<human>:  What is the difference between a 401k and a Roth IRA?
<bot>: The main difference between a 401k and a Roth IRA is the way they are taxed. With a 401k, contributions are made with pre-tax dollars, meaning taxes are paid upon withdrawal. A Roth IRA, on the other hand, utilizes after-tax dollars, and the resulting earnings are tax-free. Additionally, 401ks typically offer employer contributions and match, whereas Roth IRAs do not.