200+ Free API 653 Practice Questions
Pass your API 653 Aboveground Storage Tank Inspector exam on the first try — instant access, no signup required.
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Key Facts: API 653 Exam
170
Total Questions
140 scored + 30 pretest
110 / 60
Closed / Open Book
API 653 exam page
400 / 500
Scaled Passing Score
API exam scoring page
$875 / $1,125
2026 Exam Fee
API schedules & fees
1-5 years
Experience Pathways
Depends on education
3 years
Certification Term
API recertification cycle
As of March 12, 2026, API's current API 653 exam is still a 170-question in-person CBT with 110 closed-book questions, 60 open-book questions, and a 400 scaled passing score. The March 2026 to November 2026 Publications Effectivity Sheet updates API RP 575, API RP 576, API RP 651, selected API RP 571 damage mechanisms, and lists API 653 addenda and errata that now drive the current exam references. API publishes the official Body of Knowledge and the 110/60 closed-book versus open-book structure, but it does not publish a public percentage-by-domain blueprint, so the percentages below are practice-weighted estimates based on the current BOK emphasis.
About the API 653 Exam
API 653 is the core API Individual Certification Program for inspectors responsible for in-service aboveground storage tanks. The exam tests inspection planning, corrosion and damage recognition, thickness and interval calculations, repair and alteration decisions, welding and NDE oversight, settlement evaluation, and documentation under API 653 and the related open-book references on the current effectivity sheet.
Assessment
170 multiple-choice questions: 110 closed-book + 60 open-book (140 scored + 30 pretest)
Time Limit
7.5-hour exam day (2.75 hours closed-book, 45-minute lunch, 3.75 hours open-book)
Passing Score
400 scaled score on API's 200-500 scale
Exam Fee
$875 API member / $1,125 nonmember (American Petroleum Institute (API) / Prometric)
API 653 Exam Content Outline
Inspection Scope, Planning, and Tank Components
API 653 scope, tank types and terminology, owner-user and authorized inspector roles, inspection preparation and safety, records review, external versus internal inspection, and practical checks on shells, roofs, bottoms, nozzles, foundations, and attached items.
Damage Mechanisms, Materials, and Protection
Atmospheric, soil-side, underside, and product-side corrosion; brittle-fracture risk and material toughness; cathodic protection; tank-bottom linings; and the specific API RP 571 mechanisms called out on the current effectivity sheet.
Thickness, Remaining Life, and Integrity Calculations
Corrosion-rate and remaining-life calculations, inspection interval logic, shell and bottom evaluation, pitting and localized loss assessment, settlement interpretation, joint efficiency, and impact-testing triggers that inspectors need to judge code compliance.
Repairs, Alterations, Reconstruction, and Welding
Repair-versus-alteration decisions, reconstruction concepts, replacement plates, hot taps, patch plates, API 650 and API 653 welding rules, WPS/PQR/WPQ control, and repair-organization or authorized-inspector responsibilities.
NDE and Testing
Radiographic, liquid penetrant, magnetic particle, and ultrasonic examination principles, when each method is appropriate for tank work, and how leak tests, hydrotests, and related post-repair testing decisions fit the API 653 workflow.
Relief Devices, Settlement, and Documentation
Pressure and vacuum venting basics, settlement monitoring, nameplates, inspection reports, repair records, and the documentation trail needed to support in-service fitness decisions and future inspection planning.
How to Pass the API 653 Exam
What You Need to Know
- Passing score: 400 scaled score on API's 200-500 scale
- Assessment: 170 multiple-choice questions: 110 closed-book + 60 open-book (140 scored + 30 pretest)
- Time limit: 7.5-hour exam day (2.75 hours closed-book, 45-minute lunch, 3.75 hours open-book)
- Exam fee: $875 API member / $1,125 nonmember
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
API 653 Study Tips from Top Performers
Frequently Asked Questions
How many questions are on the API 653 exam?
API states that API 653 contains 170 multiple-choice questions, but only 140 are scored. The remaining 30 are pretest items that do not count toward the final result. The exam is split into 110 closed-book questions and 60 open-book questions.
How long is the API 653 exam?
The official API 653 exam day is 7.5 hours long. API breaks that into a short tutorial, 2.75 hours for the closed-book portion, a 45-minute lunch break, and 3.75 hours for the open-book portion.
What score do I need to pass API 653?
API's current exam-scoring page states that Individual Certification Program exams are reported on a 200-to-500 scaled-score scale and that 400 is the minimum passing score. That means you should not treat the exam as a simple raw-percentage cutoff. The better goal is to be consistently strong across calculations, corrosion judgment, welding and NDE controls, and code-application questions.
What references are current for API 653 in 2026?
As of March 12, 2026, the current public API 653 exam materials point to the March 2026 to November 2026 Body of Knowledge and Publications Effectivity Sheet. Those official files list API 653 with addenda and errata plus selected sections of API 650, API RP 571, API RP 575, API RP 576, API RP 651, ASME Section V, and ASME Section IX as the references used for the current exam cycle.
What changed for API 653 in 2026?
The March 2026 to November 2026 effectivity sheet updates several supporting references compared with the earlier cycle. API RP 575 moved to the 5th Edition from September 2024, API RP 576 moved to the 5th Edition from September 2024, API RP 651 moved to the 5th Edition from August 2024, the listed API RP 571 damage mechanisms now include concentration cell corrosion and ethanol stress-corrosion cracking, and the API 653 reference list now includes the February 2025 errata.
Does API publish official domain percentages for API 653?
Not publicly. API publishes the official Body of Knowledge topics and the closed-book versus open-book structure, but it does not publish a public percentage weighting by domain. For study planning, use the current BOK to prioritize inspection fundamentals, corrosion and materials, shell and bottom calculations, welding and repair rules, and open-book code navigation.
Is remote testing available for API 653 in 2026?
No. API's current schedule-exams page specifically notes that API 653 is not available for remote testing. The current certification page also describes the exam as taking place at designated Prometric computer testing centers, so candidates should plan for an in-person administration.
What experience do I need to sit for API 653?
API uses education-and-experience pathways. Candidates with a BS or higher in engineering or technology, or 3 or more years of military technical service, need 1 year of qualifying AST inspection experience; associate-degree or certificate pathways require 2 years; high school requires 3 years; and no formal education requires 5 years. API also states that the qualifying experience must have been gained within the last 10 years under the supervision of an authorized inspection agency or a technically equivalent organization.