Illinois Paycheck Calculator 2025

What changed between 2025 and 2026

The Illinois rate did not move — it has been 4.95% since July 2017 and Illinois has no brackets, so the state side of your paycheck changed only because the personal exemption rose. Everything else that moved was federal, or was a wage figure:

Two things on that table are worth pausing on. The federal standard deduction and bracket thresholds moved with the annual inflation adjustment, which is why federal withholding on an unchanged salary fell slightly between the two years. And the Illinois personal exemption rose by $75, worth about $3.71 a year in Illinois tax per exemption claimed — real, but small enough that most people never notice it.

The same salary, both years

Single filer, paid biweekly, no dependents and no pre-tax deductions. Every figure below is produced by the same engine that runs the calculator above:

The gains are modest and they come almost entirely from federal inflation indexing rather than from anything Illinois did. At the top of the table the picture reverses for some earners, because the Social Security wage base rose from $176,100 to $184,500 — an extra $8,400 of wages now carries 6.2% Social Security that previously escaped it, costing up to $521 more. That is the mechanism that makes a high earner's take-home fall in a year when rates supposedly went down, and it recurs almost every year.

What Illinois did not change

It is worth stating what stayed still, because it is unusual. The Illinois rate has been 4.95% for nine years. There are no brackets, so there was no bracket adjustment. There is no local wage tax anywhere in Illinois, so no city changed anything. There is no standard deduction to index and no itemized deductions to cap. For most Illinois workers the state side of a 2025 pay stub and a 2026 pay stub on the same salary differ by a couple of dollars a year — the exemption change and nothing else. Why Illinois has no brackets at all, and what the constitutional amendment attempt in 2020 was about, is covered on the tax brackets page.

Using 2025 figures now

Three reasons to want a 2025 calculation in 2026:

• Amending a 2025 return. Form IL-1040-X is the vehicle, and where the change flows from an amended federal return Illinois requires filing within 120 days of the federal change being finalized. Because Illinois begins at federal adjusted gross income, a federal amendment that moves AGI moves your Illinois tax; one that only changes itemized or below-the-line deductions generally does not. The Form IL-1040 guide walks the structure.
• Filing a 2025 return late. Illinois generally allows a refund claim within three years of the due date or two years of payment, so a late 2025 return can still produce a refund. If tax was owed, interest and penalties have been accruing since 15 April 2026.
• Reconciling an old pay stub. Switch the year selector above to 2025 and enter the gross and deductions exactly as they appeared, and the result should land within a dollar of what was withheld. Where it does not, the calculator comparison guide lists the usual causes.

One 2025 quirk worth knowing

The federal deductions for tips and overtime were enacted in July 2025, part-way through the year, and the IRS did not update the 2025 Forms W-2 and 1099 to accommodate them. Employers were given penalty relief for not reporting the amounts separately and were encouraged to supply them through Box 14 or a separate statement, while individuals were told to compute the 2025 deductions from Box 7, Form 4137 or their own pay records. Codes TP and TT appear for the first time on 2026 forms.

If you are reconstructing 2025 tips or overtime, your pay stubs are the primary evidence. And the Illinois answer is unchanged either way: both deductions sit below the adjusted gross income line, Form IL-1040 starts from AGI, and Illinois taxed every tipped and overtime dollar at 4.95% in 2025 exactly as it does now. The overtime calculator and tipped wage calculator both make the split explicit.