly
Supervisors can record a stop from the shop floor.
Your own reasons
Keep reasons that match your machines and your plant.
See how downtime tracking works with workstations and job cards, or read about an AI agent for production bottlenecks.
Getting started with downtime tracking
- Set up your workstations and a short list of reasons.
- Ask supervisors to open an entry the moment a machine stops.
- Close each entry with an end time and a note.
- Review minutes by reason every week.
- Fix the largest cause first, then measure again.
Two weeks of honest entries usually show one or two causes worth fixing straight away.
What it costs to start
Downtime meaning, answered
Is a planned break counted as downtime?
What is the difference between downtime and idle time?
Can we record a stoppage that is still going on?
Does Apragya calculate OEE?
What does it cost to start?
See where your machine hours go
Set up your workstations, record every stop for two weeks and read the analysis.