How Federal Income Tax Is Calculated
The US federal income tax is calculated solely on your taxable income, which equals your gross income minus your standard or itemized deductions.
For the 2026 Tax Year, the projected standard deduction for single filers is $15,000 and for married couples filing jointly is $30,000. This means the first $15,000 (or $30,000) you earn is completely tax-free at the federal level.
Frequently Asked Questions
Does this calculation include state taxes or FICA?
What are the federal tax bracket thresholds for 2026?
Primary Legal Sources: Internal Revenue Service (IRS) Publication 15-T (Federal Income Tax Withholding Methods), IRS Form 1040 Statutory Instructions, and Social Security Administration (SSA) OASDI Wage Base limit guidelines.
Calculation Methodology: Applies projected IRS standard deductions ($15,000 for Single, $30,000 for Married Filing Jointly) followed by progressive marginal brackets (10%, 12%, 22%, 24%, 32%, 35%, 37%) and statutory FICA rates (6.2% OASDI up to the cap + 1.45% Medicare, plus 0.9% high-income surtax).
Disclaimer: This calculator is provided for financial estimation and informational purposes only. It does not constitute formal legal, accounting, or professional tax advice. For personalized tax filings or complex deduction strategies, consult a licensed Certified Public Accountant (CPA) or tax attorney.