Size

• Taxpayers can deduct the fair market value of their gifts of property or the dollar amount of their cash donations. The total of their charitable donations cannot exceed 50 percent of their adjusted gross income, but some donations, such as property that has appreciated, may be limited to a smaller percentage.
  
  

Time Frame

• The deduction must be taken in the year the donation was made unless the contribution exceeds the size limits. If a taxpayer has excess charitable donations, she may carry the overage to future years for up to five years.
  
  

Warning

• The IRS only recognizes donations made to qualified charitable organizations. For example, a taxpayer could not write off a gift of a car or food made to a poor family. In addition, taxpayers cannot deduct the value of their time they donate to a cause.