How do I ﬁ gure the correct
number of allowances?
Complete the worksheet on the back of
this page to ﬁ gure the correct number
of allowances you are entitled to claim.
Give your completed Form IL-W-4 to your
employer. Keep the worksheet for your
If you have more than one job or
your spouse works, you should ﬁ gure the
total number of allowances you are en-
titled to claim. Your withholding usually will
be more accurate if you claim all of your
allowances on the Form IL-W-4 for the
highest-paying job and claim zero on all of
your other IL-W-4 forms.
What if I underpay my tax?
If the amount withheld from your com-
pensation is not enough to cover your
tax liability for the year, (e.g., you have
non-wage income, such as interest or
dividends), you may reduce the number of
allowances or request that your employer
withhold an additional amount from your
pay. Otherwise, you may owe additional
tax at the end of the year. If you do not
have enough tax withheld from your pay,
and you owe more than $500 tax at the
end of the year, you may owe a late-pay-
ment penalty. You should either increase
the amount you have withheld from your
pay, or you must make estimated tax pay-
You may be assessed a late-payment
penalty if your required estimated pay-
ments are not paid in full by the due dates.
You may still owe this penalty for an
earlier quarter, even if you pay enough tax
later to make up the underpayment from a
For additional information on penalties,
see Publication 103, Uniform Penal-
ties and Interest. Visit our web site at
tax.illinois.gov to obtain a copy.
Where do I get help?
• Visit our web site at tax.illinois.gov
• Call our Taxpayer Assistance Division
at 1 800 732-8866 or 217 782-3336
• Call our TDD (telecommunications
device for the deaf) at 1 800 544-5304
• Write to
ILLINOIS DEPARTMENT OF REVENUE
PO BOX 19044
SPRINGFIELD IL 62794-9044
Illinois Department of Revenue
Employee’s Illinois Withholding Allowance
Certiﬁ cate and Instructions
Who must complete this form?
If you are an employee, you must com-
plete this form so your employer can with-
hold the correct amount of Illinois Income
Tax from your pay. The amount withheld
from your pay depends, in part, on the
number of allowances you claim on this
Even if you claimed exemption from
withholding on your federal Form W-4,
U.S. Employee’s Withholding Allowance
Certiﬁ cate, because you do not expect
to owe any federal income tax, you may
be required to have Illinois Income Tax
withheld from your pay. If you are claiming
exempt status (see Publication 131, With-
holding Income Tax Filing and Payment
Requirements) from Illinois withholding,
you must check the exempt status box on
If you do not ﬁ le a completed Form
IL-W-4 with your employer, if you fail to
sign the form or to include all necessary
information, or if you alter the form, your
employer must withhold Illinois Income Tax
on the entire amount of your compensa-
tion, without allowing any exemptions.
When must I ﬁ le?
You must ﬁ le Form IL-W-4 when Illinois
Income Tax is required to be withheld from
compensation that you receive as an em-
ployee. You should complete this form and
give it to your employer on or before the
date you start working for your employer.
You may ﬁ le a new Form IL-W-4 any time
your withholding allowances increase. If
the number of your previously claimed al-
lowances decreases, you must ﬁ le a new
Form IL-W-4 within 10 days. However, the
death of a spouse or a dependent does
not affect your withholding allowances until
the next tax year.
When does my Form IL-W-4
If you do not already have a Form IL-W-4
on ﬁ le with your employer, this form will be
effective for the ﬁ rst payment of compen-
sation made to you after this form is ﬁ led.
If you already have a Form IL-W-4 on ﬁ le
with this employer, your employer may
allow any change you ﬁ le on this form to
become effective immediately, but is not
required by law to change your withhold-
ing until the ﬁ rst payment of compensation
is made to you after the ﬁ rst day of the
next calendar quarter (that is, January 1,
April 1, July 1, or October 1) that falls at
least 30 days after the date you ﬁ le the
change with your employer.
Example: If you have a baby and ﬁ le a
new Form IL-W-4 with your employer to
claim an additional exemption for the baby,
your employer may immediately change
the withholding for all future payments of
compensation. However, if you ﬁ le the new
form on September 1, your employer does
not have to change your withholding until
the ﬁ rst payment of compensation is made
to you after October 1. If you ﬁ le the new
form on September 2, your employer does
not have to change your withholding until
the ﬁ rst payment of compensation made to
you after December 31.
How long is Form IL-W-4 valid?
Your Form IL-W-4 remains valid until a
new form you have ﬁ led takes effect or
until your employer is required by the
department to disregard it. Your employer
is required to disregard your Form IL-W-4
if you claim total exemption from Illinois
Income Tax withholding, but you have not
ﬁ led a federal Form W-4 claiming total
exemption. Also, if the Internal Revenue
Service (IRS) has instructed your em-
ployer to disregard your federal Form W-4,
your employer must also disregard your
Form IL-W-4. Finally, if you claim 15 or
more exemptions on your Form IL-W-4
without claiming at least the same number
of exemptions on your federal Form W-4,
and your employer is not required to refer
your federal Form W-4 to the IRS for re-
view, your employer must refer your Form
IL-W-4 to the department for review. In that
case, your Form IL-W-4 will be effective
unless and until the department notiﬁ es
your employer to disregard it.
What is an “exemption”?
An “exemption” is a dollar amount on
which you do not have to pay Illinois
Income Tax. Therefore, your employer will
withhold Illinois Income Tax based on your
compensation minus the exemptions to
which you are entitled.
What is an “allowance”?
The dollar amount that is exempt from
Illinois Income Tax is based on the number
of allowances you claim on this form. As
an employee, you receive one allowance
unless you are claimed as a dependent on
another person’s tax return (e.g., your par-
ents claim you as a dependent on their tax
return). If you are married, you may claim
additional allowances for your spouse and
any dependents that you are entitled to
claim for federal income tax purposes. You
also will receive additional allowances if
you or your spouse are age 65 or older, or
if you or your spouse are legally blind.
Use your mouse or Tab key to move through the fields. Use your mouse or space bar to enable check boxes.