Credit cards let people borrow money for purchases and pay it back later, but the convenience comes with rules and costs. Credit scores summarize how reliably a person manages debt, so they affect loan approvals, interest rates, apartment applications, and sometimes insurance prices. Understanding credit cards and credit scores helps students avoid expensive fees and build a stronger financial future.

Key Facts

  • Credit utilization = credit card balance / credit limit.
  • A lower utilization ratio, often below 30%, usually helps a credit score.
  • Interest charge = balance x APR x days / 365.
  • Paying the full statement balance by the due date usually avoids interest on purchases.
  • Minimum payments reduce short-term pressure but can make debt last much longer and cost much more.
  • A credit score is influenced by payment history, amounts owed, length of credit history, credit mix, and new credit inquiries.

Vocabulary

Credit score
A credit score is a number that estimates how likely a borrower is to repay debt on time.
APR
APR, or annual percentage rate, is the yearly interest rate charged for borrowing money on a credit card or loan.
Credit limit
A credit limit is the maximum amount a card issuer allows a person to borrow on a credit card.
Statement balance
A statement balance is the total amount owed at the end of a billing cycle.
Credit utilization
Credit utilization is the fraction of available credit currently being used.

Common Mistakes to Avoid

  • Paying after the due date, because late payments can create fees and may hurt a credit score.
  • Only checking the minimum payment, because paying only the minimum can lead to large interest costs over time.
  • Using most of the credit limit, because high utilization can signal risk to lenders and may lower a credit score.
  • Applying for many cards quickly, because multiple hard inquiries can temporarily lower a credit score and suggest financial stress.

Practice Questions

  1. 1 A student has a credit card balance of 450andacreditlimitof450 and a credit limit of 1,500. What is the credit utilization ratio as a percent?
  2. 2 A card has an APR of 24%. If a $600 balance is carried for 30 days, estimate the interest charge using Interest = balance x APR x days / 365.
  3. 3 A borrower always pays on time but keeps a balance close to the card limit every month. Explain how this behavior could affect the borrower's credit score and why.