Free tool
Availability calculator
Availability has two standard definitions in manufacturing — this tool computes both, side by side, from whichever inputs you have.
Method A — OEE-component definition
Method B — reliability-engineering definition
These two methods use different inputs and are not the same calculation — Method A comes straight from a shift’s time log, Method B from a longer run of failure and repair history. A gap between them is normal and informative: Method B ignores every stop that was not a failure, so it usually reads higher, and the difference is roughly what changeovers, planned maintenance and waiting are costing you. Use whichever matches the data you already have.
How the calculation works
Method A — the OEE-component definition: availability = run time ÷ planned production time. This is exactly the Availability figure inside the OEE calculation — it comes from a single shift or period’s time log and answers “of the time we planned to run, how much did we actually run.”
Method B — the reliability-engineering definition: availability = MTBF ÷ (MTBF + MTTR). This comes from failure/repair history over a longer window and answers “across many breakdown-and-repair cycles, what fraction of time is the machine expected to be up.” See the MTBF and MTTR calculators for each half of that formula.
The two aren’t interchangeable inputs into each other — they’re independent calculations that tend to agree for a stable process, and diverge when something’s off (a machine that’s reliable in the long run but had one bad shift, or vice versa). Divergence itself is a useful signal.
This calculator is for a single machine, computed by hand from whichever inputs you have on file. ThingConnect computes both definitions continuously, for every machine, straight from controller data — no manual time log or failure tally required.