High-Yield Savings Account Calculator: Interest Growth and APY Change Scenarios
Enter a starting deposit, a monthly deposit and the APY from your bank’s disclosure to see the ending balance, the total interest and a year-by-year table. A savings account can have a variable rate, so the calculator also shows your balance if your bank changes your APY by 0.25 or 0.50 percentage points in either direction.
Maintained by Archie Chang · Formulas and sources checked October 29, 2026 · Methodology & sources
Estimates only. Your bank’s disclosures govern: the APY, how and when the rate can change, how interest is compounded and credited, minimum balances and fees all come from your account agreement. This page does not name or rank any bank or account.
Your deposits and your APY
The 4.00 shown is only an example, not a current rate. Enter the APY in your bank’s disclosure.
Leave blank to skip the after-tax view. Enter the rate that applies to you.
Amounts are held to $10,000,000, the APY to 0-20% and the term to 50 years and 11 months.
Only have an interest rate? Convert it to an APY
APY = (1 + rate / n)^n − 1, where n is the number of compounding periods a year.
Your estimated savings balance
- Ending balance
- $25,402.33
- Total deposited
- $22,000.00
- Total interest
- $3,402.33
After 60 months at 4.00% APY
What if your bank changes your APY?
The same deposits if your bank changes your APY by the amounts below for the whole term. This is arithmetic, not a forecast.
| Change in your APY | APY | Ending balance | Change |
|---|---|---|---|
| -0.50 points | 3.50% | $24,951.95 | -$450.38 |
| -0.25 points | 3.75% | $25,176.22 | -$226.11 |
| +0.25 points | 4.25% | $25,630.31 | +$227.98 |
| +0.50 points | 4.50% | $25,860.17 | +$457.84 |
Year by year
| Year | Starting balance | Deposits | Interest | Ending balance |
|---|---|---|---|---|
| 1 | $10,000.00 | $2,400.00 | $443.69 | $12,843.69 |
| 2 | $12,843.69 | $2,400.00 | $557.43 | $15,801.12 |
| 3 | $15,801.12 | $2,400.00 | $675.74 | $18,876.86 |
| 4 | $18,876.86 | $2,400.00 | $798.76 | $22,075.62 |
| 5 | $22,075.62 | $2,400.00 | $926.71 | $25,402.33 |
Monthly convention: the effective monthly rate is (1 + APY) raised to the power of 1/12, minus 1. Deposits are made at the end of each month unless you pick the start of the month. Amounts are kept in whole cents and rounded half to even. Estimates only: your bank’s disclosures govern, and this is not an offer of any account.
Fed decisions, variable APYs and what your bank can change
For context, the federal funds target range is 3.75% to 4.00%, as of October 28, 2026 (Federal Reserve — October 2026 FOMC statement). That figure is context only. This page does not tie your APY to that range and does not predict any decision.
Under 12 CFR 1030.4(b), account disclosures shall include the following, as applicable. For variable-rate accounts, 12 CFR 1030.4(b)(1)(ii) says:
“For variable-rate accounts: (A) The fact that the interest rate and annual percentage yield may change; (B) How the interest rate is determined; (C) The frequency with which the interest rate may change; and (D) Any limitation on the amount the interest rate may change.”
Regulation DD also says when a bank does not have to send advance notice of a rate change (12 CFR 1030.5(a)(2)(i)):
“No notice under this section is required for: (i) Variable-rate changes. Changes in the interest rate and corresponding changes in the annual percentage yield in variable-rate accounts.”
What if your bank changes your APY? The table in the calculator shows your ending balance if your bank changes your APY by 0.25 or 0.50 percentage points in either direction, with your deposits and timing unchanged. It is arithmetic on the numbers you enter. For the Federal Reserve’s own decision and schedule, see the Fed rate decision page and the FOMC meeting schedule.
How the calculator works
- APY to monthly rate: the effective monthly rate is (1 + APY) raised to the power of 1/12, minus 1, so twelve months of growth add up to exactly one APY. A bank that credits interest daily or monthly and rounds each credit can come out a few cents different.
