Inspection

API 653 Aboveground Storage Tank Inspector Practice Test and Exam Guide

Six full-length API 653 practice tests with 1,020 original questions, written to the March 2027 effectivity sheet and the real closed-book and open-book split.

Published 13 September 2026 · Last updated 13 September 2026

What does the API 653 Aboveground Storage Tank Inspector assessment cover?

The preparation material covers the documented assessment facts listed below. The question bank reinforces those facts without presenting a practice product as an official exam or reproducing assessment content.

• 170 questions: 140 scored and 30 unscored pretest items.
• 110 closed-book questions in 2 hours 45 minutes, then a 45-minute break, then 60 open-book questions in 3 hours 45 minutes.
• Passing is a scaled 400 on a 200-500 scale, not a published percentage.
• Exam windows run in March, July and November, with application deadlines roughly two months earlier.
• Windows from March 2027 onward use the March 2027 effectivity sheet, which moves API 650 to the 14th Edition and ASME BPVC Sections V and IX to the 2025 Edition.
• The November 2026 window is the last one on the older March 2026 sheet, which uses API 650 13th Edition and ASME BPVC 2023. These tests are written to the March 2027 sheet.
• API 653's construction standard is API 650. ASME Section VIII is not a referenced publication for this exam.
• Some formulas are supplied in the exam, while certain API 653 tables must be known without access to the documents.
• The exam is administered in person at Prometric, and the reference documents appear on screen only during the open-book section.
• As of API's April 2026 ICP status update, the most recent published pass rate is the November 2025 administration: 503 candidates at 60.8%.

Which domains should you study?

Use these supplied brief-backed domains as the study map. They are coverage areas, not invented percentage predictions.

Domain	Preparation focus
I. Calculations & Tabular Evaluations for Evaluating Thickness Measurements, Weld Sizes, and Tank Integrity	Review explanations after related questions and record the specific gap.
II. Welding on Atmospheric Aboveground Storage Tanks	Review explanations after related questions and record the specific gap.
III. Nondestructive Examination	Review explanations after related questions and record the specific gap.
IV. Practical Knowledge - General	Review explanations after related questions and record the specific gap.
V. Practical Knowledge - Specific	Review explanations after related questions and record the specific gap.

How should you use these practice tests?

Start with the Test 1 sample, then use domain labels and explanations to choose what to review. Retake missed questions after studying the underlying objective, and reserve the final test for timed practice where the brief provides assessment timing.

1. Take the sample without looking up answers.
2. Group misses by domain, not just by score.
3. Review each explanation and the governing study material.
4. Repeat under documented assessment conditions when available.

What is a practical API 653 Aboveground Storage Tank Inspector study plan?

1. Phase 1: build working knowledge of the closed-book ground. Inspection types and intervals, corrosion and deterioration of tank shells, bottoms and roofs, repairs and alterations, reconstruction, records and authorisation. 110 of the 170 questions are closed-book, the larger half and the half you cannot look up.
2. Phase 2: learn what the exam gives you and what it does not. The corrosion rate, remaining life, remaining corrosion allowance, maximum fill height and bottom plate formulas are supplied during the exam, so practise choosing the right inputs and deciding which rate or interval rule governs rather than memorising the algebra. The API 653 tables marked with an asterisk in the Body of Knowledge must be known without the documents.
3. Phase 3: rehearse the open-book navigation. Work through API 650 table and figure lookups, the one-foot method, toughness and impact-test tables, weld-size details, and the Annex B settlement procedures until you know which document and roughly which part to open. Practise on screen, because the exam supplies PDFs and you cannot bring your own tabbed books.
4. Phase 4: run full 170-question tests to the real 2:45 closed-book, 45-minute break, 3:45 open-book rhythm. Review every explanation, including on questions you answered correctly, and keep an error log by domain and by facet: calculation, code requirement, field decision, diagnosis, acceptance, authorisation and records, or selection under constraint.

API 653 Aboveground Storage Tank Inspector FAQ

Is the API 653 exam scored as a percentage?

No. The pass standard is a scaled score of 400 on a 200-500 scale. API publishes no raw percentage and no per-form raw cut score, so a claim that you need 70% or 80% is not supported. Those figures usually come from a vendor's guess or from confusion with the recertification webquiz, which is a different assessment.

How many of the 170 questions actually count?

140 are scored. The other 30 are unscored pretest items, and they are not identified on the exam, so answer every question. Unanswered questions are scored as incorrect.

How is the exam day structured?

A 110-question closed-book session of 2 hours 45 minutes, a 45-minute break, then a 60-question open-book session of 3 hours 45 minutes. That is about 1.5 minutes per question in the closed-book block and about 3.75 in the open-book block, which is the time the open-book items need for locating and applying a requirement. Once you submit the closed-book section you cannot return to it.

Which editions apply to the 2027 exam windows?

Windows from March 2027 onward use the March 2027 effectivity sheet. That sheet lists API 650 in its 14th Edition of August 2025, ASME BPVC Sections V and IX in their 2025 Editions, API 653 with Addenda 1 through 4, API RP 652 in its 6th Edition, and API RP 575 with Addenda 1 and 2. The November 2026 window is the last one on the older March 2026 sheet, and it still uses API 650 13th Edition and ASME BPVC 2023.

Does API 653 use the same references as API 510 and API 570?

No, and assuming it does is a common and expensive mistake. ASME Section VIII, ASME PCC-2, ASME B16.5, ASME B31.3, API RP 572, API RP 574, API RP 578 and API 579 are not on the API 653 effectivity sheet. Neither is API RP 2350, despite being an intuitive guess for a storage tank exam. The construction standard is API 650 and the inspection practices reference is API RP 575.

Which formulas do you have to memorise?

Fewer than candidates expect. The Body of Knowledge states that the corrosion rate, remaining life, remaining corrosion allowance, maximum fill height and bottom plate formulas will be provided in the exam. What you must carry unaided is the judgment around them: which corrosion rate governs, which interval rule applies, which thickness goes into which variable, and the content of the API 653 tables the Body of Knowledge marks with an asterisk.

Can you take API 653 remotely?

No. API states that API 510, 570, 653, 1169 and 1184 are not available for remote testing. The exam is in person at a Prometric test centre, with a calculator, scratch paper and pencil provided. Reference documents appear as on-screen PDFs, so practising with a tabbed paper copy trains the wrong skill.

What else do API 653 candidates prepare for?

Candidates sitting API 653 often sit these too, and the same study habits carry across.

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