How to measure OEE: start tracking without a big IT project

To measure OEE, record planned time, downtime, total count and good count for one machine on every shift.

Overall equipment effectiveness multiplies availability, performance and quality into one number. The number matters less than the losses behind it.

You can start measuring OEE this week with a sheet of paper. This guide explains the formula, what to record and when software starts to help.

How to calculate OEE

Availability is run time divided by planned production time. Performance is ideal cycle time times total count, divided by run time. Quality is good count divided by total count.

OEE is the three multiplied together. The OEE calculator does the math and walks through an example step by step.

The six major losses

OEE is usually analyzed through six major losses: failures, adjustments, minor stoppages, reduced speed, scrap and rework. Seiichi Nakajima described them in his work on TPM.

Each factor of OEE holds two of the losses. Knowing which loss is largest tells you which lean tool to use next.

Start with one constraint

Measure the bottleneck machine first. It sets the output of the whole line, so gains elsewhere may not raise output.

An OEE tracking sheet on paper

Put a sheet at the machine with one row per hour. Operators record the planned output, the actual output, stops longer than a few minutes and a reason code for each.

Keep the reason codes short and agreed with the team, such as no material, changeover, breakdown and quality check. Review the sheet at the daily huddle.

Make losses visible

Show the loss Pareto at the shift huddle, so the team can act on it. Andon signals help the team react while the loss is happening, not the next day.

Setup losses point to SMED. Breakdowns and minor stops point to TPM.

When to automate OEE tracking

Manual sheets catch long stops well but miss minor stops and slow running. Move to OEE software when those losses matter, or when you track more than a few machines.

The lean manufacturing guide shows how OEE fits with the other shop-floor tools.

Frequently asked questions