Calculate OEE – Simple Calculator & Formulas


Use our simple OEE Calculator below to quickly calculate OEE, Availability, Performance, and Quality. Below the OEE calculator, we discuss the formulas and details of the OEE calculations.

The Basics of OEE Performance

Most of us already know that OEE stands for Overall Equipment Effectiveness – it identifies the percentage of manufacturing run time that is spent on pure productivity.

A perfect OEE score is 100%  which means you are manufacturing only quality parts during that total time, as efficiently as possible, with zero stop time (but, this is virtually impossible). Those are 3 of the main tenants of OEE: availability, quality, and performance. You’ll learn how to calculate OEE below.

OEE performance in the manufacturing process is something more and more lean manufacturers are trying to measure more effectively and manage with greater ability. It’s considered by many as the single best metric for identifying losses, benchmarking progress, and improving the productivity of manufacturing equipment (i.e., eliminating waste). However, baselines must first be established and the data being measured must be accurate and consistent. OEE is also only effective if there’s context.

Calculate OEE in your plant. See how a SensrTrx subscription could be an easy and affordable way to use data to decrease waste and improve your bottom line.


(minutes per part)

OEE

{{oee*100 | number:0}}%

Capacity

{{capacity | number:0}}

Total Produced

{{totalQty | number:0}}

Performance

{{performance*100 | number:0}}%

Quality

{{quality*100 | number:0}}%

Availability

{{availability*100 | number:0}}%

Let’s look at how we calculated your OEE above with the formula calculator. The OEE formulas is:

Availability * Performance * Quality = OEE%

Let’s break down each component of the OEE formula calculator:

Availability

To calculate availability, we first need to determine the duration of the shift in minutes.

{{shiftStartFormatted}} – {{shiftEndFormatted}} = {{shiftLength}} minutes.

Then subtract breaks, lunches, planned stops, or maintenance included in planned downtime. (This is a downtime calculation.)

Planned Production Time Formula:

Shift Length – Planned Downtime = Planned Production Time

Planned Production Time Calculation

{{shiftLength}} – {{plannedDowntime}} = {{plannedProductionTime}}

Next, calculate the operating time of the equipment. To do this, subtract any unplanned downtime from the planned production total time.

Operating Time Formula:

Planned Production Time – Unplanned Downtime = Operating Time

Operating Time Calculation:

{{plannedProductionTime}} – {{unplannedDowntime}} = {{operatingTime}}

Now we can calculate the availability percentage.

Availability Formula:

Operating Time / Planned Production Time = Availability %

Availability Calculation:

{{operatingTime}} / {{plannedProductionTime}} = {{availability*100|number:2}}%

Performance

Performance is how the equipment is performing against its capacity. In this calculation, we use the ideal cycle time and operating time to determine how many parts the machine can produce under ideal operating conditions. We then calculate the ratio of how many parts we actually produced versus the capacity.

Capacity Formula:

(1/Ideal Cycle Time) * Operating Time = Capacity

Capacity Calculation:

(1/{{idealCycleTime}}) * {{operatingTime}} = {{capacity|number:2}}

To calculate performance, we use the total parts (units) produced, this includes any scrap or rejected parts.

Performance Formula:

Total Parts Produced / Capacity = Performance %

Performance Calculation:

{{totalQty}} / {{capacity|number:2}} = {{performance*100|number:2}}%

Quality

Quality is the ratio of good parts versus total production.

Quality Formula:

(Total Parts Produced – Total Scrap) / Total Parts Produced = Quality %

Quality Calculation:

({{totalQty}} – {{totalScrap}}) / {{totalQty}} = {{quality*100|number:2}}%

OEE Putting it Together

Now, we take each of the three components and put them in the the formula calculator above.

OEE Formula:

Availability * Performance * Quality = OEE %

Calculate OEE:

{{availability|number:2}} * {{performance|number:2}} * {{quality|number:2}} = {{oee*100|number:2}}%

Can You Really Measure & Calculate OEE?

We talk about OEE frequently in the manufacturing world; why it’s important, how to measure OEE, and why it is considered by some to be a magic number. But, to a certain extent, we need to pump the brakes on this question of measuring OEE performance. Why?

