Five factors determine your FICO score, each carrying a different weight:
Payment history (35%) is the single biggest factor. Even one late payment can drop your score significantly, and that mark stays on your report for up to seven years. Set up autopay if you're worried about missing due dates.
Credit utilization (30%) measures how much of your available credit you're using. Using more than 30% of your total credit limit starts to hurt your score. Below 10% is ideal. For example, if you have a $10,000 credit limit, try to keep your total balances under $3,000, and ideally under $1,000.
Length of credit history (15%) looks at how long your accounts have been open. This is why closing old credit cards can actually hurt your score, even if you don't use them anymore.
Credit mix (10%) rewards having different types of credit. A combination of credit cards (revolving credit) and installment loans like a mortgage, auto loan, or personal loan shows lenders you can manage various types of debt.
New credit inquiries (10%) tracks how often you apply for new credit. Each hard inquiry can temporarily lower your score by a few points. However, multiple inquiries for the same type of loan (like rate-shopping for a mortgage) within a 14-45 day window typically count as a single inquiry.