FICO Score Explained: The 5 Factors That Determine Your Credit Score and How to Improve Each

Your FICO score ranges from 300 to 850 and is calculated from five weighted factors drawn from your credit report. Lenders use FICO scores to decide whether to approve applications and at what interest rate, a difference of 50 points can mean the difference between approval and denial, or between a 7% and a 12% mortgage rate. Despite its importance, the exact calculation remains proprietary, but FICO has published the five factors and their approximate weights, giving you a clear roadmap for improvement.

The Five FICO Score Factors

• Payment History: 35%

  The single most impactful factor. Any missed payment damages your score; a 90-day late payment can drop scores 60–110 points. Conversely, consistent on-time payments are the most reliable way to build and maintain a high score. Set up autopay for at least the minimum on every account, even one missed payment is significant.

• Amounts Owed (Credit Utilization): 30%

  The ratio of your credit card balances to credit limits. Using 80% of your available credit hurts your score significantly even with perfect payment history. FICO recommends keeping utilization below 30%; top scorers typically maintain below 10%. Pay balances before the statement closing date, not just before the due date, to lower the reported utilization.

• Length of Credit History: 15%

  Includes the age of your oldest account, your newest account, and the average age of all accounts. This is why closing old credit cards (even unused ones) hurts your score, it reduces your average account age. Keep old accounts open with minimal activity to preserve this factor.

• Credit Mix: 10%

  FICO rewards borrowers who successfully manage different types of credit: revolving (credit cards), installment (auto loans, mortgages, personal loans), and open accounts. You don't need every type, but having both credit cards and an installment loan demonstrates diversified credit management.

• New Credit (Inquiries): 10%

  Each hard inquiry (generated when you apply for new credit) temporarily reduces scores by 5–10 points. Multiple inquiries within a 14–45 day window for the same loan type (mortgage, auto) count as a single inquiry. Avoid applying for new credit in the 6 months before any major loan application.

The fastest improvement typically comes from reducing credit utilization, paying down or paying off credit card balances. If you have a $10,000 limit and $7,000 balance, paying it down to $1,000 can increase your score by 40–80 points within one billing cycle. The second fastest improvement is disputing and correcting inaccurate negative items on your credit report, errors affect approximately 20% of reports. Third, becoming an authorized user on a family member's excellent-credit account adds their positive history to your report immediately. These three actions combined can raise a 600 score to 660+ within 60–90 days, with continued improvement over the following 12 months.

Credit utilization, the percentage of your available credit that you are currently using, is the second most important factor in your credit score at 30 percent of the total calculation. The general guideline is to keep utilization below 30 percent on each individual credit card and across all cards combined, but data from FICO shows that consumers with scores above 750 typically maintain utilization below 10 percent. Utilization is calculated based on your statement balance, not your current balance, so paying down your balance before the statement closing date can instantly improve your utilization ratio. If you have a $10,000 credit limit across all cards and carry a $3,000 balance, your utilization is 30 percent; reducing that balance to $1,000 drops utilization to 10 percent and can improve your score by 20 to 40 points within a single billing cycle. One strategy to reduce utilization without paying down debt is to request credit limit increases on your existing cards, which increases the denominator of the utilization calculation.

The length of your credit history accounts for 15 percent of your FICO score and includes the age of your oldest account, the age of your newest account, and the average age of all accounts. This factor rewards patience: there is no shortcut to building a long credit history, which is why financial advisors recommend opening your first credit card as early as possible, even if it is a secured card with a small limit. Avoid closing old credit card accounts even if you no longer use them, because closing an account removes its age from your average and can shorten your credit history significantly. Credit mix accounts for 10 percent of your score and reflects the variety of credit types on your report. Having a mix of revolving credit (credit cards), installment loans (auto loans, personal loans, student loans), and potentially a mortgage demonstrates your ability to manage different types of credit responsibly. You do not need to take on unnecessary debt to improve your credit mix, but if you are choosing between credit products, selecting one that diversifies your credit types can provide a small scoring benefit.

Regular credit monitoring is essential for maintaining a healthy credit score and catching errors or fraud early. You are entitled to one free credit report from each of the three major bureaus (Equifax, Experian, and TransUnion) every 12 months through AnnualCreditReport.com. Stagger your requests to check one bureau every 4 months for year-round monitoring. Free credit score monitoring through services like Credit Karma, your bank, or your credit card issuer provides monthly score updates and alerts when significant changes occur. If you find errors on your credit report, dispute them immediately in writing with the bureau that is reporting the inaccurate information. Common errors include accounts that do not belong to you (possibly from identity theft or a mixed file), incorrect payment history, wrong account balances, and closed accounts reported as open. The credit bureau has 30 days to investigate and respond to your dispute, and if the information cannot be verified, it must be removed or corrected. Placing a credit freeze with all three bureaus is a free and effective way to prevent identity thieves from opening new accounts in your name.