Many common tax filing mistakes can be prevented by organizing your documents and reviewing your return carefully before submitting it. Even a simple error involving a name, Social Security number, filing status or bank account can create unnecessary problems.
In addition, more significant mistakes can involve missing income, incorrect dependents, unsupported deductions or credits calculated incorrectly. These errors can affect the tax you owe, your refund or the processing of your return.
Therefore, accurate tax preparation involves more than completing the forms. A final review of your documents, personal information and tax calculations can help you identify problems before the return reaches the IRS.
BEFORE YOU FILE
Most Tax Return Errors Are Easier to Prevent Than Correct
The IRS encourages taxpayers to review their entire return before filing, even when a tax professional prepared it.
For example, a return can contain accurate calculations while still having an incorrect filing status, missing income document or inaccurate dependent information.
Fortunately, many common problems can be identified before filing. Compare the return with your tax documents, verify identifying information and ask questions about anything you do not understand.
Most importantly, do not approve a return simply because the refund or balance due looks reasonable. Review the information that produced that result.
THE FINAL REVIEW
Check before you submit.
A few minutes of review can catch information that was entered incorrectly or left out.
After filing, correcting some mistakes can require additional forms and more processing time.
MISTAKE #1
Filing Before You Have All Your Tax Documents
Filing early can sound like a good strategy. However, filing before all of your tax information arrives can create a different problem.
If additional income documents appear later, the return may be incomplete or inaccurate.
Wait for the Documents You Need
Before filing, gather Forms W-2, 1099 and other applicable income documents. In addition, collect records related to deductions, credits, dependents and tax payments.
For example, investment, retirement, freelance and other income can generate information forms that arrive separately. Therefore, receiving your W-2 does not necessarily mean your tax file is complete.
Compare Forms With Your Own Records
Your tax documents should also make sense when compared with your records. If a form appears incorrect, investigate the discrepancy instead of automatically entering information that you know may be wrong.
Likewise, do not ignore taxable income simply because you expected a form but did not receive one.
MISTAKE #2
Entering Names or Taxpayer Identification Numbers Incorrectly
Personal information may look like the easiest part of a tax return, but errors in names and taxpayer identification numbers can create filing problems. Therefore, verify this information instead of entering it from memory.
Check Every Name and Number
Review the name and Social Security number or other applicable taxpayer identification number for each person listed on the return.
In particular, names and Social Security numbers should match the applicable Social Security records. This review should include the taxpayer, spouse and dependents listed on the return.
Additionally, pay close attention when a family member has recently changed a name.
Don’t Reuse Last Year’s Information Without Checking
Prior-year tax information can be useful, but circumstances change. For example, a dependent’s information, address or other details may need to be updated.
Consequently, treat the prior return as a reference rather than proof that every current-year entry is correct.
A final character-by-character review of important identification numbers can prevent simple data-entry mistakes.
MISTAKE #3
Choosing the Wrong Filing Status
Filing status affects several parts of an individual federal income tax return.
Therefore, choosing a status based only on which one appears to produce the largest refund can lead to an incorrect return.
Your Circumstances Determine the Available Status
Federal filing statuses include Single, Married Filing Jointly, Married Filing Separately, Head of Household and Qualifying Surviving Spouse when the applicable requirements are met.
However, taxpayers cannot simply select whichever status they prefer. Marital status, household circumstances, dependents and other requirements determine which filing statuses are available.
More Than One Status May Need to Be Evaluated
In some situations, a taxpayer can potentially qualify for more than one filing status. Consequently, the applicable rules should be reviewed before selecting the status reported on the return.
When family circumstances changed during the year, pay particular attention to this section of the return.
MISTAKE #4
Leaving Income Off the Return
Missing income is more than a data-entry issue. It can change adjusted gross income, taxable income, credits and the final tax calculation.
First, compare Forms W-2 and 1099 with your own records. Next, consider whether you had income from freelance work, investments, interest, rental activity or other sources that may need to be reported.
Importantly, the absence of an expected information form does not automatically make taxable income disappear. Therefore, taxpayers with self-employment or other income should use complete records rather than reporting only amounts appearing on tax forms.
