Quarterly Estimated Tax Calculator — Illinois (2026)
If you earn income in Illinois without withholding — freelancing, contracting, rentals, dividends — the IRS expects payment four times a year, not once. This calculator turns your expected 2026 net profit into a per-quarter number covering self-employment tax, federal income tax and Illinois state tax. Illinois uses a flat personal income tax of 4.95% applied to taxable income after a state standard deduction of $0.
Illinois Quarterly Tax Calculator
Gross 1099 income minus business expenses.
2026 due dates and safe harbor
Federal estimated payments are due April 15, June 15, September 15 of 2026 and January 15 of 2027. You avoid penalties by paying either 90% of the current year's liability or 100% of last year's (110% if prior-year AGI exceeded $150,000) — the safe-harbor rule.
Illinois runs its own estimated-payment schedule that usually mirrors the federal dates. On $90,000 of net profit the Illinois portion alone is about $1,035 per quarter.
Underpayment penalties
The IRS charges interest-style penalties per quarter you fall short, currently around 7–8% annualized. Paying late in the year does not fix an early-quarter shortfall unless you use the annualized income method on Form 2210.
Irregular income is common in finance work around Chicago: if Q1 is slow and Q4 is huge, the annualized method usually beats four equal payments.
Paying as a Illinois taxpayer
Pay federally through IRS Direct Pay or EFTPS, and Illinois through the state revenue department's online portal — keep confirmation numbers for both.
Illinois has no separate city or county income tax, so the state figure above is the full sub-federal income tax you pay.
Local and payroll taxes Illinois adds on top
Illinois adds no state-mandated employee payroll deduction beyond FICA, so nothing extra is taken from your gross pay at the state level.
Illinois has no separate city or county income tax, so the state figure above is the full sub-federal income tax you pay.
Nobody withholds these for you when you are self-employed in Illinois. Local wage taxes, city business licences and gross-receipts style levies are yours to register for and remit alongside your quarterly federal and state estimates.
Working across a state line from Illinois
Illinois holds income-tax reciprocity agreements with Iowa, Kentucky, Michigan and Wisconsin. If you commute between them, your wages are taxed only by your state of residence — file the exemption certificate with your employer so the wrong state is not withheld from every paycheck.
Remote and hybrid work complicates this further: most states tax income where the work is physically performed, so a Chicago resident spending part of the year at a client site in Indiana may owe a nonresident return there. Keep a day-count log if you split time between states.
The rest of your Illinois tax bill
Illinois charges a 6.25% state sales tax, homeowners pay an average effective property tax of 2.07% of market value, and the minimum wage in force during 2026 is $15.00 an hour.
Chicago's combined rate reaches 10.25%, among the highest in the country.
Income tax is only one part of a state's take. Illinois recovers revenue through sales and property tax as well, which is why headline income tax rates alone are a poor guide to how far a salary really goes. Illinois does not tax retirement income at all — Social Security, pensions, 401(k) and IRA withdrawals are exempt from the flat tax.
Illinois vs Indiana on the same salary
On a $90,000 salary, a single filer keeps about $67,690 a year in Illinois against roughly $69,445 in Indiana — a difference of $1,755, or $146 a month.
Effective combined rates are 24.8% in Illinois and 22.8% in Indiana. Set that gap against living costs: index 93 here versus 90 there, with property tax at 2.07% and 0.84% respectively.
Illinois income tax brackets 2026 (single filer)
| Taxable income | Rate |
|---|---|
| $0 and up | 4.95% |