What This Calculator Does
This tool applies to United States federal income tax for the 2026 tax year. It compares two often-confused numbers: your marginal tax rate (the rate on your last dollar of income) and your effective tax rate (the average rate across all your taxable income). It does not include state taxes, payroll taxes, credits, or deductions — enter your taxable income (income after deductions).
How to Use It
Enter your taxable income and choose your filing status (Single or Married Filing Jointly). The calculator walks through the 2026 brackets, taxing each slice of income at its own rate, and reports your total federal tax, marginal rate, and effective rate.
The Formula Explained
Income is split across brackets. Each portion is taxed at that bracket's rate, then summed. Your marginal rate is the rate of the highest bracket your income reaches. Your effective rate is total tax divided by taxable income times 100. Because lower brackets are taxed at lower rates, your effective rate is always lower than your marginal rate.
$$\begin{gathered} \text{Effective Rate} = \frac{\text{Total Tax}}{\text{Taxable Income}} \times 100\% \\[1.5em] \text{where}\quad \left\{ \begin{aligned} \text{Total Tax} &= \sum_i r_i \left(\min(\text{Income},\, u_i) - l_i\right) \\ \text{Marginal Rate} &= r_k \;\text{ of the top bracket reached} \\ r_i, l_i, u_i &= \text{rate, lower, upper of bracket } i \;(\text{Filing Status}) \end{aligned} \right. \end{gathered}$$
Worked Example
Married filing jointly with $100,000 taxable income (2026): the first $24,800 is taxed at 10% ($2,480), and the remaining $75,200 falls within the 12% band, which runs $24,800–$100,800, so \(\$75{,}200 \times 12\% = \$9{,}024\). The total tax is $$\$2{,}480 + \$9{,}024 = \$11{,}504.$$ The effective rate is $$\frac{\$11{,}504}{\$100{,}000} = 11.504\%,$$ while the marginal rate is 12%.
FAQ
Why is my effective rate lower than my marginal rate? Only the income in your top bracket is taxed at the marginal rate; everything below is taxed at lower rates.
Does this include state tax? No — it covers federal income tax only.
Is this taxable income or gross income? Use taxable income (after standard or itemized deductions) for accurate results.
