Can I roll my old 401(k) into a Roth IRA and what taxes apply?

Yes, you can roll a traditional (pre-tax) 401(k) directly into a Roth IRA, but this is a conversion, so the pre-tax amount becomes taxable income in the year you do it. There is no early-withdrawal penalty on a proper rollover conversion, only ordinary income tax on the converted pre-tax dollars.

A large rollover can spike your tax bracket, so many people spread conversions over several lower-income years. Roth 401(k) money, by contrast, rolls into a Roth IRA tax-free because you already paid the tax. Have cash outside the account ready to pay the resulting tax bill rather than withholding it from the rollover. Model the tax impact with the Roth Conversion calculator at wealthserene.com/tools/roth-conversion before pulling the trigger.