For individual income tax 2020, is modified adjusted gross income = adjusted gross income + non-taxable portion of the social security and non-taxable investment income?

[swodgenske]

I need to figure out how much Roth IRA conversion I can make this year before going over the medicare limit.

[rjs]

There are about a dozen different definitions of Modified Adjusted Gross Income (MAGI) for different purposes. Are you referring to the higher Medicare premiums if your MAGI is more than a certain amount? For that purpose, MAGI is Adjusted Gross Income (AGI) plus tax-exempt interest. On your 2020 Form 1040 it's line 11 plus line 2a.

[NCperson]

this documents the answer 

https://www.ssa.gov/benefits/medicare/medicare-premiums.html

[swodgenske]

Yes, you answered my question. Thank you very much. 

[swodgenske]

Thank you for your reference. I feel much better now to make a decision of how much Roth conversion for this year. Have a happy holiday season.