- Deposit timing: the default is the end of each month, so a deposit starts earning the next month. Choose the start of the month to give every deposit, including the first, a full month of interest.
- Rounding: every amount is kept in whole cents and rounded half to even, once per figure. A year’s interest is its ending balance minus its starting balance minus its deposits, so the table adds up to the cent.
- Rate-change table: the same deposits with the APY moved by -0.50, -0.25, +0.25 and +0.50 points for the whole term. The table holds the APY at 0% at the low end.
- Limits: amounts are held to $10,000,000, the APY to 20% and the term to 50 years and 11 months. A term of 0 months returns your starting deposit.
Interest rate versus APY (Regulation DD)
“The annual percentage yield measures the total amount of interest paid on an account based on the interest rate and the frequency of compounding.”
“The annual percentage yield is expressed as an annualized rate, based on a 365-day year. Institutions may calculate the annual percentage yield based on a 365-day or a 366-day year in a leap year.”
“The annual percentage yield reflects only interest and does not include the value of any bonus (or other consideration worth $10 or less) that may be provided to the consumer to open, maintain, increase or renew an account.”
Appendix A to Regulation DD gives the formula:
The annual percentage yield is calculated by use of the following general formula (“APY” is used for convenience in the formulas):
APY=100 [(1+Interest/Principal)(365/Days in term)−1]
“Principal” is the amount of funds assumed to have been deposited at the beginning of the account.
“Interest” is the total dollar amount of interest earned on the Principal for the term of the account.
“Days in term” is the actual number of days in the term of the account.
The calculator asks for an APY. If you only have a stated interest rate, the helper under the inputs converts it with (1 + rate / n)^n − 1, where n is the number of compounding periods a year. For a dedicated conversion, see the APY calculator.
Your APY versus the national average
The FDIC’s monthly national rates page lists a national savings rate of 0.38% and a national money market rate of 0.63%, as of October 19, 2026 (FDIC National Rates and Rate Caps — October 2026). The calculator uses the savings figure as an optional comparison against the national average. It is not a recommendation or a target.
The FDIC says what the as-of date means:
“All published rates and yields are based on information available on the last business day of the prior month end (note: rates and yields published on April 1, 2021, are based on information available as of February 26, 2021).”
The FDIC describes what the national rate is:
“The Final Rule redefined the “national rate” as the average of rates paid by all insured depository institutions and credit unions for which data is available, with rates weighted by each institution’s share of domestic deposits.”
“Savings and interest checking account rates are based on the $2,500 product tier, while money market and certificate of deposit rates represent an average of the $10,000 and $100,000 product tiers.”
The same arithmetic applies to a variable-rate money market deposit account if you enter its APY. The FDIC lists money market deposit accounts among the accounts it insures. Check your account’s disclosures for its own terms.
Deposit insurance
“FDIC deposit insurance covers $250,000 per depositor, per FDIC-insured bank, for each account ownership category.”
“All of your deposits in the same ownership category in the same FDIC-insured bank are added together for the purpose of determining FDIC deposit insurance coverage. However, you may qualify for more than $250,000 in FDIC deposit insurance coverage if you deposit money in accounts that are in different ownership categories.”
“FDIC deposit insurance only covers deposits, and only if your bank is FDIC-insured.”
For a federally insured credit union, the NCUA says:
“Administered by the NCUA, the Share Insurance Fund insures individual accounts up to $250,000. Additionally, a member’s interest in all joint accounts combined is insured up to $250,000.”
Taxes on savings interest
“Most interest that you receive or that is credited to an account that you can withdraw from without penalty is taxable income in the year it becomes available to you. However, some interest you receive may be tax-exempt. If you received payments of interest and/or tax-exempt interest of $10 or more, you should receive Copy B of Form 1099-INT or Form 1099-OID reporting those payments.”
“You must report all taxable and tax-exempt interest on your federal income tax return, even if you don't receive a Form 1099-INT or Form 1099-OID.”
The optional after-tax view applies the marginal tax rate you enter to the total interest. It does not know your filing status or your other income, so it is an estimate, not tax advice.
Related calculators
To convert a stated rate to an APY, use the APY calculator. For money you can leave untouched for a fixed term, see the CD rate calculator and the CD ladder calculator. To see when Treasury bills, notes and bonds are auctioned, see the Treasury auction schedule.
