Calculate the Annual Percentage Yield (APY) for savings accounts, CDs, and investments. See how compounding frequency affects your returns and compare different accounts side by side.
Compare up to 3 accounts side by side to find the best savings or investment option.
Maria deposits $25,000 in a high-yield savings account with a 4.5% nominal rate compounded monthly.
APY: 4.59%
After 1 year: $26,147.52 (vs $26,125 with simple interest)
After 5 years: $31,277.14
Maria earns an extra $22.52 in the first year thanks to monthly compounding — that's $1.88 per month for free.
James is comparing two 1-year CDs. Bank A offers 5.0% compounded monthly (APY: 5.12%). Bank B offers 4.95% compounded daily (APY: 5.07%).
Bank A APY: 5.12%
Bank B APY: 5.07%
Winner: Bank A — Despite a lower compounding frequency, the higher nominal rate wins.
On a $50,000 deposit, Bank A earns $2,559 vs $2,537 at Bank B — a difference of $22 over one year.
Sarah opens an account with a 5.0% nominal rate compounded monthly (APY: 5.12%). She deposits $10,000 initially and adds $500 per month.
After 1 year: $16,636.80 (including $5,000 in contributions)
After 5 years: $45,678.23
After 10 years: $91,456.89
Total contributions: $70,000
Total interest earned: $21,456.89
Regular contributions dramatically increase the power of compounding — Sarah earns over $21,000 in interest over 10 years.
At the same nominal rate of 6.0% on a $100,000 deposit over 10 years:
Annual compounding: $179,084.77 (APY: 6.00%)
Quarterly compounding: $181,402.74 (APY: 6.14%)
Monthly compounding: $181,939.67 (APY: 6.17%)
Daily compounding: $182,202.94 (APY: 6.18%)
The difference between annual and daily compounding on $100,000 over 10 years is $3,118 — not trivial, but the gap between monthly and daily is only $263.
APY (Annual Percentage Yield) represents the real rate of return on your savings, accounting for the effect of compounding interest. It's the true annual rate you earn, which is always higher than or equal to the nominal (stated) rate.
r = Nominal annual interest rate (as decimal, e.g., 5% = 0.05)
n = Number of compounding periods per year (365=daily, 12=monthly, 4=quarterly, 1=annual)
APY = Annual Percentage Yield (as decimal, multiply by 100 for percentage)
FV = Future Value
P = Principal (initial deposit)
PMT = Monthly contribution amount
r = Nominal annual interest rate (decimal)
n = Compounding periods per year
t = Time in years
Input the stated annual interest rate offered by your bank or investment account. This is the rate before compounding — also called the APR.
Choose how often interest is compounded. Common options: daily, monthly, quarterly, semi-annually, or annually. More frequent compounding = higher APY.
Input your initial deposit amount and the number of years you plan to keep the account. Longer time periods amplify the effects of compounding.
If you plan to make regular deposits, enter the monthly amount. Regular contributions significantly boost the power of compounding over time.
Use the comparison mode to evaluate up to 3 different accounts side by side. Consider different rates, compounding frequencies, and fee structures to find the best option.
APR (Annual Percentage Rate) = Simple interest rate without compounding. It's the nominal rate stated by the bank.
APY (Annual Percentage Yield) = Effective rate including the effect of compound interest. It's what you actually earn.
For example, a savings account with 5% APR compounded monthly has an APY of 5.12%. The difference grows with higher rates and more frequent compounding.
Annual Percentage Yield (APY) is the real rate of return on your savings when compound interest is taken into account. Unlike the nominal interest rate (also called APR or Annual Percentage Rate), which only shows the simple interest rate, APY reveals what you'll actually earn because it includes the effect of compounding — earning interest on your interest.
For example, if a bank offers a savings account with a 5.00% nominal rate compounded monthly, the APY is actually 5.12%. That extra 0.12% represents the interest earned on previously earned interest. While this seems small on a single deposit, it adds up significantly over time and with larger balances.
The difference between APY and the nominal rate depends on two factors: the interest rate itself (higher rates produce a larger gap) and the compounding frequency (more frequent compounding results in a higher APY). Daily compounding gives the highest APY, while annual compounding gives the lowest (equal to the nominal rate).
When comparing savings accounts, CDs, or money market accounts, always compare APYs, not nominal rates. Two accounts can have the same nominal rate but different APYs due to different compounding frequencies. The account with the higher APY will earn you more money, even if the stated nominal rate is the same.
Banks are required by law to disclose the APY, making it easier for consumers to make apples-to-apples comparisons. The Truth in Savings Act (Regulation DD) mandates that financial institutions clearly state the APY alongside the interest rate when advertising deposit accounts.
Compounding frequency is one of the most important factors in determining your actual returns. Here's how different frequencies compare at the same nominal rate:
As you can see, the biggest jump in APY happens when you go from annual to semi-annual compounding. The incremental benefit of moving from monthly to daily compounding is relatively small — about 0.01% at a 5% rate. This is important to know because some banks advertise daily compounding as a major differentiator, but in practice, the difference from monthly compounding is minimal.
⚠️ Important Note: This APY Calculator is for educational and informational purposes only. While every effort has been made to ensure accuracy, actual returns may vary due to changing interest rates, fees, account minimums, and other factors. APYs for savings accounts and money market accounts are variable and subject to change. CD rates are typically fixed for the term but may have early withdrawal penalties. Always verify current rates directly with your financial institution and consult with a qualified financial advisor for personalized advice.