Very straight forward - enter the data given (initial amount, monthly deposit, and interest rate) and then guess at a time frame. The calculator will return how much you will have at the end of that time frame (i.e., I did it for 20 years - you have a bit over $95,000 after 20 years). If the amount is too low, add some years, if too high, subtract some years.

The rest is just explanation of how to save more faster (larger initial deposit, larger monthly deposits, better interest rates - if you want to impress you can add some changes and explain).

EDIT - or you can just put in a really high time frame (say 50 years) and find out when you will have that $250,000 - the time frame won't change since you are not changing anything.

It's a calculator

Use the Savings Calculator at Bankrate.com to compute how long it will take you to save $250,000 at a 5% interest rate compounded monthly if the initial balance is $5,000 with a monthly deposit of $200. (Hint: Enter the estimated number of years needed and adjust it based on your calculations). What kind of changes in your saving plan would help you accumulate this amount faster?

I've used Bankrate.com to find out my balance in so and so years, but never have I had a reversal like this. Any help is appreciated, thanks.