Interactive Roth IRA worksheets are popping up on the Net. They can help you determine whether to convert an existing IRA to a Roth, which is funded with after-tax dollars, but whose distributions are tax-free. Using a hypothetical conversion, we evaluated several. For more details, go to www.businessweek.com/today.htm or AOL, keyword: BW Daily.
-- VANGUARD GROUP (www.vanguard.com). Our favorite. To the impatient, this site may seem tedious: The footnotes and explanations go on and on. But you won't come away ignorant of the issues. And it lets you adjust the results for some subtle tax liabilities others ignore.
-- FIDELITY INVESTMENTS (personal12. fidelity.com/retirement). The site has sufficient explanations, a way of looking at investment outcomes in both nominal and inflation-adjusted dollars, plus the freedom to set your tax rate as high as 60%--good when considering state taxes.
-- CHARLES SCHWAB (www.schwab. com). Swifter than Fidelity's, it also had annoying features. For example, it gives you only six preset choices on the expected return on your investment, ranging from 7.8% to 12.9% a year.
-- STRONG FUNDS (www.strong-funds.com). It's quick and straightforward. But this calculator doesn't account for the investment gains you would forgo by paying the conversion tax with money outside of your IRA.
-- T. ROWE PRICE (www.troweprice. com).This site was the most sophisticated. Especially helpful: You can set the number of years over which you would liquidate an account.