AMT Calculator
Calculate the Alternative Minimum Tax (AMT), a parallel tax system designed to ensure high-income taxpayers pay a minimum amount of tax regardless of deductions.
How AMT Works
The AMT is calculated alongside regular tax, and you pay whichever is higher. It disallows certain deductions and uses different exemptions and rates.
2024 AMT Parameters
| Parameter | Single | Married Filing Jointly |
|---|---|---|
| Exemption | $85,700 | $133,300 |
| Phase-out starts | $609,350 | $1,218,700 |
| Phase-out complete | $952,150 | $1,751,900 |
| 26% rate | First $220,700 | First $220,700 |
| 28% rate | Above $220,700 | Above $220,700 |
AMT Calculation
``javascript
function calculateAMT(taxableIncome, preferences, filingStatus = 'single') {
const exemption = filingStatus === 'married' ? 133300 : 85700;
const phaseoutStart = filingStatus === 'married' ? 1218700 : 609350;
const breakpoint = 220700;
// Calculate AMTI (AMT Income)
// Add back preferences (SALT, certain deductions, ISO exercise, etc.)
const amti = taxableIncome + (preferences.salt || 0) +
(preferences.isoSpread || 0) +
(preferences.miscDeductions || 0);
// Calculate exemption reduction (25% of excess)
const excessOverPhaseout = Math.max(0, amti - phaseoutStart);
const exemptionReduction = Math.min(exemption, excessOverPhaseout * 0.25);
const effectiveExemption = exemption - exemptionReduction;
// Calculate tentative AMT
const amtBase = Math.max(0, amti - effectiveExemption);
let tentativeAMT = 0;
if (amtBase <= breakpoint) {
tentativeAMT = amtBase * 0.26;
} else {
tentativeAMT = breakpoint * 0.26 + (amtBase - breakpoint) * 0.28;
}
return {
amti,
exemption: effectiveExemption,
amtBase,
tentativeAMT: tentativeAMT.toFixed(2)
};
}
``
Common AMT Triggers
| AMT Preference Item | Effect |
|---|---|
| State/local tax deduction (SALT) | Added back for AMT |
| Incentive Stock Options (ISO) | Spread taxed under AMT |
| Private activity bond interest | Added back |
| Accelerated depreciation | Difference added back |
| Large capital gains | Can push into AMT |
Who Gets Hit by AMT?
Since the 2017 tax law increased regular tax rates and capped SALT at $10k, fewer taxpayers trigger AMT. Those most at risk:
- ISO exercise with large spread
- High income with significant preferences
- Large capital gains in certain situations
Worked Through the Brackets
On $75,000 of gross income, filing single, taking the $14,600 standard deduction — so $60,400 of taxable income:
| Bracket | Range | Income taxed here | Tax |
|---|---|---|---|
| 10% | $0 – $11,600 | $11,600 | $1,160 |
| 12% | $11,600 – $47,150 | $35,550 | $4,266 |
| 22% | $47,150 – $100,525 | $13,250 | $2,915 |
| Total | $8,341 |
The Same Income, Different Sources
| Source | Federal tax on it |
|---|---|
| Wages (above) | $8,341 |
| Self-employment profit | $8,341 income tax plus $10,597 SE tax |
| Long-term capital gain of $10,000 | $1,500 at 15% |