Can capital losses in non-tax-favored accounts, be used to offset the tax against a Roth IRA Conversion for an individual who is 59 and 1/2 years old or older?

[dmertz]

The taxable amount of the Roth conversion is taxed as ordinary income.  Provided it doesn't result in a a wash sale, up to $3,000 of capital losses in excess of capital gains can be applied against ordinary income in any given year.

[fanfare]

Your capital losses cannot offset your Roth Conversion .

There is no way to offset a Roth Conversion unless you have a basis in your Traditional IRA, in which case you get a partial offset (see Form 8606).

@callstoopen 

[Opus 17]

Because a Roth conversion is ordinary income, and not reported as capital gains, capital losses won't offset the conversion except up to the usual $3000 limit for losses to offset ordinary income.