SALT Deduction Cap Calculator United States

This SALT deduction cap calculator shows how much state and local tax you can deduct after the cap and the high-income phasedown, based on your MAGI.

State & local taxes paid US$

Filing status

Modified adjusted gross income (MAGI) US$

Deductible SALT —

Base SALT cap —

Effective cap (after phasedown) —

Cap reduced by phasedown —

SALT lost to cap —

We always strive to use the latest data for every variable so our results and reports are as accurate as possible. Even so, errors are possible — you should not rely on this tool or its report alone, and we accept no liability for any decision made based on it.

What it does

The SALT Deduction Cap Calculator shows how much of your state and local taxes you can deduct on a federal return, applying the statutory cap and the high-income phasedown that reduces it.

Data sources & parameters

The figures below drive this calculator. We keep them aligned with the latest official guidance, and each result recalculates automatically whenever a value changes.

Parameter	Value	Source	Last updated
SALT deduction cap	40,400	law.cornell.edu	Effective 2026-01-01Fix 2026-10-24: the row went live with country_code AU, so Resolver never saw it and the key fell back to the tool.json default. Value unchanged.
SALT cap phasedown floor	10,000	law.cornell.edu	Effective 2026-01-01Fix 2026-10-24: the row went live with country_code AU, so Resolver never saw it and the key fell back to the tool.json default. Value unchanged.
SALT cap phasedown rate	0.3	law.cornell.edu	Effective 2026-01-01Fix 2026-10-24: the row went live with country_code AU, so Resolver never saw it and the key fell back to the tool.json default. Value unchanged.
SALT cap phasedown MAGI threshold	505,000	law.cornell.edu	Effective 2026-01-01Fix 2026-10-24: the row went live with country_code AU, so Resolver never saw it and the key fell back to the tool.json default. Value unchanged.
SALT cap share for a married separate return	0.5	law.cornell.edu, irs.gov	Effective 2026-01-01Fix 2026-10-24: the row went live with country_code AU, so Resolver never saw it and the key fell back to the tool.json default. Value unchanged.

The formula

Effective cap = max(floor, cap - rate x max(0, MAGI - threshold)); deductible = min(SALT paid, effective cap)

How it works

It reduces the base cap by the phasedown rate applied to income above the MAGI threshold, floors the result, then limits your deductible SALT to that effective cap.

Where it is used

Checking how much SALT is deductible after the cap
Seeing the high-income phasedown reduce your cap
Estimating SALT lost to the cap

Worked example

A single filer with $25,000.00 of SALT and $150,000.00 MAGI has an effective cap of …, so … is deductible with … lost.

What the SALT deduction cap calculator does

SALT stands for state and local taxes: the state income tax (or sales tax) you pay plus your property tax. It is among the largest deductions for homeowners and residents of high-tax states, but federal law caps it. This calculator applies the cap, and the high-income phasedown that can shrink it further, to show how much of what you paid you can actually deduct on a federal return.

A household can pay tens of thousands of dollars to state and local governments and still deduct only part of it. Knowing that figure in advance helps you decide whether to itemize and estimate your federal bill.

How the calculation works

It selects the base cap for your filing status.
It computes the phasedown: the phasedown rate multiplied by the amount your MAGI exceeds the threshold.
It subtracts that reduction from the base cap, but never lets the cap fall below the floor.
The result is your effective cap.
Your deductible SALT is the smaller of the taxes you paid and the effective cap.

Anything you paid above the effective cap gives no federal deduction. The tool reports the base cap, the effective cap, the reduction from the phasedown, the deductible SALT and the amount lost.

The high-income phasedown

Below the MAGI threshold the full cap is available. Above it, the cap is reduced by a set rate on each dollar of income over the threshold, until it reaches a floor it cannot fall below. So there is a middle band of income where the cap shrinks steadily, then a high band where it stays at the floor.

Because the phasedown is based on modified adjusted gross income, anything that changes MAGI, such as retirement contributions or the timing of income, can change your deductible SALT. Raise the MAGI input and you can watch the effective cap fall until it reaches the floor.

Why filing status matters

Most filing statuses share the same base cap, but married taxpayers filing separately use a lower one, as separate filers split many limits between them. Select married filing separately and the calculator uses the lower cap. Couples deciding between filing jointly and separately can run both to see how much SALT deduction is at stake.

Reading your result

The output leads with your deductible SALT, the figure that goes into your itemized deductions, followed by the base cap, the effective cap, the phasedown reduction and the SALT lost to the cap. The bar chart contrasts the deductible SALT with the disallowed portion. For many residents of high-tax states the disallowed portion is large.

Enter the total state and local taxes you paid, your filing status and your MAGI. Include every levy that counts toward the cap: state income tax or general sales tax, plus real estate tax and any personal property tax. Leaving one out understates your SALT total and can make the cap look less restrictive than it is. If you are estimating before year end, use your best projection and rerun the calculation when the final figures are known.

The cap, phasedown rate, threshold and floor are set by statute and can change, so rerun the calculation each tax year. SALT only helps if you itemize, so compare your itemized total with the standard deduction as well.

This is general information only and not financial advice.

About This SALT Deduction Cap Calculator

Use this SALT deduction cap calculator to get an instant, accurate estimate. The figures follow official IRS guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.

Tax year 2026

Frequently asked questions

What is the SALT deduction cap?

The SALT cap is the maximum amount of state and local taxes you can deduct on a federal itemized return. State income or sales tax plus property tax count toward it, and anything above the cap is not deductible.

Why is my deductible SALT lower than what I paid?

If your total state and local taxes exceed the cap, only the capped amount is deductible. The tool shows both the deductible portion and the amount lost to the cap.

What is the high-income phasedown?

For taxpayers with modified adjusted gross income above a threshold, the cap is reduced by a set rate on the income over that threshold, but never below a floor. This calculator applies that phasedown automatically.

Does the cap differ for married filing separately?

Yes. Married taxpayers filing separately use a lower SALT cap, which the calculator applies when you select that status.

Do I need to itemize to use the SALT deduction?

Yes. SALT is an itemized deduction, so it only helps if your total itemized deductions exceed your standard deduction. Compare the two before relying on the SALT figure.

Is my data private?

Yes. The calculation runs entirely in your browser, so nothing you enter is uploaded, stored, or shared.

About the author

Written and reviewed by

Taha Kheirandish

Economics student and independent researcher

Taha Kheirandish reads tax codes the way other people read maps — to find out where a system actually leads, not where it claims to go.

He is an economics student, and his work here is comparative by design. A pension deferral bonus in Quebec, a commuting allowance in Germany, a rent-increase ceiling in the Netherlands: each is a decision a government made about how money should move, and each reads differently once you set it beside eight others. He builds and checks these calculators across nine markets from primary sources — the regulation rather than a summary of it, the ministry’s own circular rather than a news item quoting it.

That is the editorial standard of the site as well as his habit. Every rate, threshold and bracket here carries the document it was read from and the date it takes effect, and gets re-checked when the law moves rather than when someone happens to notice.

He is a researcher, not a licensed adviser, and nothing on this site is personal financial advice. It is arithmetic done carefully with its sources shown — so that you can check it, and take it to someone who is.

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