Your FICO score determines whether you can rent an apartment, buy a car, or get approved for a mortgage. It also affects the interest rates you pay on credit cards and loans. According to the Consumer Financial Protection Bureau, most lenders use FICO scores (ranging from 300 to 850) to evaluate creditworthiness (Consumer Financial Protection Bureau, 2026). Understanding what drives this three-digit number helps you build credit strategically rather than by trial and error.

The Five Factors That Make Up Your FICO Score

FICO scores are calculated from five weighted categories. Some matter far more than others.

Payment History: 35%

Payment history is the single largest factor in your FICO score. Every time you pay a credit card bill, loan payment, or mortgage on time, it strengthens this part of your score. Late payments, collections, charge-offs, and bankruptcies all damage it severely. A single payment that is 30 days late can drop your score by 60 to 110 points, depending on your starting score and credit profile.

How to build credit here: Set up automatic payments for at least the minimum due on every account. Even one missed payment in the past seven years (the duration it stays on your report) can hurt your score.

Amounts Owed (Credit Utilization): 30%

This measures how much of your available credit you are using. FICO compares your total balances to your total credit limits across all revolving accounts (credit cards and lines of credit). A utilization ratio below 30% is considered good, and below 10% is ideal. Maxing out a card, even if you pay it off in full each month, can temporarily lower your score because the balance is reported to credit bureaus on your statement closing date, not your payment due date.

How to build credit here: Keep balances low relative to your limits. If you have a card with a $1,000 limit, try to keep the balance under $100 at statement close. Pay down balances before the statement date, or request a credit limit increase (without a hard inquiry) to lower your ratio.

Length of Credit History: 15%

FICO considers the age of your oldest account, the age of your newest account, and the average age of all your accounts. A longer history generally signals lower risk. This is why closing your oldest credit card can hurt your score, even if you never use it.

How to build credit here: Keep old accounts open and occasionally active (one small purchase every few months prevents the issuer from closing the account for inactivity). If you are new to credit, become an authorized user on a parent’s or spouse’s long-standing account with a solid payment history. The account age and positive history can appear on your credit report and boost your score.

New Credit: 10%

Opening several accounts in a short period raises red flags. Each application for new credit typically generates a hard inquiry, which can lower your score by a few points. Multiple inquiries within a 14 to 45 day window for the same type of loan (like a mortgage or auto loan) are usually treated as a single inquiry, because FICO recognizes you are rate-shopping.

How to build credit here: Apply for new credit sparingly. Avoid opening multiple credit cards within a few months. When you do apply, space out applications by at least six months.

Read also: Credit Score Basics: How to Build and Improve Yours

Credit Mix: 10%

FICO gives a small boost to those who successfully manage different types of credit: revolving accounts (credit cards), installment loans (auto loans, student loans, mortgages), and retail accounts. You do not need every category, but having more than one type shows lenders you can handle varied payment structures.

How to build credit here: Do not take out a loan just to diversify your credit mix. If you already have a student loan or auto loan, that helps. If you only have credit cards, that is fine. The 10% weight is small, and taking on unnecessary debt to chase a few points is counterproductive.

Practical Steps to Build Credit from Scratch

If you have no credit history, start with a secured credit card (you deposit $200 to $500, and that becomes your credit limit) or a credit-builder loan from a credit union. Both report to the three major credit bureaus (Equifax, Experian, and TransUnion). Use the card for small recurring expenses, pay the full balance on time every month, and your score will begin to build within six months.

As covered in foundational texts such as Principles of Finance, consistent repayment behavior is the bedrock of creditworthiness (Principles of Finance, OpenStax, 2022). The mechanics are simple: lenders reward predictability.

Common Mistakes That Hurt Your Score

  • Closing old accounts: This shortens your average credit history and raises your utilization ratio if those accounts had available credit.
  • Carrying high balances to “build credit”: You do not need to pay interest to build credit. Paying your full statement balance every month is enough.
  • Ignoring small bills: Medical bills, utility bills, and phone bills do not directly build credit, but unpaid accounts sent to collections will destroy your score.
  • Co-signing without understanding the risk: If the primary borrower misses payments, your credit suffers equally.

What Does Not Affect Your FICO Score

FICO does not consider your income, employment history, age, marital status, or where you live. Checking your own credit report or score (a soft inquiry) also has no impact. You are entitled to a free credit report from each of the three bureaus once per year at AnnualCreditReport.com, as outlined by federal law (U.S. Financial Literacy and Education Commission, 2026).

Final Note

Building credit is a slow process, not a quick fix. Good credit takes months to establish and years to optimize, but the payoff is lower interest rates, better loan terms, and more financial flexibility. Focus on the two largest factors (payment history and credit utilization), keep old accounts open, and avoid unnecessary applications. Your score will rise as long as you stay consistent.

This information is educational and not personalized financial advice. Credit decisions depend on your individual situation, and you should verify current credit-building strategies with a financial advisor or credit counselor before making significant changes to your accounts.