Section 151 of the Internal Revenue Code establishes the personal exemption (exemption). In 2017, the exemption is $4,050. A phase out provision prevents the very wealthy from using all or part of the exemption. In 2017, the exemption begins to phase out for a single filer at an adjusted gross income (AGI) of $$261,500. For a married couple filing jointly, the phase out begins at an AGI of $313,800. the tax phases out at a rate of two percent for every $2,500 of AGI. The exemption phases out completely for an individual with an AGI of $384,000. For a married couple filing jointly, the exemption phases out completely at an AGI of $436,300.
Adjusted gross income is your gross income minus any adjustments to income..
When a married couple files jointly, they can double the exemption for a total exemption of $8,100. If a married couple files separately, each spouse can claim their own $4,050 exemption.
You can claim an exemption for each of your dependents. For most taxpayers, all you need to know is that the $4,050 exemption can be claimed for each of your children.
If a married couple files jointly and they have three children, they can claim five total exemptions worth $20,250.