U.S. workers willing to take tax pain today in exchange for tax-free gains on earnings in their 401(k) retirement accounts later have a new avenue to do so.

The budget legislation passed by Congress Jan. 1 lets 401(k) participants convert any money in their tax-deferred accounts to a so-called Roth 401(k) account, if their employer offers one, which can be withdrawn tax-free in retirement. The change is projected to raise $12.2 billion in revenue over 10 years, according to the Joint Committee on Taxation, and help defray the cost of delaying spending cuts that had been set to take effect this month.

“This dramatically expands the number of participants who can use this provision,” said Bob Holcomb, executive director of legislative and regulatory affairs for JPMorgan Chase & Co.'s retirement plan services. “It will allow any amount to be transferred.”