# 7 Wastes

Operations · `7 Wastes` · verification: source checked

The 7 Wastes is Taiichi Ohno's categorization of seven major wastes typically found in mass production: overproduction, waiting, conveyance, processing, inventory, motion, and correction. It is used to identify non-value-creating activities and to distinguish waste from value-creating and incidental work.

## Specification

| Property | Value |
|---|---|
| Kind | methodology |
| Origin | Taiichi Ohno |

## Study notes

- The seven wastes are overproduction, waiting, conveyance, processing, inventory, motion, and correction.
- Overproduction is producing ahead of what is actually needed by the next process or customer; the document calls it the worst form of waste because it contributes to the other six.
- Waiting is operators standing idle as machines cycle, equipment fails, or needed parts fail to arrive.
- Conveyance is moving parts and products unnecessarily, such as from a processing step to a warehouse and then to a subsequent processing step when the second step could be adjacent to the first.
- Processing is performing unnecessary or incorrect processing, typically from poor tool or product design.
- Inventory is having more than the minimum stocks necessary for a precisely controlled pull system.
- Motion is operators making movements that are straining or unnecessary, such as looking for parts, tools, or documents.
- Correction is inspection, rework, and scrap.
- Two categories of work are value-creating work, which is directly necessary for making products, and incidental work, which must be performed but does not create value from the customer's standpoint.
- Waste is motions that create no value and can be eliminated, such as walking to get parts or tools that could be positioned within reach.
- Type one muda creates no value but is unavoidable with current technologies and production assets; an example is inspecting welds to ensure they are safe.
- Type two muda creates no value and can be eliminated immediately; an example is disconnected steps in process villages that can be reconfigured into a cell.

## Sources

1. [What are the 7 Wastes in Lean? | Lean Enterprise Institute](https://www.lean.org/lexicon-terms/seven-wastes/) (accessed 2026-10-25)
2. [Waste - Lean Enterprise Institute](https://www.lean.org/lexicon-terms/waste/) (accessed 2026-10-25)

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