How to File a Tax Extension for Illinois

Taxes can be hard.

Do you need more time to get all your forms in order?

In this post, we'll go over an Illinois state tax extension, which will give you additional time to organize all of your tax forms.

Whether you’re filing yourself or working with a professional, this post will answer many of the questions you have about Illinois tax extensions.

So, let’s begin.

Do I Need to File a Separate Tax Extension for Illinois If I Already Filed a Federal Tax Extension?

No, you do not need to file a separate tax extension for Illinois, as Illinois automatically grants a 6-month tax extension.

When is the Deadline to File a Tax Extension for Illinois?

There is no deadline to file a tax extension for Illinois, as Illinois automatically grants a 6-month tax extension, moving the tax filing deadline to October 15th.

Work with Our Experts!

In addition to state tax requirements, if you want extra time to file your federal taxes, you'll need to request a federal tax extension. We can help. Click here to get started.

How Do I File an Illinois Tax Extension?

You do not need to do anything to be granted a tax extension in the state of Illinois. However, you still need to pay any taxes owed by April 15th. Use Form IL-505-I to calculate and determine how much you will owe the state. 

To pay online:  

• Complete Form IL-505-I to determine the amount of tax to pay

• Go to MyTax Illinois for an easy way to pay your IL-505-I tax payment

• Go to the Individuals section

• Select "Make a Payment" for IL-505-I

• You will need your IL-PIN (Illinois Personal Identification Number)

To submit by mail:

• Complete Form IL-505-I to determine the amount of tax to pay

• Write your check and include your Social Security number, tax year, and "IL-505-I" as the reason for payment

• Complete the Payment Voucher at the bottom of Form IL-505-I

• Mail the form, your check, and voucher to:

Illinois Department of Revenue, P.O. Box 19005, Springfield, Illinois 62794-9005

Do I Need to Pay My State Taxes When I File a Tax Extension for Illinois?

Yes, you still need to pay any tax owed by April 15th, even if you wait until October 15th to file your taxes. The automatic extension just gives you more time to file, not to pay. Use the Tax Payment Worksheet in the IL-505-I form to figure out how much you owe.

What Are the Penalties for Not Making Estimated Tax Payments in Illinois?

Not making estimated tax payments can cost you big time. Here are the penalties for underpaying estimated tax:

1. Estimated Tax Payments Required

• Individuals: You need to make estimated tax payments if your Illinois income tax owed is $1,000 more than your total tax withheld plus credits.

• Corporations: $400 or more.

• Partnerships or S Corporations: If you pay pass-through entity-level tax, $500 or more.

2. Late-Payment Penalty for Underpayment

• Penalty Applies: You’ll owe a late-payment penalty if you were supposed to make estimated payments and didn’t pay the full amount by the due date.

• Refunds: You can be penalized even if you’re getting a refund.

3. Penalty Amounts

• Less than 31 days late: 2% of the amount due

• 31+ days late: 10% of the amount due

Example:

• You owed $1,500 in estimated tax and paid 25 days late. The penalty would be $30 ($1,500 x 2%).

• You owed $1,500 and paid 40 days late. The penalty would be $150 ($1,500 x 10%).

4. Forms and More

• Form IL-2210: This form calculates underpayment of estimated tax penalties for individuals.

• Form IL-2220: This form calculates underpayment of estimated tax penalties for businesses.

• Publication 103: Penalties and interest for Illinois taxes—details.

How Do I Know Whether I Should File a Tax Extension for Illinois?

You should take advantage of the automatic extension if you need more time to collect information for your return or can’t file by April 15th. But an extension doesn’t give you more time to pay taxes owed.

Is There Anything Else I Need to Know About Filing a Tax Extension for Illinois?

Yes, here are a few important points:

1. If you file your return within the automatic six-month extension period, you don't need to attach anything to your return to explain your late filing.
2. Be sure to claim any Form IL-505-I payments on your 2023 Form IL-1040, Line 26.
3. If you file after the six-month extension period and the IRS gives you more time, you must attach a copy of the federal extension when you submit your Illinois return.
4. If you expect to have difficulty paying your taxes on time, it’s advisable to contact the Illinois Department of Revenue to discuss potential payment plans or other arrangements.

Not Sure Where to Start? Let Us Help!

Get started filing your tax extension now to get an additional 6 months to file your federal tax return.

2021 Illinois Individual Income Tax Collected 

The chart explains the concentration of tax revenue in the most economically active counties in Illinois. Cook County's contribution alone constitutes a significant portion of the state's total tax revenue, highlighting its critical role.

The data also shows a steep drop-off in contributions after Cook County, with DuPage and Lake counties also making substantial, though comparatively smaller, contributions.

2021 Illinois Individual Income Tax Returns Filed

The chart emphasizes the concentration of tax return filings in Illinois's most populous and economically active counties. Cook County's dominance is particularly notable as it contributed more returns than the following nine counties combined. 

Conclusion

Illinois grants an automatic 6-month tax extension to file your return, but you must know how it works and follow the rules.  

Pay any taxes owed by April 15th, and file your return by the extended deadline to avoid penalties. 

If you're unsure about any aspect of the process, it's always best to consult with a tax professional or contact the Illinois Department of Revenue directly.