California AMT Calculator 2026 β Alternative Minimum Tax + ISO Analysis
Calculate California Alternative Minimum Tax (7% rate) with 2026 exemption amounts ($107,395 single / $143,189 MFJ). Model ISO exercise scenarios and CA vs federal AMT comparison.
$
CA taxable income before AMT adjustments $
FMV at exercise minus exercise price $
Accelerated depreciation over straight-line $
CA state tax refund included in regular income ISO spread scenarios:
$0
CA AMT Owed
$0
Tentative CA AMT
$0
Regular CA Tax
$0
CA AMTI
CA AMT Calculation Steps
How to Use This California AMT Calculator
Enter your regular California taxable income and any AMT preference items (ISO spread, depreciation, state refund add-back). The calculator computes CA AMTI, applies the exemption with phase-out, and shows whether you owe CA AMT and how much.
You owe CA AMT if tentative minimum tax (AMTI Γ 7%) exceeds your regular CA income tax. The AMT amount is the excess of tentative minimum tax over regular CA tax.
The Formula
CA AMTI = Regular CA Taxable Income + AMT Preferences (ISO spread, depreciation, etc.)
Exemption = $107,395 (single) / $143,189 (MFJ) [phases out at 25% above $402,732 / $537,158]
AMT Base = max(0, CA AMTI β Exemption)
Tentative CA AMT = AMT Base Γ 7%
CA AMT Owed = max(0, Tentative CA AMT β Regular CA Tax)
Exemption = $107,395 (single) / $143,189 (MFJ) [phases out at 25% above $402,732 / $537,158]
AMT Base = max(0, CA AMTI β Exemption)
Tentative CA AMT = AMT Base Γ 7%
CA AMT Owed = max(0, Tentative CA AMT β Regular CA Tax)
Example
Sarah, Single, CA taxable income $200,000, ISO spread $150,000:
CA AMTI = $200,000 + $150,000 = $350,000
Exemption: $107,395 β phase-out: ($350,000 β $402,732) Γ 25% = $0 (below phase-out)
AMT Base = $350,000 β $107,395 = $242,605
Tentative CA AMT = $242,605 Γ 7% = $16,982
Regular CA tax (est.) = $17,500
CA AMT Owed = max(0, $16,982 β $17,500) = $0 (regular tax higher)
With $300,000 ISO spread: AMTI = $500,000; AMT = $27,370 vs est. regular $22K β CA AMT due
CA AMTI = $200,000 + $150,000 = $350,000
Exemption: $107,395 β phase-out: ($350,000 β $402,732) Γ 25% = $0 (below phase-out)
AMT Base = $350,000 β $107,395 = $242,605
Tentative CA AMT = $242,605 Γ 7% = $16,982
Regular CA tax (est.) = $17,500
CA AMT Owed = max(0, $16,982 β $17,500) = $0 (regular tax higher)
With $300,000 ISO spread: AMTI = $500,000; AMT = $27,370 vs est. regular $22K β CA AMT due
Extended
ISO Exercise Scenarios + CA vs Federal AMT
Model different ISO exercise amounts and compare CA with federal AMT exposure
How CA AMT exposure grows with increasing ISO bargain element at your income level.
| ISO Spread | CA AMTI | Tentative CA AMT | CA AMT Owed |
|---|
California AMT and Federal AMT are separate taxes β you can owe one or both simultaneously.
| Component | Federal AMT | California AMT |
|---|
Frequently Asked Questions
What is the California Alternative Minimum Tax (CA AMT) rate for 2026?
California charges a 7% AMT rate on California Alternative Minimum Taxable Income (AMTI). This is separate from and in addition to the federal AMT. California has its own exemption amounts: $107,395 for single filers and $143,189 for married filing jointly (2026). The exemption phases out starting at $321,975 (single) and $429,276 (MFJ). You owe CA AMT if it exceeds your regular CA income tax.
What triggers California AMT?
California AMT is most commonly triggered by: (1) exercising Incentive Stock Options (ISOs) β the spread between FMV and exercise price is an AMT preference item; (2) accelerated depreciation on California property; (3) certain tax-exempt income from private activity bonds; (4) depletion deductions. High earners exercising ISOs are the most common CA AMT payers. CA AMT can arise even when federal AMT does not, because California has separate rules.
How is California AMT different from federal AMT?
Federal AMT has two rates: 26% (on first $220,700 of AMTI) and 28% above that, with a 2026 exemption of $88,100 (single) / $137,000 (MFJ). California AMT is a flat 7% rate with different, lower exemptions ($107,395 single / $143,189 MFJ). You calculate both separately and pay the higher of regular tax or AMT for each jurisdiction. ISO exercises are a preference item for both federal and CA AMT.
Can I claim a credit for CA AMT paid in prior years?
Yes. California allows a minimum tax credit (CA Form 3510) for CA AMT paid in prior years. The credit can offset regular CA income tax in future years (but not below the CA AMT amount in those future years). If you paid CA AMT in year 1 due to ISO exercise, and the ISOs are later sold, you can claim back the AMT credit over subsequent years as your regular tax exceeds your AMT liability. This reduces the long-term cost of ISO-triggered AMT.
Does California AMT apply to all taxpayers or only high earners?
The CA AMT exemption ($107,395 single) phases out for higher incomes and is eliminated when AMTI exceeds approximately $535,000 (single). Below exemption thresholds, most taxpayers are not subject to CA AMT. The primary risk group is employees exercising ISOs whose spread creates a large AMTI preference item that exceeds the exemption. Regular W-2 employees without stock options rarely owe CA AMT.