After you file

• Start with your Gross Income Line 7b of your Form 1040.
• To get your AGI you then deduct
  • IRA contributions
  • Student Loans
  • Moving expenses
  • One half of self-employment tax (If self-employed)
  • Self Employed health insurance
  • Contributions to SEP, SIMPLE and qualified plans for yourself
  • Any Alimony paid
  • Deduction for Archer Medical Savings Account
  • Penalties paid for early withdrawal of savings
• To get your Modified AGI
  • Any amount excluded from gross income in section 911 (Foreign earned income and housing costs for qualified individuals)
  • Any amount of interest received or accrued by the taxpayer during the taxable year which is exempt from tax
  • Any amount equal to the portion of the taxpayer’s social security benefits (as defined in Section 86 (d)) which is not included in gross income under section 86 for the taxable year.

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