Guides

Educational guides, not tax advice — every figure here is rendered at build time from this site's versioned tax-year data by the same tested engine that powers the calculators. Federal taxes only.

Every calculator on TaxesCalculations.com produces a number. For the rules these guides cover — the federal income tax on a taxable income, a paycheck after Social Security and Medicare, the self-employment tax on a year's profit, the 2026 deductions OBBBA added — the matching guide explains what produced it: what the formula does, why each input matters, where the computation stops, and how to read the output without the usual misreadings.

The scope is the same on both sides: US federal taxes only, except where a page states otherwise. The ordinary-income engine applies the brackets, the standard deduction, and the Social Security and Medicare rules for the supported tax years, and deliberately leaves out state and local income taxes, tax credits, itemized-deduction strategy, and the alternative minimum tax; the OBBBA tools model only the specific 2026 deductions their guide covers, each with the exclusions its own page lists. Where a guide touches an excluded area, it says so and stops — a number the engine did not compute is not one this site prints.

Every year-dependent constant — bracket thresholds, standard deductions, the Social Security wage base, the Medicare thresholds — lives in a single versioned data file keyed by tax year. The calculators and guides currently cover tax years 2025 and 2026, defaulting to 2026; when the IRS publishes the next year's inflation adjustments, that file gains an entry and every page updates together. The One Big Beautiful Bill Act provisions live in a second file where each constant carries its own statutory citation, last verified against primary sources on 2026-08-18. The methodology page documents the formulas in full.

How Tax Brackets Actually Work

The foundational guide. Federal income tax is progressive in slices: 2026 has 7 rates from 10% to 37%, and each rate applies only to the taxable income inside its own range. It starts with the standard deduction — $16,100 single, $32,200 married filing jointly, $24,150 head of household for 2026 — which comes off before any bracket applies. Its central example is a single filer earning $85,000 in 2026: $68,900 of taxable income, a 22% marginal rate, and $9,870.00 of federal income tax — 11.61% of gross — because the top rate touched only the top slice. A second computed example follows a raise across a bracket threshold, FICA included, to show why a raise into a new bracket cannot lower take-home pay. Pairs with the Tax Bracket Calculator, the Federal Income Tax Calculator, and the Take-Home Pay Calculator.

2026 Federal Tax Brackets: The Complete Tables

The reference page for tax year 2026 — income earned during 2026, reported on the return filed in 2027. It renders the full bracket table for each of the three filing statuses the ordinary-income tools model (single, married filing jointly, head of household), the 2026 standard deductions ($16,100 / $32,200 / $24,150), and a bracket-by-bracket comparison with 2025 computed from the two years' data files. One line from it: the ceiling of the single filer's 22% bracket moved from $103,350 to $105,700, up $2,350. The page also carries a warning that matters this year: the 2026 standard-deduction figures already include OBBBA's permanent increase, so no separate bump belongs on top.

What OBBBA Changes on Your 2026 Tax Return

Five provisions of P.L. 119-21 (the One Big Beautiful Bill Act) as they apply to tax year 2026, each with its own calculator: the age-based $6,000 senior deduction, the $40,400 state-and-local-tax deduction cap, car-loan interest of up to $10,000, the higher standard deduction, and the reworked charitable rules. The mechanism the guide hangs on is a form: three of the new deductions are claimed on Schedule 1-A and subtracted after adjusted gross income, so they are available whether or not you itemize but never reduce AGI or MAGI. The guide states which provisions are temporary (2025–2028) and which are permanent, and its own currency: constants verified against the enacted statute, the Internal Revenue Code, and IRS guidance as of 2026-08-18 — an absence-of-evidence check, not a promise about future law.

Self-Employment Tax, Explained

The guide for the tax that W-2 paychecks keep invisible. Self-employment tax is both halves of Social Security and Medicare collected from one person — 12.4% plus 2.9%, 15.3% together — charged on 92.35% of net earnings rather than all of them. The guide traces one 2026 example end to end, a single filer taking the standard deduction: $80,000 of net self-employment earnings produces $11,303.64 of self-employment tax, an effective 14.13% of profit rather than the headline rate, with a deductible half of $5,651.82 that reduces taxable income for the income-tax computation only. It also covers the Social Security wage base ($184,500 for 2026), the Additional Medicare surtax that sits outside the deductible half, and the quarterly payment rhythm that replaces withholding. Pairs with the Self-Employment Tax Calculator and the Quarterly Tax Calculator.

From the guides back to the calculators

The guides explain; the calculators compute. The full directory of tools starts on the home page; every tool page carries its own worked example and states its own exclusions. For the formulas and the primary sources behind every constant, see the methodology page; for the cautions that apply to everything on this site, gathered in one place, see the disclaimer.

Not tax advice: these guides are educational explainers of the federal core — no state or local taxes, credits, itemized deductions, or AMT — and nothing in them is tailored to your situation. Every figure here is rendered at build time from this site's versioned data files by the same tested engine as the calculators, so the guides cannot drift from the tools. Consult a tax professional or IRS.gov for your situation. See the methodology page and the disclaimer.