In addition, carefully enter the amounts shown on your tax documents. Transposing numbers or entering information on the wrong line can also create discrepancies.
INCOME REVIEW
Check for Multiple Sources
✓ W-2 wages
✓ Forms 1099
✓ Self-employment income
✓ Interest and investments
✓ Retirement income
✓ Rental income
✓ Other reportable income
The exact reporting requirements depend on the type of income and your circumstances.
MISTAKE #5
Claiming a Dependent Without Checking the Rules
Dependent eligibility can affect filing status and several tax benefits.
However, providing financial support to someone does not automatically mean that person qualifies as your dependent for every federal tax purpose.
Review the Dependency Requirements
Relationship, age, residency, support and other requirements can affect whether an individual qualifies as a dependent.
In addition, individual credits can have requirements beyond the basic dependent rules. For example, qualifying for the Child Tax Credit involves requirements that are not identical to every other dependent-related tax provision.
Watch for Duplicate Claims
Problems can also occur when more than one taxpayer attempts to claim the same dependent. Therefore, divorced or separated parents and other households with shared family responsibilities should determine the proper treatment before filing.
Most importantly, do not assume that an informal family agreement overrides federal tax eligibility rules.
MISTAKE #6
Claiming Credits or Deductions Incorrectly
Tax credits and deductions can reduce tax when the requirements are satisfied. Nevertheless, entering an expense or dependent on the return does not automatically establish eligibility for a particular tax benefit.
Check Eligibility Before Entering the Amount
Credits such as the Child Tax Credit, Earned Income Tax Credit and education credits each have their own requirements.
Likewise, deductions can have income limits, documentation requirements or other restrictions.
Therefore, use the rules applicable to the tax year you are filing rather than assuming last year’s eligibility automatically continues.
Avoid Double-Using the Same Expense
Some tax provisions prevent the same expense from being used for multiple benefits.
For example, education expenses can require careful allocation when determining which credit or other tax benefit applies.
Consequently, review related credits and deductions together rather than calculating each one independently.
MISTAKE #7
Mixing Personal and Business Expenses
Self-employed taxpayers should pay particular attention to business deductions.
After all, paying an expense from a business account does not automatically make the cost deductible.
Separate Business Activity
Qualifying business expenses generally need to satisfy the applicable business deduction requirements. By contrast, personal, living and family expenses generally are not ordinary business deductions.
Some expenses can have both personal and business use. Therefore, vehicle, phone, home and similar mixed-use costs may require additional calculations and records.
Use Reliable Records
Accurate bookkeeping can make it easier to separate personal transactions from business activity.
As a result, tax preparation becomes less dependent on reconstructing an entire year from bank statements and memory.
MISTAKE #8
Entering the Wrong Bank Information
Direct deposit can provide an efficient way to receive a federal tax refund. However, routing and account information needs to be entered accurately.
Before filing, compare the numbers on the return with the information provided by your financial institution. In particular, verify the routing number, account number and account type.
Do not assume that tax software or a preparer can identify every incorrect banking number. Instead, personally review the information before authorizing the return.
Additionally, if you use a paid preparer, understand how your refund will be delivered and review the banking information shown on the return.
DIRECT DEPOSIT
Check Every Digit
✓ Routing number
✓ Account number
✓ Checking or savings
✓ Account ownership
A tax refund is not the place to discover that an account number was entered incorrectly.
MISTAKE #9
Forgetting Signatures or Required Forms
A return can be mathematically correct and still be incomplete.
Therefore, the final review should include signatures and required attachments or schedules, not only income and deductions.
Unsigned Returns Can Be Invalid
An unsigned federal return is generally not considered valid. For a joint return, both spouses generally need to sign unless an applicable exception or valid authorization applies.
Electronic returns use the applicable electronic signature process instead of a handwritten signature.
Include Required Schedules and Forms
Some income, deductions and credits require additional schedules or forms. Consequently, confirm that the complete return includes the supporting tax forms required for the items being reported.
Tax preparation software can help identify missing information, but taxpayers should still review the completed return.
