Six Sigma Exam Prep
Lean Six Sigma Green Belt & Black Belt
1,000+ practice questions · DMAIC methodology · Statistical tools · Built-in reference
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Six Sigma Green Belt exam at a glance (ASQ CSSGB)
ASQ's Certified Six Sigma Green Belt (CSSGB) exam has 110 questions (100 scored) with 4 hours 18 minutes of exam time, and it is open book. You need 550 out of 750 points to certify, plus 3 years of qualifying full-time work experience to apply.
| Questions | 110 (100 scored + 10 unscored), computer-based |
|---|---|
| Time | 4 hours 18 minutes of exam time in a 4.5 hours appointment |
| Passing score | 550 of 750 points |
| Book policy | Open book (bring your own bound reference materials) |
| Delivery | Computer-based at Prometric (paper-based in some locations) |
| Fee | $483 non-member (ASQ members save $100) · retake $283 |
| Eligibility | 3 years of full-time, paid on-the-job experience in one or more areas of the CSSGB Body of Knowledge; no education waivers |
These facts are for ASQ's CSSGB only; the passing score is from ASQ's exam-results FAQ. Other bodies differ — for example, IASSC's Green Belt is 100 questions, closed book, in 3 hours with a 70% minimum — and Black Belt exams have their own formats.
Source: ASQ — Six Sigma Green Belt Certification (CSSGB) · checked 2026-10-16
What the Six Sigma Exam Covers
Six Sigma certifications test your command of the DMAIC framework, statistical process control, lean tools, and root cause analysis. Both Green Belt and Black Belt content is covered.
The DMAIC Framework
Six Sigma Exam FAQ
What is the Lean Six Sigma Green Belt exam?
The Lean Six Sigma Green Belt (LSSGB) is a certification that demonstrates competency in the DMAIC problem-solving methodology and basic statistical tools. Major certifying bodies include ASQ (American Society for Quality), IASSC, and Villanova. Exam format varies by body: ASQ's CSSGB has 110 questions (100 scored) with 4 hours 18 minutes of exam time in a 4.5-hour appointment; IASSC's Green Belt has 100 questions in 3 hours.
What is the difference between Green Belt and Black Belt?
Green Belts lead improvement projects part-time alongside their regular roles. Black Belts are dedicated full-time Six Sigma practitioners who lead complex, high-impact projects and mentor Green Belts. The Black Belt exam tests advanced statistics (regression, DOE, ANOVA) and project management at a deeper level than the Green Belt.
How hard is the Six Sigma Green Belt exam?
ASQ does not publish a CSSGB pass rate on its certification page; you need 550 out of a possible 750 points to certify. The exam requires both conceptual understanding of statistical tools and the ability to apply them to real process scenarios, so practice the statistical calculations, not just the definitions.
Do I need to know statistics for Six Sigma?
Yes — statistics is the foundation of Six Sigma. For the Green Belt you must understand process capability (Cp, Cpk), control charts (when to use X-bar-R vs. X-bar-S vs. P vs. C charts), basic hypothesis testing (t-tests, chi-square, ANOVA at a conceptual level), and normal distribution. The Black Belt exam requires a deeper applied statistics background.
What is the DMAIC methodology?
DMAIC is the Six Sigma problem-solving framework: Define (define the problem, project scope, and customer requirements — CTQ), Measure (baseline the process — data collection, measurement system analysis), Analyse (identify root causes — fishbone, 5 Whys, hypothesis testing), Improve (implement and verify solutions — DOE, pilot), Control (sustain the gains — control charts, control plan, standardisation).
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