A large number of manufacturers we talk to are concerned only about their OEE number and not if it is being collected in an accurate or consistent way that can truly be tracked over time. The OEE definition manufacturing uses doesn’t take into context of what’s happening in the plant. Don’t get us wrong, they are carefully thinking about OEE, but they are more concerned with reaching a certain benchmark than they are about measuring it in a way that will allow them to see incremental progress over time. Which, is what we would argue is by far the most important thing to consider. Let us explain how you should think about and measure OEE performance.

Why it’s the Percentage Change, not the Number, that Matters

Let’s say your OEE is theoretically very high, but month to month, it averages out to little to no real change. The most important thing to observe with shop floor operations is data consistency and improvement. You want to identify outliers that are causing wild swings in OEE one way or the other.

Monitoring OEE numbers, but not overall percentage changes can hide these important observations. They also open the door to subjective interpretations of OEE versus objective data-driven changes.

How We Should Change our Thinking about OEE

Let’s pretend that most manufacturers think they need to be at a certain percentage number. Maybe they think they should be at 80% (but, world-class OEE is a myth, more on that here). Staff and stakeholders will often manipulate the calculations to arrive at those target numbers by arguing over what should be counted as downtime. This makes downtime calculation difficult, too. It does not give a true picture of how efficient the shop floor really is. It only gives a picture of how the data is calculated, collected, and skewed.

Should you include lunches and smoke breaks? Should you classify a lack of orders or a lack of raw material as planned downtime? Do planned stops count or the time to repair? These things affect those numbers. If your goal is to get to 80%, but these things can be included, or not, to arrive at the target. By focusing on percentage improvements, you will be able to measure true improvements versus goal setting achievements.

The key to doing this is by collecting consistent data and looking at percentage changes. What the actual OEE number is absolutely does not matter.

Don’t Fight about the Number, just Collect Manufacturing Data Consistently

Many organizational staff members will get into fights about how to classify this stuff and it skews the real results. It actually doesn’t matter what the OEE number is, or what you choose to collect and include and what you don’t. What fundamentally matters the most is the percentage changes over time.

What has to be done to achieve this is to collect the data the same way and ensure you have the same measurements in place over the long term. This is so important. Consistency is key to accurate data and the ability to make decisions based on that data.

Few organizations can actually do this today. This requires the ability to look at things in real-time and to see what actually occurs on the shop floor (not someone’s subjective data). But, manufacturing productivity and analytics software can do this.

You Can’t Improve What You Can’t Measure

But, let’s say you’re still focusing on OEE, and you find it is increasing. One of the most important parts about understanding what to do once you’ve increased OEE is establishing – in a credible fashion – that you actually have increased it. Duh, right? Not so fast. There are a lot of manufacturers out there that think they are reliably collecting machine data, but the data is neither accurate nor consistent.

Step 1 in determining if you are working from a consistent number should start by asking yourself, “How do I know for sure my data is right?” If you aren’t confident in your answer, consider what could be done about it. Tools like SensrTrx make it very easy to view all of your data from machines or operators. It’s easy to get the full picture of what’s happening in the plant.

Once you can confirm the reliability of the data, you can identify key metrics that you can benchmark and measure against. This is the whole point of OEE. It’s the ability to establish an efficiency metric and see if the initiatives you put in place or improvements you make in processes can improve those things (but, OEE can be flawed, so be careful). If your data is good, you can usually identify issues and do something to improve them.

Increased OEE Performance for the Win

So, you’ve done it. You’ve collected accurate data, identified inefficiencies, made improvements, and measurably increased OEE. What else is there to do?

Look closely at is exactly why you were able to increase OEE. If you fully understand the mechanisms behind the increase you can determine if improvements are permanent, seasonal, or part of a larger, more complex process, etc. Knowing this information could help you make improvements in other parts of your business.

Finalizing Changes

Fully understanding how to calculate OEE and why it goes up can be just as important as understanding why it goes down. Both impact all parts of your business and planning, and if systems of record don’t reflect performance, accuracy, and quality improvements you may never truly reap the benefits of marked improvements.

This means you need analytics that you can count on. This is where most manufacturers should start, not with an OEE number that provides almost no real context.

Interested in tracking OEE? See how a SensrTrx subscription could be an easy and affordable way to use data to decrease waste and improve your bottom line.