Getting Certified as a “GD&T Professional”

For those of you who actively use GD&T on a daily basis, you should be aware of the certification process for GD&T Professionals.

The American Society of Mechanical Engineers (ASME) has established a credential for GD&T proficiency, called GDTP, which stands for Geometric Dimensioning and Tolerancing Professional.

It is a testing process that measures your ability to interpret and apply tolerances correctly.

There are actually two certification levels: the Technologist Level, which measures your ability to read GD&T; and the Senior Level, which tests not only interpretation, but also the application of GD&T to a design. One does not necessarily need to become a Technologist first; some people go right for the Senior Level, although they are required to document at least five years of experience in GD&T (and they have a more difficult test!).

If you decide to pursue either level, be aware that the questions on the test can be taken from any section of the Y14.5 standard. Each chapter has a “weight” that determines the number of questions from the chapter that appear on the test. This means that there is more than just GD&T; you need to be familiar with the nuances of traditional tolerancing as well as the many definitions contained in that standard. Some questions representative of the Technologist Level:

Sample question #1:

A dimension “not to scale” is symbolized by:

 a. placing the number in parentheses

b. placing a line under the number

c. including NTS after the number

d. italicizing the number

Sample question #2:

If a datum feature of size is applied RFS, a datum displacement is:

a. not allowed

b. allowed at MMC

c. allowed at LMC

d. allowed at the resultant condition


Sample question #3:  

Which of the following datum feature symbols is incorrect?


The GDTP process is not for everybody, but if it’s something that might interest you, contact us for some guidance or you may visit ASME’s website for more detail:


  1. I am using GD&T quite frequently but we are following DIN (German) Standard in our company so will it be useful to aply for ASME certification. Also how much ASME 14.5 is different from DIN EN 1101 (standard for GD&T)

  2. Well, be careful about that. The ASME standard for dimensioning and tolerancing is quite different from the ISO 1101 standard (and its related standards, of which there are many).

    And it’s not just things like using a decimal point or a comma (which some countries use). They are actually different in big things, such as how to interpret a simple size dimension: ISO sees a size as just the “local size” (cross-sectional size) where ASME sees a size as governing both the “local size” and the “actual mating envelope.”

    So while I encourage people to try for the ASME certification exam, it only makes sense if you are very well-versed in the ASME standard. ISO rules are different (and ISO doesn’t have a certification process).

  3. I am interested in the tech certification i have been in the field since 2006. I want a guide from where to start??

  4. How does one become certified to train others in GD&T?

    • Hi Jim,
      Technically there is no specific credential required to train others. All you have to do is convince your customer (internal or external) that you know enough about GD&T to impart proper knowledge upon them!
      So the biggest “certification” is to know the GD&T system very well. Then I might advise someone to do informal training for colleagues in your department, and gradually look for opportunities for more formal teaching as you gain confidence. Then, if trying to sell your services to other companies, a good resume showing GD&T experience is essential.

      ASME offers an official certification called “GD&T Professional” (GDTP) — see main article above. That is certainly helpful to have when trying to sell your training services to others. (When I began teaching GD&T in 1995 there was no ASME GDTP certification. But when it became available in 1997 I was eager to take the test, and here I am 20 years later.)
      Good luck!

  5. I’m interested in becoming a GD&T instructor

    • Hello Robert,
      The comments about should give you some ideas on how to start. Again, the first thing is to make sure that you are thoroughly familiar with GD&T — not just learning the symbols, but all of the underlying rules and nuances.
      The next step would be to connect with a group that needs training and offer them your service. Many instructors teach classes as contractors to an agency that can organize classes, such as a quality consulting company or even a local college that offers technical training to outside companies.

  6. I want an online training and certification in gd&t but i don’t know a good company/institution that can deliver and also issue a globally recognized certification. Please help. Thanks

    • According to the examples and rules of Y14.5, I would say yes.

  7. Sir, I interest to become GD&T professional.

    But in which way cracking GD&T technologist exam will helpful?

    What are the benefits of passing ASME GD&T exam ?

    Can u explain me ,please?

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