Within the individual phases of a DMAIC or DMADV project, Six Sigma utilizes many established quality-management tools that are also used outside Six Sigma. The following shows an overview of the main methods used.

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• 5 Whys
• Analysis of variance
• ANOVA Gauge R&R
• Axiomatic design
• Business Process Mapping
• Cause & effects diagram (also known as fishbone or Ishikawa diagram)
• Check sheet
• Chi-squared test of independence and fits
• Control chart
• Correlation
• Cost-benefit analysis
• CTQ tree
• Design of experiments
• Failure mode and effects analysis (FMEA)
• General linear model
• Histograms
• Pareto analysis
• Pareto chart
• Pick chart
• Process capability
• Quality Function Deployment (QFD)
• Quantitative marketing research through use of Enterprise Feedback Management (EFM) systems
• Regression analysis
• Rolled throughput yield
• Root cause analysis
• Run charts
• Scatter diagram
• SIPOC analysis (Suppliers, Inputs, Process, Outputs, Customers)
• Stratification
• Taguchi methods
• Taguchi Loss Function
• TRIZ​