This calculator assumes that interest compounds monthly and that the interest rate is fixed.

Field summary:

• Savings Goal - how much money you want to have saved.
• Starting Amount - how much you currently have saved, can be negative if you are in debt.
• Growth Rate - this is the interest rate on your savings, also called the yield or the annual return on your savings.
• Years to Save - how many years you give yourself to meet your goal.

Some things to think about with savings:

• The higher the growth rate the higher the risk.  Remember there is no 'free lunch' on Wall Street, with the one exception - diversification. Having your assets spread across a multitude of asset classes as opposed to a few concentrated areas eliminates the possibility of getting rich quick, but makes your portfolio very efficient from a risk vs return standpoint.
• The more time you give yourself to save the better. Extra time gets the power of compound interest working in your favor.

The math:

In order to calculate what you would need to save per month to reach a savings goal, use the formula:

r = annual interest rate, eg 7% = 0.07

G = savings goal

P = amount already saved

Y = number of years to save for

For example, if r = 4% (0.04), G = $400,000, P = $500, and Y = 30:

Which equals $537.94, just as the calculator shows!