Alternative Minimum Tax (AMT) Calculator 2026 — Check If You Owe Extra Before Filing

What Is the Alternative Minimum Tax?

The Alternative Minimum Tax (AMT) is a parallel tax system the IRS runs alongside the regular income tax. It was originally designed to stop high earners from using so many deductions that they paid little or nothing in federal tax. The idea is simple: calculate your tax twice — once under regular rules, once under AMT rules — and pay whichever is higher.

For most middle-income filers, the AMT never triggers. But if you have significant itemized deductions, exercised incentive stock options (ISOs), or live in a high-tax state, it can hit in ways that are genuinely surprising — sometimes adding thousands of dollars to your bill.

Check your 2026 AMT exposure now: AMT Calculator 2026

2026 AMT Exemption Amounts (OBBB-Updated)

The One Big Beautiful Bill (OBBB) updated the AMT exemption thresholds for 2026. The exemption is the amount subtracted from your Alternative Minimum Taxable Income (AMTI) before the AMT rate applies:

• Single / Head of Household: $88,100 exemption, phaseout begins at $626,350
• Married Filing Jointly (MFJ): $137,000 exemption, phaseout begins at $1,252,700
• Married Filing Separately (MFS): $68,500 exemption

Above those phaseout thresholds, the exemption reduces by $0.25 for every $1 of AMTI, eventually eliminating the exemption entirely for very high earners.

The AMT rates themselves are straightforward: 26% on the first $116,300 of AMTI (after exemption), and 28% on anything above that.

Who Is Most at Risk in 2026?

Not everyone needs to run this calculation — but if any of the following apply, you should:

1. ISO stock option exercises. When you exercise incentive stock options without selling the shares, the bargain element (fair market value minus exercise price) is counted as AMTI. A large ISO exercise can push even a modestly paid employee into AMT territory.

2. High state and local taxes (SALT). Regular tax lets you deduct up to $10,000 in SALT. AMT adds that entire amount back. If you itemize and claim the SALT cap, you have a $10,000 AMT preference item baked in automatically.

3. High overall deductions. Miscellaneous itemized deductions, home equity interest on loans not used for home improvements, and private activity bond interest are all disallowed under AMT. The more deductions you take, the more your AMTI diverges from regular taxable income.

4. High-income households with many dependents. More deductions generally mean a wider gap between regular taxable income and AMTI.

5. Real estate investors using accelerated depreciation. The difference between MACRS/ACRS depreciation and straight-line depreciation is a preference item that adds directly to AMTI.

How the Calculator Works

The 2026 AMT Calculator follows IRS Form 6251 step by step:

1. Start with your regular taxable income (Form 1040, line 15) 2. Add back AMT preference items (SALT, ISO bargain element, PAB interest, depreciation differences, etc.) 3. Subtract your applicable 2026 exemption (with phaseout if AMTI is high enough) 4. Apply the 26%/28% AMT rate brackets to get tentative minimum tax 5. Compare to your regular tax — AMT owed = max(0, tentative minimum tax − regular tax)

The tool breaks down every step so you can see exactly what is driving your exposure — not just a final number.

Free, Private, No Sign-Up

Everything runs in your browser. No data is sent to any server, no account required, no email needed. Your financial figures stay on your device.

If you are filing a complex 2026 return — especially one involving ISO exercises, significant SALT deductions, or business depreciation — run this check before you file. A five-minute calculation now can prevent an expensive surprise later.

Open the AMT Calculator 2026 →

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Originally published at https://tool.teamzlab.com?utm_source=blogger&utm_medium=article&utm_campaign=2026-06-nightly-37-amt-tax-calculator-2026