Entrepreneurs in Illinois: taxes and retirement for 2026
For solo founders and small-business owners in Illinois. Illinois has a flat 4.95% state income tax for 2026. Here are the 2026 rules, a worked example and the official sources.
Illinois rules for entrepreneurs
- State income tax (2026)
- Illinois has a flat 4.95% state income tax for 2026. The 2026 IL-1040-ES worksheet computes tax as net income times 4.95%.
- State estimated tax
- You must make estimated payments if you reasonably expect your 2026 Illinois tax liability to exceed $1,000 after Illinois withholding, pass-through withholding, and allowed credits. Same dates as federal (April 15, June 15, and September 15, 2026, and January 15, 2027). Form IL-1040-ES.
- Freelance Worker Protection Act (820 ILCS 193)
- Covers independent contractors who provide products or services in Illinois, or work for an Illinois hiring entity, when the work is worth $500 or more over 120 days. Applies to contracts that took effect after July 1, 2024. Covered freelancers get a written contract, full payment by the contract due date (or within 30 days of finishing if no date is set), and protection from retaliation.
- Employee Classification Act (construction, 820 ILCS 185)
- People doing construction work for a contractor are presumed to be employees unless all three parts of a test are met: free from control, outside the contractor's usual course of business, and an independently established business. Civil penalties run up to $1,500 per person per day, doubled for willful violations, and up to $2,500 per violation for repeat violations.
- Unemployment Insurance Act ABC test
- For unemployment insurance, a worker is an employee unless all three are true: free from control or direction, work outside the usual course or places of the business, and engaged in an independently established trade or business.
- State retirement program
- My Illinois Savings (formerly Illinois Secure Choice) is live. It is built around W-2 employers and does not cover 1099 contractors through the employer mandate; self-employed residents can enroll on their own.
Federal rules for 2026
Entity choice changes your taxes
A single-member LLC is taxed like a sole proprietorship unless it elects S-corp status. The S-corp can lower payroll tax but adds payroll, a separate return and a reasonable-salary requirement.
Retirement as a tax lever
With no employees, a Solo 401(k) allows up to $72,000 in 2026. With employees, a SEP IRA or a 401(k) must generally cover eligible staff too.
Quarterly estimated taxes
No one withholds tax from self-employment income, so you generally pay estimates four times a year if you expect to owe $1,000 or more. For 2026 income the federal dates are April 15, June 15 and September 15, 2026, and January 15, 2027. Paying 100% of last year's tax (110% if your AGI was over $150,000) in four equal installments avoids the underpayment penalty.
Self-employment tax
On top of income tax, self-employed people pay 15.3% on 92.35% of net profit: 12.4% Social Security up to the 2026 wage base of $184,500, plus 2.9% Medicare with no cap. Half of it is deductible.
A worked example
| Self-employment tax as a sole proprietor | $28,234 |
|---|---|
| Solo 401(k) maximum as a sole proprietor | $61,677 |
| Payroll tax saved as an S-corp on a $100,000 salary | $12,934 |
| Solo 401(k) maximum as that S-corp | $49,500 |
Federal figures only. S-corps add running costs (payroll, an 1120-S return, state fees) not shown here. Computed from 2026 IRS limits (Notice 2025-67, Rev. Proc. 2025-32) and the SSA wage base.
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Guides by job and platform
Questions
Do entrepreneurs in Illinois pay state income tax?
Illinois has a flat 4.95% state income tax for 2026. The 2026 IL-1040-ES worksheet computes tax as net income times 4.95%.
When are Illinois estimated tax payments due for 2026?
You must make estimated payments if you reasonably expect your 2026 Illinois tax liability to exceed $1,000 after Illinois withholding, pass-through withholding, and allowed credits. Same dates as federal (April 15, June 15, and September 15, 2026, and January 15, 2027). The state form is IL-1040-ES.
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Sources
- tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-es.pdf
- labor.illinois.gov/laws-rules/fls/minimum-wage-law.html
- labor.illinois.gov/laws-rules/legal/freelance-worker-protection-act.html
- labor.illinois.gov/faqs/ecafaq.html
- ides.illinois.gov/employer-resources/taxes-reporting/employee-misclassification.html
State and local facts researched from official sources and independently re-checked; last verified October 2026, next scheduled review 2027-01-02. Educational information for 2026, not tax, legal or investment advice. Rules change; check the official sources listed and a tax professional for your situation. Gigaverse AI, Inc. is a financial technology company, not a bank, and not itself a registered investment adviser or broker-dealer.