MISTAKE #10
Ignoring an E-File Rejection
An electronically submitted return is not necessarily filed successfully just because it was transmitted. If the IRS rejects the return, the rejection needs to be reviewed and addressed.
Read the Rejection Information
An e-file rejection generally provides information about why the return was rejected.
For instance, an incorrect Social Security number, payer identification number, omitted form or misspelled name can cause certain rejections.
In many cases, the information can be corrected and the return can then be electronically submitted again.
Don’t Assume Rejected Means Filed
A rejected electronic return requires action. Therefore, correct the problem promptly and follow the applicable IRS filing instructions.
Some rejection situations may ultimately require a paper return. In addition, special procedures can apply when a rejected electronic return is converted to paper near a filing deadline.
For that reason, do not ignore a rejection notice or wait unnecessarily to investigate it.
FINAL REVIEW
Use a Tax Return Checklist Before You File
A systematic final review can catch mistakes that are easy to miss when preparing different sections of the return separately.
Therefore, compare the finished return with the documents and information you originally gathered.
Personal Information
First, verify names, taxpayer identification numbers, filing status, dependents and current contact information.
Income and Tax Payments
Next, compare wages, Forms 1099, withholding and estimated tax payments with your records.
Credits and Deductions
Then, confirm that each claimed tax benefit has been calculated under the applicable rules and that you have the necessary supporting information.
Bank Information and Filing
Finally, verify direct-deposit information, required signatures and the method used to submit the return.
ALREADY FILED?
What Should You Do if You Find a Mistake After Filing?
Discovering an error after filing does not automatically mean that you need to submit another return immediately. The appropriate response depends on the type of mistake.
For example, the IRS can correct some mathematical errors while processing a return. Similarly, the agency may contact you when it needs a missing form or additional information.
However, changes involving filing status, income, deductions, credits, dependents, tax withholding or other significant items can require an amended return using Form 1040-X.
Therefore, identify what is wrong before deciding how to correct it. If you receive an IRS notice related to the error, review the notice carefully because it may contain specific instructions.
ASB Tax & Accounting can also assist taxpayers who need help understanding tax correspondence. Learn more about our tax and accounting services.
FORM 1040-X
Not Every Error Requires an Amendment
Some math errors may be corrected during IRS processing.
However, changes to major items such as income, filing status, deductions, credits or dependents can require an amended return.
COMMON QUESTIONS
FAQ About Tax Filing Mistakes
These answers address common questions about preventing and correcting federal income tax return errors.
Common errors include filing before all tax documents arrive, choosing an incorrect filing status, entering names or Social Security numbers incorrectly, omitting income, making dependent errors and entering incorrect bank information. In addition, taxpayers can make mistakes when calculating deductions and credits.
Not necessarily. Before filing, make sure you have received all of the tax documents relevant to your return. For example, you may also be expecting Forms 1099 or other income documents. Therefore, filing before your records are complete can create an avoidable error.
The IRS can correct some mathematical errors during processing, so those mistakes may not require an amended return. However, other changes, including certain errors involving income, filing status, deductions, credits or dependents, can require Form 1040-X.
Review the rejection information to determine the cause. In many cases, an error can be corrected and the return can be electronically filed again. However, some circumstances can require different filing procedures. Therefore, address the rejection promptly rather than assuming the return was successfully filed.
A change to income can require an amended federal return. However, consider whether the IRS has already contacted you or adjusted the return before filing Form 1040-X. The appropriate action depends on the specific situation.
A knowledgeable tax preparer can help review documents, identify missing information and prepare the return under the applicable rules. Nevertheless, taxpayers should still review their completed returns and ask questions before filing.
Review Your Return Before It Becomes a Tax Problem
Many common tax filing mistakes can be prevented by starting with complete records and carefully reviewing the return before filing.
ASB Tax & Accounting can help you organize your tax information, prepare your federal and state income tax returns and review the details before submission.
We serve individuals, families and businesses in Oxnard and surrounding Ventura County communities. In addition, assistance is available in English and Spanish.
Last reviewed: October 2026. Tax forms, credits, deductions and filing procedures can change. Therefore, verify the requirements for the tax year you are filing. This article provides general federal tax information and does not replace individualized tax advice.
