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High-yield savings account calculator
Enter a deposit, the APY or interest rate and how many months to see the interest earned and your ending balance. Add a bank bonus to see it as an APY, after fees and tax, next to what the same money earns in savings.
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Formula and sources checked
Balance = $10,000.00 × (1 + 4.00%)^(12 ÷ 12) = $10,400.00. Contributions land at the end of each month. Assumes the APY stays the same the whole time; savings rates can change.
Tools use the numbers you enter. They do not check live terms, eligibility, limits, account balances or whether a quote is still available.
How is high-yield savings interest calculated?
APY already includes compounding. Your balance after a number of months is the deposit × (1 + APY) raised to the power of months ÷ 12. Each monthly contribution grows the same way from the end of the month you add it, and the interest earned is the ending balance minus everything you put in.
Daily or monthly compounding changes the interest rate behind an APY, not the APY itself. The APY equals (1 + rate ÷ n) to the power of n, minus 1, where n is 365 for daily and 12 for monthly compounding. So a 4.00% APY pays the same over a year either way, while a 4.00% interest rate pays a little more when it compounds daily. Over a full year this matches the APY formula in Regulation DD, the Truth in Savings rule.
doddo turns a bank bonus into an APY-style rate with the same math: (1 + bonus after fees ÷ required deposit) to the power of 365 ÷ days held, minus 1. Banks must leave bonuses out of the APY they advertise, so this rate is doddo's comparison, not a bank figure. The comparison then subtracts what that deposit would have earned in savings over the same days and applies your tax rate, since the IRS treats bank interest as taxable income and banks report cash sign-up bonuses as income, usually on Form 1099-INT or 1099-MISC. Monthly fees count once for each month or part month of the hold.
Results are estimates from the numbers you enter. Savings APYs can change, and a bonus pays only if you meet the bank's terms. Compare current offers on bank bonuses.
Frequently asked questions
How much interest does $10,000 earn in a high-yield savings account?
It depends on the APY and how long the money stays. At a 4.00% APY, $10,000 earns about $400 in 12 months and about $198.04 in 6 months, if the rate does not change. Most savings APYs are variable, so the bank can change them.
Does daily compounding earn more than monthly compounding?
Not for the same APY, because APY already includes compounding. For the same interest rate, daily compounding earns slightly more: a 5.00% rate is about a 5.13% APY compounded daily and about a 5.12% APY compounded monthly.
Is a bank bonus better than a high-yield savings account?
Sometimes. A $300 bonus on a $5,000 deposit held 90 days works out to about a 26.7% APY before tax, while the same $5,000 at a 4.00% APY earns about $48.59 in those 90 days. Monthly fees, a long hold or a large required deposit can shrink the gap, so the calculator shows each one.
Are bank bonuses and savings interest taxed?
Generally, yes. The IRS counts bank interest as taxable income (Topic 403), and banks report cash sign-up bonuses as income, usually on Form 1099-INT or 1099-MISC. The calculator applies the one tax rate you enter; it is not tax advice.
Where can I find current bank bonuses?
doddo's bank bonuses page lists reviewed checking and savings offers with their requirements, fees and payout timing. Offers change, so confirm the terms with the bank before you open an account.
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