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How to fill out Schedule 1-A

Schedule 1-A is the new IRS form for the four deductions in the 2025 tax law: tips, overtime, car loan interest and the senior deduction. You figure your income once in Part I, fill in only the parts that apply to you, and carry the total to Form 1040, line 13b.

Line numbers below are from the 2025 form. The 2026 version may renumber lines, but the parts and the math are the same.

Part I: modified adjusted gross income

Line 1 is your adjusted gross income from Form 1040, line 11b. Lines 2a to 2e add back income from Puerto Rico or abroad that you excluded, which most people don't have. Line 3 is your MAGI, used by every part below.

Part II: no tax on tips (lines 4 to 13)

  • Line 4a: qualified tips in box 7 of your W-2. Line 4b: tips from Form 4137. Line 4c: the larger, if you had one employer.
  • Line 5: tips on a 1099-NEC, 1099-MISC or 1099-K if you're self-employed, no more than your net profit.
  • Line 7: the smaller of your tips or $25,000. Lines 8 to 12: the income limit, $100 off for each full $1,000 over $150,000 ($300,000 joint).
  • Line 13: your tips deduction.

Part III: no tax on overtime (lines 14 to 21)

  • Line 14a: qualified overtime included in W-2 box 1. Line 14b: from a 1099, if any. Line 14c: the total.
  • Line 15: the smaller of that or $12,500 ($25,000 joint). Lines 16 to 20: the same $100 per $1,000 income limit.
  • Line 21: your overtime deduction.

Part IV: car loan interest (lines 22 to 30)

  • Line 22: each vehicle's VIN and the interest you paid, minus any part already deducted on Schedule C, E or F.
  • Line 24: the smaller of the total or $10,000. Lines 25 to 29: $200 off for each $1,000, or part of $1,000, over $100,000 ($200,000 joint).
  • Line 30: your car loan interest deduction.

Part V: enhanced deduction for seniors (lines 31 to 37)

  • Lines 31 to 35: $6,000 minus 6% of MAGI over $75,000 ($150,000 joint).
  • Line 36a: that amount if you were born before January 2, 1961 (for 2025) and have a valid Social Security number. Line 36b: the same for your spouse on a joint return.
  • Line 37: your senior deduction.

Part VI: total

Line 38 adds lines 13, 21, 30 and 37. Enter it on Form 1040, line 13b. It comes off your income after adjusted gross income, alongside the standard or itemized deduction, so you don't need to itemize to use it.

Common mistakes

  • Filing married separately: the tips, overtime and senior deductions all require a joint return.
  • Entering all overtime pay instead of only the premium, the extra half.
  • Leaving out the VIN on Part IV. Without it, the car loan interest doesn't qualify.
  • Forgetting that each part uses the same MAGI from line 3.

Updated November 3, 2026. Sources: 2025 Schedule 1-A (Form 1040), Internal Revenue Code §§224, 225, 151(d)(5) and 163(h)(4), IRS Fact Sheet 2025-03.