About the High-Yield Savings Calculator
This high-yield savings calculator projects how your money grows in a high-yield savings account (HYSA) and compares it side by side with a traditional savings account. Enter your opening deposit, what you add each month, the APY of each account and how many years you plan to save to see both balances, the interest each earns and the extra money the higher rate puts in your pocket.
It is designed for anyone deciding whether to move an emergency fund, a house deposit or short-term savings from a big-bank account paying close to nothing to an online bank or credit union paying a competitive APY. Because both accounts receive the same deposits, the difference you see comes purely from the rate.
Rates on savings accounts are variable and can change at any time, so treat the result as an estimate at today’s rates. Deposits are assumed at the end of each month and interest compounds monthly at the rate equivalent to each APY.
With the default inputs, the high-yield savings balance is $32,342.69. Change any value above to recalculate instantly.
How to use the high-yield savings calculator
- 1Enter your opening deposit and how much you will add each month.
- 2Enter the APY offered by the high-yield savings account.
- 3Enter the APY of your current or traditional savings account.
- 4Choose how many years you plan to keep saving.
- 5Compare the two balances and the extra interest the HYSA earns.
Formula and method
Each account is simulated month by month. The APY is first converted to the equivalent monthly growth rate i, so that twelve months of compounding reproduces the advertised APY exactly. Every month the balance grows by i and then your monthly deposit D is added.
Interest earned is the ending balance minus the opening deposit and all monthly deposits. The difference between the two accounts is caused only by the rate because both receive identical deposits. The final monthly interest figure is the ending HYSA balance multiplied by the monthly rate.
- Bₘ
- Balance after month m
- D
- Monthly deposit
- i
- Monthly rate equivalent to the account APY
Worked examples
$10,000 plus $300/month, 4.3% vs 0.4% APY for 5 years
Both accounts receive $28,000 in deposits. At 4.3% APY the balance grows to $32,342.69, while at 0.4% it reaches only $28,379.42 — the high-yield account earns about $3,963 more.
Parking $25,000 for 3 years at 4.0% vs 0.01%
With no further deposits, $25,000 × 1.04³ = $28,121.60 in the HYSA. A big-bank account paying 0.01% earns just $7.50 over the same three years.
Saving $1,000/month from zero for 10 years
You deposit $120,000 over ten years. At 4.5% APY it grows to about $150,476, compared with $123,017 at 0.5% — a difference of roughly $27,458 just from choosing the better account.
Frequently asked questions
Are high-yield savings accounts safe?+
Yes, when they are held at an FDIC-insured bank or NCUA-insured credit union. Deposits are protected up to $250,000 per depositor, per institution, per ownership category — the same as a traditional savings account.
Why do online banks pay higher savings rates?+
Online banks have no branch network to maintain, so they can pass lower costs on as higher APYs. Many large branch banks keep savings rates low because customers rarely move their money.
Can a high-yield savings rate change?+
Yes. HYSA rates are variable and usually move with the Federal Reserve’s policy rate. If you want a guaranteed rate for a fixed period, a CD locks it in at the cost of early-withdrawal penalties.
Is interest from a high-yield savings account taxable?+
Yes. In the US, savings interest is taxed as ordinary income in the year it is earned, and banks send Form 1099-INT when interest reaches $10 or more. The calculator shows pre-tax figures.
How much interest will $10,000 earn in a high-yield savings account?+
At 4.3% APY, $10,000 earns about $430 in a year if left untouched. At a traditional account’s 0.4%, it would earn about $40. Multiply the balance by the APY for a quick one-year estimate.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.