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High-Yield Savings Calculator

Use this high-yield savings calculator to work out how much interest a high-yield savings account (HYSA) will pay on your balance and monthly deposits, how that compares with a traditional savings account, what's left after tax, and whether a certificate of deposit (CD) would pay more for money you won't touch.

Updated October 1, 2026. Every formula on this page is published below and tested against an independent implementation. Embed on your site

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How the high-yield savings calculator works out your interest

Banks advertise savings accounts by their annual percentage yield (APY), which already includes the effect of compounding. Most high-yield accounts accrue interest daily and credit it monthly. Because the APY bakes the compounding in, the monthly growth factor follows directly from it:

g=(1+APY)1/12g = (1 + \mathrm{APY})^{1/12}
Monthly growth factor implied by the APY

Each month the balance grows by that factor and your deposit is added. After t years:

B=P g12t+D g12t−1g−1B = P\,g^{12t} + D\,\frac{g^{12t} - 1}{g - 1}
Balance with monthly deposits made at the end of each month
B
Balance after t years
P
Opening deposit
D
Deposit added at the end of each month
APY
Annual percentage yield as a decimal (4% is 0.04)
t
Number of years

A quick check: $10,000 left alone for one year at a 4% APY becomes $10,400.00, which is exactly what an APY promises. The calculator applies the formula month by month, so you can also see each year's interest in the table.

APY vs. interest rate

The interest rate (sometimes shown as APR) is the nominal rate before compounding; the APY is what you actually earn in a year. With daily compounding, APY = (1 + rate ÷ 365)365 − 1, so a 4.00% APY corresponds to an interest rate of about 3.922%. When comparing accounts, always compare APY to APY.

Taxes and the comparison account

Savings interest is taxed as ordinary income in the year it is credited, and banks report it on Form 1099-INT. The calculator estimates your after-tax interest by applying your combined tax rate to the interest figure. It also runs the same deposits through a second account at the comparison APY you enter, such as the savings account at your current bank, so you can see what moving the money is worth.

Worked example: $10,000 plus $500 a month

Open a high-yield account with $10,000, add $500 at the end of every month, and earn a steady 4.00% APY. Compare it with a traditional savings account paying 0.40%:

Five years of saving $500 a month on top of $10,000
High-yield (4.00% APY)Traditional (0.40% APY)
Total deposited$40,000.00$40,000.00
Interest earned$5,256.04$497.97
Balance after 5 years$45,256.04$40,497.97

Moving the money earns $4,758.07 more over five years for the same deposits. At a 22% tax rate you would keep $4,099.71 of the $5,256.04 in interest. By the end, the balance earns about $148.16 a month on its own. These figures assume the APY stays at 4.00%; savings rates are variable and usually move with the Federal Reserve's policy rate.

Would a CD pay more?

Suppose a 12-month CD pays 4.25% APY. On $10,000 it returns $10,425.00 at maturity, $25.00 more than the high-yield account at 4.00%. If savings rates fall and the high-yield account averages 3.50% instead, the CD's lead grows to $75.00. The catch is access: break the CD early and a typical penalty of three months' interest would cost about $106.25, wiping out the advantage.

HYSA, CD or something else?

A high-yield savings account and a CD can both be insured and both pay far more than a typical big-bank savings account. The right choice depends on when you might need the money and where you think rates are headed. Treasury bills are another option for money you won't need for weeks or months: their interest is exempt from state income tax, which the T-bill vs CD calculator weighs against a CD's higher yield.

Matching the account to the money
The money is forGood fitWhy
An emergency fundHigh-yield savingsAvailable any day, with no penalty to withdraw.
A known expense 6 to 24 months awayA CD maturing just before itLocks today's rate for the whole wait.
Saving toward a goal monthlyHigh-yield savingsAccepts deposits whenever you add them.
Cash you expect to hold while rates fallCD or a ladder of CDsKeeps the higher rate after banks cut theirs.
Money you won't need for 5+ yearsConsider investingSavings rarely outpace inflation by much over long periods.

Before you move your money

  • Check the insurance. Deposits at an FDIC-insured bank are covered up to $250,000 per depositor, per bank, per ownership category; credit union deposits have the same limit through the NCUA. If you save through an app, confirm which bank actually holds the deposits.
  • Read the rate terms. Look for minimum balances, balance tiers and introductory rates that expire after a few months.
  • Plan for withdrawals. Some banks still limit monthly withdrawals from savings, and transfers to an outside checking account can take a business day or two.

For long horizons and investment returns, the compound interest calculator lets you change the compounding schedule and add yearly contribution increases.

The bottom line

A high-yield savings account is the right home for money you may need soon: it is FDIC- or NCUA-insured, you can withdraw at any time, and in the example it ends five years at $45,256.04, $4,758.07 ahead of a traditional account.

Rates are variable, so recheck yours in the high-yield savings calculator a few times a year, compare a CD for money you won't touch, and remember that the interest is taxable in the year it is paid.

Frequently asked questions

How is interest calculated on a high-yield savings account?

Most high-yield accounts calculate interest daily on your balance and credit it to the account monthly. The advertised APY already includes this compounding, so your balance grows by a factor of (1 + APY)^(1/12) each month. Deposits you add start earning from the day they arrive. This calculator compounds monthly and adds deposits at the end of each month, which matches a typical account closely.

How much interest will $10,000 earn in a high-yield savings account?

At a 4.00% APY, the interest on $10,000 is $400 in a year if the rate holds, for a balance of $10,400.00. Over five years without further deposits it would earn more than $2,000, because each year's interest also earns interest. Rates on these accounts are variable, so treat any projection as an estimate.

What is the difference between APY and interest rate?

The interest rate is the nominal annual rate before compounding. APY, the annual percentage yield, is the return you actually get in a year once compounding is included. With daily compounding, a 4.00% APY corresponds to an interest rate of about 3.922%. Banks are required to disclose APY on deposit accounts, so use it to compare offers.

HYSA vs. CD: which is better?

A CD is better when you won't need the money before it matures and its APY beats what you expect the savings account to average over the same period. A 12-month CD at 4.25% earns $25.00 more on $10,000 than savings at a steady 4.00%. A high-yield savings account is better for emergency funds and ongoing deposits because you can withdraw at any time without a penalty. Enter a CD's APY and term in the calculator to use it as a CD calculator for your own balance.

Is interest from a savings account taxable?

Yes. Interest from savings accounts and CDs is generally taxable as ordinary income for the year it is credited to you, even if you leave it in the account. Banks send Form 1099-INT when they pay you $10 or more of interest in a year, but interest is taxable even when you don't receive the form. Interest earned inside tax-advantaged accounts such as IRAs follows those accounts' rules.

Is my money safe in a high-yield savings account?

Deposits at an FDIC-insured bank are protected up to $250,000 per depositor, per insured bank, for each account ownership category, and credit union deposits have the same coverage through the NCUA. Verify that the institution is insured before you deposit. If you use a fintech app, check which partner bank holds your money and whether pass-through coverage applies.

Sources and further reading

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