High-Yield Savings Calculator

It projects your future balance from four inputs: your initial deposit, a recurring monthly contribution, the account APY, and your time horizon in years. The initial deposit grows by (1 + APY) each year, while monthly contributions are treated as an ordinary annuity added at the end of each month. The result splits your balance into total deposits and interest earned.

APY (Annual Percentage Yield) is the effective annual return after the bank's compounding is already baked in, which is the number banks advertise for high-yield savings accounts. Because it is the effective yield, you can apply it directly to your balance without specifying a separate compounding frequency. The calculator converts the APY to an equivalent monthly rate, (1 + APY) to the power of one twelfth minus one, so monthly contributions compound correctly.

Each monthly contribution is added at the end of the month (an ordinary annuity), so the balance compounds first and then the new deposit lands. This matches how most automated transfers and the other Calcoid finance calculators work. Depositing at the start of each month instead would earn slightly more interest, since each contribution would compound for one extra month.

Interest earned is your projected final balance minus everything you deposited (initial deposit plus all monthly contributions). For example, 10,000 to start plus 500 per month at a 4.5% APY for 10 years grows to about 90,768, of which roughly 20,768 is interest. Higher APYs and longer horizons increase the interest share, since earnings compound on earlier earnings.

Probably not. High-yield savings APYs are variable and move with the federal funds rate, so a bank can raise or lower your rate at any time. This calculator assumes a single fixed APY for the entire horizon, which is useful for comparison but will not match a real account whose rate changes. Re-run it with a lower APY to see a more conservative estimate.

No. It is an educational estimate, not financial or tax advice. Results assume a constant APY and regular contributions, and they ignore taxes on interest, account fees, and inflation. Confirm current rates and terms with the bank before making decisions, and consult a qualified advisor for guidance specific to your situation.