Don’t Make These 5 Common Mistakes on Your Tax Return
The IRS warns taxpayers to watch out for these common errors as they prepare to file.
The 2026 tax season is in full swing, and the last thing you want is to file an incorrect return and wait through delays or worse — a rejected return.
The IRS has pointed out the most common errors taxpayers make as they file their taxes, from something as seemingly small as a misspelled name to accidentally entering the wrong bank account number for a direct deposit.
These kinds of subtle tax preparation flaws can be easy to miss, especially when dealing with multiple documents. However, watching for these inaccuracies can save you the headache of correcting or re-filing your tax return if you’re filing.
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Here are some common tax errors you should avoid on your current tax return.
Common tax return mistakes to avoid
Note: These are just five mistakes the IRS points out as commonly made on federal income tax returns. If you're uncertain about whether your return is correct, you may want to consult a trusted tax professional.
1. Missing or incorrect Social Security Number
The IRS requires taxpayers to include their Social Security number (SSN) on a tax return exactly as the number is printed on their Social Security card.
The same goes for other identification numbers on your tax return, such as an individual taxpayer identification number (ITIN) and employer identification number (EIN).
If you don’t have a SSN, but are eligible for one, you must fill out a Form SS-5 to apply and receive your Social Security number. This form can be used to apply for an original SSN, request a replacement for your card, or change or correct information on your SSN record.
There is one exception, if a child or dependent is age 12 or older and never received a SSN, the application process must be in person. The Social Security Administration will determine if you are eligible for the SSN.
Don’t have a SSN? There’s another option:
- Taxpayers not eligible for an SSN must have an IRS individual taxpayer identification number (ITIN).
- ITINs are 9-digit numbers issued by the IRS to taxpayers that don’t have a SSN for U.S. federal tax purposes.
- If you do not have one, you must apply for the ITIN using a Form W-7.
Additionally, businesses, tax-exempt organizations, and other employers engaged in business as a sole proprietor must have an Employer Identification Number (EIN). If you don’t have an EIN, you can apply online.
2. Filing with an expired ITIN
Speaking of identification numbers, another common mistake is filing with an expired individual taxpayer identification number.
An ITIN expires if it remains inactive on a U.S. federal tax return for 3 consecutive tax years. The identification number effectively expires on December 31 after the third tax year of non-use.
This may happen to individuals who don’t earn enough to file for taxes, and more commonly, younger adults or students. You can check the status of your ITIN on your IRS Online Account.
What happens if you file taxes with an expired ITIN? You may face a delay in processing your return or not be able to claim certain credits, unless you renew your ITIN. Worse off, that may result in penalties and interest, or a reduced refund.
Notably, you don’t need an ITIN to request an extension or pay an estimated tax.
3. Typos and math mistakes
It’s only human error to have a typo once in a while, but having one on your tax return may result in a rejected return or delayed return. What are some common slip-ups?
Misspelled names: The name on your tax return should match the name on your Social Security card, for example.
Incorrect bank account number: If you entered the wrong bank account number, you should contact the IRS to stop the direct deposit. The IRS will mail you your refund.
Math mistakes: Even a simple calculation error on your return may lead to delays in some circumstances. Generally, math errors are caught during processing and corrected by the IRS, so you don’t have to worry about filing an amended return.
The IRS should notify taxpayers of the correction with a “math error notice” and provide further instructions if more information is needed.
As Kiplinger has reported, a new law makes these notifications mandatory and will hopefully clarify the process for addressing minor math mistakes. For more information, see our report: IRS Says You Made a Tax Return Mistake? A New Law Could Help You Fight Back.
4. Incorrect filing status, dependents, and more
If you accidentally filed your tax return with an incorrect filing status, dependents, total income, or deductions or credits, you’ll have to file an amended return. To do so, use Form 1040-X (Amended U.S. Individual Income Tax Return).
Avoid errors when figuring tax credits and deductions: If you’re unsure how to figure your Earned Income Tax Credit (EITC), or Child and Dependent Care Credit. The IRS offers an interactive tax assistant that can help you calculate your credits and deductions, and identify the required forms and schedules you must complete.
Related: A Bunch of Tax Credits and Deductions You Need to Know
5. Unsigned forms
Lastly, an unsigned tax return is not considered a valid return by the IRS. This error may result in a delinquency penalty on your tax return if the agency finds the taxpayer willfully did not sign the tax return.
The IRS will return unsigned income tax returns requesting that you sign and resubmit the form for processing.
Filing taxes: What you can do
As you prepare to file your tax return this year, review your tax documents before submitting them to the IRS.
One pro-tip to avoid errors this tax season is to file your taxes electronically. According to the IRS, this reduces errors because the tax software does the math for you and flags common errors or missing information as you complete your return.
You can file for free or with the help of a Volunteer Income Tax Assistance (VITA) or tax counseling for the elderly (TCE) programs. You should also opt for a direct deposit to avoid getting your refund lost or stolen in the mail.
Lastly, using a reputable tax preparer, a certified public accountant, or commercial tax preparation software can help you avoid unwanted mistakes on your tax return.
Read More
- Tax Season 2026 is Here: Key IRS Changes to Know Before You File
- A Bunch of IRS Tax Deductions and Credits You Need to Know
- IRS Audit Red Flags to Avoid
