With the passage of the "American Tax Relief Act", any 401(k) plan that allows for Roth contributions will now be eligible to convert existing pre-tax 401(k) balances to an after-tax Roth 401(k). Previously an employer-sponsored plan [401(a)/(k), 403(b) and governmental 457(b)] could only be converted to a Roth IRA. The Roth 401(k) conversion amount would be taxable in the year of conversion, but all gains (or growth) would be distributed completely tax-free at retirement. Is this a good option for you? A conversion has both advantages and disadvantages that should be carefully considered before you make a decision. This calculator compares two alternatives with equal out of pocket costs to estimate the change in total net-worth, at retirement, if you convert your per-tax 401(k) into an after-tax Roth 401(k).