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Tax year 2026

Illinois vs Kentucky Income Tax — 2026

A single filer earning $100,000 pays $1,423 less per year in Kentucky than in Illinois — $119 a month. Illinois charges $4,805; Kentucky charges $3,382.

Why this pair has a page: bordering states.

Illinois at $100K
$4,805
4.81%
Kentucky at $100K
$3,382
3.38%
Annual difference
$1,423
$119 a month
National ranks
42 vs 20
of 50, lowest tax first

The bill at every income

Single filer, standard deduction, no dependents. State income tax only.

Illinois and Kentucky income tax compared at seven income levels, 2026
Gross incomeIllinois taxKentucky taxDifference
$50,000$2,330$1,632$698 less in KY
$75,000$3,568$2,507$1,060 less in KY
$100,000$4,805$3,382$1,423 less in KY
$150,000$7,280$5,132$2,148 less in KY
$250,000$12,230$8,632$3,598 less in KY
$500,000$24,605$17,382$7,223 less in KY
$1,000,000$49,355$34,882$14,473 less in KY
Annual state income tax, Illinois versus Kentucky
IL at $50,000: $2,330IL at $50,000$2,330KY at $50,000: $1,632KY at $50,000$1,632IL at $75,000: $3,568IL at $75,000$3,568KY at $75,000: $2,507KY at $75,000$2,507IL at $100,000: $4,805IL at $100,000$4,805KY at $100,000: $3,382KY at $100,000$3,382IL at $150,000: $7,280IL at $150,000$7,280KY at $150,000: $5,132KY at $150,000$5,132IL at $250,000: $12,230IL at $250,000$12,230KY at $250,000: $8,632KY at $250,000$8,632IL at $500,000: $24,605IL at $500,000$24,605KY at $500,000: $17,382KY at $500,000$17,382IL at $1,000,000: $49,355IL at $1,000,000$49,355KY at $1,000,000: $34,882KY at $1,000,000$34,882

How the two systems differ

Illinois and Kentucky income tax systems compared
IllinoisKentucky
Tax structureFlat rateFlat rate
Top marginal rate4.95%3.5%
Number of brackets11
Standard deduction (single)None$3,360
Personal exemption$2,925None
Local income taxesNoYes
Capital gainsordinaryordinary
Population (2024)12,710,1584,588,372

By filing status

Illinois and Kentucky tax on $100,000 by filing status, 2026
Filing statusIllinoisKentuckyDifference
Single$4,805$3,382$1,423 less in KY
Married filing jointly$4,660$3,382$1,278 less in KY
Married filing separately$4,805$3,382$1,423 less in KY
Head of household$4,805$3,382$1,423 less in KY

Change the assumptions

Adjust income and filing status, or swap either state. The URL updates so you can share the exact comparison.

At $100,000 as a single filer, Kentucky costs $1,423 less per year than Illinois — $119 a month.

Illinois compared with Kentucky at $100,000
IllinoisKentuckyDifference
State income tax$4,805$3,382$1,423
Per month$400$282$119
Effective rate4.81%3.38%1.42 pts
Marginal rate4.95%3.5%1.45 pts
Standard deduction$0$3,360$3,360
Taxable income$97,075$96,640$435
Tax structureFlat rateFlat rate
Local income taxesNoYes

Local taxes are not included above. Kentucky has localities that levy their own income tax on top of the state figure. See each state page for the rates that apply.

Full detail: Illinois · Kentucky · methodology

Local income taxes change this picture

What this comparison leaves out

Sources for both states

  1. 1.Illinois Department of RevenueState revenue department
    FY 2026-15, What's New for Illinois Income Taxes
    https://tax.illinois.gov/research/publications/bulletins/fy-2026-15.html
    Retrieved · "The personal exemption amount for tax year 2026 will increase to $2,925." Also states the $500,000 / $250,000 AGI cut-off.
  2. 2.Kentucky Department of RevenueState revenue department
    2026 Kentucky Withholding Tax Formula (42A003 (TCF)(10-2025))
    https://revenue.ky.gov/Forms/2026%20Withholding%20Formula.pdf
    Retrieved · "2026 Kentucky Standard Deduction: $3,360. 2026 Kentucky Tax Rate: 3.5% of taxable income."
  3. 3.Tax FoundationResearch organisation (cross-check)
    Kentucky Tax Rates & Rankings
    https://taxfoundation.org/location/kentucky/
    Retrieved · Cross-check: "Kentucky has a flat 3.50 percent individual income tax rate."

Figures on this page were last checked against these sources on . Found something wrong? Report it.