Human: What's the difference between a 401k, IRA, and a Roth IRA? Assistant: 
The main difference between a 401(k), an IRA, and a Roth IRA is the way they are taxed. A 401(k) is funded with pre-tax dollars and is subject to income tax when withdrawn, while an IRA is funded with after-tax dollars and is not taxable until withdrawal. A Roth IRA is similar to a traditional IRA in that contributions are made with post-tax dollars, but withdrawals are tax-free if certain conditions are met.