API 510 pass rates by exam window (from API's published statistics)

Recent published results by window

Candidate totals and pass percentages as printed in that report's API 510 table, with API's own mark where it prints one:

• January 2023: 911 candidates; 62.0% passed.
• May 2023: 1,084 candidates; 63.5% passed.
• September 2023: 1,167 candidates; 64.0% passed.
• January 2024: 902 candidates; 69.2% passed.
• May 2024: 1,146 candidates; 68.5% passed.
• September 2024: 1,211 candidates; 65.9% passed.
• January 2025: 997 candidates; 66.9% passed.
• May 2025: 1,000 candidates; 61.8% passed.
• September 2025: 1,024 candidates; 54.7% passed. API marks this row "*Underwent standard setting".
• January 2026: 688 candidates; 61.6% passed.

The report is the breakdown as of 30 April 2026, printed page 14. The September 2025 row prints 561 passes out of 1,024 candidates beside 54.7%. The report has no results yet for the May or September 2026 windows. The Program Updates statistics index is where API posts its reports.

How API 570 and API 653 compare

The same April 2026 report prints API 653 on page 14 and API 570 on page 15, with a pass point of 400 on every row of all three tables. The latest windows with results:

• API 510 (pressure vessels): January 2026, 688 candidates, 61.6% passed. The 2025 windows (January, May, September) were 66.9%, 61.8% and 54.7%.
• API 570 (piping): February 2026, 592 candidates, 68.9% passed. The 2025 windows (February, June, October) were 63.7%, 66.5% and 66.3%.
• API 653 (storage tanks): November 2025, 503 candidates, 60.8% passed. The 2025 windows (March, July, November) were 62.9%, 60.2% and 60.8%. The March 2026 row has no figures yet and is marked "Undergoing standard setting."

Each program runs its own windows, so the rows don't line up month for month. Page 13 also notes standard settings in November 2019 for API 510 and 653 and in November 2020 for API 570. A higher rate for one program does not make that exam easier for you, because the three share a format and differ in equipment and codes. Our API 510 vs 570 vs 653 guide sets the eligibility, format and code editions side by side.

A pass rate is different from a passing score

A pass rate describes how many candidates succeeded. A passing score is the standard used to assess an exam result. API's scoring explanation describes equating for differences between exam forms and says another candidate's performance does not determine whether you pass.

So the published rate is background, not a target percentage for practice. Use your missed topics to decide what to review next.

What a window pass rate tells you, and what it doesn't

A window pass rate is a group result: everyone who sat that administration, counted together. In the API 510 rows above, between about 31% and 45% of each window's candidates did not pass, so the exam deserves a real study plan. The rows also show how outcomes moved from one window to the next.

It doesn't tell you your own odds. Your result is measured against the passing standard, not ranked against the room. The API 510 table does not separate first attempts from repeat attempts, show candidates' experience or identify preparation providers, and it does not say why a window rose or fell. A higher rate in a particular month does not make that month easier. Choose a window around your application readiness, study time and availability, and read the schedule and fees guide before changing an application or appointment.

Use the numbers to plan preparation

Start with the Body of Knowledge guide, then confirm your code books against the effectivity-sheet guide. Build a review log that separates an unfamiliar topic, an incorrect calculation setup (see the API 510 calculations guide) and a slow reference lookup. Each category tells you what to practice next.

Know where you stand today

The free 10-question check takes a few minutes, needs no signup and shows which Body of Knowledge domains to review first, with an explanation for every answer. The Long Seam course turns that into a lesson for each domain, timed practice exams and a study plan from your exam date. Back to the Long Seam overview.

FAQ

What is the API 510 pass rate?

In API's April 2026 report, the latest API 510 window is January 2026, when 424 of 688 candidates passed (61.6%). From January 2023 to January 2026 the window rate ranged from 54.7% to 69.2%.

Is API 510 hard?

API does not publish a difficulty rating, but its figures show the exam takes real preparation: in the ten windows above, between about 31% and 45% of candidates did not pass. API's API 510 page lists 110 closed-book questions in 2.75 hours and 60 open-book questions in 3.75 hours. Our post on how hard the API 510 exam is covers what makes it tough.

How many people take the API 510 exam?

API's April 2026 report lists between 688 and 1,211 candidates per API 510 window from January 2023 to January 2026, and 3,021 across the three 2025 windows. The same report counts 21,996 API 510 certificants as of April 2026 (page 3).

What score do you need to pass API 510?

A scaled score of 400. API's Schedule Exams page says the passing scaled score for all exams is 400 on a 200 to 500 scale. Because API equates each exam form for difficulty, the number of correct answers behind that score may be slightly different per form, and score reports show the scaled score rather than the number correct.

Does API publish a first-time pass rate for API 510?

No. The API 510 table counts every candidate in a window together and does not separate first attempts from repeat attempts.

Sources

Show the list

• Individual Certification Programs Status Update, breakdown as of 30 April 2026, American Petroleum Institute, printed pages 3 and 13–15 (API 510 and API 653 tables on page 14, API 570 on page 15). The latest verified report as of 26 Oct 2026.
• ICP Program Updates: Statistics, American Petroleum Institute. Checked 26 Oct 2026.
• ICP Policies: How are ICP exams scored?, American Petroleum Institute. Checked 26 Oct 2026.
• ICP Schedule Exams: Scaled Scoring, American Petroleum Institute. Checked 26 Oct 2026.
• API 510 Pressure Vessel Inspector certification page: Exam Structure, American Petroleum Institute. Checked 26 Oct 2026.