CWI study guide: what to learn for each part, in order

Start with the free 10-question check for the part you're taking first. It's scored by domain, so it shows you which topics below to skip and which to spend your weeks on.

How the three parts differ

Want to know where each part gets hard before you plan? See how hard the CWI exam is.

Part B comes first. Your Part B confirmation carries the eligibility code you use to book Parts A and C. Work back from a test date with the CWI exam schedule, and check you qualify with the eligibility checker before you book. The how to become a CWI guide covers the route end to end.

The study order

1. Set the frame. Read the Part A, Part B and Part C guides for the format and where the points are. Pick a timeline with the study plan builder.
2. Take the free check for your first part and write down your two weakest domains.
3. Build Part A knowledge (topics below). It's the widest part, and its topics feed Parts B and C.
4. Work Part B in the Book of Specifications. Use your gauges, replicas and the book itself, not just notes.
5. Practice Part C clause navigation on the edition your exam uses.
6. Run a timed practice test per part and fix the lowest domain first.

If you work full time, the 12-week study plan for full-time workers fits this order into evenings. Compare ways to study in CWI seminars, online courses and practice banks compared.

Part A: what to know

Part A has ten domains and it's closed book, so recall is the skill. Each topic below links the lesson, the tool and the drill for it.

• Welding and cutting processes. Know how SMAW, GMAW, FCAW, GTAW and SAW differ in shielding, equipment and the discontinuities each is prone to. Read welding processes for the CWI exam.
• Joints and positions. Be able to name a joint, a groove or fillet weld, and a position such as 1G or 2F from a description. Read weld joint types and positions.
• Welding symbols. Know arrow side versus other side, supplementary symbols and where each dimension goes. Read how to read welding symbols, then drill with the welding symbols quiz and the welding symbol builder.
• Discontinuities. Pair each flaw with its cause, its look and the method that finds it. Read weld discontinuities explained and test yourself on the weld discontinuity quiz.
• Metallurgy. Know the heat-affected zone, hardenability and carbon equivalent, and how preheat and low-hydrogen practice prevent hydrogen cracking. Read welding metallurgy for the CWI exam.
• Visual examination. Know what you check before, during and after welding. Read visual weld inspection.
• NDE. Know which method fits which discontinuity and what each one can't see. Read NDE methods for the CWI.
• Destructive testing. Know what bend, tensile and Charpy tests measure and which result tells you what. Read destructive weld tests.
• WPS, PQR and WPQ. Know what each document is for and who relies on it. Read WPS vs PQR vs WPQ.
• Math. Get heat input, carbon equivalent, tensile stress, elongation and unit conversions working by hand. The printable Part A formula sheet has each formula with a worked example. Use the heat input calculator, the carbon equivalent calculator, the fillet weld calculator and the CWI math calculator.
• Duties and responsibilities. Know what an inspector does and doesn't decide. Read what a certified welding inspector does on a shift.

Drill the terms, symbols and formulas on the free CWI Part A flashcards. Then turn knowledge into speed with how to drill Part A practice questions.

Part B: what to know

Part B is its own specification, not D1.1. Every answer comes from measuring something or checking a document against the Book of Specifications, which is a free PDF from AWS.

• Measurement. Read a fillet gauge and a V-WAC style gauge, and know which dimension each one reports. Practice with the weld gauge reading trainer and the measurement workflow guide. The Part B tool kit checklist lists every tool AWS supplies.
• Inspection and discontinuities. This is the largest domain, so judge what you measure against the criterion for the application in front of you.
• Qualification documents. Check whether a WPS, PQR or welder record covers the weld in the question.
• Finding it in the book. Learn the book's layout so each lookup takes seconds. Drill with Part B measurement drills.

Part C: what to know

Part C is D1.1 application, and the skill is navigation. Word search is switched off, so you reach clauses by number and bookmark.

• The map of the code. Know which clause covers design, prequalification (Clause 5), qualification (Clause 6), fabrication (Clause 7) and inspection (Clause 8), and how the tables and annexes are laid out.
• Task routing. Turn a question into a clause: is it about acceptance, a qualification limit or a repair? Read the Part C navigation workflow.
• The right edition. Study the edition your exam uses. The D1.1 edition guide covers which book to buy, and D1.1 or API 1104 helps you pick your code.
• Speed. Time every lookup with the code navigation drill and the D1.1 lookup drills.

Use your own licensed copy of the code. We cite clause numbers and explain in our own words.

Check your readiness

Take a timed set for each part, then work from the domain scores, not the overall number. Am I ready for the exam? shows how to read your results, and the free CWI practice test gives you one explained question per part. Missed a part? Rebuild your study plan, and check the retest rules before you book.

What to skip

• Memorizing code text for Part C. It's open book. Learn where things are.
• Answering Part B from D1.1 memory. Part B questions are written around the Book of Specifications.
• Question PDFs passed around online. You sign an attestation before each part, and sharing exam content breaks it. Every question on Fillet Gauge is original.
• Studying all ten Part A domains equally. Let your check scores decide.

More reading

Want to practice for free first? See free CWI practice resources, our free checks and tools plus the free AWS PDFs. Weighing the cost and the payoff? See what the exam costs, is the certification worth it and how to choose a prep course. Want to know what the pass rate is? Read what AWS publishes. Pay data is in certified welding inspector pay, and renewal is in the renewal guide. For a plan by timeline, see the 30, 60 or 90-day study plan.

FAQ

What is the best CWI study guide?

The best CWI study guide matches how each part is tested: recall for Part A, the Book of Specifications for Part B and fast D1.1 navigation for Part C. This guide gives you that study order and links a lesson, tool or drill for every topic. Take the free 10-question check for your part first, and let your domain scores decide where your weeks go.

What books do I need for the CWI exam?

Part B is answered from the Book of Specifications, a free PDF from AWS. Part C shows D1.1 on screen, so study with your own licensed copy of the edition your exam uses. Tests in 2026 use D1.1:2025, and the D1.1 code book guide covers which one to buy. Part A is closed book. For self-study, AWS sells the Certification Manual for Welding Inspectors and the Welding Inspection Technology workbook, and CWI training, courses and books compared lists both.

What CWI study material is free?

The free 10-question check for each part, scored by domain with no signup. The CWI Part A flashcards, the welding symbols quiz, the weld gauge reading trainer, the code navigation drill and the printable Part A formula sheet. And AWS's own free PDFs: the Book of Specifications and an information guide for each part. Free CWI practice resources links every one.

How do I prep for the CWI exam?

Follow the study order above: read the guide for each part, take the free check, build Part A knowledge, work Part B in the Book of Specifications, drill Part C clause lookups, then run a timed practice test per part and fix your lowest domain first. Book Part B first, because its confirmation carries the eligibility code for Parts A and C. The CWI study plan builder turns your exam dates and weekly hours into a printable schedule.

Is there a study guide for CWI Part A, Part B or Part C?

Yes. Each part has its own guide: Part A for the ten closed-book domains, Part B for replicas and the Book of Specifications, and Part C for D1.1 navigation. The Part A, Part B and Part C sections on this page list what to learn in each one and the drill for every topic.

Take the free 10-question check for your part

Pick your part and start now: Part A check, Part B check or Part C (D1.1) check. Each one is the free 10-question check, scored by domain, with no signup, so you know which topics above to study first. When you're ready for the full prep, the Fillet Gauge course gives you a lesson for every exam subject, two full-length timed practice exams per part, a worked explanation with every answer, and drills that train you to find answers fast in the Book of Specifications and in D1.1.