CWI Part A fundamentals: the eleven content areas, their exam weights, and how to study them

Part A is the part of the AWS Certified Welding Inspector (CWI) exam that most candidates worry about most, because it is the one you cannot look your way through. It is closed book, it is wide, and it rewards genuine recall. The good news is that AWS publishes exactly which topics it draws from and roughly how many questions each topic carries, so you do not have to study blind. This guide lays out the format, the eleven official content areas and their weights, the calculations you will be asked to do, and a study plan that puts your hours where the questions actually are. We sell no seminar, so we have no reason to make Part A sound scarier than it is.

What Part A is, in one paragraph

Part A is the closed-book fundamentals exam. It is a computer-based test of 165 questions in 135 minutes, delivered at a Prometric test center, and you must score at least 72 percent to pass it (checked against the AWS certification pages on 2026-07-23). You bring no references, so it tests what you actually know, not how fast you can look something up. That is the whole character of Part A: breadth of recall under a clock, with no book to rescue you. For most first-timers it is the hardest of the three parts for exactly that reason, and it is the part where cramming fails, because you cannot cram a body of knowledge this wide in a week.

The eleven content areas and what each is worth

AWS defines the Part A body of knowledge as eleven content areas, and it publishes a minimum percentage of the exam questions for each one (AWS B5.1, Clause 7.1). These are minimums, not an exact split, which is why the numbers below add up to about 82 percent rather than 100: the remaining questions are distributed across the same areas, but no area will carry less than its listed minimum. The table is your map of where the exam’s weight sits.

Content area	Minimum weight	What it covers
Definitions and Terminology	12%	Joint types, welding positions, and weld nomenclature: toe, root, face, throat, leg, and joint penetration.
Welding Processes	12%	SMAW, GMAW, GTAW, FCAW, and SAW: what each is, how each shields the arc, and where each is used.
Welding and NDE Symbols	10%	Reading AWS weld symbols: arrow side versus other side, fillet leg size, the field-weld flag, weld-all-around, and the NDE method in the tail.
Weld Examination	10%	Visual inspection timing and surface discontinuities: undercut, overlap, and porosity, plus the discontinuity-versus-defect distinction.
Welding Performance	9%	The WPS and PQR, essential variables, and the difference between procedure qualification and welder performance qualification.
NDE Test Methods	8%	Liquid penetrant, magnetic particle, radiographic, and ultrasonic testing: what each can and cannot detect.
Heat Control and Metallurgy	6%	Preheat, the heat-affected zone, and postweld heat treatment on carbon and low-alloy steel.
Welding Related Calculations	6%	Fillet-weld throat geometry, percentages and rejection rates, and unit and temperature conversions.
Duties and Responsibilities	4%	The inspector’s ethics and impartiality, and keeping accurate, traceable records.
Destructive Tests	3%	Tensile and guided-bend tests for strength, ductility, and weld soundness.
Cutting	2%	Oxyfuel gas cutting fundamentals and why it does not suit stainless steel or aluminum.

Where the questions actually are: read the weights before you study

The single most useful thing the weight column tells you is that Part A is front-loaded. The top four areas, Definitions and Terminology, Welding Processes, Welding and NDE Symbols, and Weld Examination, carry a minimum of 44 percent of the exam between them. Add Welding Performance and NDE Test Methods and you are past 60 percent with six of the eleven areas. The bottom three, Duties and Responsibilities, Destructive Tests, and Cutting, together carry a minimum of only 9 percent.

That does not mean you can skip the small areas, because 72 percent is a demanding bar and every question counts. It does mean the marginal hour is worth more spent shoring up processes, symbols, and examination than on the fine points of oxyfuel cutting. A candidate who is fluent on terminology, can read a weld symbol cold, knows the five common processes, and can name a surface discontinuity on sight has already secured most of the exam’s weight. Study in that order.

The calculations you will be asked to do

The Welding Related Calculations area is small by weight, 6 percent, but it is the one people most often leave to chance, and it is the most recoverable, because the formulas are finite and learnable. The calculation types that show up are:

• Fillet-weld throat geometry. For an equal-leg fillet weld, the theoretical throat equals the leg size multiplied by 0.707 (the cosine of 45 degrees). Being able to convert between leg and throat in either direction is a reliable source of easy points.
• Percentages and rejection rates. Simple ratio work: what percentage of an examined weld length was rejected, what fraction of coupons passed a bend test, and similar. No calculus, just careful arithmetic under a clock.
• Unit and temperature conversions. Fahrenheit to Celsius and back (F = C times 9/5, plus 32), inches to millimeters, and the like. These are the questions you lose by rushing, not by not knowing.

Because Part A is closed book, you cannot bring a formula sheet, so these have to be reflexes. Memorize the 0.707 throat factor and the temperature conversion, and drill enough ratio problems that the setup is automatic. This is the cheapest block of points on the exam to lock down, and the free practice test puts calculation questions in front of you so you can see whether your arithmetic holds up under time.

Why closed book changes how you study

Part C, the open-book code exam, rewards fast navigation of a book you may bring. Part A rewards the opposite: durable recall of material you may not bring. That difference should change your method. For Part A, spaced repetition beats re-reading, active recall beats highlighting, and a little every day beats a marathon the weekend before. The exam is testing whether the fundamentals are actually in your head, and the only way to get them there is to keep retrieving them until they stick. The practice test is built around that idea: it schedules missed questions to resurface when they are due, so your weak areas keep coming back until they are no longer weak.

A study plan that follows the weights

1. Take the diagnostic first. Before you study anything, run the free Part A practice test once to get a per-topic breakdown of where you already stand. You will almost always find that your weak areas are not the ones you expected, and that is the map for everything that follows.
2. Spend your first block on the heavy areas. Terminology, processes, symbols, and examination carry the most weight, so they earn the most study time. Get to the point where reading a weld symbol and naming a surface discontinuity are automatic.
3. Lock down the calculations. Memorize the 0.707 throat factor and the temperature conversion, then drill ratio and rejection-rate problems until the setup is reflex. Small area, cheap points.
4. Cover the light areas honestly, not deeply. Duties and responsibilities, destructive tests, and cutting are low weight, but 72 percent leaves no room to punt them entirely. Learn the core of each; do not rabbit-hole.
5. Give yourself weeks, not days. Breadth is the enemy of the crammer. Candidates who spread Part A study over a couple of months pass it; candidates who cram fail it. Retrieval over time is what moves this much material into long-term memory.

Where Part A fits, and what comes next

Part A is one of three parts, and you need 72 percent on each of them independently: a strong Part A does not carry a weak Part B or Part C, and there is no averaging across parts. For the full structure, eligibility, and the whole study arc, start with the CWI exam guide. For an honest, part-by-part read of what makes each part hard, see how hard is the CWI exam. The other two parts are covered in their own depth: the hands-on Part B practical with its replicas, gauges, and Book of Specifications, and the open-book Part C code exam, which is a speed test rather than a memory test. And before you book anything, the cost calculator turns your prep decision into a single number.

Sources: the AWS Certified Welding Inspector certification pages at aws.org, including the published Part A body of knowledge and content-area weights (AWS B5.1, Clause 7.1), reviewed 2026-07-23. The 165-question, 135-minute closed-book format, the eleven content areas and their minimum weights, and the 72 percent per-part passing score are set by the American Welding Society and can change; confirm the current details on the official application before you pay. The throat factor and conversion formulas are standard welding geometry. This site is independent, is not affiliated with AWS, and sells no seminar, course, or exam seat.