Illinois has a flat 4.95% personal income tax — one of the simpler state tax setups in the country. For self-employed Illinois freelancers, that means a predictable state tax bill on top of federal + SE tax.
4.95% flat rate on Illinois taxable income. There are no graduated brackets — your first dollar and your last dollar of income are taxed at the same rate. This is unusual; most states with income tax use progressive brackets.
Illinois allows a $2,850 personal exemption per filer (2026). This is subtracted from your federal AGI before the 4.95% rate is applied.
Illinois follows the federal schedule: April 15, June 15, September 15, 2026, and January 15, 2027. State quarterly is filed via Form IL-1040-ES.
The Illinois Department of Revenue (IDOR) accepts payments via MyTax Illinois at mytax.illinois.gov — free bank transfer. You can also mail Form IL-1040-ES with a check.
An Illinois freelancer making $80,000 net SE income pays approximately:
Illinois does not allow cities to levy a personal income tax (unlike NYC). However, certain occupations and businesses in Chicago are subject to specific taxes (transactional taxes, parking, etc.) that don't typically affect freelance income.
Chicago's Personal Property Lease Transaction Tax (informally "the cloud tax" or "Netflix tax") applies a 9% transaction tax on certain SaaS, cloud computing, and information services purchased from outside Chicago for use in Chicago. The relevance for freelancers:
This tax surprises tech freelancers moving to Chicago who don't realize their cloud services bill increased 9%. It's a cost of doing business in Chicago — deductible against federal SE income.
Illinois has had a 4.95% flat individual income tax since 2017 (raised from 3.75% in 2011). In November 2020, voters rejected a constitutional amendment that would have allowed graduated rates ranging from 4.75% to 7.99%. Result: Illinois remains flat-tax, but the state's structural deficit has continued growing, and a future graduated-rate amendment is widely expected by 2030.
Why this matters for your planning: if you're a high-earning Chicago freelancer ($300k+ net), Illinois currently is one of the better high-tax states because the flat 4.95% caps your state burden. A future graduated rate could change that calculus — worth modeling residency alternatives (FL, TX) before any future amendment passes.