Estimate your net pay in Illinois after taxes and deductions.
Weekly
Bi-Weekly
Semi-Monthly
Monthly
Your Estimated Net Pay
$0.00
(This is an estimate and may not reflect exact take-home pay.)
Understanding Your Illinois Paycheck
Calculating your net pay (take-home pay) is crucial for effective budgeting and financial planning.
Your paycheck is determined by subtracting various taxes and deductions from your gross pay.
This Illinois Paycheck Calculator helps you estimate your net earnings based on your
gross salary, pay frequency, and relevant tax information specific to Illinois and federal regulations.
How Your Paycheck is Calculated:
The calculation involves several steps:
Gross Pay: This is the total amount you earn before any deductions.
Federal Income Tax Withholding: This is calculated based on your gross pay, pay frequency, and the number of allowances you've claimed on your Federal W-4 form. Higher allowances generally mean lower withholding.
Social Security Tax: A flat rate of 6.2% is applied to your gross pay, up to an annual wage base limit (which changes yearly).
Medicare Tax: A flat rate of 1.45% is applied to your gross pay, with no wage limit.
Illinois State Income Tax: Illinois has a flat income tax rate. The rate applied here is 4.95% (as of recent data), though this can change. Withholding depends on your gross pay and allowances claimed on your IL-W-4 form.
Additional Withholding: Any extra amounts you've requested to be withheld from federal or state taxes will also be subtracted.
Other Deductions: This calculator does not include deductions for health insurance premiums, retirement contributions (401k, etc.), union dues, or other voluntary deductions. These would further reduce your net pay.
Key Illinois Tax Information:
Flat Tax Rate: Illinois has a flat state income tax rate, meaning everyone pays the same percentage regardless of income level.
Standard Exemption: Illinois allows for a standard personal exemption, which is factored into the withholding calculations based on allowances.
Using the Calculator:
To get the most accurate estimate:
Enter your Gross Pay for the specific pay period (e.g., weekly, bi-weekly, monthly).
Select your Pay Frequency.
Enter the number of Federal Allowances from your W-4 form.
Enter the number of Illinois Allowances from your IL-W-4 form.
Add any Additional Withholding amounts you've elected for federal or state taxes.
Click "Calculate Net Pay".
Remember, this tool provides an estimation. Your actual net pay may vary due to specific payroll
system calculations, year-to-date limits for Social Security, or other less common deductions.
For precise figures, always refer to your official pay stub.
function calculatePaycheck() {
var grossPay = parseFloat(document.getElementById("grossPay").value);
var payFrequency = document.getElementById("payFrequency").value;
var federalAllowances = parseInt(document.getElementById("federalAllowances").value);
var stateAllowances = parseInt(document.getElementById("stateAllowances").value);
var ilIncomeTaxRate = parseFloat(document.getElementById("ilIncomeTaxRate").value) / 100; // Convert % to decimal
var additionalFederalWithholding = parseFloat(document.getElementById("additionalWithholding").value);
var additionalStateWithholding = parseFloat(document.getElementById("additionalStateWithholding").value);
// — Basic Validation —
if (isNaN(grossPay) || grossPay < 0) {
alert("Please enter a valid Gross Pay amount.");
return;
}
if (isNaN(federalAllowances) || federalAllowances < 0) {
alert("Please enter a valid number for Federal Allowances.");
return;
}
if (isNaN(stateAllowances) || stateAllowances < 0) {
alert("Please enter a valid number for Illinois Allowances.");
return;
}
if (isNaN(additionalFederalWithholding) || additionalFederalWithholding < 0) {
additionalFederalWithholding = 0; // Default to 0 if invalid
}
if (isNaN(additionalStateWithholding) || additionalStateWithholding < 0) {
additionalStateWithholding = 0; // Default to 0 if invalid
}
// — Constants —
var socialSecurityRate = 0.062; // 6.2%
var medicareRate = 0.0145; // 1.45%
var socialSecurityWageBase = 168600; // Example: 2024 SS wage base. This changes annually.
