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Generally, you must withhold Illinois Income Tax if you are required to withhold (or have a voluntary agreement to withhold) federal income tax from payments you make for

You must register with us to withhold Illinois Income Tax.

As a withholding agent (person who withholds income tax), you are liable for the taxes that you are required to withhold. Because we are required to collect taxes (and issue assessments when these taxes are not paid), Illinois law states that the amounts required to be withheld and paid to us (and any penalties and interest) are considered to be a tax on you. As the withholding agent you must pay the tax even if you failed to withhold the tax from your employee.

For more detailed information, see Publication 130, Who is Required to Withhold Illinois Income Tax.

Amount withheld

For the current income tax rate, see Income Tax Rates. For more detailed information and the Illinois withholding tax amounts, see Booklet IL-700-T, Illinois Withholding Tax Tables.

Important: Per PA 100-22, effective July 1, 2017, the Illinois income tax rate increased from 3.75% (.0375) to 4.95% (.0495).

Filing and Payment Requirements

Illinois withholding income tax payments are made on Form IL-501, Withholding Payment Coupon, and Illinois withholding is reported on Form IL-941, Illinois Withholding Income Tax Return.

IMPORTANT: Make sure to use the correct version of Form IL-941 for the liability period you are filing. This is a calendar year form and each year has its own form. For example, you must use a 2017 Form IL-941 for each quarter in 2017. Also, the Form IL-941 that is available on our website must have the correct federal employer identification number (FEIN) and reporting period so the scanline that is automatically produced will have the correct information. Form IL-941s are processed according to the tax year and the scanline on the form. The scanline is the numeric code number entered on the bottom of the form that includes pertinent information for the taxpayer and filing period. Common error: a Form IL-941 is printed from our website, photocopied, the original data is covered or whited out, and new information is entered. When we receive the Form, it is applied to the period and FEIN represented in the scanline on the bottom of the page. If the scanline is incorrect or cannot be read, then the Form will not be applied to the correct period or taxpayer.

All Form IL-941 returns are due quarterly. All taxpayers are assigned to one of two payment due date schedules: semi-weekly or monthly.

Filing Requirements

Quarterly Filer
Your Form IL-941 is due by the last day of the month that follows the end of the quarter.
Quarter Months in Quarter Quarter ends IL-941 is due
1 January, February, March March 31 April 30
2 April, May, June June 30 July 31
3 July, August, September September 30 October 31
4 October, November, December December 31 January 31
Note: If a due date falls on a weekend or holiday, the due date is adjusted to the next business day.

Payment Requirements

Semi-weekly Payment Schedule
Must pay electronically

Wednesday for amounts withheld on the preceding Wednesday, Thursday, or Friday, and

Friday for amounts withheld on the preceding Saturday, Sunday, Monday, or Tuesday.

Monthly Payment Schedule
Pay electronically or use Form IL-501 by the

15th of each month for amounts withheld in the preceding month.

New taxpayers: You are automatically assigned to the monthly payment schedule and quarterly filing schedule.

See Publication 131, Withholding Income Tax Payment and Filing Requirement, for more information.

Can my due date schedule change during the year?

If you are assigned to the semi-weekly due date schedule, your schedule will not change.

If you are assigned to the monthly due date schedule, and

For more information, see Publication 131, Withholding Income Tax Filing and Payment Requirements.

Note: If you need information related to unemployment insurance or reporting new hires, refer to the Illinois Department of Employment Security.


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