The amount of your standard deduction is based on your filing status, and your filing status is based on your marital status as of the last day of the year. If you're single and meet the Internal Revenue's three qualifications, you can take a larger standard deduction by filing as head of household. None of the qualifications for head of household has anything to do with how much tax was withheld from your paycheck.
No Taxes Withheld
You might not have had taxes withheld from your paycheck for one of several legitimate reasons. If you worked as an independent contractor, your employer was not required to withhold taxes, and you are responsible for figuring your taxes and filing them with the IRS, usually on a quarterly basis. If you claimed "Exempt" when you submitted your W-4 Form, you told your employer not to withhold taxes because you had no tax liability last year and expect to have no tax liability this year. You might not have earned enough money for your employer to withhold taxes.
If you work as an employee, and it looks like you are going to incur a tax liability, you need to fill out a new W-4 and turn it in to your employer. Check your next couple of paychecks to ensure that enough taxes are being withheld. You can file a new W-4 as often as you need to, and it's a good idea to file a new one after any major life event, such as a divorce or the birth of a baby, that might change your filing status to head of household.
Failure to Withhold
Your employer's failure to withhold the proper amount of federal income taxes doesn't get you off the hook for paying them. You are responsible for your taxes whether your employer failed to withhold them or not. You are also responsible for your portion of unpaid Medicare and Social Security taxes, so you might need to file Form 8919: Uncollected Social Security and Medicare Tax on Wages along with your federal tax return.
Head of Household
The IRS has three tests to determine whether you are qualified to file your federal income tax return using the head of household filing status. You must be single as of the last day of the tax year, you must have paid more than half of the cost of keeping up a home, and a qualifying person must have lived with you in your home for at least half of the year.
You can qualify for the head of household status if you are considered unmarried. The IRS might consider you to be unmarried, even though you are still legally married according to the laws of your state, if your spouse did not live with you for the last six months of the year, you paid more than half of the cost of keeping up your home, you didn't file a joint return, your home was the main home for your child, stepchild or foster child, and you can claim an exemption for the child.
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