2024 Alternative Minimum Tax exemption, and where it starts to disappear
Photo by Kelly Sikkema · Unsplash
The Alternative Minimum Tax runs a second, parallel tax calculation next to your regular return and charges you whichever number is higher. Here is exactly what the 2024 exemption was worth, and the income level where it starts to shrink.
For 2024, the Alternative Minimum Tax exemption is $85,700 for a single filer and $133,300 for a married couple filing jointly. Above a set income level that exemption starts shrinking, and above a higher level it disappears completely, exposing more of a taxpayer's income to a separate 26%/28% rate structure that runs parallel to the regular seven-bracket system. Most people never meet it. The ones who do are usually surprised by how it works, not by the fact that it exists.
The 2024 exemption and phase-out figures
The AMT is not an additional tax layered on top of the regular one — it is a second, simplified calculation that adds back certain deductions and preference items, and a taxpayer pays whichever of the two results is higher. The exemption is the amount of AMT income that calculation ignores before applying its own rates.
| Filing status | 2024 AMT exemption | Phase-out begins at |
|---|---|---|
| Single / head of household | $85,700 | $609,350 |
| Married filing jointly | $133,300 | $1,218,700 |
Both figures rose from 2023, in line with the IRS's annual inflation adjustment. The full 2024 numbers, alongside every other inflation-indexed threshold for the year, are published directly by the IRS in its tax year 2024 inflation adjustments announcement.
How the phase-out actually works
The exemption does not vanish all at once at the threshold. Once alternative minimum taxable income (AMTI) crosses $609,350 for a single filer, the exemption shrinks by 25 cents for every dollar of AMTI above that line. A single filer with AMTI of $709,350 — exactly $100,000 over the threshold — loses $25,000 of exemption, leaving $60,700 still shielded rather than the full $85,700. The married threshold works the same way, just starting at $1,218,700 instead.
Because the reduction is 25 cents per dollar, the entire exemption is used up once AMTI exceeds the threshold by four times the exemption amount. For 2024 that puts the exemption at zero once AMTI passes roughly $952,150 for a single filer and $1,751,900 for a married couple filing jointly — past those points, the AMT calculation applies its rates to the full AMTI with no exemption left to reduce it.
The AMT's own rate structure
Where the regular system has seven brackets running from 10% to 37%, the AMT has only two. For 2024, AMT income after the exemption is taxed at 26% up to $232,600 and 28% on anything above that — half that break point, $116,300, for a married person filing separately. That flatter, narrower structure is part of what makes the AMT bite for upper-middle earners with large add-back items: once the exemption phases out, a big share of income can land in the 28% band even though the regular system would have taxed much of the same income at 22% or 24%.
What actually gets added back to reach AMT income
AMTI does not start from taxable income on a 1040 — it starts from that figure and then adds back a specific list of items the regular system allows but the AMT does not recognize as a real reduction in ability to pay. The most common add-backs are the state and local tax deduction (fully disallowed for AMT purposes, no matter how much was paid), the spread between the exercise price and fair market value on incentive stock options exercised and held rather than sold in the same year, interest on certain private activity municipal bonds that is tax-exempt for regular purposes, and accelerated depreciation claimed on business property beyond what a slower, straight-line schedule would allow. None of these add-backs change what actually happened financially — they change which version of income the tax calculation is allowed to see.
This is also why the AMT hits unevenly: two taxpayers with identical regular taxable income can owe very different amounts of AMT, or none at all, depending entirely on how much of their income came through one of these specific channels rather than as ordinary wages.
A worked example: a single filer with $700,000 of AMT income
Say a single filer's AMTI for 2024 — after adding back items like the exercise of incentive stock options or a large amount of state and local tax deducted for regular purposes — comes to $700,000. That is $90,650 above the $609,350 phase-out threshold, so the exemption first has to be recalculated before the rate table applies.
| Step | Amount |
|---|---|
| AMT income (AMTI) | $700,000 |
| Amount over the $609,350 threshold | $90,650 |
| Exemption reduction (25% of the excess) | −$22,663 |
| Remaining exemption ($85,700 − $22,663) | $63,037 |
| Taxable AMT base (AMTI − remaining exemption) | $636,963 |
| 26% on the first $232,600 | $60,476 |
| 28% on the remaining $404,363 | $113,222 |
| Tentative minimum tax | $173,698 |
That $173,698 is not automatically an AMT bill — it is compared against what the same taxpayer would owe under the regular federal brackets on the same underlying income, using the income tax calculator to work out that regular-system figure. Only the amount by which the tentative minimum tax exceeds the regular tax is actually paid as AMT, added on top of the regular liability. If the regular tax already came to more than $173,698, this taxpayer would owe no AMT at all despite the calculation above.
Who actually ends up paying AMT
Since the Tax Cuts and Jobs Act took effect in 2018, the AMT exemption has been high enough, and the regular system's state-and-local-tax deduction capped low enough, that far fewer households owe AMT than did before 2018. Before that law, the AMT reached well into upper-middle-income territory, particularly for large families in high-tax states, because the exemption was lower and the regular system's own deductions it disallowed were worth more. The 2018 law roughly doubled the exemption and capped the state and local tax deduction at $10,000 for regular tax purposes, which shrank the single largest AMT add-back for most filers and pulled millions of households out of AMT exposure entirely.
The taxpayers who still meet it in 2024 tend to share a few features: exercising incentive stock options without immediately selling the shares, living in a high-tax state with substantial itemized deductions large enough to matter even after the cap, or realizing a large one-time item — a big capital gain, private activity bond interest, or accelerated depreciation from a business — that regular tax treats favorably but AMT adds back. Income level alone is a poor predictor; a household earning $400,000 in ordinary salary with no unusual deductions is unlikely to owe any AMT at all, while a household with a smaller salary but a large ISO exercise in the same year can owe a substantial amount.
Checking whether the AMT applies to you
The only reliable way to know is to run the numbers: Form 6251 walks through the add-backs, the exemption and its phase-out, and the two-rate calculation, then compares the result against the regular tax figure. Tax software runs this automatically for every return, which is why most filers never notice it happening. It becomes worth checking manually in the specific situations above — particularly the year incentive stock options are exercised, since that single event is one of the most common AMT triggers and one most taxpayers do not expect.
Sources
- IRS: IRS provides tax inflation adjustments for tax year 2024
- IRS: 2024 Instructions for Form 6251 (Alternative Minimum Tax — Individuals)
This is general information, not tax advice. It describes the federal AMT exemption and phase-out for tax year 2024 only; state tax treatment, your specific add-back items, and other parts of your return can change whether AMT applies to you. For a decision about your own return, consult a licensed tax preparer or the IRS directly.