A Roth 401(k) retirement plan is one of several account options available for retirement savings. The key difference between this plan and a traditional 401(k) plan is that a Roth 401(k) is funded by money calculated after taxes, while a traditional 401(k) is funded by pretax money. This makes the Roth 401(k) a good choice for investors who expect to be in a higher tax bracket when they retire than when they open the account. 

You can set up a Roth 401(k) through your employer. Employers are required by federal law to offer retirement plans for full-time employees. These plans are opt-in, which means that employees can choose whether or not they want to contribute to them. If you have already elected not to contribute to a Roth 401(k) set up by your employer, it is generally possible to reverse the decision by contacting your employer's human resources or accounting department. Choosing this method to set up a Roth 401(k) has a few advantages. Contributing to the account is easier since the money is taken out of your salary automatically by your employer. Employers choose which financial institution their employees must use, however, and the terms laid out in the contract may not be the best available.