Sales tax in Illinois is a multi-layered tax applied to the retail sale of tangible personal property. It's composed of a state rate and various local rates (city, county, special districts), making the final tax rate variable depending on the specific location within Illinois.
How Illinois Sales Tax is Calculated
The total sales tax rate is the sum of the state sales tax rate and applicable local sales taxes. The calculation involves applying this combined rate to the purchase price of taxable goods and services.
State Base Rate: Illinois has a base state sales tax rate of 6.25%.
Local Taxes: These include municipal, county, and special district taxes, which vary significantly across the state. Common rates can add anywhere from 1% to over 4% to the state rate.
Combined Rate:Combined Rate (%) = State Base Rate (%) + Local Rate (%)
It's important to note that certain items may be exempt from sales tax or taxed at different rates. For example, groceries intended for home consumption are generally exempt from the state portion of the sales tax, though local taxes may still apply. This calculator assumes all entered amounts are subject to the standard state and provided local rates.
When to Use This Calculator
To estimate the total cost of a purchase in Illinois, including taxes.
For businesses to understand their tax obligations.
For consumers to budget effectively for purchases.
To compare prices across different locations within Illinois, considering varying local tax rates.
This calculator uses the provided state base rate (defaulting to 6.25%) and a user-inputted local rate. Always verify the exact tax rate for your specific location with the Illinois Department of Revenue or your local tax authority for official figures.
function calculateIllinoisSalesTax() {
var purchaseAmountInput = document.getElementById("purchaseAmount");
var stateRateInput = document.getElementById("stateRate");
var localRateInput = document.getElementById("localRate");
var salesTaxResultDiv = document.getElementById("salesTaxResult");
var totalCostResultDiv = document.getElementById("totalCostResult");
var purchaseAmount = parseFloat(purchaseAmountInput.value);
var stateRate = parseFloat(stateRateInput.value);
var localRate = parseFloat(localRateInput.value);
// Input validation
if (isNaN(purchaseAmount) || purchaseAmount < 0) {
alert("Please enter a valid purchase amount.");
purchaseAmountInput.focus();
return;
}
if (isNaN(stateRate) || stateRate < 0) {
alert("Please enter a valid Illinois base rate.");
stateRateInput.focus();
return;
}
if (isNaN(localRate) || localRate < 0) {
alert("Please enter a valid local rate.");
localRateInput.focus();
return;
}
var combinedRate = stateRate + localRate;
var salesTax = purchaseAmount * (combinedRate / 100);
var totalCost = purchaseAmount + salesTax;
salesTaxResultDiv.textContent = "$" + salesTax.toFixed(2);
totalCostResultDiv.textContent = "$" + totalCost.toFixed(2);
}
function resetCalculator() {
document.getElementById("purchaseAmount").value = "";
document.getElementById("stateRate").value = "6.25"; // Reset to default
document.getElementById("localRate").value = "1.75"; // Reset to a common example local rate
document.getElementById("salesTaxResult").textContent = "$0.00";
document.getElementById("totalCostResult").textContent = "$0.00";
}
// Optional: Trigger calculation on Enter key press in input fields
document.getElementById("purchaseAmount").addEventListener("keypress", function(event) {
if (event.key === "Enter") {
calculateIllinoisSalesTax();
}
});
document.getElementById("stateRate").addEventListener("keypress", function(event) {
if (event.key === "Enter") {
calculateIllinoisSalesTax();
}
});
document.getElementById("localRate").addEventListener("keypress", function(event) {
if (event.key === "Enter") {
calculateIllinoisSalesTax();
}
});