How much interest will I pay if I file a tax extension?

Asked by: Jedediah Morissette  |  Last update: August 12, 2026
Score: 4.8/5 (52 votes)

A tax extension (Form 4868) gives you six extra months to file, but not more time to pay, so you will owe interest on any unpaid taxes from the original April deadline. The IRS charges interest at the federal short-term rate plus 3%, compounded daily, with rates adjusted quarterly. You may also face a 0.5% monthly failure-to-pay penalty.

Do you pay interest if you file an extension on taxes?

It lets you delay filing and paying taxes without penalty. But you'll still be charged interest after the April deadline.

Is there a downside to filing a tax extension?

An extension gives you extra time to file, but not extra time to pay. After you file an extension, if you owe taxes when you file your return, you might also have to pay penalties and interest on the tax due.

What is the interest rate on late taxes?

Generally, interest accrues on any unpaid tax from the due date of the return (without any extensions) until the date of payment in full. The interest rate is determined quarterly and is the federal short-term rate plus 3 percent. Interest compounds daily.

Will I be penalized for filing an extension on my taxes?

If you need more time to file your taxes, request an extension by the April tax filing due date. This gives you until October 15 to file without penalties.

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Is filing an extension a red flag?

For those who are terrified of extensions, remember that they're okay. Unless you file for extensions for years and years, they're not going to increase your chance of being audited, and they won't have any consequences if you pay your taxes on time.

What happens if I file taxes after October 15th?

If you file taxes after the October 15 extension deadline, the IRS will assess penalties and interest, primarily a failure-to-file penalty (5% per month, max 25%), plus a separate failure-to-pay penalty (0.5% per month) and daily interest on the unpaid taxes, though you can request penalty abatement for reasonable cause like natural disasters. The October deadline is for filing, not paying; if you owe, payment was due in April, so you'll likely face both penalties and interest until you file and pay, but you won't be penalized if you're due a refund. 

Can I get an extension to avoid the penalty?

You may request up to an additional 6 months to file your U.S. individual income tax return. There are three ways to request an automatic extension of time to file your return. You must request the extension of time to file by the due date of your return to avoid the penalty for filing late.

How much interest is payable on delayed payment of taxes?

Interest is levied at 1% per month or part of a month on the tax amount outstanding. The interest that needs to be paid is simple interest. The taxpayer is liable to pay simple interest at 1% per month or part of a month for the delay in filing their tax return.

Does filing an extension trigger an audit?

And remember: tax filing extensions do NOT increase your audit risk. As long as you pay any taxes owed by the original deadline and file your return by the extended deadline, you're in good shape.

What are the biggest tax mistakes people make?

The biggest tax mistakes people make include filing late, math errors, incorrect personal info (like Social Security numbers), forgetting deductions/credits (like EITC), misreporting income, not signing forms, and making errors with bank details for direct deposit, all leading to delays, penalties, or missed savings, with using tax software or professionals helping avoid these common pitfalls.

How much does the IRS charge for an extension?

How much does a tax extension cost? Filing a tax extension is free and automatic once you file Form 4868. You don't need to pay any fees to file and it's approved by the IRS once you file electronically or on paper by the filing deadline.

How much interest do you pay on a late tax return?

Is there a penalty for filing taxes late? If you file your taxes late and owe money, the CRA charges you a penalty on the taxes owed. The first time you are late on your taxes, the CRA interest rate on your balance owing is 5%, plus an additional 1% percent for each month they're late—up to 12 months.

Does filing a tax extension hurt your credit?

Your taxes don't affect your credit scores in any way. However, taking out a loan or credit card to pay your taxes can impact your credit scores.

Should I file an extension if I owe nothing?

Do I Need to File an Extension If I Don't Owe? If you are due a refund, you do not need to file an extension. The IRS allows up to three years from the original filing deadline to submit your return and claim your refund.

What is a reasonable excuse for late filing penalty?

A reasonable excuse is something that stopped you meeting a tax obligation for a valid reason, for example: your partner or another close relative died shortly before the tax return or payment deadline. you had an unexpected stay in hospital that prevented you from dealing with your tax affairs.

What are valid reasons for a tax extension?

However, the IRS does grant you an automatic extension to file your taxes every year, as long as you complete Form 4868. Common reasons for requesting an extension include a lack of organization, unanticipated events or tax planning purposes.

What is the IRS $10,000 rule?

The IRS "10k rule" primarily refers to the requirement for businesses and financial institutions to report cash transactions over $10,000 by filing Form 8300 (for businesses) or a Currency Transaction Report (CTR) (for banks), under the Bank Secrecy Act. This rule helps combat money laundering, tax evasion, and terrorist financing, requiring reporting for single transactions or related transactions totaling over $10,000 in cash within a year, with penalties for non-compliance.

How do you avoid the 22% tax bracket?

To avoid the 22% tax bracket (or any higher bracket), focus on reducing your taxable income through strategies like maxing out 401(k)s and HSAs, deferring bonuses, tax-loss harvesting, smart charitable giving, and strategic asset location, understanding that higher rates only apply to income within that bracket, not your entire income.

What is the 20k rule?

The "20k rule" refers to the traditional IRS threshold for reporting income from payment apps and online marketplaces on Form 1099-K: over $20,000 in gross payments AND more than 200 transactions in a calendar year. While a law (the American Rescue Plan) temporarily lowered the threshold to $600, recent legislation, the One Big Beautiful Bill Act (OBBBA) (OBBBA), has reinstated the $20,000/200-transaction rule for tax years starting in 2025, providing relief for casual sellers and gig workers. 

What happens if I file taxes after April 15, 2025?

But here's generally what you can expect. No penalty if you're getting a tax refund. However, you must file your 2025 taxes by April 15, 2029 (or October 15, 2029 if you filed an extension). After that, any unclaimed tax refund gets turned over to the US Treasury.

Does filing an extension increase audit risk?

❌ False. Filing an extension does not increase your chances of being audited. The IRS selects returns for audits using a variety of methods, including: Discriminant Information Function (DIF): This computerized system scores returns based on various factors, with higher scores more likely to trigger an audit.

How late can I file a tax extension?

At a glance

October 15 is the final extended tax deadline to file your return if you requested an extension with Form 4868. If you miss the October extended tax filing deadline, you'll have failure-to-file penalties and, potentially, failure-to-pay penalties if you still owe taxes.