1099 Tax Calculator for Illinois Freelancers
Illinois applies a flat 4.95% state income tax to all income levels, making it simpler to calculate than progressive-tax states but still adding to your overall tax burden. Combined with the 15.3% self-employment tax and federal income tax, an Illinois freelancer earning $100,000 in net business income can expect to pay roughly $4,000-$5,000 in state income tax.
While the flat rate is lower than top brackets in California or New York, it still represents a significant portion of your income. Maximizing business expense deductions and retirement contributions can reduce both your federal and Illinois taxable income.
Use our free 1099 tax calculator to estimate your total tax liability as an Illinois freelancer — including state tax, self-employment tax, federal income tax, and quarterly payment amounts.
Frequently Asked Questions
What is the Illinois state tax rate for 1099 contractors?
Illinois has a flat 4.95% state income tax rate for all income levels.
Do Illinois freelancers need quarterly state tax payments?
Yes, if you expect to owe more than $1,000 in Illinois state tax.
Does Illinois have special tax deductions for freelancers?
Illinois conforms to most federal expense rules but does not conform to the QBI deduction.
Data source: IRS 2026 tax brackets and state revenue department publications. Last reviewed: 2026-07-05.