Your credit score is extremely dynamic. It changes from day to day (at least).

Your score will thus go down as you go through the month and charge more and more, and will bump up when your credit card issuer reports that they received your monthly payment.

If you’re shopping for a mortgage and need to bump your score up to get a better rate, you should consider paying off your credit cards early, and pay as much as you can in cash or by checks or debit cards. This until your lender locks your rate for you.

If you work with a good loan officer, she can help you figure this out.