12 source-backed guides
Understand the rule behind the result.
Detailed US federal and state tax explainers for 2025 returns and 2026 planning. Each guide separates what Afterax calculates from the eligibility and filing questions that still need IRS instructions or professional advice.
Federal tax basics
Brackets, deductions, filing status, and payroll tax.
2025 federal income tax brackets
See every 2025 federal income tax bracket by filing status, the final standard deductions, and a worked single-filer calculation.
Read guide2026 federal tax brackets and changes
Plan with the 2026 federal brackets, standard deductions, Social Security wage base, and clear warnings about estimate status.
Read guideStandard deduction versus itemizing
Compare the 2025 standard deduction with Schedule A itemizing, including SALT, mortgage interest, charity, medical costs, and common limits.
Read guideUS filing statuses explained
Understand single, married filing jointly, married filing separately, head of household, and qualifying surviving spouse tax status.
Read guideFICA, Social Security, and Medicare
Learn employee and employer Social Security, Medicare, Additional Medicare Tax, wage bases, spouse treatment, and common payroll misconceptions.
Read guideInvesting and gains
Capital gain stacking and the Net Investment Income Tax.
Planning
Pretax accounts, work type, and estimated payment rules.
401(k), HSA, and pretax contribution tax savings
Compare current federal tax savings, payroll tax treatment, contribution cost, limits, and future tax tradeoffs for pretax benefits.
Read guideW-2 versus 1099 and self-employment tax
Understand worker classification, self-employment tax, deductible business expenses, estimated payments, QBI, and why gross offers are not comparable.
Read guideEstimated tax safe harbors
Plan US estimated federal tax payments with current-year and prior-year safe-harbor concepts, withholding timing, annualization, and high-income cautions.
Read guideState taxes
What changes across all 50 states and DC.
High earners
Overlapping federal surtaxes, AMT risk, equity, and payment timing.
Credits and dependents
Refundable and nonrefundable credit boundaries.
Editorial standard
Sources, scope, and limitations stay visible
Every guide names its sources, review date, worked example, and excluded topics. Federal calculations are estimates, state profiles are not state liability calculations, and eligibility-sensitive credits are never presented as automatic.