The SIPOC Diagram – A Basic Process Mapping Tool

One of the first steps in any improvement project is to describe the current process using a map of some sort.  One basic mapping tool is the Supplier-Input-Process-Output-Customer diagram, commonly referred to as a SIPOC diagram.  Another commonly used tool is the cross-functional process map.

Both of these tools are important first steps in understanding the current process.  It is not uncommon to find that several individuals understand part of a business process but no one understands the entire process from start to finish.  As a result, people think in terms of their own function but not in terms of the best overall way to complete the process.

The SIPOC diagram is typically used in the Define phase of a Six Sigma project to identify the steps in the process, the inputs to those steps, the source of the inputs (i.e. the suppliers), the outputs of the process, and the customer or customers for the outputs.  The SIPOC diagram ensures that all project team members understand the process in the same way.   It may also be used at the end of the project to document the new, improved process.

The following steps are used to create a SIPOC diagram:

  1. Identify the process to be diagrammed.
  2. Identify the output(s) of the process.
  3. Identify the customer(s) for each output.
  4. Identify the input(s) for each process step.
  5. Identify the supplier(s) for each input.

Here is a simple example of a SIPOC diagram for the process of baking a cake:

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About the author:  Mr. Roger C. Ellis is an industrial engineer by training and profession.  He is a Six Sigma Master Black Belt with over 50 years of business experience in a wide range of fields.  Mr. Ellis develops and instructs Six Sigma professional certification courses for Key Performance LLC.   For a more detailed biography, please refer to