The seven wastes of Lean are called Muda, non-value-adding activity. Practitioners remember them using the acronym TIMWOOD. Taiichi Ohno identified them at Toyota decades ago. But Muda is only one of three related concepts. Mura and Muri usually cause Muda to appear. This guide names all seven wastes and explains the root-cause order. You’ll also see real examples beyond the factory floor.
| Waste | One-Line Meaning |
| Transportation | Moving materials with no added value |
| Inventory | Stock sitting idle, unused |
| Motion | Unnecessary movement by people or machines |
| Waiting | Idle time between process steps |
| Overproduction | Making more than the customer needs |
| Over-processing | Doing more work than required |
| Defects | Output that requires rework or scrap |
Table of contents
Key Takeaways
- The seven wastes of Lean are remembered by the acronym TIMWOOD.
- Muda, Mura, and Muri are three distinct, related concepts.
- Mura and Muri usually cause Muda to appear in the first place.
- Overproduction is the root waste; it triggers the other six.
- A later, eighth waste, Non-Utilized Talent, expanded TIMWOOD to TIMWOODS.
What Are the 7 Wastes of Lean?
TIMWOOD is the acronym for the seven categories of waste.
Transportation, Inventory, Motion, Waiting, Overproduction, Over-processing, and Defects make up TIMWOOD. Taiichi Ohno identified these seven categories while building the Toyota Production System. Each category represents a way resources get consumed without adding customer value. The table above summarizes what each waste actually looks like.
1. Transport
This is when you move resources (materials) and the movement doesn’t add value. The excessive movement of materials can cause quality problems and cost your business. Transport can often force you to pay additional for space, time, or machinery.
2. Inventory
A company may have excess inventory because they keep “just in case” stocks. Companies may overstock to meet unanticipated demand or protect against production delays, low quality, and other problems. These excessive inventories are often not sufficient to meet customer needs and do not add value. They increase storage costs and depreciation costs.
3. Motion
This type of waste can include the movement of employees or machinery, which is complicated and unneeded. They can lead to injuries and prolonged production times. Also, you should do everything possible to make sure workers do their jobs as efficiently as possible.
4. Waiting
This is the most obvious waste that you can identify. The “waiting waste” is when goods or tasks stop moving. Because lost time is the most obvious indicator, it is easy to identify. It could be goods that are still to be delivered, equipment that is not yet fixed, or documents waiting for approval from executives.
5. Overproduction
It is easy to see why excess production is Muda. Overproducing means you produce more than the customer needs, which can lead to higher costs. Overproduction actually causes the six other wastes to emerge. Excessive products or tasks can lead to increased transportation costs, more motion, longer waiting times, and other problems. If a defect occurs during overproduction, your team will have to rework additional units.
6. Over-processing
This is usually caused by work that does not add value or provides more value than necessary. These extra features can add cost to your business by adding unnecessary features to products that no one will use. A car manufacturer might decide to install a TV in the trunk of its vehicle. It is unlikely that anyone will use it. It will also cost resources and increase the price of the product, which customers will not be willing to pay.
7. Defects
Defects may lead to rework or worse, scrap. Defective work must be returned to production, which can lead to lost time. In some cases, additional reworking is necessary, which can lead to increased exploitation of labor and other tools.
The 7 types of waste can be toxic for your business, as you can see. You can view them as opportunities to improve work processes, and most importantly, optimize resource utilization. Different businesses may have different requirements for the seven types of waste.
Public, Onsite, Virtual, and Online Six Sigma Certification Training!
- We are accredited by the IASSC.
- Live Public Training at 52 Sites.
- Live Virtual Training.
- Onsite Training (at your organization).
- Interactive Online (self-paced) training,
Where the 7 Wastes Fit Inside Muda, Mura, and Muri
The seven wastes are all Muda; two other concepts often cause them.
Muda means waste, and the seven wastes are all Muda. Mura means unevenness, or inconsistent pace and volume of work. Muri means overburden, or pushing a person or machine past capacity. In practice, Mura and Muri often create the Muda you actually see.
Not All Muda Is Equal: Type 1 vs. Type 2
Some waste is unavoidable; other waste should be eliminated entirely.
Type 1 Muda covers non-value-added steps the customer still requires. A safety inspection adds no direct value but keeps the customer safe. Type 2 Muda covers waste with no benefit to anyone at all. A duplicate approval step nobody actually needs falls into this category. Teams should tolerate Type 1 waste but aggressively eliminate Type 2 waste.
Fix Mura and Muri First, Not the Waste You See
Attacking visible waste without fixing its root cause lets that waste return.
