Standard deductions on federal income taxes are based upon an individual's filing status--single, widower with dependent child, married filing jointly, married filing separately or head of household. It is also dependent upon age, if the person is blind and if the individual has any dependents.

Single

While single individuals had a standard deduction of $5,150 in 2008--and they could deduct an additional $1,250 in 2008 if they were over the age of 65 or blind--those amounts are subject to change year to year. So it is important to note that individuals who file as single taxpayers enjoy less favorable standard deductions than their married counterparts.

Married Filing Separately

Married couples who file separately have the same standard deduction as their single counterparts, with one exception: they get even less of a deduction (approximately $250 less) for age or blindness conditions.

Married Filing Jointly

The standard deduction for a married couple who files jointly is almost double that of a single person or married person who files separately (it was more than $10,000 in 2008). But like singles, this standard deduction amount is subject to change each year too.

Qualified Widow(er)

Like the "married filing jointly" category, a widow or widower who has a dependent child living at home will have a standard deduction almost double that of single or "married filing separately" taxpayers.

Head of Household

Individuals who file under the "head of household" category have a standard deduction amount that sits between the single's standard deduction ($5,150 in 2008) and the "married filing jointly" standard deduction ($10,300 in 2008)--it was $7,550 in 2008.

Standard Deduction

This standard deduction, which varies among different tax-paying groups, is meant to help even the taxpaying field to some degree by aiding those whose spouse died (and have children who depend on them), as well as those who are trying to support a household as a single parent for other reasons. In addition, those with a two-person family income are given a slight tax break because they likely would be in a higher tax bracket than single filers.

Source:

World Wide Web Tax.com: How Much is My Standard Tax Deduction?

Internal Revenue Service.com - Topic 551: Standard deduction