Filing as head of household has a number of benefits that can potentially save you a lot of money on your taxes. One of the filing status' requirements is that at least one “qualifying person” live with you for a majority of the tax year, which can be your son, father or any other person. To use the head of household filing status, however, it isn't necessary that you actually claim your son as a dependent.
Son as Qualifying Person
In order to be a qualifying person, your son must satisfy either the qualifying child or qualifying relative requirements -- the two tests used to determine whether a taxpayer is eligible to claim a dependent. Your son is a qualifying child if he's under the age of 19, or if a student, under the age of 24, he lived with you for more than half of the tax year, doesn't contribute more than half of the funds he requires for support and doesn't file a joint return other than for the purpose of claiming certain tax refunds. Alternatively, he may qualify as a relative if his annual gross income is less than the dependent exemption for the year and you provide more than half of his financial support. If you're divorced or separated and have custody of your son, but your former husband claims his exemption because of special rules, you can still file as head of household provided all remaining requirements are met.
Unmarried or Considered Unmarried
Head of household filers must be unmarried, or considered unmarried by the Internal Revenue Service, on the last day of the tax year. If you're still legally married but don't live with your husband during the last six months of the tax year, don't file a joint return and pay more than half the costs associated with maintaining a home that you reside with your son at for more than six months -- you may be considered unmarried as long as you take your son's exemption, or would be eligible to if your husband didn't already claim it.
Financial Responsibility for Maintaining Home
The last requirement to satisfy before checking the head-of-household box on your return is that you pay more than half the costs needed to maintain your home. When figuring out the percentage of costs you contribute, include expenses such as rent, utilities, property taxes, meals prepared in the home and mortgage interest -- but not the payments you make towards the actual mortgage loan.
Head of Household Tax Benefits
Two of the more significant tax benefits that the head of household filing status offers in comparison to filing as single is a bigger standard deduction and tax brackets that allow you to pay lower rates of tax on larger portions of taxable income. Tax rates and brackets always are subject to change, but in the 2013 tax year, for example, single filers enjoy a 10-percent rate on the first $8,925 of taxable income before the 15-percent rate is used. For head of household filers, however, this 10-percent rate covers an additional $3,825 of taxable income, or the first $12,750, before higher rates kick in.