To get MAGI you first need to first calculate (or estimate) your adjusted gross income (AGI). That is line 8b of Form 1040. Looking at Form 1040, AGI is the sum of:
Line 1 (Wages, salaries, tips, etc.),
Line 2b (taxable interest),
Line 3b (ordinary dividends),
Line 4b (taxable amount of IRA distributions),
Line 4d (taxable amount of pensions and annuities),
Line 5b (taxable amount of social security benefits),
Line 6 Capital gain or (loss),
Line 7a Other income from Schedule 1, line 9
From the total of the above items, deduct adjustments to income (if any) from Schedule 1, line 22. This gives AGI.
To get MAGI you also need to add to AGI the non-taxable part of any SS payments and non-taxable interest you received.
I trust others will add anything I missed or note any corrections.
My question is can a $3000 capital loss carryover be deducted from income to get MAGI and I have not seen the answer anywhere, but I assume you can because this deduction is allowed/included in the calculation of AGI, per Form 1040, line 6.