Next to the joint return rates, the best tax rate schedule applies to single taxpayers who qualify for head of household (HOH) status.

However, some complicated rules determine whether you are eligible to file as an HOH. Whether you are divorced or have never been married is not important; what is important is that you maintain a home for one or more of your children or dependent relatives.

Beginning with the 2005 tax year, a taxpayer qualifies for head of household status if he/she is unmarried at the end of the tax year, is not a surviving spouse, pays at least half of the costs to maintain a home, and shares that home with:

• at least one qualifying child;
• a dependant for whom the taxpayer is entitled to claim a personal exemption (e.g., $3,300 per person in 2006); or
• his/her mother or father, provided that the taxpayer is entitled to claim a personal exemption for the mother or father.

A qualifying child is an individual who:

• is a child (including an adopted or foster child) , brother, sister, stepbrother, stepsister, or descendant of any such relative of the taxpayer;
• has the same principal place of abode as the taxpayer for more than half the tax year;
• is 18 years old or younger at the close of the calendar year in which the taxpayer's tax year begins or is a student that is 23 years old or younger (this rule does not apply if the individual is permanently and totally disabled); and
• has not provided for over one-half his/her own support for the calendar year in which the taxpayer's tax year begins.

There are a few other details to be aware of, regarding what it means to be:

• maintaining a household
• residing in the same household

If you are not married, and you can't qualify as a head-of-household, you are treated as single for federal income tax purposes.