Why compounding matters
Compound interest means you earn returns on your past returns, not just your original deposit, so growth accelerates the longer you leave money invested. This calculator compounds monthly and adds your monthly contribution each period, then splits the final balance into what you put in versus what the market added.
Private by design. Projections are calculated in your browser; nothing is uploaded.
Frequently asked questions
How often does it compound?
Monthly, which matches most savings and investment accounts and your monthly contributions.
Is the return guaranteed?
No. The percentage is an assumed average annual return. Real markets vary year to year, so use it to compare scenarios, not as a promise.
Is my data uploaded?
No. Everything is computed locally in your browser.
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