Economics
Loan Basics
Quick fact
The total interest paid on a 30-year mortgage can be more than the original loan amount, even with a moderate interest rate.
Why this is interesting
You’ve probably heard that a loan lets you buy something now and pay later—but why does that small extra percentage (interest) often double what you actually owe?
Read the full explanation
Understanding Loan Basics
Imagine you want to buy a car but don't have the full price. A bank offers to lend you the money: they give you $20,000 today, and you promise to pay it back in monthly chunks over 5 years. The catch? You pay back more than $20,000—the extra is interest, the lender's fee for letting you borrow. The original $20,000 is the principal. The interest rate (e.g., 5% per year) determines how much extra you pay. The loan term (5 years) sets the repayment schedule. Each monthly payment covers a bit of the principal and a bit of interest; over time, the portion going to principal grows. This process is called amortization. If you stop paying, the lender can take the car (collateral) to recover their money. Your credit score influences the interest rate you're offered—higher scores mean lower risk and lower rates.
A deeper explanation
Loans work because lenders take on risk: they give money now in exchange for future payments. The interest rate compensates them for three things: the time value of money (money today is worth more than the same amount later), inflation (future dollars buy less), and the risk of default (you might not pay back). The rate is expressed as an annual percentage rate (APR) that includes both the interest and any fees. Amortization schedules show how each payment is split—early payments mostly cover interest, later ones mostly principal. This matters because a longer term lowers monthly payments but increases total interest. Collateral secures the loan—if you default, the lender seizes the asset. Unsecured loans (like credit cards) have higher rates because there's no collateral. Understanding these basics helps you compare loans, avoid predatory lending, and plan repayments strategically—for example, paying extra toward principal early can save years of interest.