The maximum contribution limit for a Roth 401(k) is determined by the IRS. As of 2024, the maximum contribution limit for individuals under the age of 50 is $20,500. For individuals aged 50 and over, there is an additional catch-up contribution limit of $6,500, bringing the total maximum contribution to $27,000. It's important to note that these limits are subject to change based on IRS regulations and may be adjusted in the future. It's advisable to consult with a financial advisor or tax professional for the most current contribution limits and personalized guidance on retirement savings strategies.