Salt Deduction Calculator

The SALT Deduction Calculator estimates how much of your state and local taxes you can actually deduct under the current SALT cap rules, including the income-based phase-out that quietly shrinks the cap for high earners. Enter your state and local income (or sales) tax, property tax, filing status, tax year, and modified adjusted gross income.

How It Works

Under the rules the calculator models for 2025 and 2026, the statutory cap is $40,000 in 2025 and$40,400 in 2026 (half for married filing separately). Once MAGI passes the phase-out threshold, $500,000 in 2025 or$505,000 in 2026 (half for MFS), the cap is reduced by 30 cents for every dollar of MAGI above the threshold, but never below a floor of $10,000 ($5,000 MFS). Your deductible SALT is your total SALT paid, limited to that effective cap. The calculator also totals your itemized deductions and compares them with the standard deduction for your status and year, because a capped SALT figure only matters if itemizing wins.

$\text{Deductible SALT}=\min(\text{Total SALT paid},\ \text{Effective cap})$

Parameters

| Input | Required | Meaning | |---|---|---| | State/local income or sales tax | Yes* | Income tax paid, or sales tax if you elect it instead | | Property tax | Yes* | Real estate and other property taxes paid (*at least one tax type required) | | Filing status | Yes | Single, married filing jointly, separately, or head of household | | Tax year | Yes | 2025 or 2026 rule set | | MAGI | Yes | Modified adjusted gross income; drives the phase-out | | Marginal tax rate | No | Used to estimate the federal saving from the deduction | | Other itemized deductions | No | Mortgage interest, charitable gifts, and similar, for the itemize comparison |

Worked example 1: under the cap

A married couple filing jointly for 2025 pays $18,000 of state income tax and$14,000 of property tax, $32,000 of SALT in total, with MAGI of$400,000. MAGI is below the $500,000 threshold, so no phase-out applies and the cap stays$40,000. Deductible SALT is the full $32,000.

Worked example 2: inside the phase-out

Same couple, but MAGI is $600,000. The excess over the threshold is$100,000, and 30% of that is $30,000, so the cap falls from$40,000 to $10,000, where the floor stops it. Only$10,000 of their $32,000 SALT is deductible, and$22,000 of deduction is lost. This cliff-like band is why a dollar of income between $500,000 and about$600,000 of MAGI can cost far more than its nominal tax rate.

Itemizing versus the standard deduction

For 2025 the standard deductions in the calculator are $15,750 single,$31,500 joint, and $23,625 head of household, rising to$16,100, $32,200, and$24,150 in 2026. If SALT (as capped) plus your other itemized deductions does not exceed the standard deduction for your status, the SALT computation is academic and you should take the standard deduction. The calculator makes that call for you and shows which side wins.

Planning notes

Because the phase-out is driven by MAGI, timing income and deductions matters: bunching charitable gifts into a lower-MAGI year, deferring a Roth conversion that would push MAGI through the band, or paying property tax in the year where the deduction is usable can all change the answer. Pass-through entity tax elections, where a state lets the business pay the SALT at entity level outside the individual cap, are a major planning route this calculator does not model.

Limitations

The calculator models the federal cap mechanics for the selected year using the amounts you enter. It does not verify which taxes qualify, apply state-level rules, model pass-through entity elections, or compute your full return. SALT rules have changed repeatedly and may change again; confirm against current IRS guidance before filing.

What changed for 2026

The calculator's 2026 rule set raises the statutory cap slightly to $40,400 ($20,200 for married filing separately) and the phase-out threshold to $505,000 ($252,500 MFS), with the $10,000 floor unchanged. Standard deductions also rise modestly in its tables, to$16,100 single, $32,200 joint, and$24,150 head of household, which slightly raises the bar itemizing must clear. Because both the cap and the thresholds are indexed in this model, run both years before deciding which year to accelerate or defer a large deductible payment into.

Common errors

The most frequent mistake is entering SALT paid during the year rather than SALT owed for it: property tax counts when paid, so a January payment of a bill assessed the prior December belongs to the payment year. A second error is mixing the sales-tax election with income tax; you deduct one or the other, never both. A third is forgetting that the phase-out runs on MAGI, which includes items such as Roth conversion income that do not appear in a simple salary figure, so a conversion planned for December can retroactively shrink the SALT deduction for the whole year.

Frequently Asked Questions

What counts toward SALT?

State and local income taxes (or general sales taxes if you elect them instead, not both), real property taxes, and personal property taxes, subject to the rules for your filing year.

Why did my cap come out as $10,000?

That is the statutory floor. When MAGI is far enough above the phase-out threshold, the 30% reduction brings the cap down to $10,000 ($5,000 for married filing separately) and it goes no lower.

Does a bigger SALT deduction always save tax?

Only if you itemize and only at your marginal rate. If the standard deduction is larger, extra SALT saves nothing, which is why the calculator compares both totals.