AMT Calculator: Who Pays the Alternative Minimum Tax and How to Avoid It

The Alternative Minimum Tax was created in 1969 to ensure wealthy taxpayers pay at least some federal tax after using deductions and preferences. Today it primarily affects upper-middle-income earners with Incentive Stock Options or large itemized deductions.

The calculation is a parallel tax system. You compute tax twice and pay the higher amount.

AMT Exemptions and Phase-Out (2026)

| Filing Status | Exemption | Phase-Out Begins | Phase-Out Ends | |--------------|-----------|-----------------|----------------| | Single | $89,075 | $637,500 | $993,800 | | Married filing jointly | $138,700 | $1,275,000 | $1,829,800 | | Married filing separately | $69,350 | $637,500 | $916,900 |

The exemption is phased out by $0.25 for every $1 over the phase-out threshold.

AMT Rates

| AMT Income | Rate | |-----------|------| | Up to $232,600 (single) / $232,600 (MFJ) | 26% | | Above $232,600 | 28% |

How AMT Is Calculated

Step 1: Start with taxable income from regular calculation. Step 2: Add back AMT "preference items" and adjustments. Step 3: Subtract the AMT exemption. Step 4: Apply AMT rates. Step 5: Compare to regular tax. Pay the higher.

AMT adjustments include:

• ISO spread at exercise (ISO stock granted vs. exercise price difference)
• Accelerated depreciation (difference between AMT and regular depreciation)
• Standard deduction (not allowed under AMT)
• State and local tax (SALT) deduction (not allowed under AMT)
• Miscellaneous itemized deductions (not allowed under AMT)

Who Actually Pays AMT in 2026

The Tax Cuts and Jobs Act (2017) significantly reduced AMT exposure by raising exemptions and eliminating several preference items. Today, AMT primarily affects:

| Situation | AMT Exposure Level | |-----------|-------------------| | Exercised ISOs (Incentive Stock Options) | High | | Very large SALT deductions | Moderate (SALT already capped at $10,000 for regular tax) | | Business with accelerated depreciation | Moderate | | $500k-$1M income without ISOs | Low (regular tax usually higher) | | Standard W-2 employee | Almost zero |

ISO Exercise and AMT

This is the most common AMT trigger for tech and startup employees. When you exercise ISOs (not sell them, just exercise), the spread (FMV − exercise price) is NOT income for regular tax purposes but IS income for AMT.

Example:

• 10,000 ISO shares, exercise price $5, FMV $50
• Regular tax: $0 additional income at exercise
• AMT: $450,000 added to AMT income ($50-$5 × 10,000)

If this creates a large AMT bill, you have options:

1. Exercise fewer shares in a given year
2. Exercise early in the year so you can sell some shares if the stock declines
3. Model the AMT before exercising

The AMT credit: AMT paid on ISOs generates an AMT credit that can offset regular tax in future years when the regular tax exceeds AMT. It is recoverable, but timing matters.

Checking Your AMT Exposure

Quick screen: If you are a W-2 employee with no ISOs and your income is below $400,000, you almost certainly owe no AMT. Run the full calculation if:

• You exercised ISOs this year
• You have significant business depreciation
• Your total itemized deductions are unusually large

Tax software (TurboTax, H&R Block) automatically calculates AMT on your return.

Frequently Asked Questions

Does selling ISOs trigger AMT?

Exercising creates the AMT preference item. Selling does not create a new preference. If you sell the shares in the same year you exercised, it may convert the ISO to a disqualifying disposition. Taxed as ordinary income for regular tax purposes. Which can eliminate or reduce the AMT impact. The exercise-and-immediate-sale strategy avoids AMT at the cost of the preferential ISO tax treatment.

How do I find out if I owe AMT before filing?

IRS Form 6251 calculates AMT. Run through it manually or use tax software that shows the AMT worksheet. The key variable is always the AMT income before exemption. If it is below the exemption amount ($89,075 single, $138,700 MFJ), you owe nothing.

What is the AMT credit and how does it work?

When you pay AMT, you accumulate an AMT credit (Form 8801). In future years when your regular tax exceeds your tentative minimum tax (the amount before comparing to regular tax), you can use the credit to offset your regular tax. ISO-related AMT generates a recoverable credit. The credit is use-it-or-lose-it only in the sense that it can only be used in years your regular tax exceeds your tentative minimum tax. It carries forward indefinitely.

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