Six Sigma Certification: Who Certifies It and Which One to Choose
There is no single owner of the term “Six Sigma.” Anyone can run a course and print a belt certificate, which is why two Green Belts on the same team can have very different preparation behind them. This guide sorts the main certifying bodies by what they actually require, how their exams work, what they cost, and how long the credential stays current, so you can pick the one that fits your situation.
Written by a quality engineer who passed the ASQ CSSBB exam. Fees and exam details were checked against each organization’s official site on October 20, 2026. They change, so confirm on the linked page before you apply.
The four kinds of Six Sigma credential
- Professional-society certification (ASQ). Eligibility rules, a proctored exam, and recertification every three years at the Black Belt level and above.
- Independent exam-only bodies (IASSC, CSSC). They test your knowledge against their own Body of Knowledge. They do not require training, work experience, or a project.
- Training-provider certificates (universities, consultancies, online vendors). You take a course and the provider awards a belt, usually after a course exam and sometimes after a project. Quality varies widely.
- Company-internal belts. Your employer trains you, coaches you through real projects, and awards the belt. These often carry the most weight inside that company and the least portability outside it.
ASQ: Yellow, Green, Black Belt and Master Black Belt
ASQ, the professional society behind the CQE, offers four Six Sigma certifications: the Certified Six Sigma Yellow Belt (CSSYB), Green Belt (CSSGB), Black Belt (CSSBB), and Master Black Belt (CMBB). All ASQ exams are delivered by Prometric, either at a test center or by live remote proctoring for most exams, and all of them are open book with bound references only.
- CSSYB: no experience or education requirement. Computer-based exam of 90 questions (80 scored) in 2 hours 18 minutes. Exam fee $434, retake $234. Lifetime credential, with no recertification.
- CSSGB: three years of full-time, paid work experience in one or more areas of the Green Belt Body of Knowledge, and no education waivers. 110 questions (100 scored); exam time is 4 hours 18 minutes. Exam fee $483, retake $283. Lifetime credential, with no recertification.
- CSSBB: at least one completed Six Sigma project with a signed project affidavit, together with three years of full-time, paid experience in the Black Belt Body of Knowledge, or two completed projects with signed affidavits. 165 questions (150 scored); exam time is 4 hours 18 minutes. Exam fee $585, retake $385. ASQ states the CSSBB program is accredited by ANAB under ISO/IEC 17024. Recertify every three years.
- CMBB: you must hold a current CSSBB and pass a portfolio review showing either five years in a Black Belt or Master Black Belt role or ten completed Black Belt projects. The exam has 110 multiple-choice items (100 scored) plus a performance-based section, 5 hours 20 minutes of exam time, offered only in July and November, at a test center only (no remote proctoring). Fees: $800 portfolio review plus $1,599 exam for non-members ($700 + $1,499 for members); retake $1,399. Recertify every three years.
Recertification. Per ASQ’s recertification page, the CSSBB and CMBB must be renewed every three years by earning 18 recertification units (from continuing education, conferences, employment in the field, and similar activities) or by retaking the exam. Renewing by journal costs $120 for members or $160 for non-members. The CSSYB and CSSGB are lifetime certifications.
IASSC: Yellow, Green and Black Belt
The International Association for Six Sigma Certification is an exam-only body: it sets a Lean Six Sigma Body of Knowledge and tests against it, and it does not train candidates. It has no prerequisites and no project requirement. All of its exams are closed book and proctored, either online or at a test center, and you need 70% to pass.
- Yellow Belt: 60 questions, 2 hours, exam voucher $250.
- Green Belt: 100 questions, 3 hours, exam voucher $350.
- Black Belt: 150 questions, 4 hours, exam voucher $450.
Recertification. IASSC recognizes a certification indefinitely, but it only counts as “Current” for three years. To keep that status you pass a shorter, closed-book recertification exam: $115 for Yellow, $175 for Green, and $235 for Black Belt, according to the IASSC recertification policy. If you skip it, the status changes to “Elapsed.”
The Council for Six Sigma Certification (CSSC)
The Council for Six Sigma Certification does two things: it accredits training providers that follow its Body of Knowledge, and it runs its own exams. It publishes free self-study guides, its standard exams are open book and taken online or at a test center, and its certifications have no expiration date. There are no prerequisites. The standard belt exams have no project requirement; CSSC offers separate “Level II” Green and Black Belt credentials that do require one.
- Yellow Belt: standard exam of 50 questions in 1 hour, $99.
- Green Belt: standard exam of 100 questions in 2 hours, $195.
- Black Belt: standard exam of 150 questions in 3 hours, $295.
The standard exam fee includes up to three attempts within one year. There is also a self-paced path made of short, untimed chapter exams that earns each belt along the way for a single fee ($399 as listed on the exam pages).
