Printable checklist for your desk
Print this worksheet, fill in your numbers with your tax preparer, and see where you stand on each threshold.
Download the PDF (large print)The short version. There is no single "MAGI." Each rule starts with your adjusted gross income (AGI) and then adds back or removes different items. That is why the same person can be under one limit and over another.
Start with AGI
AGI is on your tax return (line 11 on Form 1040, split into 11a and 11b on the 2025 form). Everything below starts there. Taxable income, the number the tax brackets use, comes later, after the standard or itemized deduction. [1]
Which number each rule uses
| Rule | The income number it uses | Where to look |
|---|---|---|
| Traditional IRA deduction (if you are covered by a workplace plan) | AGI figured without the IRA deduction, student loan interest deduction, and certain exclusions for foreign income, savings bond interest, and employer adoption benefits. | Publication 590-A |
| Roth IRA contributions | Modified AGI. See Publication 590-A for the exact adjustments. | Publication 590-A |
| Medicare premium surcharges (IRMAA) | AGI plus tax-exempt interest, from your return two years earlier. | Social Security |
| Premium tax credit for marketplace insurance | AGI plus foreign income exclusions, tax-exempt interest, and nontaxable Social Security. | Form 8962 instructions |
| Taxation of Social Security benefits | Half your benefits plus all other income, including tax-exempt interest. | Publication 915 |
| Senior deduction ($6,000, 65 and older) | AGI plus certain foreign and Puerto Rico income. Phases out above $75,000 single, $150,000 joint. | Schedule 1-A |
| Net investment income tax (3.8%) | Modified AGI above $200,000 single or $250,000 joint. Tax applies to the lesser of your investment income or the excess. | IRS Topic 559 |
| Additional Medicare Tax (0.9%) | Not AGI. Based on wages and self-employment income above $200,000 single or $250,000 joint. | IRS Topic 560 |
Why tax-exempt interest matters
Interest from municipal bonds is not taxed by the federal government, but it is added back for Social Security taxation, Medicare premiums, and marketplace credits. So an investment that looks tax-free can still raise these costs. [3, 5, 6]
Capital gains use taxable income
The 0%, 15%, and 20% capital gain rates depend on taxable income. For 2026, the 0% rate applies up to $49,450 (single) or $98,900 (joint). The 15% rate runs up to $545,500 (single) or $613,700 (joint). Short-term gains are taxed as ordinary income. [9]
Where common thresholds sit in 2026
| Threshold | Single | Married filing jointly |
|---|---|---|
| Roth IRA contribution phase-out | $153,000 to $168,000 | $242,000 to $252,000 |
| Traditional IRA deduction (covered at work) | $81,000 to $91,000 | $129,000 to $149,000 |
| First Medicare surcharge above | $109,000 | $218,000 |
| Social Security: up to 50% taxable above | $25,000 | $32,000 |
| Social Security: up to 85% taxable above | $34,000 | $44,000 |
| Net investment income tax above | $200,000 | $250,000 |
Questions worth asking
- What is my AGI, and what are the other income numbers for the rules that affect me?
- Which threshold am I closest to, and by how much?
- Would a withdrawal, conversion, or sale push me over a threshold?
- Does my tax-exempt interest count against me anywhere?
Frequently asked questions
Is there one MAGI number?
No. Each rule starts with adjusted gross income and then adds back or removes different items, so the same person can be under one limit and over another.
Which income does IRMAA use?
AGI plus tax-exempt interest, from your return two years earlier.
Where do I find AGI?
On your tax return, Form 1040 line 11 (11a and 11b on the 2025 form).
Sources and review notes
General education, not individualized investment, tax, or legal advice. Discuss tax decisions with your tax professional, and recheck annual limits before using this page for another tax year.