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State tax guide

Illinois income tax guide for individuals and businesses

A plain-English overview of Illinois individual and business taxes for 2026: rates, forms, deadlines, sales tax, payroll and multi-state rules, with CPA help when you need it.

OverviewIndividuals, all statesBusinesses, all statesMulti-state and reciprocityCompliance calendarTax ratesStartup compliance

Illinois at a glance

Individual income taxFlat tax, about 4.95%
Main resident returnForm IL-1040
Business taxesCorporate income tax about 9.5% (7% income tax plus a 2.5% personal property replacement tax). Partnerships and S corporations pay a 1.5% replacement tax. Elective pass-through entity tax available. LLCs and corporations file an annual report with the Secretary of State.
Sales taxAbout 6.25% state rate
Local taxesCities, counties and transit districts add to the 6.25% state rate; Chicago and some other cities have higher combined rates and their own taxes.
Individual return dueApril 15
Tax agencyIllinois Department of Revenue (MyTax Illinois)
Wage reciprocityIowa, Kentucky, Michigan, Wisconsin

Individuals

Illinois has a flat individual income tax (about 4.95% at every income level). Residents generally file Form IL-1040 and start from their federal income.

Nonresidents and part-year residents who earn income from Illinois sources (for example wages for work performed in Illinois, rental property or a business here) generally file the nonresident or part-year version of the return or a schedule. Your home state normally gives a credit for tax paid to Illinois, so the same income is rarely taxed twice.

Good to know: Illinois does not tax Social Security benefits or most retirement income, and has a flat rate (the same rate at every income level).

Businesses

Entity-level taxes: Corporate income tax about 9.5% (7% income tax plus a 2.5% personal property replacement tax). Partnerships and S corporations pay a 1.5% replacement tax. Elective pass-through entity tax available. LLCs and corporations file an annual report with the Secretary of State.

Pass-through businesses. S corporations, partnerships and most LLCs pass income to their owners, who report it on personal returns. Many states, including a large number of those that tax income, offer an elective pass-through entity tax (PTET) that can help work around the federal limit on deducting state taxes. Ask us whether it fits Illinois and your situation.

Sales tax. About 6.25% state rate. Cities, counties and transit districts add to the 6.25% state rate; Chicago and some other cities have higher combined rates and their own taxes. After the Wayfair decision, out-of-state sellers can owe sales tax once their sales into Illinois pass the state's threshold, even with no office there.

Payroll. Employers must register for state income tax withholding (where the state has an income tax) and for state unemployment insurance before the first payroll, and report new hires. Workers' compensation insurance is also required in most cases.

Annual filings. Most states also require corporations and LLCs to file a yearly report or pay a fee to the Secretary of State.

Working in more than one state

Illinois has wage reciprocity agreements with Iowa, Kentucky, Michigan, Wisconsin. A resident of a partner state who works in Illinois can generally file an exemption certificate with the employer so no Illinois tax is withheld.

Working or living in more than one state, or moving during the year? See our multi-state tax guide.

Compliance calendar snapshot

WhenWhat
January 15, April 15, June 15, September 15Federal estimated tax payments. Most states with an income tax follow similar dates.
April 15Illinois individual return due date (calendar-year filers)
Monthly or quarterly, usually the 20th of the next monthState sales tax returns and payroll withholding deposits, depending on volume
Quarterly (end of month after quarter)State unemployment insurance and withholding reconciliation returns
Yearly, on the entity's anniversary or by a fixed dateSecretary of State annual report or franchise fee

Common questions

What is the Illinois income tax rate for 2026?

Illinois charges a flat income tax of about 4.95%.Rates, brackets and credits change, so confirm with the Illinois Department of Revenue (MyTax Illinois).

Which form do I file for Illinois income tax?

Residents generally file Form IL-1040. Nonresidents and part-year residents use the nonresident or part-year version or a schedule. The state agency's website has the current forms and instructions.

Do I need to file a Illinois return if I live in another state?

If you earned income from Illinois sources (wages for work performed here, rental property, or a business or partnership interest), you may need to file in Illinois even if you live elsewhere. Your home state usually gives a credit for tax paid to another state.

Does Illinois have reciprocity with other states?

Yes, for wages with Iowa, Kentucky, Michigan, Wisconsin. Reciprocity applies only to wages and there are exceptions, so confirm before you stop withholding.

What business taxes apply in Illinois?

Corporate income tax about 9.5% (7% income tax plus a 2.5% personal property replacement tax). Partnerships and S corporations pay a 1.5% replacement tax. Elective pass-through entity tax available. LLCs and corporations file an annual report with the Secretary of State. Sales tax, payroll withholding and unemployment insurance may also apply.

