Roth 401(k) Plan combines the features of a traditional 40(k) with those of a Roth IRA. A Roth 401(k) is offered by employers (similar to a 401(k)), but like a Roth IRA, contributions are made with after-tax dollars rather than pre-tax dollars. However, at retirement contributions and any earnings are tax-free. A Roth 401(k) cannot stand alone as a retirement plan, it must be added to an existing 401(k) plan.