Compound Interest & Savings Calculator
See how a starting balance and regular monthly deposits grow at a given APY. APY already includes compounding, so the calculator grows your balance at that effective yearly rate.
Free · runs in your browser · Checked 30 September 2026Savings calculator
Move the sliders or type your own numbers. Results are estimates that assume a constant rate and are not guaranteed.
🧠 How this is calculated
The balance grows each month by the monthly equivalent of your APY, (1 + APY)^(1/12) − 1, and your monthly deposit is added at the end of each month. Interest earned = ending balance − total deposits.
Calculations run in your browser; nothing you enter is sent to us. Results are estimates that depend on the assumptions shown.
❓ FAQs
What is the difference between APY and APR?
APY (annual percentage yield) includes the effect of compounding within the year; APR is the simple annual rate before compounding. Savings accounts advertise APY.
Are savings rates fixed?
Most high-yield savings rates are variable and can change at any time. CD rates are fixed for the term.
Is this financial advice?
No. The calculator shows what happens under the numbers you enter. Rates, limits and tax rules change; confirm with the provider or a licensed professional.
Benchmark rates: FDIC national average savings rate 0.37% and 12-month CD 1.73% (effective September 21, 2026). Many online banks pay more; see Savings & CD rates.
Results are illustrations, not offers or advice. Investments can lose value; bank deposits are FDIC-insured up to $250,000 per depositor, per insured bank, per ownership category.