Credit score in the U.S. is based on the information in your credit report. One of the factors of your credit score is credit utilization, which is a function of your credit card balances and your available credit. These balances are reported monthly to your credit report by your credit card company. However, there are a few reasons why trying to maximize your credit score in this way is tricky:
Different credit card companies report balances to your credit reports at different times. Many banks report your balance when they generate the statement, but some banks may report at a different time. To figure out your bank’s timing, you’ll need to look at your report monthly for several months and see if the balance numbers reported match your statement balances, or if they are different. If different, you’ll need to puzzle out when your balance was the amount that was reported.
Only the most recent credit card balance is on your report. Each month, when your bank provides a new balance for your report, it replaces last month’s number. Credit utilization is only based on the latest number. That means that if you do happen to figure out the optimal time of month to pay your bill to get your balance reported where you want it, it will only have a temporary effect on your score. You would need to consistently pay your bill at the right time each month to keep whatever score boost that you are getting.
The optimal utilization number you are aiming for is not known. Credit score formulas are proprietary secrets. Lower numbers seem to be better than high numbers, but too low is also not ideal.
The best advice I give to people about improving your credit score is to stop worrying about it. If you are carrying balances on your credit cards and paying interest, pay those cards off ASAP, and make sure you pay your card statements in full each month. If you have outstanding loans, get those paid off ASAP. If you do that and you make sure you always pay your bills on time, your score will automatically improve over time, and you won’t even have to think about it.
Finally, I don’t know what your score is, but it may already be higher than you really need.