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9 Best Six Sigma Certifications of 2026
This list is for operations managers, quality engineers, process improvement leads and analysts who want a Lean Six Sigma credential an employer will recognize, and for people deciding whether to pay a certifying body, a university or a training company. It mixes three kinds of provider: certifying bodies that only set exams (ASQ, IASSC, CSSC), a university program (Purdue), and training companies that bundle a course with their own certificate (SSGI, Acuity Institute, 6Sigma.us, MSI, Simplilearn). We compared documented features and published prices from each provider's own pages; we did not take the exams or courses. Scores weigh features (recognition, rigor and what is included) at 40 percent, and ease of use (entry requirements, format and time) and value at 30 percent each. Prices are for the Green Belt level unless noted. Simplilearn showed prices in euros from our location, so its U.S. price is marked as pending.
By the Mojolin research desk · Updated November 11, 2026 · 9 tools compared · Prices checked on vendor pages, latest November 11, 2026
Questions or corrections: editorial@mojolin.com
Mojolin is self-funded How we score
If you already have three years in a quality or operations role, take ASQ's exam: it is the only credential here that checks your experience, and its Black Belt asks for a signed project affidavit. If you lack the experience or want an exam you can sit from home on demand, IASSC is the independent alternative at $402 for Green Belt. CSSC is the budget route at $195, open book and with a free study guide, but it carries less weight with employers that name ASQ or IASSC in job posts. If you need teaching rather than just an exam, Purdue's instructor-led online courses are the most structured option, while SSGI at $399 and MSI at $299.95 bundle training and a certificate for much less. Acuity Institute and 6Sigma.us sit between the two, with included software or live virtual classes.
Top picks
Best overall
ASQ Certified Six Sigma Green Belt and Black Belt (CSSGB, CSSBB)
8.4 / 10
Quality and operations professionals with three or more years of experience
Read the review →Runner-up
IASSC Certified Lean Six Sigma Green Belt
8.3 / 10
Self-studiers who want an independent, proctored exam they can take from home
Read the review →Also great
Council for Six Sigma Certification (CSSC)
8.2 / 10
Budget-minded professionals who can study on their own
Read the review →Comparison table
| # | Tool | Pricing | Score | |
|---|---|---|---|---|
| 1 | ASQ Certified Six Sigma Green Belt and Black Belt (CSSGB, CSSBB) | Quality and operations professionals with three or more years of experience | Green Belt exam $483 and Black Belt exam $585; ASQ members save $100 on the initial exam fee | 8.4 |
| 2 | IASSC Certified Lean Six Sigma Green Belt | Self-studiers who want an independent, proctored exam they can take from home | Green Belt on-demand web-based exam voucher $402; Black Belt and Yellow Belt vouchers sold separately | 8.3 |
| 3 | Council for Six Sigma Certification (CSSC) | Budget-minded professionals who can study on their own | Green Belt standard exam $195 and Black Belt standard exam $295; self-paced multi-belt path $399 | 8.2 |
| 4 |  Purdue University Lean Six Sigma Online | Professionals who want a university-run course with live instructors | Green Belt course $2,195; Black Belt course $3,750; 3-course package saves $805 | 8.1 |
| 5 |  Six Sigma Global Institute (SSGI) | Self-paced learners who want training and exam for under $400 | Green Belt $399 with training and exam included; Black Belt $499 | 8.0 |
| 6 |  Acuity Institute Lean Six Sigma | Learners who want instructor support and statistics software included | Green Belt course $1,599; Black Belt course $2,299 | 7.6 |
| 7 |  6Sigma.us Lean Six Sigma Green Belt | Teams and individuals who want live classes on a set schedule | Green Belt virtual instructor-led training $2,950; classroom sessions $4,923; Black Belt virtual from $3,250 | 7.5 |
| 8 |  Management and Strategy Institute (MSI) | People who want a fast, low-cost certificate with no renewal fees | Green Belt $299.95 and Black Belt $399.95, training and exam included | 7.4 |
| 9 |  Simplilearn Lean Six Sigma Green Belt | Learners who want live online classes before taking the IASSC exam | See vendor pricing (USD check pending); the IASSC exam voucher is purchased separately | 7.3 |
Scoring weights
Every tool gets three editorial scores out of 10, from vendor documentation, product pages and the published price. The overall score is the weighted average below, the same method on every list. Full method
The full ranking
Rank 1 · Best overall
ASQ Certified Six Sigma Green Belt and Black Belt (CSSGB, CSSBB)
The American Society for Quality's Six Sigma exams, which require three years of on-the-job experience before you can sit them.