General information only, for tax year 2026. Rates, forms and rules change and have many exceptions. Confirm with the state agency or contact us before you act. Rates shown are approximate top or flat rates.

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Did you know?
  • You can put up to $24,500 of your pay into a 401(k), 403(b) or TSP in 2026. At 50 or older you can add $8,000, and at ages 60 to 63 you can add $11,250 (up to $35,750 in all). IRS: 2026 retirement limits →
  • Work for yourself with no employees? A solo 401(k) lets you save $24,500 as the "employee" and add an employer contribution on top, for up to $72,000 in total before catch-up. A SEP-IRA has the same top limit. IRS: One-participant 401(k) plans →
  • A SEP-IRA can be opened and funded as late as your tax filing deadline, including extensions. That makes it one of the best last-minute ways for a self-employed person to lower the tax bill. IRS: SEP plans →
  • You can put $7,500 in an IRA for 2026, or $8,600 if you are 50 or older, and you have until the April 2027 filing deadline to do it. IRS: IRA contribution limits →
  • A SIMPLE IRA is an easy retirement plan for a small business. Employees can defer $17,000 in 2026, $21,000 at 50 or older, and $22,250 at ages 60 to 63. IRS: SIMPLE IRA plans →
  • An HSA is taxed in your favor three times: money goes in tax-free, grows tax-free and comes out tax-free for medical costs. The 2026 limit is $4,400 for self-only and $8,750 for family coverage, plus $1,000 if you are 55 or older. IRS: Publication 969 →
  • A defined benefit or cash balance plan can let a business owner with steady, high income put away far more than a 401(k) allows, especially after 50. The yearly benefit limit for 2026 is $290,000. IRS: Defined benefit plans →
  • New in 2026: if your Social Security wages from the employer that sponsors your 401(k) were over $150,000 in 2025, your catch-up contributions must go in as Roth (after-tax) money. IRS: 2026 retirement limits →
  • If your income is modest, the saver's credit can cut your tax bill by up to $1,000 ($2,000 for a couple) just for saving for retirement. For 2026 it reaches incomes up to $40,250 single and $80,500 joint. IRS: Saver's credit →
  • When you work for yourself you pay both halves of Social Security and Medicare tax: 15.3% on net earnings up to $184,500 in 2026, and 2.9% above that. Half of it is deductible on your return. IRS: Self-employment tax →
  • The qualified business income deduction can take up to 20% off the tax on pass-through business income. The 2025 law made it permanent and added a $400 minimum deduction if you have at least $1,000 of qualified income. IRS: QBI deduction →
  • Estimated taxes are due four times a year: April 15, June 15, September 15 and January 15. Paying 100% of last year's tax (110% if your income was over $150,000) usually protects you from the underpayment penalty. IRS: Estimated taxes →
  • The business mileage rate rose to 76 cents a mile on July 1, 2026 (it was 72.5 cents from January to June). A simple log of dates, miles and purpose is what turns miles into a deduction. IRS: Standard mileage rates →
  • Tips, overtime and car loan interest can now be deducted even if you do not itemize. The tips deduction is up to $25,000, overtime up to $12,500 ($25,000 joint), and car loan interest up to $10,000. IRS: New deductions →
  • Work from home regularly and exclusively for your business? The simplified home office deduction is $5 per square foot, up to 300 square feet, which is up to $1,500. IRS: Home office deduction →
  • If you are self-employed, the health insurance premiums you pay for yourself, your spouse and your dependents may be deductible even if you do not itemize, up to your net profit. IRS: Self-employed health insurance →
  • In 2026 a business can deduct up to $2,560,000 of equipment it buys and uses, in the year of purchase. And 100% bonus depreciation is now permanent for property acquired after January 19, 2025. IRS: Section 179 and bonus depreciation →
  • You only have to send a 1099-NEC or 1099-MISC to a contractor you paid $2,000 or more in 2026. It used to be $600. Still collect a W-9 from every contractor before the first payment. IRS: Information returns →
  • S corporation owners who work in the business must pay themselves a reasonable salary. Too low, and the IRS can recharacterize distributions as wages and charge payroll tax and penalties. IRS: S corporation compensation →
  • Illinois lets partnerships and S corporations elect to pay Illinois tax at the entity level. The owners can then get a federal deduction that works around the $40,400 cap on state and local taxes. Illinois tax guide →
  • Startup costs for a new business: up to $5,000 can be deducted in the first year and the rest over 15 years, so keep every receipt from before opening day. IRS: Publication 535 →
  • Business meals are generally 50% deductible when they are directly related to your business and you keep the receipt and a note of who attended and why. IRS: Publication 463 →
  • Good news for U.S. companies: since August 14, 2026 they no longer have to file beneficial ownership reports with FinCEN. Only foreign companies registered to do business in the U.S. still report. FinCEN: BOI reporting →
