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Illinois tax calculator

Planning estimate

2026 Illinois Income Tax Calculator

Estimate your Illinois state income tax, then review key facts, tax brackets, how the calculation works, and common questions.

State income tax calculator

Calculate your 2026 estimate

Enter your income and filing details to get your state tax estimate.

Enter dollars, for example $75,000.
Tax detailsRequired
Tax details

Use amounts from the relevant state or federal worksheet where requested. Enter $0 when a required component does not apply.

This calculator starts from state taxable income rather than deriving it from annual income.
Enter the applicable amount from the state worksheet, or $0 when none applies.

Planning estimate only. Your actual tax can differ based on your complete return and individual circumstances.

Overview

Illinois state income tax overview

Illinois has a supported 2026 state income-tax calculator for the supported taxpayer scope. Enter the requested income and filing information to calculate state income tax.

Use the calculator above as a planning estimate. Your final tax can differ based on deductions, credits, residency, local taxes, and other details that may not be included in the supported calculation.

At a glance

Key facts

Tax structure
Flat tax
Tax year
2026
Starting income basis
State taxable income
Supported filing statuses
Single, Married filing jointly, Married filing separately, Head of household, Qualifying surviving spouse
Local tax treatment
See calculator limits and exclusions.

Rates & structure

Tax brackets

4.95%

Flat state income tax rate

The supported calculation applies a flat rate to the applicable state tax base, subject to the inputs and adjustments shown in the calculator.

Bracket tables are a simplified reference. Your actual state tax can depend on deductions, credits, filing status, special taxes, and other state-specific rules.

Simple process

How it works

1

Enter your details

Choose your filing status and enter the income amount requested by the calculator.

2

Add state-specific inputs

If Illinois needs additional tax, credit, or worksheet values, the form asks for them directly instead of guessing.

3

Review your estimate

See the estimated state income tax, effective rate, and calculation breakdown for the supported scope.