High-yield savings calculator FAQ
How is high-yield savings interest calculated here?
You enter an APY. The effective monthly rate is (1 + APY) raised to the power of 1/12, minus 1, so twelve months of growth add up to exactly one APY. Each deposit is added at the end of each month unless you choose the start of the month, and every money figure is rounded half to even to whole cents. Your bank may credit interest daily or monthly and round each credit, so your statement can differ by a few cents, and your bank’s disclosures govern.
What is the difference between an interest rate and APY?
Regulation DD says: “The annual percentage yield measures the total amount of interest paid on an account based on the interest rate and the frequency of compounding.” The APY is therefore the figure that already includes compounding. The helper in the calculator turns a stated interest rate and a compounding frequency into an APY with (1 + rate / n)^n − 1, where n is the number of compounding periods a year.
What happens if my bank changes my APY?
Under 12 CFR 1030.4(b), account disclosures shall include the following, as applicable. For variable-rate accounts, 12 CFR 1030.4(b)(1)(ii) says: “For variable-rate accounts: (A) The fact that the interest rate and annual percentage yield may change; (B) How the interest rate is determined; (C) The frequency with which the interest rate may change; and (D) Any limitation on the amount the interest rate may change.” The scenario table shows your ending balance if your bank changes your APY by 0.25 or 0.50 percentage points in either direction for the whole term. It is arithmetic on the numbers you enter, not a forecast, and your account’s disclosures say how and when your rate can change.
How is my savings APY determined, and where do Fed decisions fit?
Your account disclosures say how your rate is determined. Under 12 CFR 1030.4(b), account disclosures shall include the following, as applicable. For variable-rate accounts, 12 CFR 1030.4(b)(1)(ii) says: “For variable-rate accounts: (A) The fact that the interest rate and annual percentage yield may change; (B) How the interest rate is determined; (C) The frequency with which the interest rate may change; and (D) Any limitation on the amount the interest rate may change.” Regulation DD also says, in 12 CFR 1030.5(a)(2)(i): “No notice under this section is required for: (i) Variable-rate changes. Changes in the interest rate and corresponding changes in the annual percentage yield in variable-rate accounts.” This page does not claim any link between a Federal Reserve decision and your APY, and it does not predict any decision. The federal funds target range shown on the page is context only.
Is the money in a savings account insured?
The FDIC says: “FDIC deposit insurance covers $250,000 per depositor, per FDIC-insured bank, for each account ownership category.” It also says: “All of your deposits in the same ownership category in the same FDIC-insured bank are added together for the purpose of determining FDIC deposit insurance coverage. However, you may qualify for more than $250,000 in FDIC deposit insurance coverage if you deposit money in accounts that are in different ownership categories.” For a federally insured credit union, the NCUA says: “Administered by the NCUA, the Share Insurance Fund insures individual accounts up to $250,000. Additionally, a member’s interest in all joint accounts combined is insured up to $250,000.” Check that your institution is insured and how your accounts are titled.
Is savings account interest taxable?
The IRS says: “Most interest that you receive or that is credited to an account that you can withdraw from without penalty is taxable income in the year it becomes available to you. However, some interest you receive may be tax-exempt. If you received payments of interest and/or tax-exempt interest of $10 or more, you should receive Copy B of Form 1099-INT or Form 1099-OID reporting those payments.” It also says: “You must report all taxable and tax-exempt interest on your federal income tax return, even if you don't receive a Form 1099-INT or Form 1099-OID.” The optional after-tax view applies the marginal tax rate you enter to the total interest. It is an estimate, not tax advice.
Authoritative sources: FDIC: National Rates and Rate Caps, October 2026 · FDIC: Understanding Deposit Insurance · NCUA: Share Insurance Fund Overview · Regulation DD, Appendix A to 12 CFR part 1030: Annual Percentage Yield Calculation (eCFR) · 12 CFR 1030.4, account disclosures (eCFR) · 12 CFR 1030.5, subsequent disclosures (eCFR) · IRS Topic no. 403, Interest received