APY Calculator

APY Calculator

Banks can advertise the same product with different numbers depending on whether they quote the nominal rate or the effective yield. Annual Percentage Yield (APY) is the standardized figure that accounts for compounding -- it tells you the true annual return regardless of how often interest is calculated. This calculator converts any stated interest rate (APR) into APY for any compounding frequency, so you can compare a daily-compounding savings account against a quarterly-compounding CD against an annually-compounding bond on exactly equal terms.

How APY Is Calculated

APY measures how much a single dollar grows in one year after compounding is applied. The formula is:

APY = (1 + r/n)^n - 1

Where r is the nominal annual interest rate expressed as a decimal (e.g., 5.00% = 0.05) and n is the number of compounding periods per year: 1 for annual, 4 for quarterly, 12 for monthly, 365 for daily. For continuous compounding -- where interest accrues at every instant -- the formula becomes APY = e^r - 1, where e is approximately 2.71828. This represents the theoretical ceiling for any given nominal rate.

Worked Examples

Example 1 -- Comparing two savings accounts. Bank A advertises 4.80% APR compounded monthly. Bank B advertises 4.75% APR compounded daily. Which earns more? Bank A APY = (1 + 0.048/12)^12 - 1 = 4.907%. Bank B APY = (1 + 0.0475/365)^365 - 1 = 4.862%. Bank A wins despite the lower stated rate -- its monthly compounding plus the slightly higher APR produces more interest. On a $20,000 deposit over 1 year, the difference is about $9.

Example 2 -- CD vs. high-yield savings. A 12-month CD offers 5.10% APR compounded monthly: APY = 5.221%. A high-yield savings account offers 4.90% APR compounded daily: APY = 5.013%. The CD pays $208 more per year on a $10,000 deposit ($522 vs. $501), but locks your money for 12 months. If you need access to the funds, the savings account's 5.013% APY may be the better real-world choice even though the CD's APY is higher.

Example 3 -- Fee impact on effective yield. An account pays 4.50% APR compounded daily (APY = 4.603%) but charges a $12/month maintenance fee. On a $5,000 balance, gross annual interest = $230. Monthly fees = $144/year. Net earnings = $86 -- an effective yield of 1.72%, not 4.60%. Moving to a fee-free online account at 4.00% APY yields $200/year, which is 133% more.

APY by Compounding Frequency Reference Table

When to Use This Calculator

• You are comparing a savings account, CD, and money market account that all quote different rates with different compounding schedules
• A bank advertises a rate without specifying whether it is APR or APY, and you want to find the true effective yield
• You are evaluating a bond or investment that uses a different compounding convention than standard bank accounts
• You want to know exactly how much a 0.20% APY difference translates to in dollars on a specific balance
• You are modeling savings growth and need the correct effective rate to plug into a compound interest formula

Common Mistakes

1. Treating APR and APY as interchangeable. Banks are legally required to disclose APY on deposit accounts, but some financial products advertise APR. A 5.00% APR compounded daily is a 5.127% APY -- not the same number. Always confirm which figure you are looking at before comparing accounts or calculating projected earnings.

2. Overvaluing daily vs. monthly compounding. On a $25,000 balance at 5.00% APR, the difference between daily compounding (APY 5.127%) and monthly compounding (APY 5.116%) is $2.75 per year. That difference matters on a $1,000,000 balance ($275/year) but is negligible for most savers. Focus on getting a higher rate rather than a more frequent compounding schedule -- a 0.25% better APR beats any compounding advantage.

3. Forgetting that APY does not account for fees. APY assumes no fees. A 5.00% APY account with a $10/month fee on a $2,400 balance has an effective yield of 0.00% -- the $120 in fees exactly cancels the $120 in interest. Net yield = APY - (annual fees / average balance). Always run this calculation before opening an account with a maintenance fee.

4. Using APY to compare loans against deposits. APY applies to what you earn. For what you pay on a loan, the equivalent metric is the Annual Percentage Rate (APR), though loan APR typically includes fees and differs from deposit APR. Never compare a loan's APR directly to a savings account's APY as if they measure the same thing.

Current Context for 2026

The Federal Reserve held the federal funds rate at 4.25%--4.50% through early 2026, keeping savings account APYs well above their 2020--2021 lows of 0.01%--0.50%. The highest-yielding online savings accounts and money market accounts are paying 4.50%--5.00% APY as of early 2026. By contrast, the national average savings rate at traditional banks sits around 0.45% APY -- a gap of more than 4 percentage points. On a $30,000 balance, moving from the national average to a top-tier online account generates roughly $1,365 more per year in interest. Understanding APY is the first step to capturing that difference.

Tips

1. Always compare savings products using APY, not APR -- APY is the legally standardized metric and accounts for compounding automatically
2. A higher stated APR with annual compounding can still lose to a lower APR with daily compounding -- always convert to APY to compare
3. The gap between APR and APY grows larger at higher rates; this matters more in a 5%+ rate environment than in a 1% environment
4. Online banks typically offer 4--10x the APY of traditional banks because of lower overhead -- switching for a $20,000 balance can mean $500--$800 more per year
5. When a CD's APY locks in a rate, that is an advantage if rates are likely to fall -- calculate whether a 2-year CD at 5.00% APY beats two consecutive 1-year renewals if rates drop 0.50% next year
6. Use this calculator before opening any deposit account -- plugging in the APR and compounding frequency takes 30 seconds and confirms the effective yield

Related Calculations

• Compound Interest Calculator -- apply the APY you calculate here to project actual dollar growth over time
• Money Market Calculator -- model growth in a money market account with the correct APY
• CD Calculator -- compare CD APYs across different terms and compounding schedules