<prompt> Human: Im in my mid-20s. For the past few years Ive just had my money sitting in a bank. This last year I decided to try out Betterment, and I had relatively good returns 9, though I invested at a pretty high time so I imagine it wouldve been much better had I started earlier in the year. I currently have zero debts and about 38k in Betterment, 10k in my bank account for a rainy day. I have my stockbond split at 9010, which I will make less aggressive as time goes on. Betterment is predicting that if I continue my 1,000mo contribution for 40 years, I can plausibly expect 2.1-4.6 million in investments if the market trend continues as it has Betterment says I have a 90 chance of 2.1m, 50 chance of 4.6m. Of course I realize there are no guarantees and I could wind up with 50,000 for all I know. If market trends do continue, though, is 2,000,000 realistic? I thought that sounded rather high for a paltry 1,000month, but I guess I dont really understand compound interest and all of that. Im also maxing out my employer-matched 401k in addition to this 1,000mo. Im watching my parents struggle a bit with retirement at the moment and its making me freak out a bit about my future.Thanks  <response>: Of course I realize there are no guarantees and I could wind up with 50,000 for all I know. If market trends do continue, though, is 2,000,000 realistic? It may or may not be realistic, depending on what assumptions you make. You should focus on the things you can control - i.e. minimizing costs, savings rate, and asset allocation. 1kmonth until you retire may or may not be enough to retire on, depending on your expenses in retirement. 