To fill out Illinois Form UI-3/40, the Employer’s Contribution and Wage Report, enter your seven-digit UI Account Number and nine-digit FEIN at the top, report total gross wages paid during the quarter, calculate taxable wages using the $14,250 per-employee wage base, multiply by your assigned contribution rate to get the amount due, and list every employee’s Social Security number, name, and gross wages on the wage-listing pages.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report The report and the payment are both due by the last day of the month following the quarter’s end, and most employers file through the MyTax Illinois portal.2Illinois Department of Employment Security. Employer Tax Information
What You Need Before You Start
Three pieces of information drive the whole form.
Your UI Account Number is seven digits. IDES issues it after you register as a new employer, along with your assigned contribution rate. If you see a reference to a 15-digit account number in older instructions, ignore it; the number on your IDES correspondence is seven digits.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report
Your contribution rate comes from the Rate Notice IDES mails each year. For 2026, experience-rated rates run from 0.750% to 7.050%, plus a fund-building surcharge of 0.550%. Employers with fewer than three years of experience in the system pay the standard ineligible rate of 3.350% until enough history accumulates for an experience-based calculation.3Illinois Department of Employment Security. 2026 Historical Rate Chart Use the rate on the notice for every quarterly filing in that calendar year.4Illinois Department of Employment Security. Annual Employer Contribution Rates
The taxable wage base is $14,250 per employee for the year. You owe contributions only on the first $14,250 each worker earns during the calendar year. Once a worker’s year-to-date wages pass that figure, their additional earnings for the rest of the year drop out of your taxable total, though their gross wages still show up on the wage listing.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report
Filling Out the Summary Section
The summary section sits at the top of the form and produces the amount you owe.
Enter your seven-digit UI Account Number and your nine-digit FEIN in the identifying fields.
Report total wages paid to all employees during the quarter. This is the full gross figure, before any deductions for taxes, insurance, or retirement.
Calculate taxable wages. For each employee, count only wages up to the $14,250 annual cap. Add those capped amounts across all employees to get the quarter’s taxable wage total. Early in the year most employees will still be below the cap and their full wages count; later quarters typically show taxable wages well below total wages as more workers cross the threshold.
Multiply taxable wages by your assigned contribution rate. That result is the contribution due for the quarter. Subtract any prior overpayments you’re applying. If you’re filing late, the form also has lines for penalty and interest, which are covered further down.
Filling Out the Employee Wage Listing
For every person who earned wages during the quarter, list:1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report
- Social Security number — all nine digits, no hyphens
- Full legal name — first name, middle initial, last name
- Total gross wages paid during the quarter
Report each worker’s full gross wages on the listing, including amounts above the $14,250 annual cap. The cap applies to your taxable-wage calculation in the summary, not to what appears here. IDES uses the wage listing to determine individual eligibility for benefits and to track your account’s experience rating.
Before you submit, add the individual wages on the listing and confirm the sum matches the total wages line in the summary section. Mismatches between the two figures are one of the most common errors on this form and will trigger a notice from IDES.
How and Where to File
IDES accepts the UI-3/40 through four channels:2Illinois Department of Employment Security. Employer Tax Information
- MyTax Illinois (mytax.illinois.gov). The primary online portal. Enter wages, verify totals, and submit with an electronic signature. Save the confirmation number the system produces.
- Fed/State Employment Taxes Program (FSET). An electronic channel that lets employers and payroll companies file federal and Illinois employment taxes together.
- File Transfer Protocol (FTP). For large employers and payroll processors handling many accounts. IDES publishes ICESA and CSV file-format guides for structuring the upload.5Illinois Department of Employment Security. FAQs for Employers
- Paper form. Available only to employers with fewer than 25 employees. Mail to IDES, PO Box 19300, Springfield, IL 62794-9300.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report
Employers with 25 or more employees during the prior calendar year must file electronically. Paper is not an option at that size.
Quarterly due dates:
- Q1 (January–March): April 30
- Q2 (April–June): July 31
- Q3 (July–September): October 31
- Q4 (October–December): January 31
The report and the payment are both due by these dates.6Illinois Department of Employment Security. Quarterly Filing Requirements If you need more time, email DES.TaxNetExtensions@Illinois.gov before the due date with your account number and the quarter involved. A granted extension adds 30 days to the filing deadline.2Illinois Department of Employment Security. Employer Tax Information
File every quarter, even when you paid no wages. You can submit a zero-wage report through MyTax Illinois without logging in by entering your FEIN and UI Account Number.
Paying the Contribution
Contributions are due at the same time as the report. IDES accepts two payment methods: ACH debit (free) from a checking or savings account through MyTax Illinois, and check or money order sent by mail.7Illinois Department of Employment Security. MyTax Illinois Employers Credit card payments are not currently available for UI contributions.
If You File or Pay Late
The late-filing penalty is $5 for each $10,000 (or fraction) of total wages reported, or $2,500 per month, whichever is less. If the report runs more than one month late, the penalty doubles to $10 per $10,000 of total wages or $5,000, whichever is less. The minimum penalty is $50.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report
Unpaid contributions accrue interest at 2% per month, calculated on a daily basis (12/365 of 2% per day) for the first 30 days past the due date. After 30 days, payments are treated as received on the last day of the month before the month IDES actually gets them, so the interest calculation rounds up.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Report The effective annual rate is 24%.
Monthly Reports for Larger Employers
If your workforce reached a cumulative total of 25 or more employees during the prior calendar year, the quarterly UI-3/40 is not the whole obligation. You also file monthly wage reports electronically through MyTax Illinois containing each employee’s name, Social Security number, and total wages for the month.2Illinois Department of Employment Security. Employer Tax Information No payment goes with the monthly report; the contribution is still paid quarterly with the UI-3/40. A monthly filing extension of 15 additional days is available through the same email address used for quarterly extensions.