AMT vs Regular Tax: Which One You Actually Pay

The alternative minimum tax (AMT) and regular income tax are calculated entirely separately. You then pay whichever amount is larger. For most filers, regular tax is higher—but high-income earners with substantial deductions, preferences, or credits often bump into the AMT as a floor on their tax liability.

The Two-System Mechanics

Filing a federal return means running two separate tax calculations in parallel. The first is straightforward: your income, minus standard or itemized deductions, produces taxable income. Apply the regular tax brackets, account for credits, and you have your regular income tax.

The second calculation starts from taxable income but adjusts it upward by adding back certain deductions and accounting for what the Internal Revenue Service calls “tax preferences”—items that Congress wanted to prevent high-income filers from escaping tax entirely. The result is Alternative Minimum Taxable Income (AMTI).

You then claim an AMT exemption against that AMTI. The remaining amount is taxed at 26% up to the AMT bracket threshold, then 28% above it. That produces your tentative minimum tax.

The IRS’s rule is simple: file whichever produces the larger bill. For roughly 95% of filers, regular tax is higher and the AMT never triggers. But for filers with high incomes, large deductions, stock options, or certain business income, the AMT often becomes the binding constraint.

What Gets Added Back to AMTI

The AMT adjustments fall into two categories: add-backs that reverse specific deductions, and preferences that reflect income Congress didn’t want sheltered.

Common add-backs include:

• State and local taxes (SALT): Itemized SALT deductions above $10,000 are added back to AMTI. This was a major driver of AMT liability after the 2017 cap on SALT deductions.
• Miscellaneous itemized deductions: Investment advisory fees and other miscellaneous deductions (which weren’t available after 2017, but matter for prior returns) are added back.
• Depreciation: Accelerated depreciation on property placed in service after 1986 is adjusted; you recalculate it using a slower straight-line method.
• Depletion: Percentage depletion on mineral extraction may exceed cost depletion; the excess is added back.

Common preferences include:

• Tax-exempt interest on private activity bonds is treated as income for AMT purposes.
• Incentive stock option (ISO) gain: The spread between the exercise price and fair market value at exercise (not the eventual sale gain) can be an AMT preference.
• Passive activity losses and some long-term capital gains (in certain scenarios).

The result is that a filer with $500,000 of regular taxable income, $200,000 in SALT deductions above the cap, and significant depreciation may end up with AMTI of $600,000—well above the regular income amount.

The AMT Exemption and Phase-Out

The AMT doesn’t apply to everyone. Congress provides an exemption—a block of AMTI that escapes tax entirely. For 2024, the exemptions are:

• Married filing jointly: $141,700
• Single: $70,850
• Married filing separately: $70,850

The catch: the exemption phases out at high income levels. For every dollar of AMTI above the phase-out threshold, 25 cents of the exemption is lost. The phase-out threshold (also 2024) is $578,150 for married filing jointly and $289,075 for single filers.

Here’s a worked example:

Scenario: Married couple, AMTI of $700,000

• Exemption before phase-out: $141,700
• AMTI above phase-out threshold: $700,000 − $578,150 = $121,850
• Exemption reduction: $121,850 × 0.25 = $30,462.50
• Allowed exemption: $141,700 − $30,462.50 = $111,237.50
• AMT income subject to tax: $700,000 − $111,237.50 = $588,762.50
• Tentative minimum tax (26% + 28% split): ~$163,662

At high enough AMTI, the exemption is fully phased out and the entire AMTI is taxed.

When Regular Tax Exceeds Tentative Minimum Tax

For most filers, regular tax wins the comparison. A single filer earning $200,000 in W-2 wages, claiming $12,000 in standard deduction, and with minimal preferences will have regular tax of roughly $39,000. Their AMTI might be identical or only slightly higher. The tentative minimum tax will be lower, so regular tax applies.

The ratio shifts sharply for high-income earners with specific triggering items. Someone with $1 million in combined W-2 and business income, $300,000 in SALT deductions (now added back to AMTI), and $150,000 in depreciation can easily face AMTI of $1.45 million, producing a tentative minimum tax that exceeds their regular tax.

The Crossover Point

The practical crossover depends heavily on individual circumstances. For a married couple with joint return, AMT risk typically rises noticeably at adjusted gross income above roughly $400,000, especially if they:

• Have large state and local tax deductions
• Own real estate or equipment with substantial depreciation
• Exercise incentive stock options
• Earn passive income or have passive losses
• Have partnerships or S-corporation stakes with adjustable deductions

Below $400,000 AGI, most filers with standard income sources never compute AMT.

Credits Against AMT Liability

If you owe AMT, certain credits still apply—but with a key constraint. Credit for child and dependent care, foreign tax credit, and the earned income credit can reduce both regular tax and tentative minimum tax.

However, the AMT foreign tax credit and other nonrefundable credits against AMT are limited. And some credits—notably the child tax credit and education credits—cannot reduce tentative minimum tax below a floor (26% of AMT income). This means AMT filers sometimes cannot claim all their credits.

A parallel system called AMT credit allows you to carry forward disallowed credits and claim them in future years when regular tax exceeds tentative minimum tax. Over time, this often provides relief, but it creates timing mismatches and requires careful record-keeping.

Planning Around AMT

Taxpayers who regularly face AMT have limited levers. Deferring income or accelerating deductions in alternate years can shift AMTI between years, but because the exemption phases out slowly, the benefit is modest. Some strategies include:

• Timing of large one-time deductions: If you’re claiming a major deduction in year one, year two may offer AMT relief.
• Charitable giving via donor-advised fund: Bunching contributions may help manage itemization across years.
• Partnership and S-corp elections: Material participation and grouping elections can shift characterization of passive vs. active income, affecting both AMTI and net investment income tax.
• Review of depreciable assets: Electing out of bonus depreciation or Section 179 expensing can lower AMTI.

In all cases, the baseline truth remains: you pay the higher of regular tax or tentative minimum tax, whichever results in a larger bill to the IRS.

See also