How to Prepare for API 653: A 12-Week Study Plan
A 12-week API 653 study plan: why API 653 itself deserves the most time, how to handle API 650 and settlement, and how to practise the open-book part.
Written by Nilanjan SenReviewed by Deepak Rawtal
Published 20 Oct 2026Reviewed 20 Oct 20263 min read
The API 653 exam draws on about nine codes and standards, and the most common mistake is to give them equal time. They are not equal. This plan puts the effort where the questions are, and builds the open-book speed the exam needs.
Short answer: make API 653 itself your main text. At around 40 pages it typically accounts for close to half the questions, while the other documents, together over 1,000 pages, share the rest. Give settlement and the shell calculations dedicated time, and finish with full-length timed practice.
The documents
Your exact list is on the Publications Effectivity Sheet for your window. For 2026 and 2027 it is built around:
- API 653: tank inspection, repair, alteration and reconstruction. The core.
- API 650: new tank construction.
- RP 651 (cathodic protection of tank bottoms) and RP 652 (tank bottom linings).
- RP 575: tank inspection practices.
- Listed parts of RP 571, RP 576 and RP 577, and ASME Sections V and IX.
Several of these move to new editions for 2027. Read what changed for 2027 before you buy books.
A 12-week plan
Weeks 1 to 3: API 653, front to back
Read API 653 slowly, twice. Learn its structure: scope and definitions, the owner-user's and inspector's responsibilities, suitability for service, inspection, materials, design for reconstruction, repair and alteration, welding, examination and testing. Most closed-book questions start here.
Week 4: inspection intervals
Routine in-service, external and internal inspection, how the intervals are set, and the maximum values. Practise interval questions until they are automatic.
Weeks 5 and 6: shell and bottom calculations
Shell minimum thickness, joint efficiency and maximum fill height; corroded areas and pitting; bottom plate minimum thickness. These are the open-book calculation questions, and they reward method more than memory.
Week 7: settlement
Settlement evaluation is the area most distinct to API 653. Work through the survey, the optimum cosine curve, out-of-plane deviation and edge settlement until you can do it without notes.
Week 8: API 650
Use API 650 as a reference for construction rules that API 653 points to. You need to find things in it quickly, not memorise it.
Week 9: the supporting standards
RP 575, RP 651 and RP 652, and the RP 571 mechanisms listed for tanks. Then the welding and NDE content from RP 577 and ASME Sections V and IX.
Weeks 10 to 12: timed practice
Sit full mocks under exam timing: 110 closed-book questions in 2 hours 45 minutes, then 60 open-book in 3 hours 45 minutes. Use PDFs for the open-book part, since that is how the codes appear on the day. Review every wrong answer and note the clause it came from.
Habits that help
- Answer open-book questions from memory first, and keep the PDFs for questions that need a number or a table.
- Keep a clause map: one page listing where intervals, repairs, hydrotest exemptions and settlement live.
- Log your mistakes by document, so the weak area is obvious.
Before you start
Check your eligibility and the exam windows and deadlines, then count back 12 weeks from your window. For what the standard covers in plain terms, read What is API 653? Exam details and sample questions are in our API 653 certification guide.