asq.org8.4
out of 10
Best for: Quality and operations professionals with three or more years of experience
ASQ is the certifying body most quality departments know, and its Six Sigma exams are built around that reputation. Both the Green Belt and Black Belt require three years of full-time, paid experience in areas of the body of knowledge, and educational waivers are not granted. The Black Belt adds a project requirement: one completed project with a signed affidavit, or two. The computer-delivered Green Belt exam has 110 questions with 100 scored, the Black Belt has 165 with 150 scored, and both allow 4 hours 18 minutes. All ASQ exams are open book, so the CSSGB Handbook can come into the exam with you. Fees are $483 for Green Belt and $585 for Black Belt, with $100 off for ASQ members, and a failed attempt costs $283 or $385 to retake. ASQ does not bundle training into the fee; prep books, question banks and classes are sold separately. We compared documented features and published prices, and for experienced professionals this is the strongest credential.
Standout feature
The only certification on this list that checks three years of work experience before you sit the exam.
Use cases
Quality engineers in regulated manufacturing
Prove Six Sigma skills to employers that list ASQ in job posts
Outcome: An experience-checked Green Belt or Black Belt
Continuous improvement leads with finished projects
Turn completed projects into a Black Belt credential
Outcome: CSSBB backed by a signed project affidavit
Key features
- Green Belt and Black Belt both require 3 years of full-time, paid, on-the-job experience
- Black Belt also requires one completed project with a signed affidavit, or two projects
- Computer-delivered Green Belt exam: 110 questions (100 scored), 4 hours 18 minutes
- Computer-delivered Black Belt exam: 165 questions (150 scored), 4 hours 18 minutes
- All ASQ exams are open book with bound reference materials
Pros
- Only provider here that verifies work experience before the exam
- ASQ members save $100 on the initial exam fee
- Open-book format lets you bring the ASQ CSSGB Handbook
Cons
- Not open to anyone with less than 3 years of relevant experience
- Retakes cost $283 (Green Belt) or $385 (Black Belt)
- Computer-based exams run in fixed testing windows with application deadlines
Rank 2 · Runner-up
IASSC Certified Lean Six Sigma Green Belt
An independent certifying body that sells proctored Lean Six Sigma exams with no training requirement and no prerequisites.
iassc.org8.3
out of 10
Best for: Self-studiers who want an independent, proctored exam they can take from home
IASSC, the International Association for Six Sigma Certification, calls itself an independent third-party certification body: it sets the exam and leaves training to accredited providers. The Green Belt exam has 100 questions, is closed book and proctored, and allows three hours, with some forms adding up to 10 ungraded questions. You need 70% to pass and there are no prerequisites. The Green Belt on-demand web-based voucher is listed at $402 in IASSC's order store, and a $78 evaluation exam lets you test your readiness first. Black Belt (150 questions) and Yellow Belt (60 questions) follow the same model, and IASSC also certifies Lean-only levels. Under IASSC's recertification policy, a certification counts as current for three years, and a Green Belt recertification voucher costs $268. The trade-off is a harder, closed-book exam with no course included. We compared documented features and published prices, and IASSC is the strongest choice for people without ASQ's three years of experience.
Standout feature
A proctored, closed-book Green Belt exam with no prerequisites that you can schedule on demand online.
