7 common tax mistakes and how to avoid them

Filing an accurate tax return is critical, whether you owe money or expect a refund. But according to the IRS, more than 1.2 million potential math errors were flagged in 2024.

Filers also err by claiming the wrong credits, neglecting to include the right form or even forgetting to sign their return.

These mistakes can lead to delayed refunds and additional tax liabilities. You can fix many of them after the fact, but it's far better to get it right the first time.

"You don't want to amend your return unless you have to," says Luis Rivero Vazquez, director of tax at Taxfyle.

Check out the most common filing errors, according to the IRS, along with tips on how to avoid them.

Employers should have sent out W-2s by the end of January. But if you haven't received all the tax documents you need, you're not ready to file.

"A taxpayer will go to an accountant or boot up tax software without everything they need," said Vazquez.

Make sure you have a W-2 from your employer or know how to download one, and that you have 1099s from any freelance gigs. You may also need forms for investments, health savings accounts, retirement income, and detailed records of medical expenses, property taxes and other deductions you may take.

"A taxpayer might say, 'Oh, hey, I forgot my crypto or the small investment that I sold — but I'm getting this huge refund, so it's okay.'"

Review our list of tax forms and documentation before you sit down to do your taxes.

Math mistakes are among the most common errors, according to the IRS, ranging from basic addition and subtraction blunders to more advanced miscalculations.

Tax preparation software like TurboTax and TaxAct can upload your forms and handle the calculations automatically, avoiding errors.

Itemizing your return can save you money if your deductions and credits add up to more than the standard deduction, but it exposes you to more mistakes.

According to the IRS, filers often err with the Earned Income Tax Credit and Child Tax Credit, either in misunderstanding their eligibility or entering incorrect figures.

An accountant or tax preparation software can walk you through your eligible deductions and credits, but you'll still need to provide accurate dollar amounts, dependents and other data points.

Your filing status determines tax rates, standard deductions and eligibility for some credits. Options include:

Single: Filers who are unmarried, divorced, or legally separated on Dec. 31 can claim "Single" filing status. If you are married but lived apart from your spouse for the last six months of the year, you may be able to file as single or head of household.

Married filing jointly: Any couple in a legal marriage as of Dec. 31 can file a joint return. Partners in common-law marriages, who live apart but aren't legally separated and filers whose spouse died during the tax year can, as well. If you divorced during the tax year, you can't file jointly. 

Married filing separately: Any couple legally married as of Dec. 31 can file their tax returns separately. It's often used to avoid liability for one spouse's debts, manage individual medical expenses, or lower student loan repayments.  

Head of household, you must be unmarried or legally separated on Dec. 31 of the tax year in question. You can also be head of household if your spouse did not live with you in the last six months of the tax year. You must pay more than half of the total household costs, and have a qualifying child or dependent relative living with you for more than half the year. A dependent parent does not have to live with you, but you must pay more than half the cost of their household.

Qualifying surviving spouse: You can claim the qualifying surviving spouse filing status if all these requirements are met:

• You have had a spouse who died in either of the two prior years. You must not remarry before the end of the current tax year.
• You were entitled to file jointly the year your spouse died.
• You pay more than half the cost of keeping up your home
• Have a child, stepchild or adopted child who qualifies as your dependent or would have qualified except they don't meet the gross income test, don't meet the joint return test or you are claimed as a dependent of another taxpayer. You live with this child in your home all year.

Choosing the wrong status can mean higher tax payments, delayed or reduced refunds, penalty fees or IRS audits. But it's surprisingly common, especially the misuse of "Head of Household" status.

If you've had a big life change (such as a marriage or divorce), double-check that your filing status is correct before sending in your tax return.

Choosing direct deposit can mean receiving your refund more than twice as fast as with another payment method. But you need to use the correct routing and account numbers.

You'll find both in the bottom-left corner of your checks. The 9-digit routing number usually appears first, followed by your account number. You can also check on a statement, using your bank's app or app/website or by calling your bank.

Check that your name and Social Security number are correct on your W-2, other forms or the return itself. You may find a misspelling or a transposed digit that would have caused the IRS to delay sending your refund.

Mismatched or incorrect Social Security numbers and corresponding names are a primary cause of tax return rejections, according to the IRS. Whether caused by typos, unreported name changes or mismatched dependent information, they can lead to delayed refunds and increased attention from the IRS.

As you finish your taxes, the final step is to sign your return. According to the IRS, an unsigned tax return isn't valid. If you're filing jointly, both spouses must sign.

Have you followed all these steps and are now ready to file your return? Vazquez recommends giving it a second read-through, paying close attention to your adjusted gross income, charitable contributions and medical expenses (if you itemize), and the amount of tax you've already paid through withholding or estimated tax payments.

Whether you've done your taxes yourself or had an accountant work on them, don't just swiftly sign off to be done with the process.

"I'd want to know, 'Does this agree with what I was expecting?' If it doesn't, can the CPA explain to me why I was off?"

And after you file, make sure you get confirmation it's been accepted.

"Get a confirmation that your return got filed on time and that you have something that says your return with your Social Security number got accepted," Vazquez said

You can confirm with your accountant or via the IRS online portal or the Where's My Refund page.

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