Tax Tip Tuesdays: Watch Out for These Common DIY Filing Mistakes

Every year, many taxpayers choose to file their own tax returns using online software or fillable forms. While this can be a cost-effective option, it also comes with the risk of making errors that could delay your refund—or worse, lead to penalties. As an Enrolled Agent who's reviewed thousands of self-prepared tax returns, I can tell you: even small oversights can create big problems.

Here are some of the most common mistakes taxpayers make when filing their own taxes—and how you can avoid them.

1. Wrong Social Security Numbers or Name Mismatches: It’s more common than you’d think: entering a Social Security number incorrectly, or using a name that doesn’t match what's on file with the Social Security Administration. This includes newlyweds who forget to update their names or parents using nicknames for dependents. Always refer to your Social Security card when entering your info.

2. Choosing the Wrong Filing Status: Software programs try to help, but many people still end up picking the wrong filing status—especially between “Single” and “Head of Household.” Filing with the incorrect status can reduce your refund or increase your tax liability. Use the IRS Filing Status Tool if you’re unsure.

3. Overlooking Income You Still Need to Report: Just because you didn’t receive a 1099 doesn’t mean the IRS doesn’t know about your side hustle or gig income. Failing to report freelance income, unemployment benefits, or even interest income can result in a CP2000 notice months later. When in doubt, report it.

4. Missing Deductions or Credits: One of the biggest drawbacks of filing solo is missing out on tax savings. I often see self-prepared returns that skip credits like the Earned Income Tax Credit (EITC) or deductions for student loan interest, educator expenses, or IRA contributions. If the software doesn’t prompt you—or you’re not sure where to enter something—you could leave money on the table.

5. Errors in Banking Info for Direct Deposit: A common issue: mistyping your routing or account number when setting up direct deposit. One wrong digit can lead to major delays or the IRS depositing your refund into someone else’s account. Always double-check your banking details.

6. Not E-Filing or Failing to Sign the Return: Some taxpayers still mail in paper returns but forget to sign them. Others file online but don’t complete the identity verification step using their prior-year AGI or self-select PIN. The IRS will reject unsigned or unverified returns.

7. Filing Late or Forgetting to File at All: Even if you can’t afford to pay your balance due, you should still file on time to avoid the failure-to-file penalty, which is typically higher than the failure-to-pay penalty. If you need extra time, file Form 4868 for an extension—but remember, that doesn’t extend your payment deadline.

Doing your own taxes can work just fine—but it’s important to slow down, read the instructions carefully, and make sure your return is accurate. One overlooked item can mean a missed refund or an IRS notice you weren’t expecting.

If you're unsure about something or just want a second set of eyes, feel free to reach out to us at info@mkhstaxgroup.com. At MKHS Tax Group, we help taxpayers file confidently and correctly—whether you DIY or need full support.