Use cases
Analysts early in an operations career
Earn a recognized Green Belt without the ASQ experience bar
Outcome: A proctored IASSC credential
Graduates of a training company's course
Add an independent exam on top of the course certificate
Outcome: Third-party validation from IASSC
Key features
- Green Belt exam: 100 questions, closed book, proctored, 3 hours
- Passing score of 70% and no prerequisites to sit the exam
- Taken through an on-demand web-based testing system or at testing centers
- Black Belt exam has 150 questions; Yellow Belt has 60
- Optional $78 Green Belt evaluation exam voucher
Pros
- Independent third-party exam with no required training purchase
- On-demand web-based exam means no fixed testing window
- Separate Lean credentials (Lean Practitioner, Leader, Expert) are available
Cons
- Closed book, unlike ASQ and CSSC
- Certifications count as current for 3 years; recertification voucher costs $268
- No training included in the voucher price
Rank 3 · Also great
Council for Six Sigma Certification (CSSC)
A certifying body with free self-study guides and low-cost open-book exams for every belt level.
sixsigmacouncil.org8.2
out of 10
Best for: Budget-minded professionals who can study on their own
The Council for Six Sigma Certification keeps the cost of a Six Sigma credential low. Its self-study guides are free, and the Green Belt standard exam costs $195: 100 multiple-choice and true/false questions, open book, in two hours, taken online or at designated testing centers. The Black Belt standard exam is $295 for 150 questions in three hours, and CSSC says there is no project requirement for it, though the Level II Black Belt does require a project. A second path at $399 suits people who want to earn several belts as they progress, with untimed exams. CSSC argues that renewals only add cost, so its certifications do not expire, and you can resit later if you want a newer date. The weakness is rigor: an open-book, two-hour exam with no experience check carries less weight than ASQ with employers that name a body. We compared documented features and published prices, and CSSC is the clear budget pick.
Standout feature
A $195 open-book Green Belt exam paired with a free self-study guide.
Use cases
Team members on a first improvement project
Get a Green Belt for under $200
Outcome: A CSSC Green Belt with no renewal fees
Self-learners using free material
Study and certify without buying a course
Outcome: Certification using only the free self-study guide
Key features
- Free self-study guides for each belt level
- Green Belt standard exam: 100 questions, open book, 2 hours
- Black Belt standard exam: 150 questions, open book, 3 hours, $295
- Exams taken online or at designated testing centers
- No renewal requirement for certifications
Pros
- Lowest exam fee on this list at $195 for Green Belt
- Study guide is free and can be used during the open-book exam
- Standard Black Belt has no project requirement
Cons
- Open-book, two-hour format is lighter than ASQ or IASSC
- No experience check, so the credential proves knowledge only
- Project-based Black Belt requires the separate Level II certification
Rank 4
Purdue University Lean Six Sigma Online
Purdue University's instructor-led online Lean Six Sigma Green Belt and Black Belt certificate courses.
purdue.edu8.1
out of 10
Best for: Professionals who want a university-run course with live instructors
Purdue's Lean Six Sigma Online program is the university option on this list, and it is taught rather than self-study. The Green Belt certificate course is instructor-led, runs online for 10 weeks, starts every month and has no prerequisites. It covers the DMAIC framework and Lean tools, and Purdue says graduates are certified Lean Six Sigma Green Belts from Purdue University. The fee is $2,195 and the course earns 4.5 CEUs. The Black Belt costs $3,750, runs 16 weeks about five times a year, earns 9 CEUs and has you run your own Black Belt project, which gives you a finished project to discuss in interviews. It requires Purdue's Lean Principles and Green Belt courses first, and the three-course package saves $805. The downside is cost and schedule: Purdue's Green Belt costs more than ASQ, IASSC and SSGI combined. We compared documented features and published prices, and Purdue is the best online pick for people who want instruction.
Standout feature
A university-run, instructor-led online Green Belt that starts every month.
Use cases
Managers moving into operations
Learn Lean Six Sigma with live instruction
Outcome: A Purdue Green Belt certificate in 10 weeks
Employees with tuition reimbursement
Use a training budget on a university program
Outcome: CEUs and a Black Belt project from Purdue
Key features
- Green Belt: instructor-led online, 10 weeks, starts monthly, no prerequisites
- Green Belt earns 4.5 CEUs; Black Belt earns 9 CEUs
- Black Belt: 16 weeks, offered about 5 times per year
- Black Belt has you run your own Lean Six Sigma Black Belt project
- 3-course package (Green Belt, Lean Principles, Black Belt) saves $805
Pros
- Live instructors rather than recorded lessons only
- Green Belt has no prerequisites and starts every month
- Black Belt includes a real project of your own
Cons
- Most expensive Green Belt here at $2,195
- Black Belt requires Purdue's Lean Principles and Green Belt courses first
- Fixed course schedules, not fully self-paced
Rank 5
Six Sigma Global Institute (SSGI)
Self-paced online Lean Six Sigma training with the certification exam, Minitab training and lifetime access in one price.
