Is there a limit on how much can be converted to Roth?

[Pobeka]

12. no limit. Consider the mariginal tax rate for the conversion though.

Since the Roth conversion money is coming out after your RMD, it will be taxed at the highest level for your situation.

I did some analysis, and considered two scenarios:

1) No Roth conversions at all.

2) Heavy Roth conversions (for us moving 50% of our IRA's to Roths)

I computed what the net asset value would be, after tax for both scenarios year by year. It's tricky because you have to realize you don't own all the money in a qualified IRA, so estimate your long term average tax rate and knock the asset value of qualified IRA down by that tax. Estimate your RMD every year and withdraw it from the qualified IRA.

At average interest rates of 4-6%, I found it would take many, many years for the Roth conversion scenario to have a net asset value greater than the no conversion scenario. And then it gets better and better. For us, given our time horizon, conversions make sense even with a large tax burden up front.

All that is extremely dependent on the situation, but maybe it will help give you an idea how to approach the amount you should convert given your particular situation.