It’s impossible to know exactly how much a credit inquiry will affect a credit score, because many variables come into play with each individual score. Some people's scores will go down with a credit inquiry, and others will not.
In fact, if you ever hear anyone tell you, “An inquiry is equal to 10 points” (or any point value), you know you’re listening to someone who doesn’t know much about credit scoring.
Inquiries do not have an exact point value. However, normally consumers who have an excessive amount of inquiries will get fewer points for that category than consumers who do not have an excessive amount of inquiries. The moral of this story is to shop for credit only when you really need it and not as a hobby or as a way to save 10 percent off of your Christmas shopping at the mall.
Also remember that only hard inquiries will affect your credit scores; soft inquiries are not visible to anyone except for you and will not affect your scores.
You can sum up the question this way: Opening a new credit account can
lower your credit scores, but not always. In many cases, applying for
credit it will have no impact to your credit score at all. However,
excessively applying for credit will likely lower your credit scores.