API 653 Prep – Exam Practice

LabSuto

In-app purchases

About this app

API 653 Prep is exam practice for the API 653 Aboveground Storage Tank Inspector certification — and every answer shows the clause it comes from, so you learn where the rule lives, not just which letter to pick.

2,523 QUESTIONS ACROSS THE WHOLE BODY OF KNOWLEDGE
API 653, API 650, API RP 575, RP 577, RP 651, RP 652, RP 571, RP 576, ASME Section V and ASME Section IX — practised in closed-book and open-book runs, the way the real exam is split.

WHAT MAKES IT DIFFERENT
• The clause behind every answer. Each question is traced to its section of the standard.
• Worked solutions for the calculation questions, step by step, in inches or millimetres.
• 16 working calculators for the formulas the exam leans on — shell minimum thickness, remaining life, maximum fill height, hydrotest height, pitting, bottom and annular plates, critical zone, patch plates, nozzle reinforcement, opening spacing, hot taps, settlement and bottom bulges. Free, no account needed.
• A clause browser with 4,500+ clause summaries in plain words, searchable by number or term.
• Works offline. The whole question bank lives on your phone — study on site, on a plane, anywhere.

HOW YOU STUDY
• Today — a daily session sized to your exam date, with a countdown and a streak.
• Practice — pick a standard and a book mode, work at your own pace; your place and your answers are kept.
• Progress — coverage for every standard, your right and wrong history, and every question you flagged or missed, ready for another look.
• Library — the calculators and the clause browser.
• Light and dark themes, adjustable text size, and phone and tablet layouts.

FREE AND PRO
Free: 5 questions in every standard (including a worked calculation where the standard has one) and every calculator. No account, no card, no trial clock.
Pro: every question in every standard, with one yearly subscription. Cancel anytime in Google Play; access continues until the end of the period you paid for.

You only need an account for Pro, and to keep it when you change phones. Your study progress stays on your phone.

PLEASE NOTE
API 653 Prep is an independent study aid. It is not affiliated with, endorsed by or sponsored by the American Petroleum Institute (API). API 653, API 650 and the other document names belong to their owners. The questions are original practice questions written for this app, not questions from the actual exam, and no study aid can guarantee a pass. They were drafted with AI assistance from the text of each standard, and every question is traced to the clause it tests; if you spot a mistake, tap Report on the question and we'll fix it.

Questions or problems: [e-mail]

What’s new

What's new in 0.2.1:
- Your exam date now starts three months after you first open the app, and an info icon explains how to set your own.
- Clearer Pro upgrade prompts on the Progress and You screens.
- A short note appears when a purchase is not completed.
- Pro access now shows right after you sign in.
- The app version is shown on the You screen.
- Updated privacy policy and terms links.