Finance calculators

APY Calculator

Updated Sep 10, 2026 By Infinity Calculator
Rate Formulas Sources
yrs
mos
Results Summary

APY

4.20%

APR

4.12%

Total Balance

$2,246.18

Interest Earned

$46.18

Total Contributions

$2,200.00

Initial Deposit

$1,000.00

Monthly Deposits Total

$1,200.00

Effective Rate Gain

+0.08%

Compounding Frequency Comparison

How different compounding frequencies affect your final balance and APY, given the same APR of 4.12%.

Frequency Periods/Year APY Interest Earned Final Balance
Year-by-Year Breakdown
Year Starting Balance Contributions Interest Earned Ending Balance Cumulative Interest

Introduction

APY stands for Annual Percentage Yield. It tells you how much money you will earn on your savings in one year, including compound interest.1 Compound interest means you earn interest on your interest, which helps your money grow faster. Our APY Calculator makes it simple to see how much your savings can grow over time. Just enter your deposit amount, interest rate, and how often interest is compounded, and the calculator does the rest. Knowing the APY helps you pick the best option for your money when you compare savings accounts, certificates of deposit (CDs), or money market accounts.

How to Use Our APY Calculator

Enter your deposit details below to find out how much interest you will earn over time. This calculator shows your total balance and interest earned based on your annual percentage yield.

Interest Rate (%): Type in the annual interest rate your bank or financial institution offers. This is the base rate before compounding is applied.

Compounding Frequency: Choose how often your interest is compounded. Options typically include daily, monthly, quarterly, or annually. The more often interest compounds, the more you earn.

Initial Deposit ($): Enter the amount of money you plan to deposit or already have in your savings account. This is your starting balance.

Time Period: Enter how long you plan to keep your money in the account. You can usually set this in months or years.

Once you fill in all the fields, the calculator will show you your APY, total interest earned, and final account balance. APY stands for annual percentage yield, which is the real rate of return you earn in one year after compounding is factored in. It gives you a clearer picture of your earnings than the basic interest rate alone.

What Is APY?

APY stands for Annual Percentage Yield. It tells you how much money you will earn on your savings over one year, including compound interest. Compound interest means you earn interest not just on the money you put in, but also on the interest you've already earned. This is what makes your savings grow faster over time.

APY vs. Interest Rate: What's the Difference?

A simple interest rate only tells you the basic percentage your money earns. APY goes a step further. It factors in how often your interest compounds, whether that's daily, monthly, or yearly. The more often interest compounds, the higher your APY will be compared to the simple interest rate. That's why APY gives you a more accurate picture of what you'll actually earn. Understanding this difference is also important when evaluating loans; if you're financing a vehicle, an auto loan shows how interest impacts your payments on the borrowing side.

Why APY Matters for Your Savings

When you're comparing savings accounts, certificates of deposit (CDs), or money market accounts, APY is the best number to look at. Two accounts might show the same interest rate, but if one compounds daily and the other compounds monthly, they will give you different returns. The one with the higher APY will earn you more money. Federal rules require banks to disclose the APY, using that term, in their account disclosures, which makes it easier for you to compare options side by side.2

Beyond traditional savings, understanding APY can help you evaluate other financial strategies. If you're planning for early retirement, Coast FIRE uses similar compound growth principles to show when your investments can grow on their own without additional contributions.

How APY Is Calculated

The formula for APY is:

APY = (1 + r/n)n − 1

In this formula, r is the interest rate (as a decimal), and n is the number of times interest compounds per year. For example, if your interest rate is 5% and it compounds monthly, you would plug in r = 0.05 and n = 12. The result is your true annual yield.

Tips to Get the Most from APY

  • Look for high-yield savings accounts. Online banks often offer much higher APYs than traditional banks.
  • Check how often interest compounds. Daily compounding will earn you slightly more than monthly compounding.
  • Leave your money in the account. The longer your savings sit and compound, the more you earn. This is the power of compound interest working in your favor.
  • Compare APYs, not just interest rates. APY is the truest measure of your earnings and the fairest way to compare accounts.

Formulas used

APR to APY (Discrete Compounding)
APY = \left(1 + \frac{r}{n}\right)^{n} - 1
APR to APY (Continuous Compounding)
APY = e^{r} - 1
APY to APR (Discrete Compounding)
APR = n \times \left((1 + APY)^{\frac{1}{n}} - 1\right)
APY to APR (Continuous Compounding)
APR = \ln(1 + APY)
Monthly Interest (Discrete Compounding)
I_{month} = B \times \left(\left(1 + \frac{r}{n}\right)^{\frac{n}{12}} - 1\right)
Monthly Interest (Continuous Compounding)
I_{month} = B \times \left(e^{\frac{r}{12}} - 1\right)
Effective Rate Gain
\text{Effective Rate Gain} = APY - APR

Frequently asked questions

What is the difference between APR and APY?

