Interest savings calculator
The same compounding that works against you on a card balance works for you in savings. Put in a starting amount and a monthly habit and see where it lands.
Your estimate
Estimates only, not an offer or financial advice. Assumes monthly compounding at a steady rate; real rates move and returns are not guaranteed.
How to read the results
The gap between total contributed and final balance is the part the account earned on its own, and it grows disproportionately with time. A hundred dollars a month at 4.5% is about $15,100 after ten years, of which roughly $2,100 is interest; leave the same habit running for twenty years and the interest share more than triples. Time in the account beats almost everything else you can adjust.
The starting balance matters less than people think and the monthly habit matters more. Doubling the start from $1,000 to $2,000 changes the ten-year answer modestly; doubling the monthly contribution changes it dramatically. Which is good news, because the monthly number is the one you actually control.
Even a small cushion changes how emergencies play out: a few hundred dollars saved is the difference between absorbing a repair and financing it. If you are building that cushion while paying down debt at the same time, run the credit card payoff calculator too, because money usually earns less in savings than a card balance charges. The other calculators are in the Tools menu above, and the FAQ covers how borrowing through this site works.