The single most-asked tax question is simple: "how much tax will I owe?" The honest answer is: it depends on filing status, deductions, and whether you also owe state tax. This article walks through worked examples for common incomes using the 2026 federal figures from IRS Rev. Proc. 2025-32, so you can see exactly how the numbers are built.
Short answer for a single filer with $100,000 of W-2 wages in 2026: roughly $20,820 in federal income tax plus FICA (Social Security and Medicare), an effective rate of about 20.8% — before any credits, pre-tax 401(k)/HSA contributions, or state income tax.
How the 2026 federal income tax is calculated
Federal income tax is marginal. You subtract the standard deduction (or itemized deductions) from gross income to get taxable income, then apply each bracket rate only to the income that falls inside it. The 2026 standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly.
Worked example: single filer, $75,000 W-2 wages
| Step | Amount |
|---|---|
| Gross wages | $75,000 |
| Standard deduction (single 2026) | − $16,100 |
| Taxable income | $58,900 |
| Federal income tax (10%/12%/22% brackets) | $7,670 |
| Social Security (6.2% up to $184,500) | $4,650 |
| Medicare (1.45%) | $1,088 |
| Total federal burden (income tax + FICA) | $13,408 |
| Effective rate (total ÷ wages) | 17.9% |
| Marginal bracket | 22% |
Worked example: single filer, $100,000 W-2 wages
| Step | Amount |
|---|---|
| Gross wages | $100,000 |
| Standard deduction (single 2026) | − $16,100 |
| Taxable income | $83,900 |
| Federal income tax | $13,170 |
| Social Security (6.2%) | $6,200 |
| Medicare (1.45%) | $1,450 |
| Total federal burden | $20,820 |
| Effective rate | 20.8% |
| Marginal bracket | 22% |
Worked example: married filing jointly, $200,000
| Step | Amount |
|---|---|
| Gross wages | $200,000 |
| Standard deduction (MFJ 2026) | − $32,200 |
| Taxable income | $167,800 |
| Federal income tax | $26,340 |
| Social Security (6.2% up to $184,500) | $11,439 |
| Medicare (1.45%) | $2,900 |
| Total federal burden | $40,679 |
| Effective rate | 20.3% |
| Marginal bracket | 22% |
Where your actual number will differ
These examples assume no pre-tax 401(k) or HSA contributions, no credits, and no state income tax. Real-world adjustments that lower your bill include traditional 401(k)/IRA contributions, HSA contributions, the child tax credit, and the 20% QBI deduction if you have business income. Your state adds its own layer — nine states have no broad income tax, while California's top rate reaches 13.3%. Run your exact numbers with the federal income tax estimator and the state income tax calculator, both built on the same sourced dataset.
Disclaimer: This article is general educational information, not tax, legal, or investment advice. Dollar amounts come from the 2026 sources listed at the end of this article and may change. Before you act, talk to a licensed CPA, EA, or tax attorney about your own situation.