Comparing loan costs helps students understand the real price of borrowing money before signing an agreement. This cheat sheet explains how principal, interest, fees, APR, monthly payments, and loan length affect what a borrower pays. It is especially useful for comparing auto loans, personal loans, student loans, and credit offers.
Students need these skills to make informed financial decisions and avoid costly borrowing mistakes.
The most important idea is that the lowest monthly payment is not always the cheapest loan. APR gives a broader yearly cost because it includes interest and certain fees, while the total repayment amount shows the full cost over time. A longer loan term usually lowers the monthly payment but increases total interest paid.
To compare loans fairly, use the same loan amount, term, payment schedule, and fee assumptions whenever possible.
Key Facts
- Principal is the amount borrowed, and total repayment equals the sum of all payments made over the life of the loan.
- Simple interest is calculated with I = P x r x t, where P is principal, r is annual interest rate as a decimal, and t is time in years.
- Finance charge equals total repayment minus the amount borrowed, so Finance charge = Total of payments - Principal.
- APR is the annual percentage rate that reflects the yearly cost of credit, including interest and certain required fees.
- A lower monthly payment can cost more overall if the loan term is longer and interest continues for more months.
- Monthly loan payment comparisons should include interest rate, APR, fees, loan term, down payment, and total amount financed.
- For a fixed-rate installment loan, the payment stays the same each month, but early payments include more interest and later payments include more principal.
- To compare two loans, calculate Total cost = Down payment + All monthly payments + Fees not included in the loan.
Vocabulary
- Principal
- The original amount of money borrowed before interest and fees are added.
- Interest
- The cost paid to borrow money, usually calculated as a percentage of the unpaid loan balance.
- APR
- The annual percentage rate that estimates the yearly cost of borrowing, including interest and certain required fees.
- Finance Charge
- The total dollar cost of borrowing, including interest and applicable fees paid over the loan period.
- Loan Term
- The length of time a borrower has to repay a loan, such as 36 months or 60 months.
- Amortization
- The process of paying off a loan through scheduled payments that gradually reduce the balance.
Common Mistakes to Avoid
- Choosing the lowest monthly payment only, because a longer term may create a much higher total cost even when each payment feels affordable.
- Comparing interest rate instead of APR, because APR includes certain fees and usually gives a more complete cost comparison.
- Ignoring fees, because origination fees, application fees, and closing costs can make one loan more expensive than another.
- Forgetting to convert percentages to decimals, because using 8 instead of 0.08 in a formula makes the interest calculation 100 times too large.
- Comparing loans with different terms without checking total repayment, because a 72-month loan and a 36-month loan do not have the same time cost.
Practice Questions
- 1 A borrower takes a $6,000 loan at 7% simple annual interest for 3 years. What is the interest charge using I = P x r x t?
- 2 Loan A has 48 monthly payments of 200 fee. Loan B has 60 monthly payments of $260 and no fee. Which loan has the lower total cost?
- 3 A student borrows 15,480 over the life of the loan. What is the finance charge?
- 4 Why might a loan with a lower monthly payment be more expensive than a loan with a higher monthly payment?
Understanding Comparing Loan Costs and APR Reference
Most installment loans use amortization. The lender applies each payment first to interest that has built up since the previous payment. The rest reduces the unpaid balance.
At the beginning, the balance is large, so interest takes a large share of each payment. As the balance falls, more of the same payment goes toward reducing debt. This pattern explains why an early payoff can save money.
It prevents future interest from being charged on the part of the balance paid off early. A payment schedule, often called an amortization table, shows the balance after every payment. Reading this table makes the loan less mysterious.
APR is useful, but it is not a complete prediction in every situation. It works best when a borrower keeps the loan for its stated term and makes every payment on time. Some charges may be excluded under lending rules, while optional products such as insurance, extended warranties, or add-on services can still raise the amount paid.
A loan may advertise a starting rate that only applicants with excellent credit receive. Variable-rate loans create another limit.
Their rate can change after borrowing begins, so future payments or the payoff date may change. Students should check whether a rate is fixed or variable before treating a quoted APR as final.
A careful comparison starts by finding the cash price, the down payment, and the amount actually financed. Then list each required charge separately. One offer might have a lower stated rate but an origination fee added to the balance.
That fee can earn interest too. Another offer may require a larger down payment, which reduces borrowing but requires more cash immediately. Compare offers at the same point in time.
For example, two car loans can have equal monthly payments only because one includes a larger upfront payment or a final balloon payment. A balloon payment is a large amount due at the end. Missing it can make a seemingly affordable deal unaffordable.
Loan documents contain details that matter after the application is approved. Look for the payment due date, late fee, grace period, prepayment rule, and consequences of missed payments. A late payment can lead to extra charges and harm a credit record, making later borrowing more expensive.
Automatic payments can reduce missed due dates, but the account needs enough money before the withdrawal. For student loans, learn when repayment starts and whether interest grows during school or a delay period.
For credit cards, the minimum payment is especially risky because it can stretch a balance for years. Keep written quotes, use a calculator, and compare the full required cash outflow before choosing.