Universities and training providers
Many universities, consultancies, and online schools run Lean Six Sigma courses and award their own belt certificates. Some programs include coached projects and a rigorous final exam. Others award a certificate for finishing a video course. A provider listing itself as “accredited” by a Six Sigma body usually means that body reviewed its curriculum. It does not mean the belt was tested by an independent exam. Before paying, ask the provider four questions:
- Is the final exam proctored, and who writes it?
- Is a real project required, and who reviews it?
- Does the course prepare you for an independent exam (ASQ, IASSC, or CSSC), or only for its own certificate?
- Can an employer verify the credential in a public register?
Company-internal belts
Large manufacturers and service companies often run their own belt programs. An internal Black Belt often involves several weeks of classroom training spread across a few months, plus one or more completed projects with documented savings that a Master Black Belt or a finance partner signs off. These programs build real project experience, which is the hardest thing for any exam to measure. The drawback is portability: a hiring manager at another company cannot easily check what your program required. Many practitioners pair an internal belt with an independent exam for that reason. The projects from an internal program can also count toward the ASQ CSSBB project affidavit.
Side-by-side comparison (Black Belt level)
| ASQ CSSBB | IASSC Black Belt | CSSC Black Belt (standard) | Training provider / internal | |
|---|---|---|---|---|
| Experience or project | Project affidavit(s) required, plus experience in the BoK | None required | None for the standard exam; Level II requires a project | Varies; internal programs usually require projects |
| Exam | 165 questions (150 scored), 4 h 18 min | 150 questions, 4 h | 150 questions, 3 h | Provider’s own, if any |
| Open or closed book | Open book (bound references) | Closed book | Open book | Varies |
| Proctoring | Prometric test center or live remote | Test center or online proctoring | Online or test center | Varies |
| Exam fee (Oct 2026) | $585 (retake $385) | $450 | $295 (up to 3 attempts in a year) | Usually bundled into course price |
| Recertification | Every 3 years: 18 RUs or retake | “Current” for 3 years; recert exam $235 | Does not expire | Usually none |
For Green and Yellow Belt fees, see the sections above. ASQ also offers member pricing on some exams.
Which should you choose?
- You work in a regulated or manufacturing quality role and want the credential that hiring managers in quality tend to recognize: ASQ. If you already have completed projects, go for the CSSBB. If you don’t have a project yet, the CSSGB has no project requirement and never expires.
- You have projects under your belt and want proof that is hard to fake: the ASQ CSSBB, because the project affidavit is the main thing that sets it apart.
- You have strong knowledge but no project you can document yet: the IASSC Black Belt tests you without prerequisites. Because it is closed book, it measures what you actually remember.
- You are on a tight budget or new to the field: CSSC’s free self-study guides and lower-cost exams, or the ASQ CSSYB if you want an ASQ credential with no prerequisites.
- Your employer runs a belt program: take it. The coached projects are worth more than any exam, and you can add an independent exam later for portability.
- You are deciding between a Six Sigma belt and the CQE: see CQE vs CQA vs CSSBB. The statistics overlap heavily, so studying for one helps with the other.
Common myths
- “There is one official Six Sigma certification.” No one owns the method. Every certifying body defines its own Body of Knowledge, exam, and rules.
- “A Black Belt always means someone has led projects.” Only some credentials require a documented project. Several Black Belt exams have no project or experience requirement at all.
- “You must get a Green Belt before a Black Belt.” Neither ASQ, IASSC, nor CSSC requires a Green Belt before the Black Belt exam. ASQ’s Master Black Belt is the only level here that requires a lower belt (a current CSSBB).
- “Open book means easy.” Open-book exams are timed, so you have roughly a minute and a half per question on the ASQ CSSBB. If you don’t know where to look in your references, the book won’t save you.
- “Lean Six Sigma and Six Sigma are different credentials.” Most modern programs teach both Lean tools and DMAIC. The label matters less than the Body of Knowledge behind it.
FAQ
Which Six Sigma certification is most recognized?
Recognition depends on the industry and the employer. In manufacturing, medical device, pharmaceutical, and other quality-heavy fields, ASQ certifications are widely known, and the CSSBB’s project requirement sets it apart from exam-only Black Belts. IASSC and CSSC credentials are also common. Check job postings in your own field to see which credential they name.
Do Six Sigma certifications expire?
It depends on who issued it. ASQ’s CSSBB and CMBB must be renewed every three years, while its CSSGB and CSSYB are lifetime credentials. IASSC certifications stay on record permanently but are only “Current” for three years without a recertification exam. CSSC certifications do not expire.
Can I take a Six Sigma Black Belt exam without a project?
Yes, with IASSC or with the CSSC standard exam. The ASQ CSSBB requires at least one completed project with a signed affidavit.
Is the ASQ Six Sigma Black Belt exam open book?
Yes. All ASQ exams are open book, but every reference, including your notes, must be permanently bound. Sticky notes are allowed only as tabs.
Can I take Six Sigma exams online?
Most can be taken online. ASQ offers live remote proctoring through Prometric for most exams, but not for the Master Black Belt. IASSC and CSSC both offer online exams.
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