Compare 2026 current-law taxes against pre-TCJA 2017 law to see how the standard deduction, SALT cap, and child credit changed the result.
This calculator compares 2026 current-law federal tax against the pre-TCJA 2017 tax code. The current-law side reflects the 2026 brackets, standard deductions, child tax credit, and SALT cap used on this site. The historical side restores the old 2017 deductions, personal exemptions, and higher rates so you can see the effect of the TCJA-era changes in context.
It is a comparison tool, not a filing calculator. Use it to see whether the standard deduction, child credit, or SALT cap is doing most of the work for the case you are modeling.
This calculator is useful when you want to separate the effect of 2026 current-law rules from the older pre-TCJA system without treating the older law as something you can file today. It shows whether the standard deduction, child credit, or SALT cap is the dominant driver of the difference.
2026 current law: standard deduction $16,100 single/MFS, $32,200 MFJ/QSS, $24,150 HOH; child credit $2,200 per child; SALT cap $40,000 ($20,000 MFS) in the current-law model. Pre-TCJA 2017 law: standard deduction $6,350 single/MFS, $12,700 MFJ/QSS, $9,350 HOH; child credit $1,000 per child; personal exemption $4,050 per person; no SALT cap. Savings = Pre-TCJA Tax − 2026 Current-Law Tax
Result: 2026 current-law tax $13,180 vs pre-TCJA tax $16,226
At this income level, the larger 2026 standard deduction and the lower 2026 rate schedule generally outweigh the older 2017 structure. The exact gap depends on how much of the return is itemized versus standard and how much SALT is entered.
This calculator compares 2026 current law against the older 2017 tax code. The 2026 side reflects the current brackets, standard deduction, child credit, and SALT cap; the historical side restores the pre-TCJA deduction and exemption structure.
Match filing status, children, and SALT as closely as you can to the scenario you want to test. High-tax-state filers usually see the biggest change because SALT is capped on the current-law side.
This is not a return-prep calculator. It is a historical comparison that helps explain why the same income level can produce a different tax bill under the old code versus 2026 current law.
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The current-law side uses IRS-published 2026 inflation-adjusted ordinary brackets and standard deductions, plus the current-law child credit and SALT cap used on this site. The pre-TCJA side restores the 2017 rate schedule, standard deduction, personal exemptions, and child credit so the comparison isolates the effect of TCJA-era changes.
Individual TCJA provisions were scheduled to sunset after 2025 unless Congress extended them. This page uses 2026 current-law values on the baseline side so the comparison stays current.
Middle-income families with children usually benefit from the larger standard deduction and the higher child credit, while high-tax-state filers can lose some of the gain because of the SALT cap.
The SALT cap limits the federal deduction for state and local taxes. In this calculator, the current-law side models a $40,000 cap, with a lower limit for married filing separately.
They were removed under TCJA and replaced by a larger standard deduction and higher child credit. The comparison shows how that tradeoff affects a return with and without children.
The long-term capital-gains rate structure itself stayed at 0%, 15%, and 20%, but the income thresholds moved. This calculator focuses on the standard deduction, SALT cap, and child credit changes that most often drive the result.
TCJA raised AMT exemption amounts and phase-out thresholds, which reduced AMT exposure for most households. This page does not model AMT directly.