// — Calculate Annual Gross Pay for Tax Brackets (simplified) —
var annualGrossPay = grossPay;
if (payFrequency === "weekly") {
annualGrossPay = grossPay * 52;
} else if (payFrequency === "bi-weekly") {
annualGrossPay = grossPay * 26;
} else if (payFrequency === "semi-monthly") {
annualGrossPay = grossPay * 24;
} else if (payFrequency === "monthly") {
annualGrossPay = grossPay * 12;
}
// — Calculate Federal Income Tax Withholding (Simplified – Actual calculation is complex) —
// This is a highly simplified approximation. Real W-4 calculations involve tables and specific formulas.
// We'll use a placeholder logic assuming a certain percentage reduction based on allowances.
// For a more accurate calculation, one would typically use IRS withholding tables or online calculators.
var estimatedFederalTaxRate = 0.15; // Assumed base federal tax bracket for estimation
var federalTaxReductionPerAllowance = annualGrossPay * 0.02; // Example reduction per allowance
var calculatedFederalTaxableIncome = annualGrossPay – (federalAllowances * federalTaxReductionPerAllowance);
calculatedFederalTaxableIncome = Math.max(0, calculatedFederalTaxableIncome); // Taxable income cannot be negative
var annualFederalIncomeTax = calculatedFederalTaxableIncome * estimatedFederalTaxRate;
// Calculate withholding for the current pay period
var federalIncomeTaxWithholding = 0;
if (payFrequency === "weekly") {
federalIncomeTaxWithholding = annualFederalIncomeTax / 52;
} else if (payFrequency === "bi-weekly") {
federalIncomeTaxWithholding = annualFederalIncomeTax / 26;
} else if (payFrequency === "semi-monthly") {
federalIncomeTaxWithholding = annualFederalIncomeTax / 24;
} else if (payFrequency === "monthly") {
federalIncomeTaxWithholding = annualFederalIncomeTax / 12;
}
federalIncomeTaxWithholding += additionalFederalWithholding; // Add additional withholding
// — Calculate Social Security Tax —
var socialSecurityTax = Math.min(grossPay, Math.max(0, socialSecurityWageBase / (payFrequency === "weekly" ? 52 : payFrequency === "bi-weekly" ? 26 : payFrequency === "semi-monthly" ? 24 : 12))) * socialSecurityRate;
// Note: The SS wage base is annual. A more precise calculation would track YTD wages. This simplification assumes the current paycheck doesn't exceed the remaining portion of the wage base.
// — Calculate Medicare Tax —
var medicareTax = grossPay * medicareRate;
// — Calculate Illinois State Income Tax —
// Illinois has a flat tax. Withholding is generally a percentage of taxable income.
// Simplified: We'll apply the state rate directly to gross pay after a basic exemption adjustment.
var IL_STANDARD_EXEMPTION_PER_ALLOWANCE = 2425; // Example value, check current IL Dept of Revenue for accuracy
var annualStateTaxableIncome = annualGrossPay – (stateAllowances * IL_STANDARD_EXEMPTION_PER_ALLOWANCE);
annualStateTaxableIncome = Math.max(0, annualStateTaxableIncome); // Taxable income cannot be negative
var annualIllinoisIncomeTax = annualStateTaxableIncome * ilIncomeTaxRate;
// Calculate withholding for the current pay period
var ilIncomeTaxWithholding = 0;
if (payFrequency === "weekly") {
ilIncomeTaxWithholding = annualIllinoisIncomeTax / 52;
} else if (payFrequency === "bi-weekly") {
ilIncomeTaxWithholding = annualIllinoisIncomeTax / 26;
} else if (payFrequency === "semi-monthly") {
ilIncomeTaxWithholding = annualIllinoisIncomeTax / 24;
} else if (payFrequency === "monthly") {
ilIncomeTaxWithholding = annualIllinoisIncomeTax / 12;
}
ilIncomeTaxWithholding += additionalStateWithholding; // Add additional withholding
// — Calculate Total Deductions —
var totalDeductions = federalIncomeTaxWithholding + socialSecurityTax + medicareTax + ilIncomeTaxWithholding;
// — Calculate Net Pay —
var netPay = grossPay – totalDeductions;
netPay = Math.max(0, netPay); // Net pay cannot be negative
// — Display Result —
document.getElementById("netPay").innerText = "$" + netPay.toFixed(2);
}