Economics
Annual Percentage Rate (APR)
Quick fact
APR can be misleading if interest compounds within the year—an 18% APR compounded monthly actually costs about 19.56% per year, a detail many miss.
Why this is interesting
You've seen 'APR' on credit card offers, but does a low APR always mean you'll pay the least?
Read the full explanation
Understanding Annual Percentage Rate (APR)
Imagine borrowing $10,000 with a 10% interest rate and a $500 origination fee. The nominal rate says you pay $1,000 in interest annually, but the fee adds $500 to your cost. APR bundles both: it calculates the yearly percentage that makes the total payments equal to the loan amount plus all charges. For the example, the APR would be higher than 10% because the fee effectively reduces the amount you receive. APR standardizes offers: a low-rate loan with high fees may have a higher APR than a higher-rate loan with no fees. It's a tool for honest comparison.
A deeper explanation
APR is derived from the periodic interest rate (e.g., monthly) multiplied by the number of periods per year, then adjusted to include mandatory fees. However, this does not reflect the effect of compounding within a year. The true cost is the Effective Annual Rate (EAR), which accounts for compounding frequency. APR is mandated by truth-in-lending laws to be disclosed prominently, making it a legal standard for transparency. Why it matters: when comparing loans—especially mortgages with points and origination fees—APR reveals the actual annual cost. But savvy consumers must also consider whether the loan's term and compounding match the APR calculation. The principle behind APR is to convert all costs into a single percentage so that you can compare apples to apples.