6sigmacertificationonline.com8.0
out of 10
Best for: Self-paced learners who want training and exam for under $400
The Six Sigma Global Institute sells Lean Six Sigma training and its own certification as one package. The Green Belt costs $399 and includes about 60 hours of self-paced training, Minitab training, a simulated project and the exam: 100 questions in two hours with a 70% pass mark and unlimited retakes. Course access is lifetime and the certification does not need renewal. SSGI is a PMI Authorized Training Partner, and the Green Belt counts for 60 PMI PDUs and 45 SHRM PDCs, which helps PMP holders. The Black Belt costs $499, and SSGI's Black Belt page offers a 24-hour money-back guarantee before the exam is attempted. The limits are the ones every training-company certificate shares: the provider that teaches you also grades you, there is no real project requirement, and retakes are unlimited. We compared documented features and published prices, and SSGI is the best value for people who want training and a certificate in one purchase.
Standout feature
Training, Minitab lessons, the exam and unlimited retakes for $399.
Use cases
PMP holders
Learn Lean Six Sigma while earning PDUs
Outcome: A Green Belt plus 60 PMI PDUs
Supervisors with irregular hours
Study at their own pace with no deadline
Outcome: A certificate with lifetime course access
Key features
- About 60 hours of self-paced training with lifetime access
- Exam: 100 questions in 2 hours, 70% to pass, unlimited retakes
- Includes Minitab training and a simulated project
- 60 PMI PDUs and 45 SHRM PDCs
- No project required and no certification renewal
Pros
- Training, exam and retakes all included for $399
- PDUs count toward PMP renewal
- Lifetime course access
Cons
- Certificate is issued by the training company, not an independent body
- No real project required, so it shows knowledge rather than results
- Unlimited retakes lower the bar compared with ASQ or IASSC
Rank 6
Acuity Institute Lean Six Sigma
Self-paced online Lean Six Sigma courses with instructor support, a simulated project and a lifetime SigmaXL license.
acuityinstitute.com7.6
out of 10
Best for: Learners who want instructor support and statistics software included
Acuity Institute, founded in 2005, sells self-paced online Lean Six Sigma courses with more support than the cheap certificate mills. The $1,599 Green Belt includes 12 months of lessons and quizzes, 12 months of instructor support, a Lean Six Sigma toolkit of templates, a course eBook and a full SigmaXL license you keep for life. A simulated project is required to finish. The exam is open book, online, up to four hours, and you have two attempts to reach 80%. Acuity says the average learner spends around five hours a week and finishes in about five months. The Green Belt earns 10.5 CEUs and 105 PDUs, and the $2,299 Black Belt earns 15 CEUs and 150 PDUs. The catch is price: you pay four times what SSGI charges for a certificate that is still issued by the training provider. We compared documented features and published prices, and Acuity fits learners who value coaching and software over a low fee.
Standout feature
Includes a full SigmaXL license with lifetime use and 12 months of instructor support.
Use cases
Analysts without a Minitab license
Run Six Sigma statistics at work
Outcome: A lifetime SigmaXL license with the course
Learners who want guidance
Get help from instructors while studying
Outcome: 12 months of instructor support
Key features
- 12 months of lessons, quizzes and instructor support
- Full SigmaXL license with lifetime use
- Simulated Lean Six Sigma project required to complete the course
- Open-book online exam, 4 hours, 80% to pass, two attempts
- Green Belt earns 10.5 CEUs and 105 PDUs
Pros
- Statistics software included, so no separate Minitab license
- Instructor support for the full 12 months
- Project work is part of completion
Cons
- Costs four times SSGI's Green Belt
- 80% pass mark with only two exam attempts
- Acuity estimates about 5 months at 5 hours a week
Rank 7
6Sigma.us Lean Six Sigma Green Belt
Live virtual and classroom Lean Six Sigma training from an IASSC-accredited provider, plus self-paced online options.
