IRC §§1(i) and 1(j) explain how Congress has modified the individual federal income-tax rate tables. Section 1(i) was the pre-2018 adjustment framework. Section 1(j), enacted by the Tax Cuts and Jobs Act (TCJA), replaced that framework for post-2017 years and supplied new rates and brackets. A Hilo, Hawaii address does not change these federal rules.
What §1(i) did
Before the TCJA, §1(i) modified the regular §1(a)–(e) tables by substituting lower rates in selected brackets, preserving a 10% rate, and setting 25%, 28%, and 33% bracket substitutions. It also used inflation-adjusted thresholds and high-income transition rules. In practical terms, §1(i) was a statutory overlay: taxpayers started with the regular filing-status table, then applied Congress’s rate and bracket modifications.
For taxable years beginning after December 31, 2017, current §1(j)(1) says §1(i) does not apply. References to §1(i) in older tax materials therefore describe historical law, not the current computation.
What §1(j) changed
Section 11001 of the TCJA (Public Law 115-97, enacted December 22, 2017) created seven individual rates—10%, 12%, 22%, 24%, 32%, 35%, and 37%—and reset bracket widths for each filing status. The design lowered several statutory rates while retaining progressive marginal taxation: only income inside a bracket receives that bracket’s rate.
The TCJA originally made most §1(j) changes temporary through 2025. The 2025 One Big Beautiful Bill Act (Public Law 119-21) removed the sunset for the §1(j) rate-table modifications, so the framework continues subject to future legislation and annual inflation adjustments.
Inflation indexing and why brackets move
Section 1(j) directs annual cost-of-living adjustments to bracket dollar amounts. The indexing mechanism uses the chained Consumer Price Index (C-CPI-U), with statutory base-year rules and rounding. Indexing is intended to prevent “bracket creep,” where nominal wage increases caused solely by inflation push a taxpayer into higher rates. It changes bracket boundaries, not the taxpayer’s actual income or eligibility for every credit.
The policy logic
- Progressivity: graduated rates ask taxpayers with greater taxable capacity to pay a larger marginal share.
- Predictability: published tables let taxpayers, employers, and software compute withholding and estimated payments.
- Inflation protection: indexing keeps real tax burdens from rising solely because prices and wages rise.
- Legislative tradeoffs: lowering rates can support work and investment incentives, while bracket design and sunsets limit revenue effects and invite later congressional review.
These are policy rationales, not guarantees. Distributional effects depend on deductions, credits, capital gains, payroll taxes, filing status, and household income composition.
Illustrative marginal-rate example
Assume a single Hilo taxpayer has $70,000 of federal taxable income in a year governed by the §1(j) tables. The taxpayer does not apply one rate to all $70,000. The first layers are taxed at 10% and 12%, and only the dollars falling in the applicable 22% bracket are taxed at 22%. The exact tax comes from the year’s IRS rate schedule, deductions, credits, and any preferential capital-gain worksheet.
Hawaii and filing practice
Sections 1(i) and 1(j) govern federal regular income tax. Hawaii has separate conformity and nonconformity rules, state brackets, deductions, credits, and filing forms. Prepare the federal return first, then complete Hawaii adjustments rather than copying a federal tax amount into Form N-11 or N-15. Keep the tax year clear because statutory amendments and inflation adjustments can change the tables.
Bottom line
Section 1(i) is primarily historical after 2017; §1(j) is the operative rate-table modification for current individual returns. Understanding the legislative timeline explains why older bracket charts differ from current IRS tables and why annual inflation adjustments matter. This article is educational and should be checked against the current Internal Revenue Code, IRS instructions, and Hawaii guidance.
