How to avoid costly tax day mistakes

[UNITED STATES] As Tax Day rapidly approaches, millions of Americans are scrambling to prepare their tax returns. Whether you're filing as an individual or a business, it's important to avoid common mistakes that can lead to penalties, delayed refunds, or missed opportunities for deductions. In this article, we'll highlight the most costly tax mistakes and provide tips on how to avoid them, ensuring a smooth filing process.

1. Missing the Tax Filing Deadline

The most common mistake taxpayers make is simply missing the tax filing deadline. Each year, the IRS sets a deadline for individual tax returns, typically on April 15th, unless that date falls on a weekend or holiday. In 2025, the filing deadline is April 15th, so be sure to mark your calendars.

How to Avoid This Mistake:

• File early to avoid last-minute stress.
• Use IRS tools like "Free File" or consider hiring a tax professional if you're unsure about the filing process.
• If you can't file on time, consider filing for an extension, which gives you until October 15th to submit your return. However, remember that an extension to file is not an extension to pay. If you owe taxes, interest and penalties may accrue.

2. Not Double-Checking Your Information

A simple mistake on your tax return, like a misspelled name or incorrect Social Security number, can result in delays or even penalties. It's easy to overlook these small details, but they are essential to ensuring your tax return is processed smoothly.

How to Avoid This Mistake:

• Review your tax forms carefully before submitting.
• Cross-check your Social Security number and other personal details on your return with the information on your W-2 or 1099 forms.
• If filing jointly, verify your spouse's information as well.

3. Forgetting to Report All Income

One of the most expensive tax mistakes you can make is underreporting your income. Whether it's from freelance work, side gigs, or investment earnings, failing to report all sources of income can result in hefty penalties and fines.

How to Avoid This Mistake:

• Gather all your income documents, such as W-2s, 1099s, and investment earnings.
• Be diligent about reporting income from freelance work, side jobs, and other non-traditional sources.
• If you're unsure about a specific source of income, consult with a tax professional to ensure you report it correctly.

4. Overlooking Deductions and Credits

Taxpayers often overlook valuable deductions and credits that could reduce their taxable income and lower their tax liability. This mistake can leave money on the table.

How to Avoid This Mistake:

• Take advantage of common deductions such as mortgage interest, student loan interest, and medical expenses.
• Explore tax credits that could apply to you, such as the Child Tax Credit, Earned Income Tax Credit, and Education Credits.
• Keep track of your expenses throughout the year to ensure you're not missing any deductible expenses.

As tax expert Jean Chatzky stated, "Many taxpayers leave money on the table because they don’t realize they qualify for certain credits or deductions."

5. Incorrectly Claiming Dependents

Claiming a dependent on your tax return can provide significant tax benefits, including increased deductions and eligibility for various credits. However, incorrectly claiming dependents—whether due to confusion or mistake—can lead to delays and potential penalties.

How to Avoid This Mistake:

• Ensure that your dependents qualify under IRS guidelines.
• If your child or relative is claimed by someone else, make sure you don’t claim them again.
• Double-check the number of dependents you’re claiming to avoid discrepancies.

6. Failing to Account for Changes in Your Life

Life changes—such as marriage, divorce, having a child, or buying a home—can significantly affect your taxes. Failing to update your filing status or claim the appropriate deductions could result in overpaying or underpaying your taxes.

How to Avoid This Mistake:

• Inform the IRS of any major life changes that could affect your tax situation.
• Review your withholding status (e.g., withholding allowances) to reflect any changes in your personal situation.
• Use the IRS Tax Withholding Estimator to adjust your withholding and avoid surprises at tax time.

7. Not Taking Advantage of Tax-Advantaged Accounts

Tax-advantaged accounts, such as IRAs and 401(k)s, can significantly reduce your taxable income. Failing to contribute to these accounts throughout the year is a missed opportunity to save on taxes.

How to Avoid This Mistake:

• Max out contributions to retirement accounts like IRAs and 401(k)s.
• Consider setting up automatic contributions throughout the year to ensure you don’t miss the opportunity to reduce your taxable income.
• If you're over 50, take advantage of catch-up contributions to further reduce your taxable income.

8. Underestimating How Much You Owe

Some taxpayers make the mistake of underestimating how much they owe when filing their taxes. This can be a costly mistake, especially if you're not prepared to pay the full amount when the IRS comes calling.

How to Avoid This Mistake:

• Use online calculators or consult with a tax professional to estimate your tax liability before filing.
• Pay attention to your tax withholding throughout the year to ensure you're not under-withholding.
• If you owe more than you can pay, explore options for setting up a payment plan with the IRS.

9. Filing as "Head of Household" Incorrectly

Filing as "Head of Household" provides taxpayers with a higher standard deduction and a more favorable tax bracket. However, this status has specific requirements. If you're not eligible, claiming this status can lead to penalties and interest.

How to Avoid This Mistake:

• Ensure you meet the criteria to file as "Head of Household." You must be unmarried, provide more than half of the financial support for a dependent, and have a qualifying dependent living with you for more than half the year.
• If you're unsure, consult with a tax professional to ensure you're filing under the correct status.

10. Ignoring State Taxes

Many taxpayers focus only on their federal taxes and neglect state taxes. Depending on where you live, you may need to file a state return and pay state income taxes. Failing to do so can result in fines and penalties.

How to Avoid This Mistake:

• If you live in a state that imposes income taxes, make sure you're filing your state return in addition to your federal return.
• Be aware of any state-specific deductions or credits that could apply to you.
• Use a tax software or consult with a professional who can help you navigate both federal and state tax filing requirements.

As the tax deadline approaches, it's essential to stay organized and informed. By avoiding these common tax mistakes, you can ensure a smoother tax filing experience and potentially reduce your tax liability. Remember to file on time, double-check your information, and take full advantage of available deductions and credits.

Tax preparation doesn't have to be stressful, but it does require attention to detail. As Jean Chatzky advises, "Tax season doesn't have to be overwhelming, but it does require preparation."

By following these steps and seeking help when needed, you can avoid costly mistakes and take control of your financial future.