Illinois Employer Cost Calculator

The four mandatory costs

Before any benefit decision, four items sit on top of every Illinois wage. They are small individually and they are entirely predictable, which makes them easy to forget when you are budgeting a hire:

Two features of that table deserve attention. First, both unemployment taxes are capped at low wage bases, so they cost the same on a $200,000 employee as on a $25,000 one — which means their weight as a percentage of payroll falls sharply as wages rise. Second, the employer does not match the 0.9% Additional Medicare Tax on high earners; you must withhold it, but it is an employee-only tax. Both points are covered from the employee's side on the Illinois payroll taxes guide.

Your unemployment rate is not a fixed number

Illinois unemployment insurance is experience rated, which is why two identical businesses can pay wildly different amounts. Your benefit ratio — benefit charges multiplied by the benefit conversion factor, divided by taxable wages over a three, four or five year lookback — is multiplied by the state experience factor, which is 102% for 2026, then the 0.550% fund building rate is added, and the result is bounded by the 0.750% floor and 7.050% ceiling. New employers start at 3.350%.

The practical consequence is that layoffs are expensive twice: once in severance and once for years afterwards in your contribution rate. On the $14,250 wage base, moving from the minimum to the maximum rate costs about $898 per employee per year. What that money funds on the other side is set out on the unemployment benefits calculator.

Workers' compensation

Illinois requires coverage from the first employee, part-time included. Since 1983 the state has allowed insurers to set their own rates in open competition, so there is no official table to look up — your premium comes from a class code rate applied per $100 of payroll and adjusted by your experience modification factor, and a clerical class code costs a small fraction of a construction one. Enter the figure from your own policy in the calculator above rather than a rule of thumb.

What is worth knowing precisely is the cost of not having it. Illinois provides for a civil penalty of up to $500 per day of noncompliance with a $10,000 minimum, criminal exposure as a Class A misdemeanour for negligent failure and a Class 4 felony for knowing failure, personal liability for corporate officers, and work-stop orders from the Commission. And an uninsured employer forfeits the exclusive remedy protection of the Act, meaning an injured employee can sue in civil court without the damage limits the workers' compensation system imposes. That last consequence is usually far larger than the fines.

Benefits: where the real variation lives

The mandatory items above came to 9.7% of the wage in the worked example. Everything above that is a choice. National figures from the Bureau of Labor Statistics for March 2026 put total benefits at 30.1% of compensation for private industry workers — health insurance 7.3%, paid leave 7.6%, retirement 3.4%, supplemental pay 4.1%, and legally required benefits 7.2%. Those are national averages across all industries and firm sizes, so treat them as a sanity check on your own numbers rather than a prediction.

Three Illinois-specific obligations belong in the benefits column:

• Paid Leave for All Workers — one hour per 40 worked, up to 40 hours a year, for any reason and without documentation, usable after 90 days. Roughly 1.9% of payroll at the cap. Chicago and Cook County ordinances displace the state Act for employers they cover, and Chicago's requirement is larger.
• Illinois Secure Choice — mandatory to facilitate for employers with five or more Illinois employees, in business two years or more, with no qualified plan of their own. It costs nothing in contributions or fees, but not registering costs $250 per employee in the first year and $500 per employee thereafter. More detail on the Secure Choice page.
• Expense reimbursement — under 820 ILCS 115/9.5 employers must reimburse necessary expenditures incurred within the scope of employment that primarily benefit the employer. A written policy can cap the amount but cannot set it at zero or something de minimis. For remote staff this reaches internet and equipment.

Administrative obligations people forget

None of these cost much, and all of them cost something if missed:

• Register with IDES within 30 days of starting up, through MyTax Illinois or Form REG-UI-1.
• Report new hires to the Illinois New Hire Directory within 20 days of the first day on payroll.
• File Form IL-941 quarterly, due the last day of the month after each quarter. Illinois has no annual reconciliation return. Withholding payments are monthly if you withheld $12,000 or less in the lookback period, and semi-weekly above that.
• File the UI-3/40 quarterly wage report alongside your contribution payment.
• File W-2s with Illinois electronically by 31 January. Paper filing without a waiver carries a $5 penalty per form.

Employee, contractor, or the expensive mistake

Once you see the loaded cost, hiring a contractor instead starts to look attractive — and that instinct is where a great deal of Illinois enforcement activity begins. Classification is not a choice you make; it is a conclusion the facts produce, and Illinois applies a stricter test than the federal one. For unemployment purposes 820 ILCS 405/212 imposes an ABC test where the employer must prove all three prongs, and in construction the Employee Classification Act treats each misclassified person on each day as a separate violation, which compounds daily. The economics and the legal tests are worked through on the 1099 versus W-2 comparison.

If the arithmetic above is for a role you are still pricing, the salary after taxes page shows the same figures from the candidate's side — useful when a negotiation is really about take-home rather than headline salary.