8 Types of Lean Waste (TIMWOODS) and How to Eliminate Them

What is Lean Waste?

If you’ve ever felt like your workday is filled with delays, rework, unnecessary steps, or constant firefighting, you’re not alone. These inefficiencies are what Lean calls “waste”, and they exist in almost every process, across industries.

Understanding and eliminating waste is one of the most powerful ways to improve productivity, efficiency, and customer satisfaction. Whether you’re a student learning process improvement or a working professional trying to optimize operations, mastering this concept can transform how you work.

In Lean, waste (or “muda” in Japanese) refers to any activity that does not add value to the customer and that the customer is unwilling to pay for.

The 8 Wastes of Lean

Waste within Lean is categorized into eight types. Originally developed within the Toyota Production System, the seven classic types of waste were identified. There is one additional type, underutilized skill or talent, that has gained recognition over time. The acronym TIMWOODS can be used to remember the eight types of waste. Let’s walk through each type of waste, along with examples:

1. Transportation

Transportation waste refers to the unnecessary movement of materials, products, or information between locations that does not add value. This can include transferring items between distant workstations, moving documents across multiple systems, or excessive handoffs between teams. Such movement increases handling time, raises costs, and creates more opportunities for damage, delays, or errors.

This waste can be reduced by optimizing physical or digital layouts, minimizing handoffs, and positioning materials, tools, or information as close as possible to the point of use.

2. Inventory

Inventory waste refers to excess finished goods, products that are still work-in-progress, and raw materials beyond what is needed. While some inventory is necessary to support smooth operations and meet demand, excess stock ties up space, capital, and effort in counting, handling, and storage. For example, a hospital that stores more PPE (personal protective equipment) than required may face expiry and disposal costs, turning that inventory into waste.

This waste can be controlled by setting clear minimum and maximum stock levels, limiting work-in-progress (WIP), and aligning inventory more closely with actual demand.

3. Motion

Motion waste refers to unnecessary movement or physical strain by people while searching for tools, parts, or information. This can include excessive walking, reaching, bending, or repeated trips between locations. For example, a nurse frequently moving between patient rooms and a central supply station spends time on non-value-added activities that could be used more productively.

This waste can be reduced by organizing workspaces effectively, placing tools and materials close to the point of use, and designing ergonomic setups that minimize unnecessary movement and strain.

4. Waiting

Waiting waste refers to idle time when people, materials, or equipment are not actively adding value. This commonly occurs when waiting for approvals, information, documents, or the completion of prior tasks. In manufacturing, it may include delays for raw materials, machine cycles, or maintenance activities. Such delays contribute directly to non-value-added time and slow down overall process flow.

This waste can be reduced by identifying bottlenecks and delays using tools like Value Stream Mapping, and then improving coordination, balancing workloads, and streamlining processes to keep work moving efficiently.

5. Overproduction

Overproduction waste occurs when more is produced than needed or earlier than required by customer demand. It is one of the most critical wastes, as it often triggers others, such as excess inventory, transportation, motion, and waiting. This typically happens in batch production environments or when machines and workers are kept running to avoid idle time.

For example, if a bakery makes 200 pastries each morning but consistently sells only 150, the surplus results in waste of materials, time, and labor. This waste can be reduced by aligning production closely with actual customer demand and adopting a more demand-driven approach.

6. Overprocessing

Overprocessing waste occurs when more work, features, or complexity are added than what the customer actually values or requires. It often stems from unclear requirements or assumptions about what customers need.

For example, a team may spend significant time creating highly detailed reports that are rarely read in full. This effort does not add value and could be better used elsewhere. Outputs should be tailored to meet actual customer needs, providing only the necessary level of detail.

This waste can be reduced by clearly understanding customer expectations and regularly validating what is truly required.

7. Defects

Defects waste occurs when outputs—whether products, services, parts, or work-in-progress—fail to meet required specifications. These errors lead to rework, additional inspections, scrap, or replacements, increasing costs and often resulting in dissatisfied customers. It is essential to identify and address the root cause of defects to prevent them from recurring. For example, a batch of printed flyers with multiple typos requires reprinting, wasting both materials and labor on errors that could have been avoided.

This waste can be reduced through error-proofing and by improving quality at the source.

8. Skills (Unused Skills)

Skills, or rather the unused skills waste, refers to the failure to fully utilize employees’ skills, knowledge, and ideas. Often, those closest to the process are not involved in problem-solving, even though they are best positioned to identify issues and suggest improvements. Empowering employees to contribute can enhance engagement, build skills, and unlock valuable insights.

For example, a nurse in a busy hospital may spend significant time ordering supplies or transporting patients. These are tasks that could be handled by administrative staff or orderlies. This allows the nurse to focus on patient care while ensuring better use of all team members’ capabilities.

This waste can be reduced by actively involving teams in problem-solving and decision-making.

Applying Your Learning: Where to Start

Assess your own process and answer the following questions:

Do items wait between steps?
Is work often redone?
Do people search for tools or info?
Are approvals slowing progress?
Are skills underused?

If you answered “yes” to any of the questions above, there are already opportunities to reduce waste in your process.

Final Thought

Whether you’re a student learning Lean, a manager improving operations, or a professional looking to boost productivity, eliminating waste is one of the most powerful skills you can develop.

Remember:
Improvement doesn’t require big changes—just consistent, small steps in the right direction.

If you want to delve deeper into understanding the different types of waste in Lean and how one can reduce them, you can read our upcoming book, Lean Management Essentials, authored by Sona Murgai. Lean Management Essentials is a beginner-friendly guide to applying Lean principles to improve efficiency and eliminate waste. It explains key concepts through real-world examples and a service-based case study. Designed for managers, students, and entrepreneurs, it focuses on practical, easy-to-apply strategies for smarter, more effective business operations.