AGI vs MAGI

for different items on your return, there are different rules for how MAGI is computed.  for what purpose do you want to know what your MAGI might be? 

Yes!

But how can my Magi be less than my AGI?

MAGI for what purpose?  There are dozens of different ways to modify AGI for different purposes.

@Mike9241 Medicare 

TurboTax does not calculate MAGI for the purpose of Medicare IRMAA.  You must do that yourself.  All of the different MAGI's calculated by TurboTax are for purposes other than Medicare IRMAA.