Tax phase-outs are the income ranges over which a credit, deduction, or contribution limit shrinks from its full value down to zero. For 2026, dozens of them are in play at once: the Child Tax Credit starts shrinking at $200,000 for single filers and $400,000 for joint filers, Roth IRA contributions phase out between $153,000 and $168,000 for single filers, and the newly expanded SALT deduction fades away above roughly $500,000 of income. Knowing where each threshold sits, and how fast the benefit disappears past it, is the difference between smart year-end planning and a surprise bill in April.
How a Phase-Out Actually Works
A phase-out has two edges. The bottom edge is the threshold: stay below it and you get the full benefit. The top edge is where the benefit hits zero. In between, each additional dollar of income shaves off a slice of the credit or deduction.
Most phase-outs run on a steady slope. The Child Tax Credit, for example, drops by $50 for every $1,000 of income (or any fraction of $1,000) above the threshold. A single parent earning $210,000 loses $500 of the credit, not the whole thing. That rounding rule bites: one dollar over a $1,000 increment still costs the full $50.
A few benefits skip the slope and use hard tiers instead, which creates mini-cliffs where a single dollar of extra income drops your credit rate immediately. The Saver’s Credit works this way. And the Premium Tax Credit for 2026 carries the harshest cliff of all: once household income crosses 400% of the federal poverty level, the entire subsidy is gone, not just a portion of it.
Modified Adjusted Gross Income Is the Number That Counts
Nearly every phase-out is measured against Modified Adjusted Gross Income, not gross salary and not taxable income. MAGI starts with the Adjusted Gross Income on line 11 of Form 1040, then adds back certain excluded items such as tax-exempt municipal bond interest, foreign earned income you excluded, and certain adoption-related amounts.1Internal Revenue Service. Modified Adjusted Gross Income
There is no single universal MAGI. Each provision defines its own version, specifying which items get added back. For most filers the differences are minor, but if you have foreign income or adoption expenses, check the instructions for the specific credit or deduction you’re claiming.
2026 Phase-Outs for Tax Credits
Credits cut your tax bill dollar for dollar, so losing one to a phase-out hurts more than losing a deduction of the same size.
Child Tax Credit
The credit is worth up to $2,000 per qualifying child under 17. You get the full amount with income at or below $200,000 single or $400,000 joint.2Internal Revenue Service. Child Tax Credit Above those thresholds the credit falls $50 for every $1,000 of excess income, or any fraction of $1,000.3Office of the Law Revision Counsel. 26 USC 24 – Child Tax Credit A family claiming $4,000 for two children sees the credit reach zero at $280,000 single or $480,000 joint.
Earned Income Tax Credit
The EITC is generous at lower incomes and phases out faster than almost any other provision. Maximum credits for 2026 run from $664 with no qualifying children to $8,231 with three or more.4Office of the Law Revision Counsel. 26 USC 32 – Earned Income The 2026 income cutoffs where the credit reaches zero:
- No children: $19,540 single, $26,820 joint
- One child: $51,593 single, $58,863 joint
- Two children: $58,629 single, $65,899 joint
- Three or more: $62,974 single, $70,224 joint
Workers near the top of eligibility should watch overtime, bonuses, or side income that could push them across the cutoff.
American Opportunity and Lifetime Learning Credits
Both education credits share the same 2026 phase-out. The American Opportunity Tax Credit, worth up to $2,500 per student for the first four years of college, begins phasing out at $80,000 MAGI single or $160,000 joint and hits zero at $90,000 single or $180,000 joint.5Internal Revenue Service. American Opportunity Tax Credit That $10,000 single-filer window means the credit shrinks by $25 for every $100 of excess income.
The Lifetime Learning Credit, worth up to $2,000 per return for any post-secondary education, uses the identical $80,000–$90,000 single and $160,000–$180,000 joint range. If you’re phased out of one, you’re phased out of the other.
Saver’s Credit
The Retirement Savings Contributions Credit rewards lower-income workers who put money into a 401(k), IRA, or similar plan, and it uses hard tiers rather than a slope. For 2026, a joint filer earns a 50% credit at AGI up to $48,000, 20% from $48,001 to $52,000, 10% from $52,001 to $80,500, and nothing above $80,500. Single filers hit zero at $40,250. A single dollar over a tier boundary drops your credit rate immediately.
Premium Tax Credit
For 2026 the marketplace Premium Tax Credit has reverted to its pre-pandemic rules after the enhanced subsidies expired at the end of 2025. The 400% of federal poverty level income cliff is back: cross it and you lose the entire credit. For a family of four in 2026 that cliff sits at roughly $130,000. Below the cliff, the credit gradually shrinks as income rises through increasing “applicable percentage” rates that determine how much of the premium you’re expected to pay yourself. This is the most dangerous phase-out in the code because a single dollar of extra income can cost thousands in subsidies.
2026 Phase-Outs for Deductions and Contributions
Traditional IRA Deduction
You can always contribute to a traditional IRA, but the deduction depends on whether you or your spouse participates in a workplace retirement plan and how much you earn.6Internal Revenue Service. Retirement Topics – IRA Contribution Limits With no workplace plan on either side, the deduction is available at any income. With workplace coverage, it phases out over an income range that adjusts each year. The 2026 contribution ceiling is $7,500, or $8,600 at age 50 or older.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Even when the deduction is fully phased out, a nondeductible contribution still grows tax-deferred.
