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For tank inspectors taking the API 653 exam

API 653: work the tank calculations

Free API 653 practice: 10 questions, answers explained as you go, score by domain.

Free 10-question check

Full course $199: 347 practice questions, each explained. See the course

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Question 1 of 10 · free checkUntimed

V. Practical knowledge - specific (API 653 and 650, RP 571 listed mechanisms, RP 575, RP 576, RP 577, RP 651, RP 652)

A tank shell wrapped in mineral wool shows deep, wet corrosion where the weather jacket is torn near a nozzle. Which damage mechanism fits?

Press A-D or 1-4 to choose an answer while this question is on screen.

Choose an answer to begin

Practice thickness, weld size and tank integrity calculations by hand. Take the free 10-question check and see your study priorities by Body of Knowledge section.

  • 10 questions, untimed
  • Answers explained as you go
  • Scored by domain
Ask Patch AI Explains your misses, answers from this course, and builds practice from your weak spots.Try it free: 3 asks on the free check, 10 more with your email. What Patch can do

Original practice material. Not affiliated with API.

How it works

  1. Answer 10 questions, freeUntimed. Check each answer to see why it's right, with a hint where one helps.
  2. See your score by domainBroken down by outline domain, with your weakest one named.
  3. Study what you missedAdd your email and exam date for a study plan, or practice at exam pace.

    Want exam pace? Take the 25-question practice test (about 57 minutes)

The API 653 course

Available now · instant access

Learn every Body of Knowledge section, work the tank calculations step by step, then prove it on timed exams.

  • 8modules of lessonsEvery task on the outline
  • 2full-length timed exams170 questions in 390 minutes each
  • 347practice questionsEach one explained
  • 12worked calculationsStep by step
  • 26code-navigation drillsFind it fast in API 653
  • 1week-by-week study planSet to your exam date

Patch, your AI study assistant, comes with the API 653 course: a week-by-week plan from your exam date and weak areas, step-by-step walk-throughs and a weak-spot quiz. Up to 40 messages a day.

  • My study plan: a week-by-week course from your exam date and weak areas, with today's set ready. Lose a week and I re-plan it
  • Stuck on a question? Tap Walk me through it, Explain like I'm new or Show a worked example
  • A quiz on your weak spots, your misses back on a spaced review, and explain it back to me to lock it in
  • After 30 answers, I show you the patterns in your misses and a practice set for each one
  • Exam week: a day-by-day plan for your last 7 days
See all 8 modules
  1. API 653: scope, the inspector, inspection types and records
  2. Corrosion rates, remaining life, inspection intervals and joint efficiency
  3. Shell evaluation: minimum thickness, fill height, corroded areas and pits
  4. Bottoms, foundations, settlement, cathodic protection and linings
  5. Repairs, alterations, reconstruction and testing
  6. Welding: procedures, welder qualification and the tank welding rules
  7. Nondestructive examination: ASME V and API 650
  8. Damage mechanisms, brittle fracture, tank condition and relief devices
API 653 course$199Get the API 653 course · $199

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Every answer comes with a full explanation.

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PatchI'll show you why the right answer works, why each other option falls short, and where to look it up.

Example of how I explain. Answer question 1, then tap Ask Patch why. 3 free asks, 10 more with your email. I'm AI, so check important details against your references. Meet Patch

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Free API 653 study plan

A week-by-week plan from today to your exam, weighted to the published exam outline. We show it here and email you a copy.

Exam at a glance

Format
170 questions in 390 minutesBook: Closed-book part, then open-book part. PDFs of the pertinent codes and standards are on screen in the open-book part, and papers and books are not allowed in the Prometric centers. The BOK says only the sections of publications named on the Publications Effectivity Sheet are used for questions
Delivery
In person at designated test centers only
Exam fee (paid to API, not us)
Initial: 2026 Fees tab $875 member / $1,125 non-member; 2027 Fees tab $890 / $1,140. Recertification: 2026 $745 / $855; 2027 $760 / $870. Late application $200. Reschedule (new window) $350

What it covers

I. Calculations and tabular evaluations for thickness measurements, weld sizes and tank integrity
II. Welding on atmospheric aboveground storage tanks (ASME IX, API 650 Section 9, API 653 Section 11)
III. Nondestructive examination (ASME V, API 650 Section 8, API 653 Section 12)
IV. Practical knowledge - general
V. Practical knowledge - specific (API 653 and 650, RP 571 listed mechanisms, RP 575, RP 576, RP 577, RP 651, RP 652)

The free 10-question check follows these domains, subject to the available practice questions.

API 653 exam prep FAQ

How long is the free check?

The free check has 10 practice items, is untimed and takes about 23 minutes. You see the answer and explanation after each item.

What does the free check cover?

The five sections of API's API 653 Body of Knowledge: calculations, welding, nondestructive examination, and general and specific practical knowledge. You see which section to study first.

Is the check free?

Yes. You can start the check and see your score and weakest section for free, with no signup or payment. Your score in each section unlocks when you add your email.

What do I see after finishing?

You get your score, your weakest section and what the API 653 Aboveground Storage Tank Inspector course holds for it. Add your email to see your score in each section and get a free study plan.

Where do the practice questions come from?

Every question is original and written to the API 653 Body of Knowledge topics. We cite document and section numbers without reproducing code text. The check does not predict your exam score or certification outcome.

How long is the API 653 exam?

API lists 170 questions, 140 scored and 30 pretest: 110 closed book, then 60 open book, in 390 minutes at a test center. Our timed practice exams follow that length.

Which editions apply?

API's Publications Effectivity Sheet for your exam window sets the editions. Check API's current Body of Knowledge and effectivity sheet before studying from any edition.

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