6sigma.us7.5
out of 10
Best for: Teams and individuals who want live classes on a set schedule
6Sigma.us is a training and consulting firm that teaches Lean Six Sigma live. Its Green Belt runs as a virtual instructor-led class split into two four-day weeks roughly a month apart for $2,950, or as a classroom course in cities such as Orlando and Dallas for $4,923. Self-paced online and blended options are also listed. To certify, you complete the course and score at least 70% on the final knowledge assessment. A separate project certification has Master Black Belt instructors review and accept a submitted Green Belt project, which is useful proof if your employer wants results, not just an exam. 6Sigma.us says it is accredited by IASSC, and the Green Belt earns CEUs with IACET, PDUs with PMI and PDCs with SHRM. The Black Belt costs $3,250 virtual or $4,000 in a classroom. The trade-off is cost and time off work for fixed dates. We compared documented features and published prices, and this suits employers sending staff to live training.
Standout feature
Live Green Belt classes in two four-day blocks, with optional project review by Master Black Belts.
Use cases
Operations teams sent by their employer
Train together in a live virtual class
Outcome: Green Belts with PMI PDUs and IACET CEUs
Green Belts with a finished project
Have the project reviewed by experts
Outcome: Project certification from Master Black Belt instructors
Key features
- Green Belt virtual class: two four-day weeks about a month apart
- Classroom sessions in cities such as Orlando and Dallas
- Accredited by IASSC
- CEUs with IACET, PDUs with PMI and PDCs with SHRM
- Optional project certification reviewed by Master Black Belt instructors
Pros
- Live instruction in both virtual and in-person formats
- Project certification adds proof of applied results
- Classroom, virtual, blended and self-paced options
Cons
- Virtual Green Belt costs $2,950, classroom $4,923
- Fixed class dates require two blocks of four days off work
- Certificate is issued by the training provider
Rank 8
Management and Strategy Institute (MSI)
Low-cost self-paced online Lean Six Sigma certifications with an open-note exam you take whenever you are ready.
msicertified.com7.4
out of 10
Best for: People who want a fast, low-cost certificate with no renewal fees
The Management and Strategy Institute sells Lean Six Sigma certifications built for speed and low cost. The Green Belt is $299.95 and MSI puts the average completion time at two to four weeks; the Black Belt is $399.95 with a four to eight week average. Training is delivered as online videos and PDFs, you have one year from purchase to finish, and there are no prerequisites. The exam is timed, multiple choice and open note, and you take it online from home or work whenever you are ready, without booking a slot. Passing earns a digital certificate, a digital badge and a wallet card, and MSI says the certification is lifetime with no renewal fees or retests. The downside is weight: an open-note exam set by the course seller tells an employer less than an experience-checked or proctored exam. We compared documented features and published prices, and MSI suits people who need a credential quickly on a small budget.
Standout feature
A $299.95 Green Belt with training included and an open-note exam you can take whenever you are ready.
Use cases
Job seekers adding a skill to a resume
Earn a Green Belt in a few weeks
Outcome: A lifetime certificate and digital badge
Small business owners
Learn process improvement basics cheaply
Outcome: Course material and certificate for $299.95
Key features
- Green Belt average completion time of 2 to 4 weeks
- Online training with videos and PDFs, 1 year of access
- Timed, open-note, multiple-choice exam taken online when ready
- Lifetime certification with no renewal fees
- Digital certificate, digital badge and wallet card
Pros
- Lowest-priced training-plus-certificate bundle on this list
- No need to schedule the exam in advance
- No prerequisites
Cons
- Open-note exam is less demanding than proctored options
- Course access ends after 1 year
- No project requirement at Green Belt level
Rank 9
Simplilearn Lean Six Sigma Green Belt
Live online and self-paced Green Belt training aligned with IASSC, with the IASSC exam voucher bought separately.
