13 Common Tax Mistakes Single Filers Make (and How to Avoid Them)

Filing solo this tax season? Without a partner’s second pair of eyes, it’s shockingly easy to make common tax mistakes — and unlike Netflix passwords, there’s no one to share the pain.

A wrong filing status, simple math errors, or a missed tax credit can mean a higher tax bill, a delayed tax refund, or even a friendly note from the Internal Revenue Service (IRS).

The good news? You can avoid the most common tax errors by knowing what to look for before hitting “Submit” on your income tax return.

📌 Related: First-Time Filing Guide for Single Filers

Quick Reference Table: Common Mistakes, Their Impact, and Fixes

Mistake #1: Choosing the Wrong Filing Status

Your filing status determines your standard deduction, tax rate, and eligibility for tax benefits. Many single filers choose “Single” when they qualify for Head of Household, leaving money on the table.

Real-world example:

In addition, the amount that is taxed reaches higher marginal brackets earlier. As a result, he pays more on the taxed portion.

👉 How to Avoid It: Use the IRS Interactive Tax Assistant to confirm your correct filing status.

Source: U.S. Congress, One Big Beautiful Bill Act, H.R. 1, 119th Cong.

📌 Related Links:

• Can You Change Your Filing Status?
• Why the Tax Code is Broken for Singles

Mistake #2: Math Errors and Mismatched Numbers

A small math mistake can change your adjusted gross income (AGI), affecting tax deductions and credits.

👉 How to Avoid It: Use tax software for math calculations, and review your tax form for typos or misplaced decimals. Also, update your W-4 yearly to ensure your withholding is accurate.

📌 Related: W-4 Withholding for Single Filers

💡 Pro Tip: If you’re filing returns, check each line as if proofreading a contract. Simple human error is one of the IRS’s top audit triggers.

Mistake #3: Forgetting to Report All Income

Many taxpayers remember their main W-2, but forget items like:

• 1099-NEC for freelance work
• 1099-INT for bank interest
• Prize winnings
• Cash tips
• Rental income

Some of these are reported to the IRS on official forms, while others rely on you to self-report. If your return doesn’t match IRS records for the forms they do receive, you can expect a notice. You’re still responsible for including income that is not automatically reported on your tax return.

👉 How to Avoid It: Keep a “tax file” folder (digital or physical) for the entire tax year. Drop in every income doc as it arrives.

📌 Related: The Real Cost of Being Single: Why It’s More Expensive to Fly Solo

Mistake #4: Incorrect or Missing Dependent Claims

A wrong Social Security number, filing status conflict, or misunderstanding of IRS dependency rules can cause you to miss dependent-related credits, such as the Dependent Care Credit and Child Tax Credit.

👉 How to Avoid It: Check dependent eligibility on the IRS site and always use correct information.

Source: IRS, Dependents

📌 Related: Single Filer with Dependents: What You Can Claim

Mistake #5: Missing Out on Tax Credits

Skipping credits is like turning down free cash. Commonly missed ones for single filers include:

• Earned Income Tax Credit (EITC)
• Saver’s Credit
• Premium Tax Credit
• Dependent Care Credit

👉 How to Avoid It: Use tax software that screens for credits automatically.

💡 Pro Tip: Tax credits don’t disappear just because you owe the IRS. Even if you already have a balance due, credits can lower the amount you owe — and in some cases (with refundable credits), they can even create or increase a refund.

Source: IRS, Credits and Deductions for Individuals

📌 Related: Lone Parent Tax Credit: Maximize Your Savings

Mistake #6: Charitable Contributions Without Proof

You can’t claim charitable contributions without receipts; only donations to IRS-qualified nonprofits count. You can use the IRS Tax Exempt Organization Search Tool to check the organization's tax-exempt status.

👉 How to Avoid It: Keep digital receipts and confirm the charity’s tax-exempt status.

