Compounder, allows you to calculate compounding interest quickly. What exactly is compound interest?
Interest calculated on the initial principal and also on the accumulated interest of previous periods of a deposit or loan.

For example, if you start with $1000 in your savings account and each month you contribute $500 at 11% interest annually. After 40 years, guess how much the account will be worth. The answer, $4.38 Million! You're only putting in $500/month(the average car payment in America) at just 11% interest(Same interest the S&P 500 has averaged over the past 90 years).
You don't have to be some big Wall Street broker to become a millionaire.