There is no single Six Sigma exam. Each certification body sets its own question count, time limit, book policy and supervision rules, so the format you face depends entirely on who issues the credential. At a glance: ASQ gives you a long, open-book paper, IASSC a shorter closed-book proctored one, and 6sigmastudy an online unproctored multiple-choice exam. This guide sets them side by side so you can prepare for the right one.
Everything below is provider-specific. Do not carry a rule from one body to another: a bound reference book that is essential for one exam is forbidden at the next.
Table of Contents
- Six Sigma exam formats at a glance
- ASQ: long, open-book and computer-delivered
- IASSC: closed-book and proctored
- 6sigmastudy: online multiple choice
- Six Sigma exam questions: what they look like
- Is the Six Sigma exam hard?
- How to prepare for each format
- Our perspective
- Choosing a GetVoucher Six Sigma voucher
- Product Owner and other 6sigmastudy-family exam questions
- FAQ
- Sources
Six Sigma exam formats at a glance
| Provider and exam | Questions | Time | Reference materials | Supervision |
|---|---|---|---|---|
| ASQ Certified Six Sigma Green Belt (CSSGB) | 110 (100 scored, 10 unscored) | 4 hours 18 minutes | Open-book | Delivered at an ASQ exam setting |
| ASQ Certified Six Sigma Yellow Belt (CSSYB) | 90 (80 scored, 10 unscored) | 2 hours 18 minutes | Open-book | Delivered at an ASQ exam setting |
| IASSC Lean Six Sigma Green Belt | 100 (some forms add up to 10 ungraded) | 3 hours | Closed-book | Proctored |
| 6sigmastudy Six Sigma Green Belt (SSGB™) | 90 | 120 minutes | Not stated on the exam page | Online, unproctored |
| 6sigmastudy Lean Six Sigma Green Belt (LSSGB™) | 100 | 120 minutes | Not stated on the exam page | Online, unproctored |
Figures come from each provider’s own pages, linked in the sections below. Check them again before you book, because providers revise exams.
ASQ: long, open-book and computer-delivered
The ASQ Green Belt page describes the CSSGB as a one-part, 110-question multiple-choice exam that measures comprehension of the Body of Knowledge. The Yellow Belt is shorter: the CSSYB page lists 90 questions in 2 hours and 18 minutes.
Scored and unscored questions
Not every question counts. On the Green Belt, 100 questions are scored and 10 are unscored pretest items. On the Yellow Belt, 80 are scored and 10 are unscored. ASQ explains in its FAQ on question numbers that pretest questions are used to validate future exam items. They are mixed in at random, and you cannot tell which they are, so treat every question as live.
What open-book really means
ASQ exams are open-book, but the rule is narrower than it sounds. You can use your own reference materials, and for computer-based testing they should be professionally bound. Loose pages and hand-stapled documents can be refused at the exam centre. Check ASQ’s current exam-day rules before you spend time tabbing a binder.
Open-book does not make the paper easy. With 110 questions in 258 minutes you have a little over two minutes per question, and flicking through a binder for every calculation will eat that margin. Candidates who do well tend to use the book for formulas and tables, not for learning topics on the day.
Time limits
Most ASQ exams have a four-hour limit, with the Yellow Belt as an exception at two hours, according to ASQ’s exam time FAQ. The extra 18 minutes on the Green Belt and Yellow Belt papers are on top of that base time on the product pages, so quote the figure from the specific certification page, not a general summary.
IASSC: closed-book and proctored
The IASSC Green Belt page describes a 100-question, closed-book, proctored exam with a three-hour allowance. Some forms add up to 10 ungraded questions. The exam draws about 20 multiple-choice and true/false questions from each major section of the IASSC Body of Knowledge, and the minimum score for the designation is 70%. It can be taken at testing centres or through online proctoring.
The practical difference from ASQ is preparation. With no binder, you need formulas, distributions and hypothesis-test selection in your head. IASSC recommends, but does not require, training from a qualified institution.
6sigmastudy: online multiple choice
6sigmastudy is the certification body behind the SSGB™ and LSSGB™ that we offer. Its SSGB page lists a multiple-choice exam of 90 questions in 120 minutes, one mark per correct answer, with no negative marking, delivered as an online unproctored exam. The LSSGB page lists 100 questions in 120 minutes with the same marking and delivery model.
Both pages list no prerequisite experience and say a Six Sigma Yellow Belt is preferred but not mandatory. Recertification is listed every three years, or you can earn another 6sigmastudy certification.
A conflict in the published sources
One source disagrees with the others. The SSGB syllabus PDF lists the exam as an online proctored exam, while the certification page says unproctored. We have gone with the certification page, which is the more recently structured source and is consistent across the SSGB and LSSGB pages, but if the supervision rules matter to you, confirm them with the provider when you schedule.
Two more points to keep straight:
- An unproctored exam is not a lesser one, and a proctored exam is not more credible by default. They are different delivery models.
- The 6sigmastudy certifications described here do not ask for a documented project on the pages above. Other bodies set their own project rules, so never assume one standard.
Six Sigma exam questions: what they look like
All the formats above use multiple choice. The skills tested follow the DMAIC cycle (Define, Measure, Analyse, Improve, Control), which is used in Six Sigma, Lean and wider process improvement. Expect questions in these families:
- Definitions and roles: what a Green Belt does compared with a Black Belt, what a charter contains, what voice of the customer means.
