APY Calculator
United States Uses U.S. IRS retirement-account and federal deposit rules. Figures are in U.S. dollars.
APY and high-yield savings calculator: savings growth with monthly deposits, interest after tax, real return, and the gain over the national average rate.
Educational estimate only. Not a lending decision. Your numbers stay in this browser.
Results
How to read this: the verdict describes how much room your numbers leave, not a decision or an offer. Change any input to see how much the result moves.
Investing and retirement guides
These guides explain compounding, contribution projections, retirement targets, inflation, and real returns.
- Compound interest explained
- Investment return with contributions
- Retirement savings target
- Inflation and real returns
For all guide topics, open Guides. For source and estimate boundaries, read Calculation Methodology and Sources and Assumptions.
Assumptions and formula
The balance grows each month at the monthly equivalent of the APY, so a year of growth equals the APY exactly, and each month’s deposit is added at the end of the month. If you enter an interest rate instead, it is converted with APY = (1 + r/n)ⁿ − 1 (Regulation DD). The same deposits are run at the comparison APY.
Interest is ordinary income in the year it is credited; the tax uses the rate you enter. The real return is the after-tax APY less inflation: (1 + APY × (1 − tax)) ÷ (1 + inflation) − 1. The comparison defaults to the FDIC national average savings rate, 0.37% as published on 21 September 2026; the FDIC updates it monthly. Savings rates are variable, so treat the APY as an assumption.
Worked example
$10,000 plus $200 a month for five years at a 4% APY grows to about $25,402: $22,000 deposited and $3,402 of interest, about $3,106 more than at the 0.37% national average. At 22% tax and 3% inflation the real return is about 0.12% a year.
Frequently asked questions
How much will $10,000 earn in a high-yield savings account?
About $400 in a year at a 4% APY, against $37 at the 0.37% national average. With $200 a month added for five years, $10,000 grows to about $25,402, about $3,106 more than at the average rate.
How much will my high-yield savings account earn?
$10,000 plus $200 a month for five years at a 4% APY grows to about $25,402: $22,000 of your money and $3,402 of interest. At the FDIC national average savings rate of 0.37% (September 2026), the same deposits reach about $22,296, so the high-yield account earns about $3,106 more.
What is APY and how is it calculated?
The annual percentage yield is the interest a year including compounding: APY = (1 + r/n)ⁿ − 1, for an interest rate r compounded n times a year. A 4.00% interest rate compounded daily is a 4.08% APY. Banks must quote the APY on savings accounts and CDs, so it is the figure to compare between banks.
Does a high-yield savings account beat inflation?
Barely, after tax. At a 4% APY, a 22% tax rate on the interest and 3% inflation, the real return is about 0.12% a year. At the 0.37% national average, money in savings loses about 2.6% a year in buying power.
Is savings account interest taxable?
Yes, as ordinary income in the year it is credited, whether or not you withdraw it. The bank reports it on Form 1099-INT once it reaches $10 in a year. At 22%, $3,402 of interest leaves you about $2,654.
Is this an APY calculator or a high-yield savings calculator?
Both. As an APY calculator it converts between the APY and the interest rate for any compounding and works as an APY return calculator; as a high yield savings account calculator, or HYSA calculator, it projects your balance with monthly deposits, after tax and inflation, against the national average. It is an annual percentage yield calculator and savings estimator for any account.
How do I convert APR to APY?
APY = (1 + APR ÷ n)^n − 1, where n is the number of compounding periods a year. A 5% APR compounded monthly is a 5.12% APY, so this works for APR to APY conversion and to calculate the interest earned at an APY.
Sources
Sources reviewed 3 October 2026: checked against their current editions on that date.
- FDIC, National Rates and Rate Caps, published 21 September 2026: national average savings rate 0.37%; updated monthly.
- Regulation DD (Truth in Savings), 12 CFR part 1030, Appendix A: the annual percentage yield formula.
- IRS Publication 550, Investment Income and Expenses: interest on deposit accounts is taxable in the year it is credited.
This page is an educational estimate, not personal financial or tax advice. Eligibility and individual circumstances can change the result.