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Adjusted Gross Income: How $6,500 of Adjustments Saves a $65,000 Earner $780 Federally and $0 in Pennsylvania
A single filer earning $65,000 who puts $4,000 into a traditional IRA and pays $2,500 of student loan interest has $58,500 of adjusted gross income for 2026. Those two adjustments lower federal income tax by $780, and they carry into the state return in most states, because most states begin from that same line. Pennsylvania is one of the exceptions, and there they save nothing.
Adjusted gross income, or AGI, is total income minus a short list of deductions the tax code calls adjustments. It sits on line 11 of Form 1040, between the income lines above it and the standard or itemized deduction below it (Form 1040 instructions).
From gross income to taxable income
The filer in this example has no workplace retirement plan, so the whole IRA contribution is deductible, and their income is below the range where the student loan interest deduction shrinks. Every figure comes from TaxMath's Form 1040 engine on the 2026 rules.
| Form 1040, 2026 | No adjustments | With the IRA and student loan interest |
|---|---|---|
| Wages, total income (line 9) | $65,000 | $65,000 |
| Adjustments from Schedule 1 (line 10) | $0 | $6,500 |
| Adjusted gross income (line 11) | $65,000 | $58,500 |
| Standard deduction (line 12) | $16,100 | $16,100 |
| Taxable income (line 15) | $48,900 | $42,400 |
| Income tax (line 16) | $5,623 | $4,843 |
The adjustments sit in Part II of Schedule 1, whose line 26 carries their total to line 10 of Form 1040. Besides the IRA deduction and student loan interest, the common ones are the deductible half of self-employment tax, contributions to a health savings account, educator expenses, and alimony paid under a divorce or separation agreement executed before 2019.
The $780 saving is $6,500 at the filer's 12% bracket rate. Line 16 uses the IRS Tax Table, which taxes the midpoint of each $50 band of taxable income below $100,000, so it differs by a few dollars from the bracket arithmetic applied to the exact figure.
Why the line matters beyond the bill
An adjustment is worth the same as a deduction taken lower down, at the filer's marginal rate. What sets AGI apart is how many other rules read it, so lowering AGI can unlock or enlarge breaks that a lower taxable income would not.
- Student loan interest phases out for a single filer between $85,000 and $100,000 of modified AGI for 2026 (Rev. Proc. 2025-32). This filer is well below the range and deducts the full $2,500.
- The senior deduction of $6,000 per person 65 or older starts phasing out above $75,000 of modified AGI for a single filer (IRS).
- Medical expenses are deductible on Schedule A only above 7.5% of AGI (Schedule A instructions). At $65,000 that floor is $4,875; at $58,500 it falls to $4,388, so $487 more of a year's medical bills would count if the filer itemized.
A modified AGI is AGI with particular items added back, and each rule names its own. For most wage earners with no foreign income, the modified figure and AGI are the same number.
The same adjustments on a state return
On TaxMath's 2025 state rules, 30 states and the District of Columbia begin their return from federal AGI, and five (Colorado, Iowa, Montana, North Dakota and South Carolina) begin from federal taxable income, which sits below AGI on the same form. In all 36, a federal adjustment lowers the state starting point too, unless the state adds it back. Alabama, Arkansas, Massachusetts, Mississippi, New Jersey and Pennsylvania build their own income base instead.
| $6,500 of adjustments, 2026 | Where the return starts | Tax saved |
|---|---|---|
| Federal | Form 1040 | $780 |
| Illinois | Federal AGI, then a flat 4.95% | $322 |
| Colorado | Federal taxable income, then a flat 4.40% | $286 |
| Pennsylvania | Its own classes of income, at 3.07% | $0 |
Form IL-1040 begins on line 1 with federal adjusted gross income (IL-1040 instructions) and adds back neither deduction, so the $6,500 comes off income taxed at 4.95%. Colorado starts Form DR 0104 at federal taxable income, Form 1040 line 15 (Colorado DOR), which the adjustments lowered by the same $6,500.
Pennsylvania taxes compensation at 3.07% with no standard deduction, and its Department of Revenue lists both the IRA deduction and the student loan interest deduction as federal adjustments with "No provision" in Pennsylvania law (PA DOR). This filer owes Pennsylvania $1,996 with or without them.
For the 36 jurisdictions that start from a federal line, a state figure built on AGI moves whenever AGI does, including when Congress adds or changes an adjustment. The states with their own base decide each item for themselves, and a deduction that lowers the federal bill can leave theirs where it was.
Sources
Ordered by authority — the law and the agencies administering it first. Every link is checked for rot; see all sources.
- GovernmentColorado Individual Income Tax Return, Form DR 0104 (2025)Colorado Department of Revenue · checked 2026-09-01Line 1 starts the return at federal taxable income — Form 1040 line 15 — so a deduction that lowers line 15 lowers the Colorado base by the same amount. The host serves 403 to non-browser clients; fetch with a browser user-agent.Other articles citing this source
- Government2025 Form IL-1040 instructionsIllinois Department of Revenue · checked 2026-10-21A resident files if required to file a federal return, or if Illinois base income exceeds the exemption allowance ($2,850 per person for 2025).Other articles citing this source
- GovernmentInstructions for Form 1040 and 1040-SR (2025), including the Instructions for Schedule 1-AInternal Revenue Service · checked 2026-10-21Schedule 1-A instructions (pp. 101–110): line 4a from W-2 box 7 or Forms 4070, the box 5 over $176,100 caution, the one-employer and multiple-employer tip worksheets, line 5 net income limitation, the overtime methods (employer statement, total overtime pay ÷ 3, double-time fractions, reasonable method), line 14a for overtime deferred out of box 1, line 22 VIN columns, the valid-SSN definition (valid for employment, issued before the due date including extensions), and the reached-65-the-day-before-the-birthday rule. Also the 2025 standard deduction chart ($33,100 joint, one spouse 65+) and the Tax Computation Worksheet (Section B: 22% less $10,172.00 for $100,000–$206,700).Other articles citing this source
- GovernmentInstructions for Schedule A (Form 1040), Itemized DeductionsInternal Revenue Service · checked 2026-10-20Line-by-line rules for SALT, mortgage interest, charitable gifts, and the medical expense floor.Other articles citing this source
- GovernmentRevenue Procedure 2025-32 — tax year 2026 inflation adjustmentsInternal Revenue Service · checked 2026-10-20The revenue procedure itself: the §1(j)(2) rate tables with their formula rows, the capital-gains thresholds, the child tax credit amount, the §4.14 standard-deduction rows and §63(f) aged/blind additional amounts, and the §2 background listing which OBBBA sections changed each figure.Other articles citing this source
- GovernmentSchedule 1 (Form 1040), Additional Income and Adjustments to Income (2025)Internal Revenue Service · checked 2026-10-21Line 3 business income from Schedule C; line 15 "Deductible part of self-employment tax. Attach Schedule SE"; line 26 totals the adjustments to income and carries them to Form 1040 line 10.Other articles citing this source
- GovernmentTax deductions for working Americans and seniorsInternal Revenue Service · checked 2026-08-02IRS summary of the tips, overtime, car loan interest, and senior deductions and their limits.Other articles citing this source
- GovernmentPA Personal Income Tax Guide — Deductions and CreditsPennsylvania Department of Revenue · checked 2026-10-21Pennsylvania allows a yearly deduction for IRC §529 contributions equal to the annual federal gift tax exclusion (IRC §2503(b)) per beneficiary, per taxpayer. Its table of deductions allowed in arriving at federal AGI but not for Pennsylvania lists "IRA deduction" and "Student loan interest deduction", each with "No provision".Other articles citing this source