What is a turtle diagram?
A turtle diagram is a visual process definition that puts everything needed to run and control a process on one page. The process sits in the shell at the centre. Inputs flow in from one side and outputs leave on the other, while four "legs" describe the resources (with what?), people (with whom?), methods (how?) and measures (what results?).
It became popular in the automotive industry with ISO/TS 16949 and IATF 16949 and is now used across manufacturing, medical devices and services to support the process approach of ISO 9001 and ISO 13485.
The six elements of a turtle diagram
| Element | Question | Typical evidence |
|---|---|---|
| Inputs | What starts the process? | Orders, materials, specifications, data |
| Outputs | What does it deliver, and to whom? | Products, records, reports |
| With what? | Which resources are needed? | Equipment, tooling, software, calibration records |
| With whom? | Who does the work? | Roles, competence matrix, training records |
| How? | Which methods apply? | SOPs, work instructions, control plans, FMEA |
| Results? | How is performance measured? | KPIs with targets and trends |
Turtle diagrams in process audits
In a process-based audit, the auditor follows the turtle: checks that inputs and outputs match customer requirements, samples equipment and calibration status, verifies training of the people involved, confirms that procedures are current and followed, and reviews KPI trends and actions taken when targets are missed. A well-prepared turtle diagram makes that audit faster and shows the process is understood and controlled.
Turtle diagram example
The example defines an injection molding process owned by the production manager. Inputs come from planning, the warehouse and engineering; outputs go to assembly and the quality records. It relies on qualified molds and dryers, certified setup technicians, a setup SOP and control plan, and is measured by scrap rate, OEE, on-time delivery and complaints.
Start broader with a SIPOC, or place this process in your overall architecture with a process hierarchy map.
How to use this Turtle Diagram tool
- Define the process. Click the centre to enter the process name, owner and purpose.
- List inputs and outputs. Add what comes into the process and what it delivers, ideally noting where each comes from and goes to.
- With what?. List equipment, materials, facilities and software needed to run the process.
- With whom?. List the roles, competences and training required.
- How?. List the procedures, work instructions, control plans and methods that govern the process.
- Results?. Add the KPIs with targets that show whether the process is effective, then export the turtle for your process files or audit.
Frequently asked questions
What is a turtle diagram?
A turtle diagram is a one-page process definition tool that places the process in the centre (the shell) and surrounds it with six elements (the legs, head and tail): inputs, outputs, resources (with what), people (with whom), methods (how) and performance measures (results).
Why is it called a turtle diagram?
The layout looks like a turtle seen from above: the process is the shell, inputs and outputs are the head and tail, and the four supporting elements (equipment, people, methods and measures) are the legs.
Is a turtle diagram required by IATF 16949?
IATF 16949 does not mandate the turtle format, but it requires processes to be defined with their inputs, outputs, resources, responsibilities, methods and performance indicators. Turtle diagrams are the most common way automotive suppliers and auditors document this, and they are widely used in process-based audits.
How do turtle diagrams help with internal audits?
Auditors use the turtle as a checklist: for each element they verify the evidence, such as calibration records for equipment, training records for people, current procedures for methods and trend data for KPIs.
What is the difference between a turtle diagram and a SIPOC?
A SIPOC scopes a process by its suppliers, inputs, steps, outputs and customers. A turtle diagram goes further on how the process is controlled: the resources, competence, methods and performance measures needed to run it.
Can I export the turtle diagram?
Yes, as a PDF report, PNG image, Excel workbook or CSV, or as a file to reopen later. It is free and requires no sign-up.