To fill out the Illinois UI-3/40, enter your UI account number, FEIN, and the quarter being reported at the top of the form, then use your quarterly payroll records to complete seven numbered lines: worker count, total wages, excess wages above the taxable wage base, taxable wages, contribution due at your assigned rate, any interest or penalty, and the total payment. Attach the wage detail pages listing each employee’s Social Security number, name, and quarterly wages, and submit through MyTax Illinois (required if you had 25 or more employees last year) or on paper.
What to Gather Before You Start
Have these in front of you before opening the form or logging in:
- Your seven-digit UI account number, assigned by IDES when you registered.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Reporting
- Your nine-digit Federal Employer Identification Number.
- Payroll records for the quarter: each worker’s full legal name, Social Security number, and total wages paid.
- Your annual contribution rate, taken from the most recent Annual Contribution Rate Determination notice IDES mails each year. New employers without three years of experience are assigned a standard rate until they build an experience rating.
You do not calculate the contribution rate yourself. IDES sets it based on your benefit ratio: the more unemployment claims charged against your account relative to your taxable payroll, the higher the rate.2Illinois Department of Employment Security. Annual Employer Contribution Tax Rates
Header Fields
At the top of the form, enter your seven-digit UI account number, your nine-digit FEIN, the calendar quarter and year being reported, and your business name and address.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Reporting If any of this has changed since your last filing, update it here.
Lines 1 Through 4: Workers and Wages
Line 1 — Number of covered workers. Count full-time and part-time workers who performed services or received pay during the payroll period that includes the 12th of each month in the quarter. Include workers on vacation or paid sick leave. Exclude workers on strike.
Line 2 — Total wages paid. Enter all wages paid during the quarter: salaries, commissions, bonuses, tips reported to you, separation pay, vacation pay, sick pay, and the cash value of non-cash compensation such as meals and lodging. Include wages paid to workers who have already exceeded the taxable wage base earlier in the year.
Line 3 — Excess wages. Enter the portion of each worker’s wages that exceeds the $14,250 taxable wage base for 2026. Only count excess wages from this quarter; do not carry forward excess from prior quarters.
Line 4 — Taxable wages. Subtract Line 3 from Line 2. This is the amount your contribution rate applies to.
The taxable wage base works like this: you pay unemployment tax only on the first $14,250 each worker earns in a calendar year. Once a worker’s year-to-date wages cross that threshold, any additional wages go on Line 3 and reduce your taxable total on Line 4.
Lines 5 Through 7: Contribution, Adjustments, and Total Due
Line 5A or 5B — Contribution due. Complete only one. If total wages for the quarter are under $50,000, multiply Line 4 by the lesser of your assigned rate or 5.4%. If total wages are $50,000 or more, multiply Line 4 by your assigned rate; the 5.4% cap does not apply.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Reporting
Line 6A — Interest. If you are paying after the due date, add interest at 2% per month. For the first 30 days past due, interest accrues daily at 12/365 of 2%. After 30 days, payments are treated as received on the last day of the prior month.
Line 6B — Penalty. If the report itself is filed late, the penalty is $5 for every $10,000 (or fraction) of total wages, or $2,500 per month, whichever is less. The maximum doubles to $10 per $10,000 or $5,000. The minimum is $50 regardless of payroll size.
Line 6C — Previous underpayment. If you owe from a prior quarter, enter that amount plus interest here.
Line 6D — Previous overpayment. If IDES credited you an overpayment, deduct it here.
Line 7 — Total payment due. Add Lines 5, 6A, 6B, and 6C, then subtract Line 6D.
The Wage Detail Pages
The “40” portion of the UI-3/40 is the attached wage detail. For each worker, list the Social Security number, full name, and total wages paid during the quarter. Include every worker who received any wages in the quarter, even those who left mid-quarter.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Reporting
When the Form Is Due
Each UI-3/40 covers one calendar quarter. Both the report and the payment must be received or electronically timestamped by:
- April 30 for Q1 (January–March)
- July 31 for Q2 (April–June)
- October 31 for Q3 (July–September)
- January 31 for Q4 (October–December)
Missing these dates triggers interest and penalties.3Illinois Department of Employment Security. FAQs for Employers You must file even for quarters with no wages paid; a zero-wage report can be submitted through MyTax Illinois without logging in, using just your FEIN and UI account number.4Illinois Department of Employment Security. MyTax Illinois Employers
How to Submit and Pay
MyTax Illinois
MyTax Illinois is the primary filing method and is mandatory for employers who had 25 or more employees during the prior calendar year.5Illinois Department of Employment Security. Employer Tax Information The portal lets you enter wage data manually or upload a pre-formatted file. After you verify the calculated contribution, the system generates a confirmation number; save or print it. Payment goes through ACH debit from a checking or savings account at no cost, or you can mail a check or money order separately.4Illinois Department of Employment Security. MyTax Illinois Employers
Paper Filing
Employers with fewer than 25 employees may file on paper. Download the interactive PDF from the IDES website, complete it on screen, print it, and mail it with your payment.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Reporting Employers with 25 or more employees who file on paper without authorization face additional penalties.5Illinois Department of Employment Security. Employer Tax Information
If You’re Filing Late
Two charges can stack on a late filing, and both go on the same return you eventually submit. Interest on unpaid contributions runs at 2% per month, calculated daily at 12/365 of 2% for the first 30 days; after 30 days, IDES treats a payment as received on the last day of the prior month, which effectively rounds interest up to a full additional month.1Illinois Department of Employment Security. UI-3/40 Employer’s Contribution and Wage Reporting The separate late-filing penalty starts at $5 per $10,000 of total wages (or $2,500 per month, whichever is less), doubles at the maximum, and never falls below $50. Put the interest on Line 6A and the penalty on Line 6B.
One other obligation sits alongside the quarterly report and often catches larger employers off-guard: if you had 25 or more employees at any point in the prior calendar year, you must also upload monthly wage files through MyTax Illinois for the first two months of each quarter, in addition to filing the UI-3/40.6Illinois Department of Employment Security. Monthly Wage Reporting The quarterly UI-3/40 itself covers the third month.