Picture a Six Sigma trainer scheduled for three back-to-back classes in one day. That schedule is Muri, since it overburdens one instructor past a reasonable pace. The uneven pace then creates Mura across the week’s other days. Muda then follows: idle classroom time on light days, rushed feedback on heavy ones. Fixing the schedule first prevents both problems from recurring. Fixing only the symptom, like adding a second grader, treats Muda alone.
Also Read: Mura, Muda, Muri: Lean Manufacturing’s 3 Key Wastes Explained
Overproduction: The Root Waste That Creates the Other Six
Overproduction is the one waste that triggers all the others.
Making more than the customer ordered creates excess inventory immediately. That excess inventory then needs extra transportation and storage space. Extra motion follows, as staff handle and move the surplus repeatedly. Waiting appears too, once downstream steps cannot absorb the extra volume. Any hidden defect in the batch now multiplies across every extra unit made. Controlling overproduction first often shrinks the other six wastes automatically.
TIMWOOD vs. TIMWOODS: Why an Eighth Waste Got Added
A later addition recognized wasted human potential as its own category.
Ohno’s original seven wastes focused entirely on materials and process flow. Practitioners later added an eighth: Non-Utilized Talent, sometimes called Skills. That waste covers ideas, skills, and knowledge a company never taps. TIMWOOD became TIMWOODS once that eighth category caught on widely.
Real Examples of the 7 Wastes in an Office, Not a Factory
Every one of these wastes shows up in knowledge work too.
Waiting shows up when an approval email sits in someone’s inbox for days. Overproduction shows up as a weekly report nobody actually reads. Over-processing shows up as a five-approval sign-off chain for a low-risk purchase. Transportation shows up when a file gets forwarded across six different people.
Motion shows up as searching a shared drive for a document with no clear owner. Defects show up as a proposal that gets sent back for the same repeated error.
Also Read: What Are The 8 Wastes of Lean?
How to Find the 7 Wastes: Value Stream Mapping
A Value Stream Map exposes waste at every single process step.
Teams map every step a product or request travels through. Each step gets marked as value-added or non-value-added. Non-value-added steps almost always map directly to one of the seven wastes. The map also reveals wait times between steps, which is where waste often hides. Teams then prioritize which mapped waste to attack first.
Where the 7 Wastes Fit in a DMAIC Project
Waste identification belongs in the Analyze and Improve phases.
Teams spot the seven wastes while analyzing the current process. Value Stream Mapping is the most common tool used here. Once identified, teams build countermeasures in the Improve phase. A verified fix then gets standardized into the control plan.
How Six Sigma Development Solutions Inc. Can Help
Spotting these wastes takes practice; fixing the root cause takes real training. Six Sigma Development Solutions Inc. teaches Value Stream Mapping in our courses. Both Green Belt and Black Belt programs cover this tool.
Students learn to trace visible waste back to its Mura or Muri root cause. That means real fixes, not just relabeled symptoms.
Ready to find the waste hiding in your own process? Explore our training options and get certified today.
Frequently Asked Questions (FAQs) on TIMWOOD
Q: What does TIMWOOD stand for?
A: Transportation, Inventory, Motion, Waiting, Overproduction, Over-processing, and Defects. These are the seven wastes of Lean.
Q: What is the difference between Muda, Mura, and Muri?
A: Muda is waste itself. Mura is uneven pace, and Muri is overburden.
Q: Is all Muda bad?
A: No. Type 1 Muda is necessary, like safety checks. Type 2 Muda should be eliminated entirely.
Q: Which waste should teams fix first?
A: Fix Mura and Muri before attacking visible Muda. Otherwise, the waste tends to come back.
Q: Why is overproduction considered the worst waste?
A: It triggers the other six wastes automatically. Excess inventory, motion, and waiting all follow from it.
Q: What is the eighth waste added to TIMWOOD?
A: Non-Utilized Talent, sometimes called Skills. It covers ideas and knowledge a company never taps.
Q: Do the seven wastes apply outside manufacturing?
A: Yes. They show up constantly in office work, like email approvals and unnecessary reports.
About Six Sigma Development Solutions, Inc.
Six Sigma Development Solutions, Inc. offers onsite, public, and virtual Lean Six Sigma certification training. We are an Accredited Training Organization by the IASSC (International Association of Six Sigma Certification). We offer Lean Six Sigma Green Belt, Black Belt, and Yellow Belt, as well as LEAN certifications.
Book a Call and Let us know how we can help meet your training needs.
Want to spot and fix waste in your own process? Six Sigma Development Solutions Inc. offers onsite, live virtual, and online training for every belt level
