Do tax-exempt social security benefits (e.g., the 15% that's never taxed) count toward Roth income limits (for contributions)? In other words, is it included in MAGI?

[roertel12]

TurboTax is not including the tax-exempt portion, but several websites state that tax-exempt Social Security benefits are included in MAGI.  (There seems to be different forms of MAGI, depending upon the purpose.)

[DavidD66]

No. Since the non-taxable portion of Social Security benefits are not included in AGI, they are not included in MAGI. 

Modified Adjusted Gross Income (MAGI) for Roth contributions is calculated by adding AGI plus:

• student loan interest deduction,
• foreign earned income and housing exclusions,
• foreign housing deduction,
• excluded savings bond interest,
• excluded employer adoption benefits, and,
• for 2017 and earlier, the domestic production activities deduction and the tuition and fees deduction paid before 2021.
• and any deduction for contributing to a Traditional IRA 

[roertel12]

Much appreciated.  Would you mind telling me where the citation is from?

It's really odd, in that MAGI is calculated in different ways - depending upon the purpose it's used for.

[dmertz]

The modifications needed to AGI for the purpose of determining eligibility to contribute to a Roth IRA are stipulated in section 408A(c)(3)(B)(i) of the tax code and are listed on in Worksheet 2-1 of IRS Pub 590-A:

https://www.irs.gov/publications/p590a#en_US_2021_publink100025085

Different modifications for different purposes is odd?  No.  The reasons one needs to modify AGI for different purposes are dependent on the purpose for which the AGI is being used.