- Measurement: sampling, process capability, measurement system analysis.
- Statistics: selecting a hypothesis test, reading a control chart, interpreting a p-value.
- Improvement and control: root-cause tools, solution selection, control plans, standard work.
- Lean tools (on Lean Six Sigma papers): 5S, Kanban, value stream mapping, waste categories.
Sample questions are useful for practising the style, but treat free papers from third parties with caution. Some are old, some are written by training sellers, and none predicts your exact paper. ASQ sells its own Green Belt question bank with timed simulations if you are sitting the ASQ exam.
Is the Six Sigma exam hard?
Difficulty cannot be generalised across providers. An open-book, 258-minute paper with a binder is a different challenge from a closed-book three-hour exam, and both differ from a 120-minute online paper. Published pass rates on a provider’s own page describe that provider’s candidates only. Judge difficulty by your own statistics background, the exam’s time per question, and whether you have practised under the same conditions.
How to prepare for each format
- Find the exact exam page for your credential and write down the question count, time, book policy and supervision rules.
- Work out minutes per question. ASQ Green Belt gives roughly 2.3 minutes per question including unscored ones. The 6sigmastudy SSGB gives about 1.3 minutes per question, so speed matters more.
- Practise in the same conditions. Open-book: build and test your reference binder. Closed-book: drill formulas from memory. Online unproctored: rehearse on the device and connection you will use.
- Map the Body of Knowledge to your weak areas. Statistics is where most people lose marks, so spend time there first.
- Do one full timed run a few days before, and review every error, not only the score.
Keep timeline expectations cautious. Study time depends on your starting knowledge, and we do not promise a fixed number of weeks.
Our perspective
We see the same mistake repeatedly: people choose a Six Sigma credential by belt colour or price, then discover the exam rules afterwards. We think the format should be part of the decision. If you work in a team that already uses ASQ-style materials, an open-book exam may fit. If you want a flexible, online route you can fit around work, the 6sigmastudy format suits many professionals. Neither is better in the abstract.
We also think certification should be described honestly. A passed exam shows you have studied a body of knowledge to the provider’s standard. It does not prove real-world performance, and we would not promise an employer reaction, a salary or a promotion. What it can do is give structure to your learning and a recognised way to show you completed it. For a wider view of exam-only versus project-backed routes, see our guide to the best Six Sigma certifications.
— Rayan
Choosing a GetVoucher Six Sigma voucher
We sell vouchers for 6sigmastudy certifications. What each purchase includes can differ by product, so read the individual course page before you buy.
| Voucher | Price |
|---|---|
| Six Sigma Yellow Belt (SSYB™) | £0 |
| Six Sigma Green Belt (SSGB™) | £149 |
| Lean Six Sigma Green Belt (LSSGB™) | £290 |
| Dual 6Sigma Pack: SSGB and LSSGB | £418 |
If you are new to the subject, the free Yellow Belt is a low-risk way to see the style of material and questions first. For a full breakdown of what else a Six Sigma route can cost, see our Six Sigma exam cost guide. ASQ and IASSC credentials are external options and are not sold by us.
Product Owner and other 6sigmastudy-family exam questions
If you arrived looking for Scrum rather than Six Sigma formats: SCRUMstudy is a separate body from 6sigmastudy, and its exams carry their own rules. Our Scrum Master Certified (SMC®) and SCRUM Agile Master Certified (SAMC™) vouchers use online unproctored exams, and the Scrum Fundamentals Certified exam is a 40-question, 60-minute online unproctored exam. Check the product page for the Product Owner voucher (SPOC®) for its details, and see our Scrum and Agile category.
FAQ
How long is the Six Sigma Green Belt exam?
It depends on the provider. ASQ allows 4 hours and 18 minutes for 110 questions, IASSC allows 3 hours for 100 questions, and 6sigmastudy lists 120 minutes for its Green Belt exams. Always take the figure from the page for your own certification.
Is the Six Sigma exam open-book?
ASQ exams are open-book, with rules about how your materials are bound. IASSC’s Green Belt exam is closed-book. The 6sigmastudy exam pages do not describe a reference-material policy, so confirm it with the provider when you book.
Are Six Sigma exams proctored?
IASSC exams are proctored. 6sigmastudy’s certification pages describe its Green Belt exams as online and unproctored, although one syllabus PDF says proctored, so confirm at booking. Proctoring is a delivery method, not a measure of credibility.
Do all questions count towards the score?
Not always. ASQ includes unscored pretest questions, 10 on both the Green Belt and Yellow Belt, and you cannot identify them. IASSC says some forms of its Green Belt exam include up to 10 additional ungraded questions.
Sources
- ASQ Six Sigma Green Belt (CSSGB)
- ASQ Six Sigma Yellow Belt (CSSYB)
- ASQ FAQ: number of questions
- ASQ FAQ: exam time
- ASQ Certified Six Sigma Green Belt Question Bank
- IASSC Green Belt certification
- 6sigmastudy Six Sigma Green Belt
- 6sigmastudy Lean Six Sigma Green Belt
- 6sigmastudy SSGB syllabus (PDF)