Alternative Minimum Tax (AMT) Calculator
This professional AMT calculator helps U.S. taxpayers estimate whether they owe Alternative Minimum Tax for the selected tax year. It’s designed for employees with incentive stock options (ISO), investors, and high-deduction filers who want a clear, fast, and accessible way to approximate AMT using IRS rules.
Interactive AMT Calculator
This tool provides an estimate based on user inputs and IRS 2024 rules. It does not constitute tax advice.
Results
Data Source and Methodology
Authoritative Data Source: IRS Form 6251 (Alternative Minimum Tax—Individuals) and Instructions; IRS Revenue Procedure 2023-34 (Inflation Adjustments for 2024). Published 2023-11, U.S. Internal Revenue Service.
- IRS Instructions for Form 6251 (2024): https://www.irs.gov/forms-pubs/about-form-6251
- IRS Rev. Proc. 2023-34 (AMT exemption, phaseouts, 26%/28% thresholds for 2024): https://www.irs.gov/pub/irs-drop/rp-23-34.pdf
All calculations strictly follow the formulas and figures provided by these sources. (Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.)
The Formula Explained
AMTI:
AMTI = TaxableIncome + SALT_{deducted} + StdDeduction_{if\ taken} + ISO_{bargain} + OtherAdjustments
LaTeX: \( \mathrm{AMTI} = TI + SALT + SD + ISO + OA \)
Exemption and phaseout:
LaTeX: \( \mathrm{ExemptionUsed} = \max\big(0,\ \mathrm{Exemption} - 0.25\cdot \max(0,\ \mathrm{AMTI}-\mathrm{PhaseoutThreshold})\big) \)
AMT Taxable Income:
LaTeX: \( \mathrm{AMTTI} = \max(0,\ \mathrm{AMTI} - \mathrm{ExemptionUsed}) \)
Tentative Minimum Tax (26%/28% rates):
LaTeX: \( \mathrm{TMT} = 0.26\cdot \min(\mathrm{AMTTI}, B) + 0.28\cdot \max(0,\ \mathrm{AMTTI}-B) \)
where B is the 28% breakpoint (2024: $232{,}600; $116{,}300 if MFS).
AMT Owed:
LaTeX: \( \mathrm{AMT\ Owed} = \max\big(0,\ \mathrm{TMT} - \mathrm{AMT\ FTC} - \mathrm{RegularTax}\big) \)
Minimum Tax Credit creation (if TMT < RegularTax):
LaTeX: \( \mathrm{MTC} = \max\big(0,\ \mathrm{RegularTax} - \mathrm{TMT}\big) \)
Glossary of Variables
| Field | Definition |
|---|---|
| Taxable Income (TI) | Your regular taxable income from Form 1040. |
| SALT deducted | State and local taxes you deducted on Schedule A; disallowed for AMT and added back. |
| Standard Deduction (SD) | Disallowed for AMT. If taken, add back the amount. |
| ISO bargain element | AMT preference from exercising ISOs and holding the shares. |
| Other adjustments (OA) | Other AMT-specific addbacks or preferences from Form 6251. |
| AMTI | Alternative Minimum Taxable Income before exemption. |
| Exemption | AMT exemption allowed, reduced by the 25% phaseout above thresholds. |
| AMT Taxable Income (AMTTI) | AMTI minus allowed exemption (not below zero). |
| Tentative Minimum Tax (TMT) | AMT computed using 26%/28% rates on AMTTI. |
| Regular Tax | Your regular tax liability used to compare with TMT. |
| AMT Owed | Amount due if TMT exceeds regular tax (after AMT FTC). |
| Minimum Tax Credit (MTC) | Potential credit created if regular tax exceeds TMT. |
Worked Example
How It Works: A Step-by-Step Example
Assume Tax Year 2024, Filing Status: Single. Taxable income: $160,000; ISO bargain element: $50,000; SALT deducted: $10,000; Standard deduction taken: $14,600; Other adjustments: $0; Regular tax: $28,000; AMT foreign tax credit: $0.
- AMTI = 160,000 + 10,000 + 14,600 + 50,000 + 0 = $234,600.
- Exemption (Single 2024 = $85,700; phaseout starts at $609,350). Since AMTI is below the threshold, no reduction. Exemption used = $85,700.
- AMT Taxable Income = 234,600 − 85,700 = $148,900.
- TMT at 26%/28% (breakpoint $232,600): AMTTI is below breakpoint → TMT = 0.26 × 148,900 = $38,714.
- AMT owed = max(0, 38,714 − 0 − 28,000) = $10,714.
- MTC created = max(0, 28,000 − 38,714) = $0.
Frequently Asked Questions (FAQ)
What is AMTI and how is it different from taxable income?
AMTI starts with your taxable income and adds back items disallowed under AMT (like the standard deduction and SALT) and adds AMT preference items (e.g., ISO bargain element).
Which amounts does this calculator use for 2024?
Exemptions: $85,700 (Single/HOH), $133,300 (MFJ), $66,650 (MFS). Phaseout thresholds: $609,350 (Single/HOH), $1,218,700 (MFJ), $609,350 (MFS). 28% breakpoint: $232,600 ($116,300 MFS).
Does exercising ISOs always cause AMT?
No. It increases AMTI by the bargain element, which may or may not push TMT above your regular tax depending on your overall situation.
How accurate is this estimate?
It follows IRS rules for 2024 but omits some specialized adjustments. Use it for planning; confirm with tax software or a professional.
Where do I find my regular tax?
Typically Form 1040 line 16 (labels vary by year), after applicable nonrefundable credits but before AMT additions.
What if I itemized instead of taking the standard deduction?
Enter 0 for the standard deduction field. If you claimed SALT on Schedule A, include that amount so it can be added back for AMT.
Can I use prior-year MTC in this calculator?
This tool focuses on current-year AMT owed and potential MTC creation. Applying prior-year credits is beyond scope; consult a tax advisor.