simplilearn.com7.3
out of 10
Best for: Learners who want live online classes before taking the IASSC exam
Simplilearn's Lean Six Sigma Green Belt is a preparation course, not a certifying exam. It is designed to align with the IASSC Green Belt standard, and the course page tells you to purchase your exam voucher from the IASSC official site, so budget for that on top. The bootcamp option includes 36 hours of live instructor-led training, often in weekend classes, four simulation assessments and two live projects, and it earns 35 PDUs. You also get lifetime access to the self-paced e-learning content, and a Flexi Pass lets you move to a different cohort within the first 90 days. Simplilearn offers a refund if you request it by email within seven days of purchase. Minitab training is sold as a separate package. Prices on the page showed in euros from our location, so the U.S. price is pending. We compared documented features and published prices, and Simplilearn suits people who want live classes before sitting IASSC.
Standout feature
36 hours of live instructor-led Green Belt training aligned with the IASSC exam.
Use cases
Working professionals with weekday jobs
Attend live weekend classes
Outcome: Preparation for the IASSC Green Belt exam
PMP holders
Earn PDUs while learning Six Sigma
Outcome: 35 PDUs
Key features
- 36 hours of live instructor-led training
- 4 simulation assessments and 2 live projects
- 35 PDUs
- Lifetime access to self-paced e-learning content
- Bootcamp Flexi Pass lets you reschedule your cohort within the first 90 days
Pros
- Live classes on weekends suit people with full-time jobs
- Prepares you for the independent IASSC exam
- Refund on request within 7 days of purchase
Cons
- IASSC exam voucher is bought separately from IASSC
- Minitab training is a separate package
- U.S. price could not be verified from our location
Frequently asked questions
+Which Six Sigma certification is best?
ASQ's Certified Six Sigma Green Belt and Black Belt are the best Six Sigma certifications for experienced professionals, because ASQ requires three years of on-the-job experience before you can sit the exam. The Green Belt exam costs $483 and the Black Belt $585, with $100 off for ASQ members. Candidates without that experience should take IASSC's Green Belt exam instead.
+What is the best online Six Sigma certification?
IASSC's Green Belt is the best online Six Sigma certification for most people, because its proctored 100-question exam can be taken on demand through IASSC's web-based testing system for $402. If you want a taught course, Purdue University's instructor-led online Green Belt takes 10 weeks and costs $2,195. SSGI's self-paced Green Belt bundles about 60 hours of training and the exam for $399.
+Is ASQ or IASSC certification better?
ASQ is better if you have three years of relevant experience, because its exams check experience and the Black Belt requires a signed project affidavit. IASSC is better if you lack that experience, since its Green Belt exam has no prerequisites and can be taken on demand online. ASQ exams are open book, while IASSC's Green Belt exam is closed book.
+How much does Six Sigma certification cost?
A Six Sigma Green Belt costs from $195 to about $3,000 depending on the route. Exam-only fees are $195 at CSSC, $402 at IASSC and $483 at ASQ, while courses with a certificate range from $299.95 at MSI to $2,195 at Purdue and $2,950 for 6Sigma.us live virtual classes. Black Belts cost more, from $295 at CSSC to $3,750 at Purdue.
+Do Six Sigma certifications expire?
It depends on the provider. IASSC treats certifications as current for three years and sells a Green Belt recertification voucher for $268. CSSC, SSGI and MSI say their certifications do not require renewal.
+Can I get a Six Sigma Black Belt without a Green Belt?
Yes, with ASQ and CSSC. ASQ's Black Belt requires three years of experience and a project affidavit but not a Green Belt, and CSSC's standard Black Belt exam has no project requirement. Purdue is an exception: its Black Belt course requires its Lean Principles and Green Belt courses first.
+Can I get Six Sigma certified for free?
No, the credential itself costs money, but the study material can be free. The Council for Six Sigma Certification publishes free self-study guides, and its Green Belt standard exam costs $195. That is the lowest-cost route to a recognized certificate on this list.
About this list
Updated November 11, 2026 by the Mojolin research desk. Mojolin is self-funded
Questions or corrections: editorial@mojolin.com
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