I can't say I know a lot about Numerology, it is a subject I wasn't intending on believing in lol.. but I magically picked up a book by Linda Goodman called Star Signs and there was a chapter about it in there and after I read that, I couldn't deny it.. I'm not sure if that is the kind of Numerology you are looking for, it is Chaldean, but if so, there is a nice automatic generator online that you can use.
If I were you I would try it a variety of ways, the long version and abbreviated if desired, though I tend to follow Goodman's advice of just using the first and last name. I did look up what my daughter's full name including middle would be before she was born though, and my own etc.. but it is the most common names that are most important.. so on that note if you always sign or are referred to with Saint or St in there, see how that feels to you when you get the results. that is interesting they put an abbreviation on your birth certificate.. maybe it means Street lol
You just write the name(s) and then click Compound Name to get that number