Do I Still Have to Pay Taxes If I File an Extension?

As the tax deadline approaches, many taxpayers in Chicago and across Illinois ask the same urgent question: do I still have to pay taxes if I file an extension?

The answer is yes. A tax extension gives you more time to submit your return, but it does not change when your taxes are due. This confusion is one of the most common reasons taxpayers end up with penalties and interest, even though they believe they followed the rules.

Understanding how extensions actually work can help you decide whether filing one makes sense and whether additional guidance before the deadline could prevent unnecessary costs later.

What a Tax Extension Actually Does

A federal tax extension moves your filing deadline, not your payment deadline.

When you file an extension, the IRS allows extra time to submit your completed return. However, the IRS still expects you to estimate your tax liability and pay what you owe by the original deadline. This distinction is especially important for taxpayers whose returns involve more than basic W-2 wages.

Taxpayers with self-employment income, investment activity, rental properties, or multiple income sources often benefit from reviewing their situation as part of a broader tax preparation process rather than relying on assumptions about how extensions work.

When Are Taxes Still Due If You File an Extension?

For most taxpayers, the payment deadline does not change when an extension is filed.

Federal income taxes remain due by the original IRS deadline, and Illinois income taxes are generally due by the same date. Filing an extension without paying enough can result in interest and penalties, even if the return itself is filed correctly later.

This situation is common for Chicago-area taxpayers who discover late in the process that they owe more than expected due to side income, under-withholding, or changes in deductions.

What Happens If You File an Extension but Do Not Pay?

If you file an extension but do not pay enough by the deadline, the IRS may still assess penalties and interest on the unpaid balance. While an extension can reduce failure-to-file penalties, it does not protect you from the cost of paying late.

Illinois applies similar rules at the state level, which means taxpayers may face both federal and state consequences if balances are not addressed on time.

This is why many taxpayers evaluate payment strategies or timing decisions before extending, especially when they expect to owe and want to minimize penalties.

Can an Extension Ever Be Helpful?

Yes, an extension can be helpful when records are incomplete or when additional time is needed to file accurately.

An extension may reduce filing-related penalties and lower the risk of errors that lead to amended returns or IRS correspondence. It can also provide time to coordinate decisions that affect how income and deductions are reported through proactive tax planning.

Illinois Extensions and Chicago Filers

Illinois generally follows federal extension rules for filing, but payment deadlines still apply. An extension allows additional time to file the IL-1040, but Illinois taxes owed are still due by the original deadline.

This becomes more complicated for taxpayers with income earned outside Illinois, recent residency changes, or multi-state filing requirements. In those cases, estimating tax owed accurately before filing an extension is especially important.

Self-Employed and 1099 Taxpayers

Self-employed individuals are among the most affected by extension misunderstandings.

Without regular withholding, it is easy to underestimate self-employment tax or overlook income reported on Forms 1099-NEC or 1099-K. Filing an extension without addressing payment can quickly compound penalties.

Many self-employed taxpayers find it helpful to review their income and estimated obligations as part of their small business tax reporting before deciding whether to extend.

Multi-State and Nonresident Returns

Taxpayers who earned income in more than one state face additional complexity when filing an extension.

Different states have different rules for extensions, payment deadlines, and credits for taxes paid elsewhere. Nonresident returns often require careful income allocation, which makes estimating tax owed more challenging.

In these situations, extensions should be used carefully, with attention to both filing and payment requirements across jurisdictions.

How CPA Oversight Helps With Extensions

A CPA’s role during an extension goes beyond submitting a form.

Professional review can help estimate federal and Illinois tax liability, identify missing income or deductions, and reduce the likelihood of penalties by addressing payment requirements early. This level of oversight is particularly valuable for taxpayers with business income, investments, or recent financial changes.

Many Chicago taxpayers choose to work with a CPA in Chicago before filing an extension so they are not surprised by penalties or notices later in the year.

Final Answer: Do You Still Have to Pay If You File an Extension?

Yes. Filing an extension does not delay when taxes are due. It only delays when your return must be filed.

If you owe taxes, payment is still required by the original deadline, and interest and penalties apply to unpaid balances. Addressing payment and planning issues before filing or extending is often far less costly than fixing problems later.