Mistake #7: Incorrect Bank Info = Delayed Refunds

An incorrect bank account number or routing number is a top cause of significant delays.

👉 How to Avoid It: Double-check your bank account information before submitting and choose direct deposit.

Mistake #8: Forgetting to Sign Your Tax Return

The IRS rejects unsigned tax return forms. E-filed returns are signed electronically, but paper returns require a physical signature.

Mistake #9: Missing Key Forms or Attachments

Forgetting to include required forms or schedules (such as Schedule 1, Schedule 2, and Schedule 3) can delay the IRS from processing your return. These schedules must be attached if you have entries on them, and many require supporting forms.

Schedule 1 — Additional Income and Adjustments to Income

Used to report income not listed directly on Form 1040 and certain deductions. Must be attached if you claim:

• Business income (Schedule C)
• Rental or royalty income (Schedule E)
• Farm income (Schedule F)
• Unemployment compensation (Form 1099-G)
• Health Savings Account deduction (Form 8889)
• Student loan interest deduction, IRA contributions, and educator expenses

Schedule 2 — Additional Taxes

Used to report taxes beyond regular income tax. Must be attached if you owe:

• Alternative Minimum Tax (Form 6251)
• Self-employment tax (Schedule SE)
• Household employment taxes (Schedule H)
• Excess advance premium tax credit repayment (Form 8962)
• Additional tax on IRAs or retirement accounts (Form 5329)
• Net investment income tax (Form 8960)

Schedule 3 — Additional Credits and Payments

Used to claim certain credits or report extra withholding. Must be attached if you claim:

• Child and Dependent Care Credit (Form 2441)
• Education credits (Form 8863)
• Residential energy credits (Form 5695)
• Adoption credit (Form 8839)
• Foreign tax credit (Form 1116)
• Credit for the elderly or disabled (Schedule R)
• General business credits (Form 3800)

👉 How to Avoid It: Let your tax prep software prompt you for all required forms. If you mail your return, double-check that every necessary schedule and supporting form is included.

Mistake #10: Poor Record Keeping

No backup for deductions like student loan interest or home office deduction? Say goodbye to them in an audit.

👉 How to Avoid It: Store tax records in encrypted cloud storage for at least 3 years.

💡 Pro Tip: Create folders by tax year, with subfolders for income, deductions, and credits.

Mistake #11: Filing Too Late or Too Soon

If you file too early, you risk missing corrected 1099s. If you file too late, you may owe penalties for unpaid federal income taxes.

👉 How to Avoid Errors: Wait until late February and request an extension if needed.

Avoid late filing penalties, start a tax extension today!

Mistake #12: Ignoring IRS Letters or Notices

Ignoring an IRS letter can escalate from interest to wage garnishment.

👉 How to Avoid It: Open, read, and promptly respond to all IRS mail.

Source: IRS, Understanding Your IRS Notice or Letter

Mistake #13: Not Asking for Help

A certified public accountant (CPA), enrolled agent (EA), or tax attorney can help you avoid common return mistakes. Be cautious of unqualified preparers or anyone promising substantial refunds — scams are common during tax season. The IRS Tax Scams and Consumer Alerts page explains how to spot and avoid fraudulent tax schemes.

👉 How to Avoid It: Avoid mistakes — file with a CPA today using our professional tax filing services.

Final Pre-Submit Checklist

Before hitting “file,” double-check if:

• ✅ You selected the correct filing status.
• ✅ You reported all income.
• ✅ Your bank account and routing numbers are correct.
• ✅ You claimed all eligible credits and deductions.
• ✅ You attached all required tax forms.
• ✅ You signed your tax form.

📌 Related: Top 10 Tax Hacks for Single Filers in 2025

Avoiding common tax return mistakes is about preparation, attention to detail, and asking for help when needed. Whether you file solo or have a tax expert do it, the key to getting your maximum refund is avoiding these 13 common errors. Don’t leave money on the table this tax season—file smart, file early, and file error-free.