<prompt> Human: I have a retirement account with Fidelity through my employer. It gives options for a 401k deferral and a Roth deferral. I set up my payments to maximize both by the end of the year 18k for the 401k, 5500 for the Roth. When I did my taxes today, I noticed that the total contribution to both stopped at 18k, with only 13,500 going into the 401k. My guess is that Ive misunderstood what my Roth contribution meant, and that it wasnt an IRA, but a different way to approach taxes within the 401k. But Im not sure. Fidelity 401k.com is a terrible website and Im never sure if I found all the informaton Im supposed to have. So, what was I paying into if not two separate accounts? What are the costs and benefits of that Roth contribution, and does it make sense for me to continue it? 34 years old, stable profession.Longtime lurker. Thanks you for the help.  <response>: Roth describes an account type for tax purposes. It sounds like you had a roth 401k and a traditional 401k which share the same cap. 