Roth IRA Contributions
The Roth phase-out restricts the contribution itself, not just a deduction. For 2026, single filers make full contributions below $153,000 MAGI, reduced contributions from $153,000 to $168,000, and none above $168,000. Joint filers contribute fully below $242,000, partially from $242,000 to $252,000, and not at all above $252,000.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Married filing separately faces a range of $0 to $10,000, which effectively rules Roth contributions out under that filing status.
Student Loan Interest Deduction
Borrowers can deduct up to $2,500 of interest paid on qualified education loans, without itemizing.8Office of the Law Revision Counsel. 26 USC 221 – Interest on Education Loans The deduction phases out as MAGI climbs and reaches zero at higher income levels.9Internal Revenue Service. Topic No. 456, Student Loan Interest Deduction Because the cap is $2,500 no matter how much interest you actually paid, the maximum benefit is modest, but recent graduates carrying real debt still feel the loss.
Qualified Business Income Deduction
Owners of pass-through businesses and self-employed workers can deduct up to 20% of qualified business income. The One Big Beautiful Bill Act widened the 2026 phase-out to $150,000 for joint filers and $75,000 for others. Joint filers with taxable income around $400,000 get the full deduction; the phase-out runs across the next $150,000, hitting zero near $550,000. For single filers, the range runs roughly from $200,000 to $275,000. The phase-out applies only to “specified service” businesses such as law, medicine, consulting, and financial services. Non-service businesses like manufacturing or retail generally keep the full deduction regardless of income.
New 2026 Rules From the One Big Beautiful Bill Act
SALT Deduction Phase-Out
The state and local tax deduction cap, frozen at $10,000 from 2018 through 2025, rose to approximately $40,000 for the 2026 tax year. The higher cap carries its own phase-out: filers with MAGI above roughly $500,000 see the allowable deduction shrink by about 30 cents per dollar of excess income until it falls back to $10,000. High earners in high-tax states may find the expected relief clawed back.
Senior Standard Deduction
A new $6,000 deduction for qualifying seniors runs for tax years 2025 through 2028. It begins phasing out at $75,000 MAGI single and $150,000 joint. Retirees combining pension income, Social Security, and investment returns can cross those thresholds more easily than expected, especially in a year with a large IRA or 401(k) distribution.
Top-Bracket Itemized Limitation
The old Pease limitation was repealed and replaced by a new limitation that reduces the tax benefit of itemized deductions for taxpayers in the top income bracket, with a steeper reduction for state and local tax deductions than for mortgage interest or charity. It reaches roughly the top 1% of earners; most filers will not encounter it.
Income-Triggered Surtaxes That Behave Like Phase-Outs
Net Investment Income Tax
A 3.8% surtax applies to the lesser of your net investment income or the amount by which MAGI exceeds $200,000 single, $250,000 joint, or $125,000 married filing separately.10Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax Investment income includes interest, dividends, capital gains, rental income, and royalties. These thresholds have not been adjusted for inflation since the tax took effect in 2013, so more taxpayers cross them each year through ordinary wage growth.11Internal Revenue Service. Topic No. 559, Net Investment Income Tax
Social Security Benefits Taxation
Social Security benefits become partially taxable once “provisional income” (AGI plus tax-exempt interest plus half your benefits) crosses $25,000 single or $32,000 joint, with up to 50% of benefits taxable above that line. At $34,000 single or $44,000 joint, up to 85% of benefits become taxable.12Internal Revenue Service. IRS Reminds Taxpayers Their Social Security Benefits May Be Taxable These figures have not been adjusted for inflation since they were set in 1983 and 1993 and have eroded sharply in real terms.13Social Security Administration. Income Taxes on Social Security Benefits A married couple with $20,000 in pension income and $30,000 in benefits will clear the 50% line easily.
Why Phase-Outs Raise Your Real Marginal Rate
A phase-out is a hidden tax on income earned inside the range. Losing $50 of Child Tax Credit for every $1,000 of income functions as an added 5% on that income, on top of your regular marginal rate. At a 24% bracket, that means an effective 29% on those dollars.
The pain compounds when phase-outs overlap. A household in the range where the AOTC, the student loan interest deduction, and the IRA deduction are all shrinking at once can face a true marginal rate well above the number in the bracket tables. That overlap is where most people get blindsided.
Keeping MAGI Below the Thresholds
You can’t move the thresholds, but you can often shape the size and timing of your income. Pre-tax retirement contributions do the most direct work. Maxing out a 401(k) at $24,500 for 2026, or $32,500 at age 50 or older, cuts AGI by that full amount.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Health Savings Account contributions add $4,400 for self-only coverage or $8,750 for family coverage in 2026, plus a $1,000 catch-up at 55 and older. Between the two vehicles, a married couple can trim MAGI by more than $65,000.
Tax-loss harvesting helps investors. Selling positions at a loss offsets capital gains, which lowers AGI and can keep you under a threshold. Timing matters too. If you have any control over when you invoice clients, exercise stock options, or take retirement distributions, shifting income between years can hold a single year’s MAGI below a critical line. Deferring a year-end bonus or accelerating a charitable donation both move the needle.
Retirees planning a Roth conversion should watch the interaction carefully. Converting traditional IRA funds generates taxable income in the conversion year, which can push you past the thresholds for Social Security benefit taxation, the net investment income tax, or the new senior deduction. Model the phase-out impact before pulling the trigger.