  • Pay your child a reasonable wage for real work in your sole proprietorship and the wages can be a business deduction. Under 18, no Social Security or Medicare tax is withheld, and their standard deduction can shelter the wages from income tax. IRS: Family employees →
  • Payroll taxes you withhold belong to the government from the moment you take them out of a paycheck. If they go unpaid, the IRS can hold the owner personally liable for the full amount. IRS: Trust fund recovery penalty →
  • Late payroll tax deposits can bring penalties of up to 15%. Payroll taxes are due on a fixed schedule, and the penalty grows the longer a deposit is late. IRS: Failure to deposit penalty →
  • Hiring someone who works from another state usually means registering for that state's withholding and unemployment taxes before their first paycheck. We handle payroll in every state. Our payroll service →
  • Not filing costs ten times more than not paying: 5% of the unpaid tax per month (up to 25%) against 0.5% per month. If you cannot pay, still file on time. IRS: Failure to file penalty →
  • An extension to file is not an extension to pay. Pay what you expect to owe by the original due date to avoid penalties and interest. IRS: Extension to file →
  • You may qualify for IRS first-time penalty abatement if you filed and paid on time for the past three years. Ask before you pay a penalty. IRS: Penalty relief →
  • A Notice of Deficiency gives you 90 days (150 if you are outside the U.S.) to challenge the IRS in Tax Court before the tax is assessed. The date is on the letter and it cannot be extended. If you got an IRS letter →
  • You generally have three years from the date you filed to claim a refund. Old returns with missed deductions can still pay off. IRS: Amended returns and refunds →
  • The IRS generally has three years to audit a return, and six years if more than 25% of income was left off. Keep your records at least that long. IRS: How long to keep records →
  • Renting out your home for 14 days or fewer in a year? The rent is generally tax-free, and you do not even have to report it. IRS: Renting residential property →
  • You deduct the cost of a residential rental building over 27.5 years, even though it may be rising in value. Land is not depreciable. A cost segregation study can speed up the deductions. Real estate investors →
  • If you actively manage your rental, you may deduct up to $25,000 of rental losses against other income. The allowance shrinks to zero between $100,000 and $150,000 of income. IRS: Rental losses →
  • Selling your main home? You may exclude up to $250,000 of gain ($500,000 if married filing jointly) if you owned and lived in it for at least two of the last five years. IRS: Sale of your home →
  • If your foreign bank and financial accounts total more than $10,000 at any time in the year, you generally must file an FBAR. It is due April 15, with an automatic extension to October 15. An honest mistake can still cost more than $16,000 per late report. Foreign accounts and FBAR →
  • Received a large gift or inheritance from abroad? Gifts over $100,000 from a foreign individual in a year generally must be reported on Form 3520, even though they are not taxable. The late-filing penalty starts at 5% a month. IRS: Form 3520 →
  • Form 8938 and the FBAR are not the same thing. They have different thresholds, are filed in different places and some people must file both. Foreign accounts and FBAR →
  • U.S. citizens and green card holders owe U.S. tax on income from anywhere in the world, wherever they live. The foreign tax credit and the foreign earned income exclusion ($132,900 in 2026) help avoid paying twice. IRS: Foreign earned income exclusion →
  • Many mutual funds sold outside the U.S. (including in India) are treated as passive foreign investment companies. They need an extra form every year, and the tax rules can be harsh. International families →
  • The 2026 standard deduction is $16,100 for single filers, $32,200 for married filing jointly and $24,150 for heads of household. Age 65 or older? There is an extra deduction, plus the new $6,000 senior deduction. IRS: 2026 inflation adjustments →
  • New in 2026: even if you take the standard deduction, you can deduct up to $1,000 of cash gifts to qualified charities ($2,000 for a married couple). IRS: Charitable contributions →
  • For 2026, long-term capital gains are taxed at 0% on income up to $49,450 (single) or $98,900 (married filing jointly) of taxable income. Hold investments more than a year to qualify. IRS: Capital gains and losses →
  • You can give up to $19,000 to any one person in 2026 without filing a gift tax return, and you can give to as many people as you like. IRS: Gift tax →
  • On October 1, 2026 Treasury opened a Trump Account for every eligible child under 18. A parent must claim it in the official app before the $1,000 government deposit (for U.S. citizen children born 2025 to 2028) or any gifts can arrive. Our Trump Accounts guide →
  • If you sell a stock at a loss and buy the same or a substantially identical one within 30 days before or after, the loss is generally disallowed for now. IRS: Publication 550 →
  • Every federal income tax return asks whether you received or sold digital assets such as cryptocurrency. Keep records of every transaction. IRS: Digital assets →
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