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Availability Calculator

Equipment Availability Calculator

Enter planned production time and downtime to get equipment availability — the first factor in OEE.

Availability
91.7%
Share of planned time the machine actually ran
Running time
440 hrs

What is equipment availability?

Availability is the share of planned production time a machine actually ran. It's one of the three factors in OEE, alongside Performance (running at full speed) and Quality (producing good parts) — and for most plants, it's where the biggest OEE losses sit.

Availability = Running time ÷ Planned production time. Running time is planned time minus downtime — both unplanned breakdowns and planned stops that happen within scheduled hours, like changeovers and setups. Only genuinely non-production time — holidays, scheduled breaks, periods with no orders — gets excluded from the planned-time denominator before you calculate.

Worked example

A machine is scheduled to run 480 hours over a month (two shifts a day). It was down for 40 hours across breakdowns and changeovers.

Availability = (480 − 40) ÷ 480 = 91.7%

A second way to get there: MTBF and MTTR

If you already track breakdown frequency and repair time per asset, there's a second route to the same number:

Availability = MTBF ÷ (MTBF + MTTR)

A machine with a 115-hour MTBF and a 6-hour MTTR has availability of 115 ÷ 121 ≈ 95%. Both methods answer the same question — use whichever numbers you already have on hand.

Availability vs. uptime vs. reliability

These get used interchangeably but answer different questions: Uptime is loosely any "machine was on" figure, often against total calendar time. Availability compares running time specifically to planned production time, so it doesn't penalize a machine for hours it was never scheduled to run. Reliability is a separate question — how likely the machine is to keep running without failure over a stretch of time, which is what MTBF measures.

Frequently asked questions

What is availability in manufacturing?
Availability is the fraction of planned production time a machine was actually running. It is calculated as running time divided by planned production time, and is one of the three components of OEE (alongside Performance and Quality).
What is the formula for availability?
Availability = Running time ÷ Planned production time. Running time is planned time minus all downtime — both unplanned breakdowns and planned stops like changeovers and setups that happen within scheduled production hours.
Do changeovers count as downtime for availability?
Yes. Nakajima's six big losses count setup and changeover time as an Availability loss because it happens during time you intended to run. Only genuinely non-production time — holidays, scheduled breaks, periods with no orders — should be excluded from planned production time.
How is availability different from OEE?
Availability is one input to OEE, not the whole picture. OEE = Availability x Performance x Quality. A machine can have 95% availability but still have poor OEE if it runs below rated speed or produces defective parts.
Is availability the same as uptime?
Related but not identical. Uptime is often measured against total calendar time (used loosely for any 'machine was on' figure). Availability specifically compares running time to planned production time — it excludes periods you never intended to run, like holidays or unscheduled shifts. Two machines can have identical uptime hours and very different availability percentages if their planned schedules differ.

Tracking this metric by hand?

MachDatum CMMS calculates it automatically from your work-order history — no spreadsheets, no manual tally.

Book a Demo Read the full OEE guide

Related calculators

OEE CalculatorMTBF CalculatorMTTF CalculatorMTTR Calculator