Compound Interest
Compound interest is interest calculated on both your original principal and the interest already earned. Because each period's earnings are added to the balance, the next period earns interest on a larger amount — so growth accelerates over time instead of staying flat, which is what makes long-term saving so powerful.
The Rule of 72 offers a quick estimate: divide 72 by your annual rate to find how many years it takes money to double. At 7%, that's roughly ten years. The longer the time horizon, the more dramatic the effect.
Put it to work
Compound Interest Calculator
See how your savings grow with compound interest and monthly contributions — final balance, interest earned, and a year-by-year growth table.
Savings Calculator
Watch your savings account grow: enter your balance, monthly deposit, and APY to see the future value and every dollar of interest along the way.
Investment Calculator
Project an investment portfolio's growth with monthly contributions — final value, your money vs market growth, and the year-by-year path.