Illinois Payroll Calculator

Estimate your Illinois take-home pay per paycheck using 2026 tax figures: federal income tax under the 2026 brackets and standard deductions, Illinois’s flat 4.95% income tax, Social Security at 6.2% up to the 2026 wage base of $184,500, and Medicare. The tool also shows what the same paycheck costs your employer once the matching payroll taxes are added.

Quick Answer

How to use the Illinois payroll calculator

Enter one paycheck’s gross pay, your pay schedule and your federal filing status, then click Calculate. The breakdown appears only after you click, and every line of it is printed so you can check the arithmetic yourself.

1. Gross pay per paycheck: the amount before anything comes out. Salaried workers divide annual salary by the number of pay periods; hourly workers use hours times rate for the period, including any overtime or bonus paid in it.
2. Pay frequency: weekly, biweekly, semimonthly or monthly. Biweekly (26) and semimonthly (24) are not the same schedule, and picking the wrong one shifts every annualized figure.
3. Filing status: single, married filing jointly or head of household, exactly as it appears on your federal W-4. It drives both the standard deduction and the bracket schedule, following the method the IRS sets out in Publication 15-T for federal income tax withholding.
4. Extra withholding: copy the per-paycheck extra amount from Step 4(c) of your W-4 if you have one. It is added dollar for dollar to the deductions.
5. Read the employer line separately: it is not money taken from you. It is your gross pay plus your employer’s matching payroll taxes, the starting point for what a job really costs.

If the paycheck you are checking covers a bonus rather than regular wages, the bonus take-home pay calculator handles the flat supplemental withholding treatment bonuses usually get. To see the same net pay expressed per day instead of per period, run the result through the daily net pay calculator.

The 2026 figures inside the tool

Four published figure sets drive every result: the 2026 standard deductions, the 2026 federal brackets, the 2026 Social Security wage base, and the Illinois flat rate.

The standard deductions and brackets come from the IRS inflation adjustments for tax year 2026, Revenue Procedure 2025-32. The 2026 single-filer brackets the tool applies to taxable income are:

Married filing jointly uses its own schedule (thresholds of $24,800, $100,800, $211,400, $403,550, $512,450 and $768,700) and head of household uses thresholds of $17,700, $67,450, $105,700, $201,750, $256,200 and $640,600. One correction worth stating openly: an earlier version of this tool carried the single-filer $201,775 and $256,225 cutoffs inside the head-of-household schedule. Revenue Procedure 2025-32 sets those two head-of-household cutoffs at $201,750 and $256,200, and the tool now uses the correct figures. The difference is worth at most about $2.75 of federal tax a year, but a payroll tool should not round its brackets.

Worked example: $3,800 biweekly, checked line by line

A single filer paid $3,800 every two weeks, with no extra withholding, grosses $98,800 a year. Every figure below is the tool’s own output for that run.

Annual gross = $3,800 × 26 = $98,800. Taxable income = $98,800 − $16,100 standard deduction = $82,700. Federal tax = $5,800 on the first $50,400 plus 22% of the remaining $32,300 = $12,906 a year, or $496.38 per paycheck. Illinois tax = $3,800 × 4.95% = $188.10. Social Security = $3,800 × 6.2% = $235.60, under the per-period cap of $7,096.15 ($184,500 ÷ 26). Medicare = $3,800 × 1.45% = $55.10. Total deductions $975.18; net pay $2,824.82.

Three more verified runs of the same tool, covering a different schedule, a different status and the Social Security cap:

In the third run the Social Security line stops at the cap: 6.2% of the $7,096.15 per-period wage base is $439.96, not 6.2% of the full $10,000. Comparing offers on an hourly basis instead? The hourly after-taxes calculator starts from an hourly rate and works forward to the same kind of breakdown.

What the additional Medicare tax line means

High earners owe an extra 0.9% Medicare tax on wages above an annual threshold: $200,000 for single and head of household filers, $250,000 for married filing jointly, as the IRS explains in its Additional Medicare Tax guidance.

Because a paycheck calculator does not track year-to-date wages, this tool approximates the tax per pay period: 0.9% of the amount by which this paycheck exceeds the threshold divided by the number of pay periods. On the $10,000 biweekly run above, that is 0.9% of ($10,000 − $7,692.31) = $20.77. If a raise pushes you over the threshold mid-year, real withholding only starts once your employer sees year-to-date wages pass the threshold, so early paychecks in a high-paying job can differ from the steady estimate shown here. There is no employer match on the additional tax, which is why it never appears in the employer cost line.

The Illinois exemption this estimate leaves out, on purpose

Illinois withholding in real payroll is 4.95% of wages minus exemptions, not 4.95% of full wages. Under Booklet IL-700-T, the Illinois withholding tax tables, each allowance claimed on Form IL-W-4 shelters $2,925 of annual wages for 2026.

This tool has no allowance input, so its Illinois line equals the zero-allowance case: the same withholding an employer applies when no IL-W-4 is on file. If you claim one allowance, expect your actual state withholding to run about $144.79 a year lower than the estimate (about $5.57 per biweekly paycheck); two allowances, about twice that. The rate, the brackets on the federal side and every other line are unaffected. Illinois households checking benefit eligibility alongside wages may also want the Illinois EBT calculator, which works the SNAP side of the same budget.

What the employer cost line shows, and what it leaves out

The employer cost line is your gross pay plus the two payroll taxes your employer matches: 6.2% Social Security and 1.45% Medicare, $4,090.70 on the worked example.

It is a floor, not a full labor cost. Federal and Illinois unemployment insurance, workers’ compensation premiums, health coverage, retirement matches and paid-leave costs all sit on top, and none of them is in this tool. Read the line as “the least this paycheck can cost the employer in cash taxes” and it is exact; read it as total compensation cost and it understates, sometimes by a wide margin.

What competing calculators miss

The Illinois paycheck field splits into heavyweight payroll engines and thin annual estimators. Both groups leave specific gaps:

• PaycheckCity’s Illinois hourly calculator is the most complete rival: full 2020 W-4 steps, dependents, other income, deductions and Illinois basic and additional allowances. The cost is a dense multi-rate form most employees cannot complete from a pay stub, and the result arrives without the per-line arithmetic shown.
• ADP’s Illinois paycheck calculator carries the payroll industry’s authority but sits inside a sales funnel for ADP services, states its figures are general guidance only, and does not print the bracket math behind its federal line.
• SmartAsset-style paycheck tools add 401(k), health premiums and local taxes, which this tool honestly lacks, but they spread one engine across all 50 states, so Illinois specifics like the IL-W-4 allowance value never surface.
• Annual salary-after-tax estimators divide the year into averages and say so themselves: the weekly or biweekly figure is an annual result split evenly, not a per-paycheck computation with a per-period Social Security cap or additional Medicare threshold.
• Smaller state paycheck pages quietly apply 4.95% to full gross pay without telling you that equals zero-allowance withholding. This page states that choice in the open, prices one allowance at about $144.79 a year, and corrects its own head-of-household brackets against Revenue Procedure 2025-32 instead of leaving the error in place.

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