APR vs APY Calculator
Confused by APR and APY? This calculator shows both rates side by side, revealing how compounding frequency affects the real annual return or cost.
APR: The Borrower's Rate
APR measures the cost of borrowing. It's the annualized rate you pay on loans, credit cards, and mortgages. Federal law requires lenders to disclose APR, which includes the interest rate plus certain fees spread over the loan term.
For a simple loan with no fees, APR equals the stated interest rate. A $10,000 loan at 6% for one year costs $600 in interest, so the APR is 6%. Add $300 in origination fees, and the effective cost rises. The lender calculates APR by treating the fees as additional interest, which might push APR to 6.3%.
APR assumes you hold the loan for its full term. If you refinance early, the effective rate is higher because you paid all the upfront fees but spread them over fewer months. This makes APR useful for comparing offers but imperfect for predicting actual costs.
APY: The Saver's Yield
APY measures the return on savings and investments. It accounts for compounding, showing the actual percentage you earn over one year. A 5% interest rate compounded monthly doesn't deliver exactly 5% annual return; it delivers 5.12% because you earn interest on interest each month.
The more frequently interest compounds, the higher the APY compared to the stated rate. Daily compounding produces the maximum APY for a given rate. This is why high-yield savings accounts often advertise daily compounding alongside their APY.
APY makes comparing accounts straightforward. One bank offers 4.5% compounded monthly (4.59% APY), another offers 4.55% compounded daily (4.65% APY). Despite the lower stated rate, the second account earns more because of more frequent compounding. Always compare APY to APY, not rates.
Why Both Metrics Exist
APR and APY serve different audiences and purposes. APR helps borrowers compare loan offers by incorporating fees into a single number. APY helps savers compare deposit accounts by incorporating compounding into a single number. Both standardize comparisons that would otherwise require complex calculations.
The names reflect their uses. 'Rate' (APR) suggests an ongoing cost, which fits borrowing. 'Yield' (APY) suggests a return or harvest, which fits saving. The distinction keeps financial marketing clear and prevents confusion between products designed for opposite goals.
Understanding both protects you from common pitfalls. If someone advertises 'high APR savings,' that's a red flag—savings should show APY. If a lender downplays fees by focusing only on the interest rate and ignoring APR, you're not seeing the full cost. Use the right metric for the right product.
Frequently Asked Questions
What is the main difference between APR and APY?
APR (Annual Percentage Rate) is the simple annual rate without compounding, often used for loans. APY (Annual Percentage Yield) includes compounding effects and is used for savings accounts. APY is always equal to or higher than the nominal rate.
When should I look at APR vs APY?
Look at APR when borrowing (loans, credit cards, mortgages) to understand your cost. Look at APY when saving or investing (savings accounts, CDs, money markets) to understand your earnings. They measure opposite sides of the same concept.
Can APR and APY be the same?
Yes, when there's no compounding (n=1, annual compounding only) or when the rate is 0%. With any other compounding frequency and a positive rate, APY will always exceed APR because interest earns additional interest.
Why do lenders use APR and banks use APY?
Federal regulations dictate disclosure standards. Lenders must show APR on loans, which includes fees spread over the term. Banks must show APY on deposits, which includes compounding effects. This gives consumers standardized metrics for comparison.
How much difference does compounding make?
At typical savings rates (1-5%), daily compounding adds 0.005% to 0.05% compared to annual compounding. At higher rates (10%+), the boost can exceed 0.5%. The absolute difference is small but compounds over time into meaningful dollars.