APR (Annual Percentage Rate) is the base interest rate on your account without compounding. APY (Annual Percentage Yield) includes the effect of compound interest. APY is always equal to or higher than APR. The more often interest compounds, the bigger the gap between the two. For example, a 4.12% APR compounded monthly gives you a 4.20% APY.

What compounding frequency should I choose?

Choose the compounding frequency that matches your bank account. Most savings accounts compound daily or monthly. Check your account terms or ask your bank. If you're just comparing options, try different frequencies in the calculator to see how they affect your earnings. Daily and continuous compounding earn slightly more than monthly or quarterly.

What is continuous compounding?

Continuous compounding means interest is calculated and added to your balance at every possible instant, nonstop. It uses a special math formula with the constant e (about 2.718). In practice, no bank truly compounds continuously, but it gives you the highest possible APY for a given APR. It's useful as a theoretical maximum when comparing options.

How do monthly contributions affect my savings growth?

Monthly contributions add money to your account each month on top of your initial deposit. Each contribution also starts earning compound interest right away. Over time, regular contributions can make a huge difference. For example, adding just $100 per month at 4% APY grows much faster than a one-time deposit alone because each new dollar also earns interest.

What is the Effective Rate Gain shown in the results?

The Effective Rate Gain is the difference between your APY and your APR. It shows how much extra return you get from compounding. A positive number means compounding is boosting your earnings above the base rate. The higher the compounding frequency, the larger this gain will be.

What is the difference between Daily (365) and Daily (360)?

Daily (365) divides the year into 365 days, which is the actual number of days in a year. Daily (360) uses a 360-day year, which is a method some banks and financial institutions use. With 360-day compounding, each period is slightly larger, which can result in a marginally different APY. Most consumer savings accounts use 365 days.

How do I convert APY back to APR?

Enter your known APY into the APY field and click on it so it shows DRIVING. Then select your compounding frequency and click Calculate. The calculator will automatically convert your APY to the equivalent APR and display it for you.

Does a higher APY always mean more money earned?

Yes, if all other factors are the same. A higher APY means you earn more interest on the same deposit over the same time period. However, always check for fees, minimum balance requirements, and withdrawal penalties. A high APY doesn't help if fees eat into your earnings.

Is the interest shown before or after taxes?

The interest shown is before taxes. In the United States, interest earned on savings accounts, CDs, and money market accounts is taxable income.3 Your actual earnings will be lower after you pay federal and possibly state income taxes on the interest. Check with a tax professional for your specific situation.

Sources

  1. 12 CFR Part 1030, Appendix A — Annual Percentage Yield Calculation (Regulation DD). Electronic Code of Federal Regulations (eCFR), Consumer Financial Protection Bureau. Part I. Accessed September 10, 2026.
  2. 12 CFR 1030.4 — Account disclosures (Regulation DD). Electronic Code of Federal Regulations (eCFR), Consumer Financial Protection Bureau. 1030.4(b)(1)(i). Accessed September 10, 2026.
  3. Topic no. 403, Interest received. Internal Revenue Service. Accessed September 10, 2026.

Related Finance calculators

All Finance calculators
Finance

529 Calculator

Use our free 529 calculator to estimate your college savings growth. Plan contributions, project returns, and reach your education savings goals.

Open Finance

CD Calculator

Calculate CD maturity balance, effective APY, and after-tax returns. Set deposit, APR, term, and compounding frequency. View year-by-year tables and growth charts.

Open Finance

Compound Interest Calculator

Calculate compound interest instantly with our free online calculator. Enter principal, rate, and time to see your investment growth with detailed results.

Open Finance

Emergency Fund Calculator

Calculate how much you need in your emergency fund based on your monthly expenses, income, and financial goals. Start building your safety net today.

Open Finance

HSA Calculator

Use our free HSA calculator to estimate your Health Savings Account savings, tax benefits, and contribution limits. Plan your healthcare finances today.

Open Finance

HYSA Calculator

Enter deposit, contributions, APY, and compounding frequency to project HYSA growth. See a stacked bar chart, step-by-step math, and yearly breakdown.

Open Finance

PPF Calculator

Calculate PPF maturity value, total interest earned, and yearly breakdown. Adjust monthly, quarterly, or yearly deposits, duration, and rate with live charts.

Open Finance

Savings Calculator

Use our free savings calculator to estimate how your money grows over time. Calculate interest, set savings goals, and plan your financial future easily.

Open