What This Calculator Does
This tool estimates US federal income tax for the 2024 tax year using the progressive bracket system set by the IRS. It supports Single and Married Filing Jointly statuses and reports your total tax, marginal rate, effective rate, and after-tax income. It applies to the United States only and uses 2024 statutory bracket thresholds applied directly to taxable income (after deductions).
How to Use It
Enter your taxable income (income after deductions) and choose your filing status. The calculator walks through each tax bracket, taxing only the portion of income that falls inside that bracket, then sums the results.
The Formula Explained
Tax is computed bracket by bracket: $$\text{Tax} = \sum_{i} \left( \min(\text{Income},\, U_i) - L_i \right)^{+} \times r_i$$ Your marginal rate is the rate of your highest applicable bracket, while your effective rate is total tax \(\div\) total income — always lower than your marginal rate under a progressive system.
Worked Example
For a married couple with $100,000 taxable income: the first $23,200 is taxed at 10% = $2,320; the next $71,100 (from $23,200 to $94,300) at 12% = $8,532; the remaining $5,700 (from $94,300 to $100,000) at 22% = $1,254. Total = $$\$2{,}320 + \$8{,}532 + \$1{,}254 = \$12{,}106$$ Effective rate = \(12{,}106 / 100{,}000 = 12.106\%\), and after-tax income = $87,894.
FAQ
Is this my total tax bill? No — it estimates federal income tax only and excludes state taxes, FICA/payroll taxes, and credits.
What income should I enter? Enter taxable income (after the standard or itemized deduction), not gross income.
Why is my effective rate lower than my bracket? Because only the income within each bracket is taxed at that bracket's rate, not all your income.
