Topic 6 of 6

Personal Finance Basics

Credit cards, loans, savings, interest, and taxes: the money basics no one hands you before your first paycheck.

💳 Credit card vs. debit card

Debit card

Pulls money directly from your own bank account. You can only spend what you already have. No debt risk, but also no credit-building benefit.

Credit card

Lets you borrow money from the card issuer, up to a limit. You must pay it back. If you don't pay the full balance by the due date, you're charged interest on what's left.

Used responsibly (paid off in full each month), a credit card helps build your credit score, a number lenders use to decide whether to trust you with loans, apartments, or even some jobs. Used carelessly, credit card debt can pile up fast because of interest.

🏦 How loans and interest work

A loan is money you borrow and agree to pay back over time, for a car, a house, school, or anything else. In exchange for lending you the money, the lender charges interest: an extra percentage on top of what you borrowed.

  • Interest rate: the percentage charged, usually per year (APR = Annual Percentage Rate).
  • Principal: the original amount you borrowed.
  • The lower your interest rate, and the faster you pay off a loan, the less you pay in total.
  • Missing payments can hurt your credit score and add extra fees.
Example: if you borrow $1,000 at 5% annual interest and pay it off over one year, you'll pay back roughly $1,050 total. The extra $50 is the cost of borrowing.

💰 How savings accounts earn interest

A savings account works the opposite way: instead of you paying interest, the bank pays you interest for keeping your money with them, because they use it while it sits there.

  • APY (Annual Percentage Yield): the rate your savings account earns per year.
  • Interest is usually calculated and added automatically, often monthly.
  • The earlier you start saving, the more time your money has to grow. This is called compound interest: interest earned on your interest.

📋 Why saving matters

  • Emergencies happen: a car repair, a lost job, a medical bill. Savings keep a bad week from becoming a financial crisis.
  • Spending everything you make leaves no cushion and no progress toward bigger goals (a car, college, a first apartment).
  • A common starting goal: save 10–20% of what you earn, even if it's a small amount at first. The habit matters more than the number.

💼 Taxes and your paycheck

Once you start working, the amount you're paid ("gross pay") isn't what lands in your bank account. Taxes get taken out before you ever see it.

  • Gross pay: what you earned before anything is taken out.
  • Net pay ("take-home pay"): what actually gets deposited, after taxes and deductions.
  • Federal & state income tax: a percentage of your income that goes to the government, based on how much you earn.
  • FICA (Social Security & Medicare): a required deduction that funds retirement and healthcare programs.
  • W-4: the form you fill out when you're hired that tells your employer how much tax to withhold.
  • W-2: the form your employer sends you each January, summarizing what you earned and paid in taxes, used to file your tax return.
Heads up: when you see a job posting that says "$20/hour," your actual take-home pay will be less than that once taxes are taken out. It's normal, just good to expect it.