How to Estimate Your Federal Tax Before Filing

Most Americans wait until April to think about taxes — then scramble to figure out whether they'll get a refund or owe money. But estimating your federal tax throughout the year gives you time to take action: adjust withholding, increase contributions, or plan a Roth conversion.

Step 1: Start With Gross Income

Your gross income is everything you earned: W-2 wages, freelance income, investment income, rental income, and any other taxable sources. For most W-2 employees, this is the number on your pay stubs.

Step 2: Subtract Above-the-Line Deductions

Before you get to your adjusted gross income (AGI), you can subtract "above-the-line" deductions — these reduce your income regardless of whether you itemize:

• 401(k) / 403(b) contributions — up to $24,500 in 2026
• Traditional IRA contributions — up to $7,000 (or $8,000 if 50+)
• HSA contributions — up to $4,400 (self) or $8,750 (family)
• Student loan interest — up to $2,500 if eligible
• OBBBA overtime deduction — up to $12,500 (single) or $25,000 (MFJ)
• OBBBA tip deduction — up to $25,000 for qualified tip income

Step 3: Apply the Standard Deduction

Most filers take the standard deduction rather than itemizing. For 2026:

• Single: $16,100
• Married Filing Jointly: $32,200
• Head of Household: $24,150

Step 4: Apply the Tax Brackets

Federal tax is not a flat percentage. Your taxable income falls across multiple brackets, each taxed at its own rate. Only the income in each bracket gets taxed at that rate.

For 2026 single filers, the brackets are approximately:

• 10% on the first $12,400
• 12% on income $12,401–$50,400
• 22% on income $50,401–$105,700
• 24% on income $105,701–$201,775
• 32% and above for higher incomes

Step 5: Subtract Credits

Tax credits reduce your actual tax bill dollar-for-dollar — more powerful than deductions. Common credits include:

• Child Tax Credit — $2,200 per qualifying child in 2026
• Child & Dependent Care Credit
• American Opportunity Credit (education)
• Earned Income Tax Credit (lower-income filers)

Don't Forget Payroll Taxes

W-2 employees also pay FICA taxes: 6.2% Social Security (up to $184,500 wage base in 2026) and 1.45% Medicare on all wages. High earners pay an additional 0.9% Medicare surtax above $200,000 (single) or $250,000 (MFJ). These are separate from income tax.