After age 59 and a half, you pay no tax or penalty on withdrawals from your Roth IRA so long as the money has been in the account for at least 5 years.
Investopedia has a good article on how to do a Roth IRA rollover including the pros and cons. There is no limit to how much you can roll over from your retirement account, but you will not want to roll over more money than you can pay tax on. Also, to avoid an underpayment penalty, you may need to increase your payroll tax deductions.
Withdrawal rules and early withdrawal penalties by H&R block. You may roll over money from your retirement account into a Roth IRA at any age, but if you are younger than 59 and a half, do not take money from your retirement account to pay the tax.
You may want to keep some money in your IRA because you may be able to avoid paying tax on some of it. Certain contributions made through "qualified charitable distributions" - funds sent directly to the charity from a traditional IRA - are excluded from your taxable income. If your age requires you to take annual required minimum distributions, RMD, from your IRA, you could reduce your tax liability on the RMD to zero. If your RMD is $3,000, but you give $3,000 to charity anyway, do the qualified charitable distribution and you don’t pay any tax on the RMD. That money is not included in your adjusted gross income (AGI).
There are also a few other ways that people at any age may might qualify for reduced taxes on IRA distributions.
If you cannot afford to pay taxes on your retirement roll over, and if you participate in your company's stock purchase plan, consider cashing out some of that money when the stock price is high. You can set that money aside or put it in a fixed income fund until you need it to pay the tax on the roll over into your Roth IRA.
Hopefully this info will be a good starting place for research and planning in order to maximize your retirement savings. Please consult your tax adviser or accountant prior to acting on any of these recommendations.
Charles Young wrote this in an effort to offer some quick and simple advice. God bless.