Estimate your federal income tax liability based on income, filing status, and deductions.
Single
Married Filing Jointly
Married Filing Separately
Head of Household
(Enter your standard deduction or itemized deductions if higher)
Estimated Federal Tax
$0.00
Effective Tax Rate: 0.00%
Understanding US Federal Income Tax
The United States federal income tax system is progressive, meaning higher earners pay a larger percentage of their income in taxes. This calculator helps estimate your federal tax liability based on your taxable income, filing status, and deductions. It uses a simplified approach based on the tax brackets for a recent tax year.
How it Works:
The calculation involves these key steps:
Determine Adjusted Gross Income (AGI): This is your gross income minus certain "above-the-line" deductions (like IRA contributions or student loan interest). For simplicity, this calculator assumes the input 'Taxable Income' is already adjusted and ready for standard deduction application.
Calculate Taxable Income: You subtract your applicable deduction (either the standard deduction or itemized deductions if they exceed the standard deduction) from your AGI.
Apply Tax Brackets: Your taxable income is then subject to a series of tax rates defined by the IRS for different income levels and filing statuses. These are known as tax brackets. The progressive nature means only the portion of your income falling within a specific bracket is taxed at that bracket's rate.
Compute Total Tax: The tax from each bracket is summed up to arrive at your total federal income tax liability.
Tax Brackets (Illustrative – Actual rates may vary by year. Please consult IRS.gov for current year data):
The tax rates and income thresholds change annually. Below are illustrative brackets for a recent tax year (e.g., 2023) for common filing statuses.
Single Filers (Illustrative Example):
10% on income up to $11,000
12% on income between $11,001 and $44,725
22% on income between $44,726 and $95,375
24% on income between $95,376 and $182,100
32% on income between $182,101 and $231,250
35% on income between $231,251 and $578,125
37% on income over $578,125
Similar brackets exist for Married Filing Jointly, Married Filing Separately, and Head of Household, typically with higher income thresholds.
Standard Deduction Amounts (Illustrative Example for 2023):
Single: $13,850
Married Filing Jointly: $27,700
Married Filing Separately: $13,850
Head of Household: $20,800
Note: You can choose to itemize deductions if the total of your eligible expenses (like mortgage interest, state and local taxes up to $10,000, charitable contributions, medical expenses above a certain threshold) is greater than your standard deduction.
Important Considerations:
This calculator provides an ESTIMATE. Actual tax liability can be affected by many factors including tax credits, specific deductions not accounted for, alternative minimum tax (AMT), capital gains, and state taxes.
Tax laws and brackets change annually. Always refer to official IRS publications or consult a tax professional for definitive advice.
The 'Taxable Income' input should represent your income after all eligible deductions (like 401k contributions, HSA contributions, etc.) but before the standard/itemized deduction.
function calculateTax() {
var taxableIncome = parseFloat(document.getElementById("taxableIncome").value);
var filingStatus = document.getElementById("filingStatus").value;
var standardDeduction = parseFloat(document.getElementById("standardDeduction").value);
var errorMessageElement = document.getElementById("errorMessage");
var taxResultElement = document.getElementById("taxResult");
var effectiveTaxRateElement = document.getElementById("effectiveTaxRate");
errorMessageElement.textContent = ""; // Clear previous errors
// Input validation
if (isNaN(taxableIncome) || taxableIncome < 0) {
errorMessageElement.textContent = "Please enter a valid positive number for Taxable Income.";
return;
}
if (isNaN(standardDeduction) || standardDeduction 0 ? standardDeduction : calculatedStandardDeduction;
var incomeAfterDeduction = taxableIncome – finalDeduction;
if (incomeAfterDeduction < 0) {
incomeAfterDeduction = 0; // Taxable income cannot be negative
}
var currentIncome = 0;
var applicableBrackets = brackets[filingStatus];
for (var i = 0; i currentIncome) {
var incomeInThisBracket = Math.min(incomeAfterDeduction, bracket.limit) – currentIncome;
taxableAtThisRate = Math.max(0, incomeInThisBracket); // Ensure we don't tax negative amounts
tax += taxableAtThisRate * bracket.rate;
} else {
break; // Income is fully accounted for
}
currentIncome = bracket.limit;
}
// Handle income exceeding the highest bracket limit
var highestBracket = applicableBrackets[applicableBrackets.length – 1];
if (incomeAfterDeduction > highestBracket.limit) {
var incomeAboveHighestBracket = incomeAfterDeduction – highestBracket.limit;
tax += incomeAboveHighestBracket * highestBracket.rate;
}
var formattedTax = tax.toFixed(2);
var formattedTaxableIncomeForRate = taxableIncome > 0 ? taxableIncome : 1; // Prevent division by zero
var effectiveRate = (tax / formattedTaxableIncomeForRate) * 100;
var formattedEffectiveRate = effectiveRate.toFixed(2) + "%";
taxResultElement.textContent = "$" + formattedTax;
effectiveTaxRateElement.textContent = "Effective Tax Rate: " + formattedEffectiveRate;
}