10 Tax-Filing Mistakes to Avoid

With the tax-filing deadline on Monday, April 15, plenty of taxpayers may be spending their weekend filling out forms. If you're one of them, you want to make sure that you don't make mistakes in your rush to complete your tax return. The IRS reports that it takes longer to process returns with mistakes. If you're getting a refund, this means that it will be delayed.

Here are 10 mistakes that taxpayers often make. A good way to avoid many of them is to prepare and file your return electronically by using tax software or the IRS Free File service (if your adjusted gross income is $57,000 or less). According to the IRS, taxpayers are about twenty times more likely to make a mistake on their return if they file a paper return instead of e-filing their return.

Note that most of these mistakes are blunders that the IRS notices. You may be making a bigger, more costly mistake if you overlook deductions. See our Most-Overlooked Deductions slide show to find out if you're overpaying your taxes by missing any breaks that you deserve.

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1. Mixing up a Social Security number. Year after year, the IRS says bad Social Security numbers are at the top of the list of taxpayer mistakes. Pull out your Social Security card -- as well as the cards of your spouse and dependents -- and check the numbers against what is on your tax form. Forgetting to enter a number, or transposing two figures, will slow down your refund (if you're getting one) or lead the IRS to reject your exemptions for dependents if you get their numbers wrong.

2. Spelling a name wrong. Make sure you enter names of all individuals on your tax return exactly as they appear on their Social Security cards.

3. Choosing the wrong filing status. There are five filing statuses: Single, Married Filing Jointly, Married Filing Separately, Head of Household and Qualifying Widow(er) With Dependent Child. The IRS recommends using Publication 501, Exemptions, Standard Deduction and Filing Information to choose the right one for you. E-filing your tax return will also help you choose the right filing status because the series of questions that the software will require you to answer.

4. Making math mistakes. Another big source of errors is basic addition and subtraction mistakes. The easiest way to avoid this pitfall is to use tax software and file your return electronically. Programs such as TurboTax, TaxAct, H&R Block at Home (formerly TaxCut) and Free File will ask you questions about your income and expenses and do the math for you. And when you e-file, you won't have to include a W-2 and you'll be prompted to sign your form electronically.

5. Figuring credits and deductions incorrectly. The IRS recommends reading the instructions in your tax booklet carefully because many filers make mistakes figuring their Earned Income Tax Credit, Child and Dependent Care Credit and the standard deduction. For example, if you are 65 or older or blind make sure you claim the correct, larger standard deduction amount.

6. Leaving off a signature. The IRS says this is one of the most common mistakes, and it won't process a return without a signature. And, remember, both spouses must sign a joint return. Everything will be put on hold while the IRS sends you a special form to sign certifying that your return is accurate.

7. Botching an electronic signature. To e-file a return, you will need a personal identification number (PIN) to sign it. You can use last year's PIN if you e-filed and remember it. Otherwise, you will need to be assigned a PIN. For security purposes, the software will ask you to enter your adjusted gross income from your original 2011 federal tax return. According to the IRS, you should not use the AGI amount from an amended 2011 return or an AGI provided to you if the IRS corrected your return.

8. Getting bank routing and account numbers wrong. If you are getting a refund and are electing to have it deposited automatically into your account, make sure you enter your information correctly so the money actually shows up in your account.

9. Forgetting to attach forms. If you file a paper return, make sure you attach your W-2 and other forms that reflect tax withheld to the front of your return. If you're claiming credits that require special documentation include those records with your return.

10. Being unwilling to admit you need more time. If you discover over the weekend that your tax situation is just too complicated to sort out in a few hours, file for an extension with the IRS to delay the due date for your return until October 15, 2013. You'll still have to mail a check to the IRS by April 15 if you owe (you can estimate the amount). Use Form 4868 to file an extension.

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