The timeline is an indexed table, not one permanent cap
Before the temporary change, the familiar SALT limit was $10,000. Pub. L. 119-21 §70120 amended the rule for the 2025–2029 period and then returns the limit to $10,000 beginning in 2030. The values are year-specific, so a calculator that hardcodes $40,000 for every year will overstate the 2026–2029 statutory cap.
The 2027–2029 values below preserve the 1% annual indexing used by the shared SALT engine. The displayed cents are useful for explaining the formula; a return preparer may apply the reporting and rounding conventions required on the actual form.
| Tax year | Statutory cap | Phase-down threshold | What happens next |
|---|---|---|---|
| 2025 | $40,000 | $500,000 | First temporary year |
| 2026 | $40,400 | $505,000 | Both values indexed |
| 2027 | $40,804 | $510,050 | 101% of prior year |
| 2028 | $41,212.04 | $515,150.50 | 101% of prior year |
| 2029 | ≈$41,624 | $520,302.01 | Final temporary year |
| 2030+ | $10,000 | Temporary phase-down ends | Reversion to old cap |
How the phase-down changes the effective cap
The statutory cap is only the starting point for higher-income filers. For a year before 2030, the effective cap equals the indexed cap reduced by 30% of MAGI above that year's threshold, with a $10,000 floor. A single filer with $320,000 of MAGI in 2025 is below the $500,000 threshold and does not lose cap space under this rule; a filer above the threshold sees the reduction grow with the excess.
The same 2025 and 2026 cap and threshold values apply to single and married-joint returns in the current UI. Married filing separately receives half under the statute but is not supported by this version of the calculator. Head of Household is grouped with single-filer tax tables elsewhere in the project, while the SALT cap table follows the enacted SALT provision described above.
The floor matters because a phase-down cannot make the allowable cap negative or erase the $10,000 baseline. Once the calculation reaches that floor, additional MAGI does not reduce the SALT cap below $10,000.
The cap is not the same as the deduction
A taxpayer may have less SALT paid than the cap. The allowed SALT deduction is the smaller of state and local income tax plus property tax paid and the effective cap. Mortgage interest and charitable gifts are then added to form the itemized total. The cap therefore limits one component; it does not guarantee that itemizing beats the standard deduction.
For 2025, the standard deduction is $15,750 for single filers and $31,500 for married filing jointly. For 2026, the corresponding shared table values are $16,100 and $32,200. The SALT calculator compares the complete itemized total with that standard amount and reports which choice is larger.
That comparison is why the timeline is useful but incomplete on its own. A household in a high-tax state may still choose the standard deduction when mortgage interest, gifts, and allowed SALT do not add up to more. Conversely, a household below the cap can benefit if its other itemized expenses create a larger total.
- Select the correct tax year before reading the cap.
- Apply the 30% phase-down only above the indexed threshold.
- Use paid state/local and property taxes, not a guessed statewide average.
- Compare the itemized total with the standard deduction before claiming a benefit.