What are the differences between contributing to a before-tax vs Roth 401k and how do these options impact my retirement savings?

Contributing to a before-tax 401(k) reduces your taxable income now, but you'll pay taxes on withdrawals in retirement. Contributing to a Roth 401(k) doesn't reduce your taxable income now, but withdrawals in retirement are tax-free. The choice impacts your retirement savings by affecting when you pay taxes on the money and how much you'll have available for retirement.