API 570 vs API 653: which API exam is right for you?
Same exam format, different equipment. API 570 covers in-service piping: B31.3 calculations, B16.5 flange ratings, piping classes and injection-point circuits. API 653 covers aboveground storage tanks: shell tmin and fill height, bottom plate limits, settlement evaluation (Annex B), hot taps, and new-tank rules from API 650, plus cathodic protection (RP 651) and bottom linings (RP 652). The welding and NDE content overlaps; the code documents and damage-mechanism lists don't.
API 570 vs API 653 at a glance
| API 570 | API 653 | |
|---|---|---|
| Full name | API 570 Piping Inspector Exam | API 653 Aboveground Storage Tank Inspector Exam |
| Questions | 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book | 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book |
| Time | 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book | 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book |
| Passing score | Passing scaled score is 400 on API's 200 to 500 scale. The number of correct answers needed isn't published and varies by form; practice to 75% or higher | Passing scaled score is 400 on API's 200 to 500 scale. The number of correct answers needed isn't published and varies by form; practice to 75% or higher |
| Format | Closed-book part, then an open-book part with the effectivity-sheet code sections as on-screen PDFs. No paper books or notes; on-screen calculator | Closed-book part, then an open-book part with the effectivity-sheet documents as on-screen PDFs. No paper books or notes; on-screen calculator |
| Cost | US$875 API member / US$1,125 non-member (2026 fee table); US$890 / US$1,140 (2027 fee table). Reschedule US$350, late application US$200 | US$875 API member / US$1,125 non-member (2026 fee table); US$890 / US$1,140 (2027 fee table). Reschedule US$350, late application US$200 |
| Languages | English; Spanish, Chinese and Korean translations available on request | English; Spanish and Chinese translations available on request |
| Where | Prometric test centers, in person only (no remote option for API 570) | Prometric test centers, in person only (no remote option for API 653) |
| Level | API Inspector Certification | API Inspector Certification |
What each exam covers
API 570
- Corrosion Rates, Remaining Life and Intervals
- Piping Calculations (ASME B31.3)
- Flange Ratings (ASME B16.5)
- Damage Mechanisms and Inspection Practices
- Repairs, Alterations and Rerating
- Welding (ASME Section IX, B31.3 and API 577)
- NDE and Pressure-Relieving Devices
API 653
- Shell Evaluation and Minimum Thickness
- Bottoms, Settlement and Foundations
- Inspection Intervals and Practices
- Repairs, Alterations and Hot Taps
- API 650 Design, Materials and Testing
- Damage Mechanisms, Cathodic Protection and Linings
- Welding and NDE
Which should you take?
Same exam format, different equipment. API 570 covers in-service piping: B31.3 calculations, B16.5 flange ratings, piping classes and injection-point circuits. API 653 covers aboveground storage tanks: shell tmin and fill height, bottom plate limits, settlement evaluation (Annex B), hot taps, and new-tank rules from API 650, plus cathodic protection (RP 651) and bottom linings (RP 652). The welding and NDE content overlaps; the code documents and damage-mechanism lists don't.
Try both, free
Each free practice test takes about 10 minutes and shows your score by topic. No signup.
FAQ
What is the difference between API 570 and API 653?
Same exam format, different equipment. API 570 covers in-service piping: B31.3 calculations, B16.5 flange ratings, piping classes and injection-point circuits. API 653 covers aboveground storage tanks: shell tmin and fill height, bottom plate limits, settlement evaluation (Annex B), hot taps, and new-tank rules from API 650, plus cathodic protection (RP 651) and bottom linings (RP 652). The welding and NDE content overlaps; the code documents and damage-mechanism lists don't.
Which is harder, API 570 or API 653?
API 570: 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book in 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book. API 653: 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book in 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book. The longer exam covers more ground, but the harder one is the one further from your daily work. Take both free practice tests to see where you stand.
Can I hold both API 570 and API 653?
Yes. API 510, 570 and 653 are separate certifications, and many inspectors hold two or all three. Each needs its own application, experience and exam, and each is renewed on its own three-year cycle.
How do I prepare for API 570 and API 653?
Start with the free practice test for each, then study by topic. Premium is per exam ($147 a month each), so most people start with the exam they'll sit first and add the second when they're ready.
More comparisons
Exam details are summarized from API's published information as of November 2026. Confirm with API before you book. APIInspectorExam is not affiliated with the American Petroleum Institute (API), ASME or Prometric.